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{"created":"2022-01-31T13:30:07.349071+00:00","id":"lit28757","links":{},"metadata":{"alternative":"Studies from the Yale Psychological Laboratory","contributors":[{"name":"Davis, Walter W.","role":"author"}],"detailsRefDisplay":"Studies from the Yale Psychological Laboratory 8: 64-108","fulltext":[{"file":"p0064.txt","language":"en","ocr_en":"RESEARCHES IN CROSS-EDUCATION\n(,Second Series')\nBY\nWalter W. Davis.\nFurther experiments on the effects of practice in voluntary movements have been made since the publication of my first paper on the subject.1\nI. Transference of practice effects.\nExperiments with the maximum grip of the hand were begun in March, 1900. An oval spring dynamometer of the usual form was employed. The dynamometer test is not one of endurance, but of strength. To make a good record requires a strong impulse for only a moment of time.\nFifty subjects were secured\u201425 men and 25 women, all students or instructors at Iowa College, Grinnell, Iowa. The maximum pressure that each could exert on the dynamometer was determined for both right and left hands. To avoid the variation due to fatigue, the records were taken in the order R, Z, L, R, and then an average taken of R, R, and of Z, Z. These average records were called the initial records for right and left hands. After the initial records were secured, practice was begun and extended over a period of three weeks, the subject exercising his grip four times per week. At the end of the practice final records were taken in precisely the same manner as at the initial test. The difference between the two records gave the amount of gain.\nGreat care was observed to have all the conditions of the initial and final tests precisely the same. Four points were carefully watched, i* The dynamometer was placed in the hand face downward. This prevented the subject from seeing his own record, and there was no danger of the fingers stopping the progress of the pointer. 2. The instrument was carefully placed so that the pressure was exerted in a line perpendicular to the long axis. 3. One side of the dynamometer was placed m the crease of the second joint of the fingers, so that when it was gripped it pressed against the second row of phalanges. 4. Care was exercised to prevent the subject from pressing the hand or arm against the body.\nThe initial and final tests and the daily practice occurred at the same time of the day and as nearly as possible under exactly the same condi-\n1 Davis, Researches in cross-edzication, Stud. Yale Psych. Lab., 1898 VI 6.\n64","page":64},{"file":"p0065.txt","language":"en","ocr_en":"Researches in cross-education.\t65\ntions The practice consisted in gripping the dynamometer 10 times on each occasion, with intervals of 2 or 3 seconds of rest after each grip. The subjects were divided into five groups. These groups with the\nmethod and manner of practice\t\t\tare shown in Table I.\t\n\t\t\tTable I.\t\n\t\tKind of practice by the subjects.\t\t\nSubjects.\t\tMethod of practice. Instrument used.\t\tHand practiced.\nGroup\tI.\tVigorous.\tDynamometer.\tRight.\nGroup\tII.\tLight.\tDynamometer.\tRight.\nGroup III.\t\tLight.\tDynamometer.\tLeft.\nGroup\tIV.\tLight.\tCylindrical stick.\tRight.\nGroup\tV.\tLight.\tDynamometer.\tRight and left.\n\t\t\tTable II.\t\n\t\tCharacteristics of the Subjects : Men.\t\t\nSerial\t\tGroup.\t\t\nnumber.\tAge.\t(See Table I. )\tPrevious training.\tTemperament.\ni\t27\tI\t\tnervous.\n2\t23\tII\t\tphlegmatic.\n3\t23\tIII\ttrack athletics.\tphlegmatic.\n4\t22\tIV\ttrack athletics.\tmotor.\n5\t22\tV\tbaseball.\tmotor.\n6\t22\tI\t\tphlegmatic.\n7\t22\tII\t\tnervous.\nVA\t22\tIII\ttrack athletics.\tphlegmatic.\n8\t21\tIV\t\tmotor-phlegmatic.\n9\t20\tV\tgeneral athletics.\tphlegmatic.\n10\t20\tI\t\tmotor.\nn\t20\tII\tgeneral athletics.\tphlegmatic.\n12\t*9\tIII\ttrack athletics.\tnervous.\n13\t19\tIV\t\tphlegmatic.\nH\t19\tV\t\tnervous.\n15\t19\tI\t\tphlegmatic.\n16\t18\tII\t\tphlegmatic.\n17\t18\tIII\t\tphlegmatic.\n18\t18\tIV\t\tnervous.\n19\t18\tV\t\tmotor.\n20\t18\tI\t\tphlegmatic.\n21\t18\tII\t\tnervous.\n22\t21\tIII\ttrack athletics.\tnervous.\n23\t27\tV\tgeneral athletics.\tmotor.\n24\t19\tII\ttrack athletics.\tmotor.\n25\t24\tIV\tlifting weights.\tnervous.\nThose subjects who practiced vigorously made 10 efforts daily, using maximum strength at every effort. Those who practiced lightly","page":65},{"file":"p0066.txt","language":"en","ocr_en":"66\nWalter H/. Davis,\nmade io efforts using from about 5- to \\ of the maximum strength. The cylindrical stick was 3 inches long by 1 inch in diameter. Those subjects who practiced with both right and left hands made 5 efforts with each hand on each day.\nIn order that the influence of age might not affect the results sought the subjects were distributed by fives among the groups as shown in Tables II. and III. By such a distribution the average ages of all the groups were nearly the same.\nTable III.\nCharacteristics of the subjects: Women,\nSerial\t\tGroup.\t\t\nnumber.\tAge. (Se'\te Table I.)\tPrevious training.\tTemperament.\n26\t25\tI\tI year.\tnervous-motor.\n27\t22\tII\t4 years.\tphlegmatic.\n28\t22\tIII\t2\t\u201c\tnervous-motor.\n29\t21\tIV\t2\t\u201c\tmotor-phlegmatic.\n3\u00b0\t21\tV\tI year.\tmoderately phlegmatic.\n31\t20\tI\t2 years.\tphlegmatic.\n32\t20\tI\t2\t\u201c\tnervous.\n33\t20\tIII\tI year.\tmoderately phlegmatic.\n34\t20\tIV\tI\t\u201c\tnervous-motor.\n35\t20\tV\t3 years.\tnervous-motor.\n36\t19\tI\t2\t\u201c\tmotor-phlegmatic.\n37\t19\tII\t2\t\u201c\tnervous.\n38\t19\tIII\tI year.\tmotor.\n39\t19\tIV\t2 years.\tphlegmatic.\n40\t18\tV\t2\t\u201c\tnervous-motor.\n41\t19\tI\tI year.\tnervous.\n42\t19\tII\ti\t\u201c\tmotor-phlegmatic.\n43\t18\tIII\t4 years.\tmotor.\n44\t19\tIV\ti year.\tnervous-motor.\n45\t17\tV\t3 years.\tmotor.\n46\t17\tI\ti year.\tphlegmatic.\n47\t25\tV\t7 years.\tmotor.\n48\t\tII\t\tnervous-motor.\n49\t21\tIII\t2 years.\tnervous.\n5\u00b0\t24\tIV\t2\t\u201c\tphlegmatic.\nThe previous training for the men and women was determined differently in the two cases. In Table III. the length of the period of physical training was reckoned from the number of years each subject had spent in the gymnasium in actual required class work, such work being compulsory except for seniors in the college. Since gymnasium work had not been required heretofore of men, it was necessary to set a different standard for them. This standard was proficiency in athletic sports.","page":66},{"file":"p0067.txt","language":"en","ocr_en":"Researches in cross-education.\n67\nThe factors of the grip that affect the strength of the pressure on the dynamometer are very complex even in one individual. Factors which favorably affect the pressure in a certain person may be entirely counteracted by factors which affect the pressure unfavorably. In another subject the factors may oppose each other in an entirely different fashion. When many conditions that are favorable to the strength of pressure are present in one person we then expect that person to make a good record of strength.\nFor convenience we have classified all factors as either, (a) those that are not affected by a short period of practice such as that during which our investigation was carried on, or (ff) those that may be affected by such practice. The first four factors belong to the former group, the others to the latter one.\ni. Effect of length of hand.\u2014 This factor is of some importance. The longer the hand the longer must be the levers on which the muscles pull and consequently the greater the strength that may be exerted on the dynamometer. This factor may be almost entirely counteracted by others, as is evidenced in the case of the men in Table IV. The importance of this factor is shown quite clearly in the case of the women.\nTable IV.\nLength of hands as a factor hi dynamometric pressure.\n\u2022\tMen:\tWomen:\nShortest hands. Longest hands. Shortest hands. Longest hands. Average length in mm.\t186.3\t200.1\t166.8\t180.2\nAverage pressure in kg.\t48.1\t48.2\t26.0\t30.3\nTo construct Table IV. the hands of all the subjects were measured with a measuring stick ; the distance was measured from the primary crease on the front of the wrist to the end of the middle finger. The result 186.3mm represents the average length of the 10 shortest hands among the men, 200.imm the average length of the 10 longest, all \u00b0f the subjects being taken into account in one or the other class. In the case of the men, those who had short hands seem to have possessed other qualities that counteracted the disadvantage of the short hand.\nThere\nwas an altogether different arrangement of favorable and unfavor-\nahle factors in the case of the women. Of course, the number of measurements taken was too small to make any very important generalizations.\n2- Effect of length of forearm.\u2014Miller1 has found a definite relation e ween the length and the strength of the forearm.\nMiller, Relations of length and strength in the forearm, Pub. of the Univ. of enn-, 1900 IV I53.","page":67},{"file":"p0068.txt","language":"en","ocr_en":"68\nWalter W. Davis,\n3.\tEffect of muscular development of the hand and arm.\u2014However important the part that this factor plays in the amount of the pressure, it is not probable that it was affected by the short practice of this experi ment. It has been pretty clearly demonstrated too in this investigation that the test under consideration is not nearly so much one of muscular power as it is one of mental power.\n4.\tEffect of temperament.\u2014Galen\u2019s universally adopted classifica tion of the temperaments into choleric, melancholic, sanguine and phlegmatic was not followed. For several reasons a different classification was more suitable to our needs. Since it was our purpose to discover the readiness of the subject to respond to practice (considering exercise as a stimulus, and development of motor ability as the response to this stimulus), our needs were subserved better by a classification based fundamentally on the ability to respond quickly to a given stinni lus, and not by one based on both the strength and quickness of the re sponse. An outline of such a classification is presented as follows :\nweak\tweak\n/\t\\ /\t\\\nNervous\u2014medium\u2014Motor\u2014medium\u2014Phlegmatic.\n\\\t/\t' \\\t/\nstrong\tstrong\nThe nervous temperament reacts quickly to a stimulus ; this reaction may be either weak, medium or strong. The phlegmatic temperament re acts slowly ; this reaction may be either weak, medium or strong. The motor temperament stands midway between the nervous and phlegmatic, if we consider time of reaction as the chief element in classification. The motor subject\u2019s reaction may be either weak, medium or strong. This classification makes strength of reaction a secondary consideration and quickness of reaction the primary consideration.\nThere is a question whether the nervous person does not as a matter of fact react more weakly than the phlegmatic one. To throw some light on this point, the average grip was determined for all the men clas sified as phlegmatic. The same was done with the records of the motor and nervous subjects. The average results are given in Table V.\nTable V.\nRelation of strength of grip to temperament.\nNumber of subjects.\nf IO\nMen. < 6\nl 6\nf 7\nWomen. < 14\nl 4\nTemperament.\nphlegmatic.\nmotor.\nnervous.\nphlegmatic.\nmotor.\nnervous.\nAver, grip in kg.\n49.7\n49.6\n43-3\n3\u00b0-3\n28.9\n22.5","page":68},{"file":"p0069.txt","language":"en","ocr_en":"Researches in cross-education.\n69\nThe table shows that the phlegmatic subjects in this particular group 0f individuals are slightly stronger than the motor subjects and considerably stronger than the nervous subjects. The fact is especially noticeable among the women. The fact noted, however, does not prove that the phlegmatic temperament per se is stronger than the nervous or the motor : nor would it be even though the results obtained here should be substantiated by similar ones secured from a large number of observations. There are several factors that tend to counteract, in the nervous type, any inherent power that it might have for the exerti-on of great strength. These \u00e0re the mechanical factors that we have enumerated above.\nIn the first place the nervous person is smaller, generally speaking, than the phlegmatic person. This fact accounts in a measure for his being nervous ; for the whole mass of muscles to be controlled being so much smaller, innervation is accomplished much more quickly. The hands are smaller and shorter, the forearm shorter, and hence the subject is placed at considerable disadvantage. Moreover, this disadvantage increases in more than arithmetical proportion, as the result of one factor at least, namely, the shortness of the hand. When the dynamometer just fits the hand and when the muscles and levers work in just the right arrangement, a good record is expected. But when the hand is so small that the pull must be made with the first phalanges rather than with the second, a tremendous disadvantage is met with, and there is a much smaller record.\nThis theory is strengthened by a comparison of the length of hand for men and women with their respective dynamometric records. Table VI. shows this comparison. While in length the women\u2019s hands averaged 89.7% that of the men\u2019s their strength was only 58.7% as great. The difference in strength would not be so great if it were not that the leverage of the small hand is not so good.\nTable VI.\nRelative strength of men and women.\nSubjects.\tAver, length of hand in mm.\tAver, pressure in kg.\nMen.\t193-2\t48.2\nWomen.\t173-4\t28.3\nAbove a certain point however great length of hand is of no advan-taSe- Reference to Table IV. makes this statement clear. The men averaging 200. imm for length of hand were very little stronger than those averaging 186.3 mm. The very large hand is at a disadvantage because * e dynamometer is pressed on one side, now, by the third phalanges","page":69},{"file":"p0070.txt","language":"en","ocr_en":"7\u00b0\nWalter W. Davis,\ninstead of the second. Table V., too, supports this conclusion. The natural inference is that the best method of grasping the dynamometer js to place one side in the crease of the second joint so that pressure is made with the second phalanges.\nIt seems necessary, then, in discussing temperament, to consider all the factors enumerated above, and the problem becomes more and more complex. An effort will be made in Part II. to present a somewhat more comprehensive view of the influence of temperament on bodily strength and its relations to muscular development.\nOf the factors influencing the strength of dynamometric pressure we have named four: (i) length of hand, (2) length of forearm, (3) muscular development of the hand and arm and (4) temperament. These four factors are not easily affected by a short period of practice.\n5.\tCo'\u00e0rdinatio7i.\u2014By coordination we mean the ability to innervate a particular muscle or set of muscles so specifically that very little of the motor impulse escapes into muscles not concerned in the movement that is being performed. It is the ability to direct motor impulse ; or speaking from another standpoint it is muscular control. The term is best expressed in common speech by the word \u201cknack.\u201d This factor is much improved by practice. Athletes possess it in a greater degree than men who have not had special physical training.\n6.\tStored energy.\u2014This must be found in two places, in the motor nerve cell and in the muscle. It must be present in the nerve cell to generate the motor impulse and in the muscle to cause the contraction. Its absence in either place would make muscular action impossible. Fatigue means simply a loss of potential energy\u2014hence fatigue is inability to do work. The authorities are agreed that complete loss of potential energy is sustained sooner by the central nerve cells than by the peripheral organs. Hence hve say that central fatigue appears before peripheral fatigue and so a protection to the muscles is afforded. Potential energy must be present in large amounts in tests requiring a maximum exertion through a long period of time.\n7.\tWill power or volitional power.\u2014Potential or reserve energy is no use until it is changed to kinetic energy. This change is effected iD all primarily conscious tests by conscious volition. One\u2019s ability to accomplish feats of strength depends, in great measure, on his power to transform the potential energy of the motor cells into the kinetic energy of the nervous impulse. In addition to this, the strength of a muscle must depend on the readiness with which the potential energy of muscle is changed by the motor impulse into the kinetic energy of muscular contraction.","page":70},{"file":"p0071.txt","language":"en","ocr_en":"Researches in cross-education.\n7t\nLombard, in his experiments with the ergograph, has shown that in tests of endurance the potential energy must fail before the will tires. In tests of strength which require the quick accumulation of the potential energy of the nerve cells and its ready change into the kinetic energy of the nervous impulse, it is the power of volition that fails. The conversion is not readily made. Still it is probable that even in tests oi strength an abundance of potential energy is favorable to great exertion.\n8. Impressibility.\u2014The fourth factor that is affected by practice is the openness of pathways for nervous impulse. By disuse of any nerve or set of nerves, the -pathway of the impulse is obstructed, and innervation of the muscle is made difficult.\nFactors 5, 6, 7 and 8 are all affected by practice and exercise. Volitional power increases by exercise. Exercise stimulates the growth of nerve and muscle cells and influences the storing up of energy. Coordination improves by practice. The frequent passing of a nervous impulse keeps the necessary paths free and open.\nTo get a basis for comparison Table VII. w'as arranged to show the average transference of the effects of practice. With the averages shown there the transference of any group may be compared. Only groups L, II. and III. were put into the table. Group IV. was left out because the conditions under which the subjects of this group worked, were not, as will appear later, at all favorable to transference. Group V. also very evidently should not appear in the table.\nAfter casting out Groups IV. and V., and certain individuals for various reasons, the results for 12 men and 14 women are shown. The results in the columns headed First final were secured immediately after the three weeks\u2019 practice ; those under Second final four days thereafter, no practice occurring in the meantime. The numbers under the heading Direct gam represent the gain made by the hand practiced ; those under Transference the gain of the hand not practiced. In Groups I. and II. the transference is from right hand to left; in Group III. it is from left hand to right.\nTwo facts show themselves clearly from a glance at the table :\n(\u00ae) The results due to fatigue.\u2014As a result of the practice the men gain, ^ the first final, 8.06% with the hand exercised, and 9.92% with the aud not exercised. At the second final after a rest these figures are reversed; 9.53% and 8.81%. That is, the hand practiced, made, at the ^rst final, a smaller percentage of gain than did the hand not practiced, ^ at the second final test its percentage of gain was the greater. In case of the hand exercised it seems that the fatigue of a three weeks\u2019 P actice had caused its low record at the first final ; but at the second","page":71},{"file":"p0072.txt","language":"en","ocr_en":"72\nWalter W. Davis.\nfinal it had reached its normal tone by reason of a four days\u2019 rest. The other hand had at the second final already lost some of its gain. Hence its lower record.\nTable VII.\nPercentages of gain by practice.\n/. Men.\nFirst final test.\tSecond final test.\n(After three weeks\u2019 practice.)\t(After four days\u2019 rest.)\nNo.\tGroup.\tDirect gain.\tTransference.\tDirect gain.\tTransference.\ni\tI\t0.48 %\t7-\u00b05 %\t2.88 %\t12.94 %\n2\tII\t12.22\tII-34\t13-33\t13-53\n3\tIII\t8.41\t14.68\t10.28\t18.81\n7\tII\t12.05\tio-35\t15.06\t00.57\nvA\tIII\t10.20\t9-74\t4.90\t\u2014 2.96\nIO\tI\t3-67\t9.42\t2.29\tII.00\nII\tII\t12.30\t26.77\t10-53\t17.70\n12\tIII\t3-45\t17.11\t5-52\t12.50\n16\tII\t\u2014 0.47\t1.12\t1.89\t\u2014 0.56\ni7\tIII\t\u2014 2.08\t0.00\t3.12\t\t 4.02\n20\tI\t20.10\t2-73\t25.92\t18.03\n24\tII\t17-39\t7-74\t18.63\t8.22\nAverage\t\t8.06\t9.92\t9-53\t8.81\n\t\t\tII. Women.\t\t\n26\tI\t12.50\t0.00\t7.69\t\u2014 6.05\n28\tIII\t6.31\t\u2014 2.56\t10.52\t\u2014 0.85\n31\tI\t9.00\t2.90\t12.82\t5-\u00b07\n32\tI\t\u2014 3 06\t\u2014 3-33\t3.82\t4.61\n33\tIII\t21.21\t15.69\t6.89\t5-21\n36\tI\t1.42\t\u2014 4-91\t10.00\t\u2014 4.10\n37\tII\t20.00\t43-94\t18.88\t33-33\n38\tIII\t2.63\t\u2014 0.77\t12.28\t13-95\n41\tI\t5-51\t\u2014 3-53\t\u2014 1.04\t1.17\n42\tII\t0.78\t7-14\t9-37\t7-93\n43\tIII\t10.68\t9 73\t25-38\t24.71\n46\tI\t\u2014 3-09\t1.06\t3-09\t\u2014 2.12\n48\tII\ti.61\t3-\u00b03\t4-83\t6.06\n49\tIII\t5.21\t9.80\t6.25\t6.86\nAverage\t\t6.45\t5-84\t10.05\t6.81\nThe effects of fatigue are seen, too, in the women\u2019s averages. Here, the hand not exercised seems to have been affected by the fatigue of the other, which it is quite evident was very great ; and it does not reach its normal tone until after a short rest. There is a point in time shortly after the end of the practice when the effects of fatigue have just vanished.","page":72},{"file":"p0073.txt","language":"en","ocr_en":"Researches in cross-education.\n73\nThis point would of course differ in all individuals. If a test could be made just at this time it would show the best record that the hand practiced could possibly make. Such a record would be better than that of the unpracticed hand at its most favorable time. Still in a test of strength like that with the dynamometer this best possible gain would undoubtedly be nearly the same for both hands.\n(b) The difference between the results securedfrom men and women.\nA comparison of the averages for men and women shows : ( i ) that the women gave more negative results ; i. e., there were more failures among them to make gains from practice, there being five negative results registered for the men and eleven for the women ; (2) that there is a greater regularity in the gains made by the men. These are only two examples among many observations made throughout the research, indicating greater reliability, in tests of motor ability, among men than among women. Boys in their abundant out-of-door life gain a more perfect and thorough muscular control than it is possible for girls to do. This is in accord with the results obtained by Gilbert in his experiments on voluntary motor ability, on reaction-time and on the judgments of weights.1\nAfter these few words in general it will now be necessary to study the results in connection with our classification of the individuals into groups.\nTable VIII. shows the average relative gain of each group for both men and women. The groups will be considered separately.\nTable VIII.\nComparison of group gains.\nFirst final.\tSecond final.\nGroups.\tDirect gain.\tTransference.\tDirect gain.\tTransference.\n( Men.\t12.68%\t7-oi%\t10.36%\t14-32%\n\\ Women.\t3.62\t\u2014 i-3\u00b0\t6.06\t\u20140.20\nf Men.\t10.69\t9.46\t11.88\t7.89\n1 Women.\t7.46\t18.03\t23-71\t15-77\nj Men.\t5.88\t11.18\t5-95\t6.08\n\\ Women.\t9.21\t6.38\t17.26\t9-77\nj Men.\tI.OO\t\u2014 2.63\t\u2014\t\t\n\\ Women.\t2.9O\t\u2014 3 38\t5-55\tI-51\nJ Men.\t1.70\t6.03\t3.88\t9.27\n\\ Women.\t3-78\t8.69\t9-31\tI3-9I\nGroup I.; Vigorous practice with dynamometer, right hand.\u2014This group ls \u00b0nly one that was practiced vigorously. A curious fact that can not be fully explained at present, is shown by a comparison of the results ^\u00b0ra the records of the men and women. There is a decided transfer-\nGilbert, Researches on the mental and physical development of school children, Stud. a e Psych. Lab., 1894 II 61, 64, 66, 78.","page":73},{"file":"p0074.txt","language":"en","ocr_en":"74\nWalter W. Davis,\nence shown by the men but more by the women. It is rather startling to note that the women did not gain with the hand not practiced. Of the six women in this group, three at the first final test gave minus results with left hand, one, zero, and two, small gains. It should also be remarked, however, that even for the hand practiced two women failed to make any gain. An improvement is also noted in the second final test, where the right gained 6.06% and the negative result of the left was reduced from 1.3% to 0.2%, indicating that the effects of fatigue had begun to pass away before the second final test was made. The temperament of women as contrasted with that of men may be suggested as a probable explanation of the facts noted. The more nervous temperament of the women was strongly affected and seriously fatigued by the vigorous practice. It may be said that the two women of this group who made gains with the left hands at the first final were classified as phlegmatic. This class of people, since they react slowly to stimulus of any kind, would not be so strongly affected by the heavy practice as persons of a more nervous temperament. This consideration will be further discussed in the section on temperament.\nGroup IL: Light practice with dynamometer, right hand. The subjects of this group show, in general, a greater gain than those in Group I. This is especially true of the women. Our conclusions in regard to the fatigue shown by Group I. are corroborated here. Especially clearly, in the case of both the men and the women, is the fact shown that fatigue causes the hand practiced to make a smaller record at the first final test than the unpracticed hand can make. And for both men and women there is a reversal of the figures at the final test : the unused hand having already begun to lose the effects of practice.\nGroup III.: Light practice with dynamometer, left hand.\u2014Three observations are made from an examination of the results secured by the practice of this group of subjects.\n1.\tPractice of the left hand increases the strength of the right as certainly as practice of the right increases the left. This has already been shown by Woodworth. In reality it would seem that the transference may be greater in right-handed persons from left to right than from right to left. This supposition is supported in a measure by the next two observations made from the results given by this group of subjects.\n2.\tThe men gained more with the right hand than with the left-Women gained more with the left.\n3.\tThere is not a reversal of these figures in the second final test as was noted in Groups I. and II. That is, the effects of fatigue are not so manifest.","page":74},{"file":"p0075.txt","language":"en","ocr_en":"Researches in cross-education.\n75\nIt is probable that these facts are explained by certain theories in regard to the conduction of the motor impulse. The impulse is more apt to follow old paths. In new paths greater resistance is met, and the impulse may be retarded or deflected. Reference is made in this connection to Wissler\u2019s conclusions on the diffusion of the motor impulse. Now the right hand is used much more than the left, though this statement is not so true of girls as of boys. Hence there would be a greater diffusion of the impulse into the right arm through the use of the left, than would happen vice versa. So there would be a greater transference in right-handed persons, from left to right than from right to left. This conclusion is strengthened by the fact that there is no reversal of the figures in the second final test. Fatigue did not appear in so great measure as in Group IL, who practiced in precisely the same manner as Group III., except that they exercised the right hand instead of the left. There was greater diffusion of the motor impulse in Group III., hence less fatigue resulted.\nGroup IV. : Light practice with cylindrical stick, right hand.\u2014Two noteworthy observations were made in regard to this group.\n1.\tThe gains in development for the hand practiced were small. The average gain for the men was only y2 kg. (i%); for the women, 0.85 kg. (2.9%). These gains are significant when compared with the gains made by the first three groups. They are much smaller than the gains made by the subjects of investigation by Anderson,1 who found a gain of 6.3 lbs. (= 2.9 kg.) for right hand and 7.8 lbs. (= 3.5 kg.) for left, the right hand alone being practiced. There was, however, a distinct; difference in the methods of practice followed in the two investigations. In one case the practice was made vigorous, in the other light. With the subjects in Group IV. the exercise was probably not favorable to the development of will power ; in Anderson\u2019s investigations the conditions were favorable for such development, the subjects being instructed in the daily practice to exert all their strength. Further comparison of these results is made on page 78.\n2.\tThere was an absence of any transference of the effects of practice to the unused side. There is an actual loss recorded for the left arm. The men lose, at the first final test, 2.6%, the women lose 3.3%.\nObservations (1) and (2) would seem to indicate: (a) the great unportance of becoming used, in the daily practice, to the instrument With which the tests are made. The muscles learned how to contract Pjjoperly for pressure of the cylindrical stick but gained no advantage\n1 Anderson, Study in the effects of physical training, Amer. Phys. Education Re-view, 1899 IV 3.","page":75},{"file":"p0076.txt","language":"en","ocr_en":"76\nWalter W. Davis,\nfrom this knowledge for gripping the dynamometer; (b) the important of volitional power and coordination in the transference of the effect of practice.\nGroup V. : Light practice with dynamometer, both hands._____In t^js\ngroup both hands together received as much practice as only one hand in the other groups : i. e., each hand made 5 pressures of the dynamometer in each daily practice. As much work was done in practice as was done by Groups IL, III. and IV., but it was distributed between the two hands.\nThe following observations are made from an examination of Group V. \u2019s practice and tests :\n1.\tThe tendency of both men and women was to refer the effects of practice to the left hand (see Table VIII.). The left hand being naturally weaker and less expert than the right there is a greater chance for development in its case.\n2.\tThe effects of fatigue are shown more clearly here than in any other group : i. e., there is a greater ratio of difference between the gains of first and second final tests. The ratio of first final gain to second final gain is represented in Table IX. There is a great regularity of the ratios comparing the results from men and women subjects, much greater than in any other group. This shows that the effects of direct exercise are more regular than the transference effects.\nTable IX.\nRatio of gains in first and second final tests.\nR.\tL.\nMen.\tI : 2.22\tI : 1.53\nWomen.\tI : 2.43\tI : 1.60\nIt is now proposed to attempt the determination of those factors of practice that are influential in causing the transference of practice effects. We do not mean to say that \u201ccross-education \u201d will be explained simply by showing the factors necessary for the transference. The deeper physiological and psychological explanation can be made only after a complete understanding is had of volition, of voluntary movement and of the coordination of mind and muscle in the production of movement. It can be pointed out, however, from results secured by several methods of practice that the development of certain factors in neuro-muscular ac tivity are of the greatest significance in bringing about the education\u00bb both of the parts practiced and also of other parts which seemingly are not directly concerned.\nThe methods of practice referred to in this connection are in part in","page":76},{"file":"p0077.txt","language":"en","ocr_en":"Researches in cross-education.\n77\nd in the groups discussed above ; in addition, an investigation by V\u00b0 Anderson, of Yale University Gymnasium, will be freely discussed. ^r' Anderson\u2019s experiments were made in the winter of \u201997-\u201998, his ,. ts being secured from one of his classes. I was a member of this class and one of the subjects of the experiment. Hence it is not overstepping the bounds of logical procedure to compare intimately, results secured by two observers at different times and places.\nDr. Anderson\u2019s subjects practiced by two methods. One group, A, practiced vigorously with a cylinder of wood, 3 X 1 in.; the other group, B practiced vigorously with the dynamometer. The only difference then between the two methods of practice was in the use of differently shaped instruments. For comparison, the methods of practice of Dr. Anderson\u2019s subjects and the results secured from their practice are arranged in a table with the methods and results of practice of the subjects of Groups II. and IV. Table X. shows this comparison together with the factors that seemed to contribute most largely to such results. In all the groups\nTable X.\nThe factors of transference.\nExperimenter.\tGroup. Instrument.\tMethod.\tR.\tL.\tFactors.\nAnderson j\tA Cylinder. B Dynamometer.\tVigorously. Vigorously.\t6.3 lbs. 7.8 lbs. \u201c\u20227\t*3Z\t{\tVolitional power. Volition. Coordination.\nDavis j\tIV Cylinder. II Dynamometer.\tLightly. Lightly.\t1.1\t\u20142.6 10.6\t11.5\t-J\tVolition. Coordination. Volition.\nonly the right hand was used in practice. The average gains for all\t\t\t\t\ngroups are given in pounds.\t\t\t\t\nWe should judge a priori : (1) that there would be a disadvantage in practicing with the cylinder ; and that subjects using it would not gain 38 much as those using the dynamometer. We say in common speech that there is always a knack to be learned in acts that involve strength or shill; (2) that those practicing lightly would not gain as much as those Practicing vigorously. Our second a priori judgment is not supported by very decisive results.\nit is not necessary to compare each group of the table with all the \u00b0thers. We may compare Groups A and B to determine the effect on the results of practice, of using differently shaped instruments when the Practice is vigorous ; and Groups IV. and II. to determine the results 'vhen the practice is light. That an intimate comparison of the four grouPs might be made is proven by an examination of the results of","page":77},{"file":"p0078.txt","language":"en","ocr_en":"78\nWalter W. Davis,\npractice of Group B, Table X., and Group I., Table VIII. The method of practice is precisely the same in the two groups, but the time of prac tice varies. In spite of the difference in the time of practice the gains made are very nearly the same in both cases. The average of first and second final for Group I. is R, ii.95 lbs.; L, 10.45. This is even less than the gain made by Anderson\u2019s Group B though the practice of Group I. was longer. This indicates that the volitional power necessary for a certain act probably reaches its maximum development with only a short practice.\nTable X. shows that the results secured vary in a remarkable degree. Group B practicing vigorously with the dynamometer makes the greatest gain; R, 11.7 lbs., L, 13.2 lbs. Group IV. practicing lightly with the cylindrical stick gains the least; R, 1.1 lbs., L,\u20142.6 lbs. An examination of the conditions of practice surrounding each group will explain, in a great measure, the reasons for such a wide variation of results.\nIt seems quite evident that vigorous practice calls for the exercise in a large degree of volitional effort. Light practice does not call for such exercise. It would seem quite as probable, too, that practice with a cylindrical stick could not cultivate a nice coordination of mind and muscle that would be efficacious in a test with the dynamometer. That is, the learning of the \u201c knack \u201d for one instrument will not help us out much in the use of another. So we are led to conclude from an examination of the striking results of Table X. that the variation of these results is due chiefly to the development in different proportions of two important factors of practice, both of which factors are very necessary and very evident in tests of this kind. These factors are : ( 1 ) volitional power or will power ; in connection with this factor attention may be named: (2) coordination; or in terms of common speech, \u201cktiack\n1.\tVolition.\u2014The dynamometric pressure is emphatically a test of will power ; a test of the subject\u2019s ability to send down to the hand and forearm at an instant of time an immense impulse for muscular contraction. The muscles involved can probably make use of all the stimulus that can possibly be sent down to them.1 Will power and attention for our purpose the terms may be considered as equivalent2\u2014are factors that may be easily and quickly developed by practice.\n2.\tCodrdinative ability or knack.\u2014The second factor is apparently of nearly as much importance in producing gains by practice. By knack we mean the proper coordination of mind and muscle in the performance\n1\tMosso, Ueber die Gesteze der Erm\u00fcdung, Arch. f. Anat. u. Physiol., Physiol-Abth., 1890, 89.\n2\tJames, Psychology, II 568, New York 1890.","page":78},{"file":"p0079.txt","language":"en","ocr_en":"Researches in cross-education.\n79\n0fa muscular act, the ability to properly adjust one\u2019s muscles to the test at hand. It was noticed that the subjects gained much more, with the hand practiced, during the first part of the test than during the last part. This was as true of those who practiced lightly as of those who practiced vigorously- Both of these factors, then, were developed early in the test. This ability to properly govern the muscles involved is learned the more quickly, the brighter and more apt the subject is.\n3. While we do not eliminate the storing of potential energy in the motor nerve cells, from among the factors affecting transference, yet it seems that in a test like this one it is of somewhat minor importance. The test is not one of endurance, but of strength. It is admitted though that the experiments carried out here have hardly been complete enough to determine this point. It may be, in fact it is quite probable that it is so, that the development of volitional power and of potential energy go along together and that it is quite impossible to separate and distinguish them by an experiment like the above. To determine this point further experiment is necessary, differing from ours both in method and kind.\nMuch less could the transference be caused by the growth of muscular tissue, the storing of potential energy in the unused arm. The method of practice was such that muscular tissue could hardly be developed, certainly to no extent appreciable by any means of measurement at hand at present. Only ten pressures of the dynamometer were allowed daily, requiring less than one-half a minute for the whole process, hence the probability of any development of muscular tissue was reduced to the minimum. Even in the dumb-bell test,1 which was an excellent one for the development of muscular tissue, the girth gains for the left arm were small and the tissue developed did not prove efficacious for lifting the weight.\nIt seems then that there are in this test two factors the development ot which are chiefly instrumental in causing a gain in the hand practiced volitional power and co\u00f6rdinative ability. These are both of them factors that one would judge might, when developed, affect the unprac-tlced side as much as the side practiced. An examination of Table X. Wl11 show when each factor is preeminently present.\nIn Group A, learning the knack of gripping the stick would be of no ^vantage to the subject because the tests for a record were made with atl entirely differently shaped instrument. There could be no gain made *n the ability to coordinate mind and muscle in the accomplishment of ^Pecial^test. But there had been an exercise of effort. Every day Researches in cross-education, Stud. Yale Psych. Lab., 1898 VI 23.","page":79},{"file":"p0080.txt","language":"en","ocr_en":"8o\nWalter W. Davis.\nthe will had been exerted to its utmost for ten successive pressures. The gain made by this group must be attributed to the development of voll tional power. This gain was shared in by the left hand, unpracticed the amount in its favor being due to the effects of fatigue on the right hand after three weeks of practice.\nIt is apparent that both factors were present in Group B. The gain of the left hand, unpracticed, was 13.2 lbs., 69% greater than its gain in Group A. Theoretically this 69% may represent the influence of coordination in causing a gain of strength, compared with 100% as representing the gain due to the development of volition.\nThe subjects of Group IV. made practically no development with either hand. There was a slight gain with the right and a loss with the left. This was true of the women too, though the left did gain slightly at the second final test. The method of practice seems altogether unfavorable to the development, in any effective sense, of either volition or coordination. It is probable that volition is developed in a limited degree but that the gain due to this development is counteracted by what may be termed a loss of coordination. The subject having become accustomed to the shape of one instrument has learned to use certain muscles after a certain order or fashion. At the final test, using a differently shaped instrument but with the same object in view, the tendency may be to use the same muscles in the same series or order as in the practice with the stick. The result is a lack of such coordination as will be effective for a good test with the dynamometer. One set of muscles obeying a mistaken impulse behind it, gets in the way of the set that should respond. The loss of effectiveness in one factor counteracts the gain in the other.\nFor the same reasons there would not be a great development of volition in Group II. Coordination was probably responsible for the greater part of the gain. The gain is not so large as that of Group B, where both factors work at their best and in harmony with each other.\nThe results and observations seem to point to the conclusion that practice with the dynamometer develops two factors chiefly\u2014volition and coordination. The development of these factors cause a gain in strength of each hand whether practiced or unpracticed. Both factors are among the faculties that we call mental.\nIt is not asserted that other factors may not run parallel with these. In fact it seems probable that the storing up of energy in the motor cells of the brain is a necessary concomitant with the development of volitional power. This is indicated by the results that were apparent all through the experiments, which are plainly due to fatigue. The most probable","page":80},{"file":"p0081.txt","language":"en","ocr_en":"Researches in cross-education.\n8i\nexplanation of such fatigue is the loss of stored energy in the brain cells. In tests of endurance it might be possible to separate the two factors which seem to be parallel in the tests involved in our experiments.\nThere are, moreover, certain considerations which seem to indicate the presence of another factor, one that is probably present under whatever conditions the practice is carried on. I have called this factor the physiological factor, or cross-influence.\nIn the tapping experiments1 it seemed to me highly improbable that a strong will was of any aid to the subject. In fact, the men seemed to tap more rapidly the less attention they paid to the movement. As several expressed the fact, they only needed to \u201cset the machinery going and it went itself.\u201d\nObservations were made, too, on F. who practiced with the right foot only.2 F. was a strong healthy man, a trained and skilled gymnast. During 2^ weeks of practice he was not able to make any marked gain. He himself said : \u201c If I try to hurry too much my foot stops almost altogether. \u2019 \u2019 His heavy gymnastic work, in which strong effort is necessary, had so developed his ability to send down to large muscles, immense stimuli for action, that for a test involving small muscles he could not become expert.\nTo discover if these observations would be supported by actual experimental results, I arranged the apparatus so that the subjects might tap with both hands and both feet, though the tapping of but one member was recorded. A sufficient number of records were taken to merit the conclusion that, after a few days of practice, enough to take away the awkwardness due to thinking of so many members, the right hand could tap even more rapidly when tapping together with the other members than when tapping alone. It is probable that when the attention was paid entirely to one member\u2019s tapping, the motor impulse was too concen-tfated for the small muscles ; or else the large impulses, overflowing into other muscles, caused contractions that hindered the free movement of the muscles concerned in the movement. This surcharging of the small muscles was relieved when the attention, and so the impulse, was directed to more than one place.\nThese observations and results lead us to conclude that the tapping ^ ls not one of will power as the term is commonly understood.\nong effort and attention are hindrances to rapid tapping. the^eit^er taPP*n& a test in which rapidity is specially dependent on e learning of any knack. The test is a very simple one, involving\nDavis, Researches in cross-education, Stud. Yale Psych. Lab., 1898 VI 44.\nUavis, as before, 12, 13.","page":81},{"file":"p0082.txt","language":"en","ocr_en":"82\nWalter W. Davis,\nonly a slight movement of the member tapping, so that no complex co ordination of mind and muscle is necessary. The movement is at least semi-automatic and the test is one of simple motor ability.\nIf, then, the gain in the rapidity of tapping is not due to either the development of volition or of coordination what must the factor be that causes the gain and its transference to the unpracticed members ? A lit-tie light is obtained from an observation of the test records and prac-tice conditions of an individual subject. The results of this subject\u2019s practice were not exhibited in the general table for reasons which will now be understood.\nAmong the men tested at the beginning of the experiment was one, S.,\nTable XI.\nAn individual record. (Subj. S., No. 15.)\nInitial.\tFirst Final.\tGain.\nSubj.\tR.\tL.\tR.\tL.\tR.\tL.\n15\t33^ kg.\t18X kg.\t58^\tkg. 39X kg.\t73-3%\tH5-\u00b07%\nwhose grip was far below the average for men. The left hand recorded only i8j^ kg., right 33^ kg.; whereas the average for the men of this experiment was 46 y2 kg. for left hand and 50 kg. for right. That is, his left hand recorded 39.5%, his right 67.1 % of the average grip of the twenty-five men subjects. There was moreover no apparent reason for such a low record. S. is a strong rugged man 19 years old and seemingly should have made an excellent record. However, some close questioning brought out a few interesting and important facts.\nTwo years before the test the metacarpal bone of S.\u2019s left thumb had been broken. About the same time in a second accident the fourth finger of his left hand had been so cut that the long extensor tendon had been separated from its attachment on the distal phalanx, leaving the flexor tendon unopposed. A thorough examination by a physician strengthened the idea I had already formed that the hand had not properly healed after the accidents. So it is very easy to explain the weak ened grip for the left hand. Why the grip of the right hand shou also be weakened is not so easily explained.\nAs with the other subjects the practice of S. was continued for three weeks. Having been placed in Group I. his practice was vigorous, right handed, with the dynamometer. At the final test, records of both h were taken. Table XI. shows the remarkable gains that were \u00ae The right hand gained 73.3% ; the left, 115.0%. At this time right hand was stronger by 17 % than the average right-hand grip f\u00b0r","page":82},{"file":"p0083.txt","language":"en","ocr_en":"Researches in cross-education.\n83\nobjects experimented with. The left increased from 39.5% to 86.5% 0f the average. At the second final test the left recorded 90.8% of the\naverage grip.\nIt would seem rash to attribute this remarkable gain to the development of either volition or coordination. We are at a loss to explain it satisfactorily. Taken in connection with the conclusions reached about Upping it seems probable that there is an additional factor here, that, working in and through the other factors, is directly responsible for the transference of practice effects to the unused side of the body ; stated more definitely to those parts of the body that are symmetrical to the parts used or else closely related to them in function or position. To put the proposition baldly this factor is one whose development makes it possible for the other factors, volition and coordination, to become effective in stimulating to a greater degree and governing in a more effective manner, the muscles of the unused side. This development probably accompanies physiological changes in the motor nerve centers in both halves of the brain. If the right hand is used, certain changes are wrought in the right side of the brain to accompany those caused directly on the left side. Whether this change is an actual laying down of potential energy in the motor nerve cells or only a clearing or enlarging of pathways of nervous impulse to the muscles involved, there is at present, of course, no means at hand of knowing\u2019 definitely. The whole matter is in a measure conjectural. We only know that there is a close nervous connection between the two halves of the brain and that the physiological changes might very readily occur, and in the light of the facts noted it seems most probable that they do really occur.\nWith the aid of this theory of transference, subject S.\u2019s case may be Partially explained. His failure to use his left hand after the accident and the failure of certain parts to properly heal had caused a partial atrophy of the motor center governing that hand. This mal-condition a been shared in by the right hand so that its strength of grip actually Weakened, though in a degree not equal to the weakening of the Then, when the practice was begun with the right hand, the motor it h W \u00ae0vern*n8 that member quickly responded to practice, gained all\na lost through the accident, and this improved condition had been\ncomm '\nunicated to and shared in by the left hand\u2019s motor center. Or, if *as .an^e<^ con<dition in the nervous apparatus governing the right hand resu-Ply a clearing up of old pathways that had been clogged as a shared \u00b0f ^ acci<^ent\u2019 this changed condition had, nevertheless, been \u2022pj^ 111 hy the nervous apparatus governing the left hand.\npath-clearing theory derives added importance from its consid\u00e9ra-","page":83},{"file":"p0084.txt","language":"en","ocr_en":"84\nWalter W. Davis,\ntion in connection with Wissler\u2019s theory of the diffusion of the mot0 impulse. For if there is a diffusion of impulse to symmetrical muscles the traveling of the impulse to the muscles will wear the paths deeper and deeper and so make a clear way for the impulse when it is voluntarily sent this way at the final test.\nThe fact that S.\u2019s grip for the right hand had weakened by an accident directly affecting only the left raises the question whether the reverse of cross-education is true; whether a mal-condition of the governing apparatus for the one side is generally transferred to the other side of the brain, and so causes a weakening of the other side of the body. Speaking theoretically it seems reasonable to suppose such to be the case. It would be interesting in this connection to study pathological cases where, for any reason, one member has fallen into disuse, to determine whether the symmetrical member has been weakened. The difficulty would be to find cases that had not used the well arm more in consequence of the other\u2019s loss of power. Such conditions would of course nullify any results secured.\nIt must not be understood that any explanation of the causes of crosseducation can be applied to all individuals or even absolutely to any individual. Even provided that all the conditions of practice could be made precisely the same, no two individuals would give the same results in development.\nAgain, any results of practice are modified by the kind of test that is made. Tests of endurance differ very materially from tests of strength. The development of the factors of practice may be required in entirely different proportions in the two kinds of tests. The summary we present here holds only for tests of strength and, even more specifically, only for practice with the dynamometer.\nThe central effects of practice are emphasized as most prominent in this investigation. It is quite probable that the peripheral effects are more necessary of development in tests of endurance than in tests of strength-In the same test we believe it quite possible that the central and periph eral effects may vary in different individuals.\nThis investigation gives prominence to the following factors of cross education.\t. -s\n(a) Volition or will power.\u2014-When developed for one act it efficacious for similar acts done by symmetrical or closely re muscles ; in a lesser degree it is possibly developed for all acts.\n{b') Neuro-muscular coordination or \u201c knack.\"\u2014When developed one set of muscles it is transferred across to the symmetrical set on other side of the body.","page":84},{"file":"p0085.txt","language":"en","ocr_en":"Researches in cross-education.\n85\n, p0tential energy must be stored in the motor nerve cells in increased mount if a gain in strength is make. To be effective for the unpracticed a.de ^ere must probably be a storing of energy in the cells governing\nthis side.\n(d) Cross influence. We simply emphasize what has been said under ,, an(j (7). The development of coordination and the storing of energy is of no use to the unpracticed muscles unless it takes place, in a measure, in that half of the brain governing those particular muscles. So too, the clearing up of nervous pathways on the unpracticed side is of probable importance. This cross influence is theoretically possible owing to the close nervous connection between the two halves of the brain. The facts secured from this and other similar investigations point to this direct cross influence of one side of the brain on the other.\n(>) If there is a peripheral transference of practice effects that is really effective for strength, skill or endurance it can be explained theoretically on the grounds of Wissler and Richardson\u2019s diffusion of the motor impulse.1 That there is such an effective transference remains to be proven.2\nII. Influence of temperament on practice effects.\nThe tables arranged in this section and the conclusions drawn from them grew out of an observation made concerning the development of two subjects, Nos. 22 and 32, the results of whose practice were averaged with those of the rest of the subjects in Section I. A comparison of these results showed such a wide difference among them that the conditions of practice were at once examined to determine a cause for such difference. The subjects were brother and sister, which fact would of itself incline one to classify them similarly in respect to temperament. Appearances would indicate that they are of the same general type. Both are small of stature, quick and active in movement. They were\nTable XII.\nA comparison of individual results. (Subjects 22 and 32.) Subject.\tMethod of practice.\tGain, first final.\n22\tLight, with the dynamom.\t9*39 %\n32\tVigorous, with the dynamom.\t\u20143.06 %.\npassed as nervous. Table XII. compares the conditions and results of ^jy practice. The methods of practice differed in that No. 22 exercised ViiW-ler and Richardson, Diffusion of the motor impulse, Psych. Rev., 1900\nI)Avisi Researches in cross-education, Stud. Yale Psych. Lab., 1898 VI 23.","page":85},{"file":"p0086.txt","language":"en","ocr_en":"86\nWalter W. Davis,\nlightly while No. 32 exercised vigorously. The percentage of gain of Subject 22 was rather large, 9.39 % at the first final, compared with the loss of 3.06 \u00b0/o of Subject 32. Since the other conditions of practice were practically the same for both subjects, it seemed rational to attribute the difference in their development as due to the difference in the severity of the practice. Looking further among the subjects it became evident that the great variation of the results of practice was caused chiefly by the various combinations of temperament with severity of practice. Persons of one type of temperament seemed to demand a certain degree of exertion in their exercise in order that they might make good gains in development. It will be our purpose in this section to investigate the influence of temperament on the effects of practice, and the influence of the severity of the practice on development in persons of certain types of temperament ; also, to determine if the type of temperament has any influence on the fact or amount of transference of practice effects to the unused side of the body.\nAn incomplete discussion of the classification of temperaments was given above, p. 69. A few considerations that are of a secondary nature are also of importance in the determination of the type of temperament. The following scheme presents a rather complete view of those considerations that were of either primary or secondary importance in our classifications.\nConsiderations in the determination of a classification of temperaments.\n\tPrimary.\t\tSecondary.\t\t\nType.\t. Muscular reaction.\tMuscular reaction.\tMental reaction.\tHeight.\tWeight.\nNervous.\tQuick -\tf Weak. Medium.\tQuick.\tShort.\tLight.\nMotor.\t1 Average <\t[ Strong. ' Weak. Medium.\tMedium.\tMedium.\tMedium.\nPhlegmatic.\t1 Slow -t\t. Strong, f Weak. Medium.\tSlow.\tTall.\tHeavy.\n( Strong. is not contended that this scheme\t\t\tis absolute. It is\t\tnot complete\nor comprehensive. In the determination of any individual\u2019s temper3 ment other considerations may enter. Moreover a particular individu may have only a few of the secondary characteristics attributed to his type. A nervous person may be tall or heavy. He might even be slow to grasp mental ideas. It is only asserted that all these characteristics were noted and that the subjects when classed as either nervouSi","page":86},{"file":"p0087.txt","language":"en","ocr_en":"Researches in cross-education.\n87\nTable XIII.\nibject.\tGroup.\nI\tI\n2\tII\n3\tIII\n5\tV\n6\tI\n7\tII'\nI'A\tIII\n8\tIV\n9\tV\n10\tI\n11\tII\n12\tIII\n13\tIV\n14\tV\n16\tII\n17\tIII\n18\tIV\n19\tV\n20\tI\n22\tIII\n23\tV\n24\t11\n25\tIV\nAverage,\nAverage of 1st and\nSubject.\tGroup.\n26\tI\n27\tII\n28\tIII\n29\tIV\n30\tV\n31\tI\n32\tI\n33\tIII\n34\tIV\n35\tV\n36\tI\n37\tII\n38\tIII\nInfluence of temperament.\nMen.\nTemperament.\nnervous.\nphlegmatic.\nphlegmatic.\nmotor.\nphlegmatic.\nnervous.\nphlegmatic.\nmot. phleg.\nphlegmatic.\nmotor.\nphlegmatic.\nnervous.\nphlegmatic. t\nnervous.\nphlegmatic.\nphlegmatic.\nnervous.\nmotor.\nphlegmatic.\nnervous.\nmotor.\nmotor.\nnervous.\nfinals,\nWomen.\nTemperament, nerv. mot. phlegmatic, mot. nerv. phleg. mot. phleg.\u2014moderate, phlegmatic, nervous.\nphleg. \u2014moderate, nerv. mot. nerv. mot. mot. phleg. nervous, motor.\nGain.\n1st final.\t2d final.\n0.48%\t2.88%\n12.22\t13-33\n8.41\t10.28\n\u2014\t7-75\n26.48\t\u2014\n12.05\t15.06\n10.20\t4.90\n2.47\t\u2014\u2014\n11.00\t7-15\n3-67\t2.29\n12.30\tio-53\n3-45\t5-52\n11.60\t\u2014\nII.12\t3.06\n\u2014 0.47\ti. 89\n\u2014 2.08\t3-12\n\u2014 7.86\t\u2014 7.86\n\u2014 3.20\t\u2014\n20.18\t25.92\n9- 39\t\u2014\n6.22\t7.88\n17-39\t18.63\n\u2014 2.22\t0.98\n6.94\t7.40\n\t7.17\nGain.\n1st final.\t2d final.\n12.50%\t7-69%\n\u2014\t13.06\n6.31\t10.52\n\u2014 0.69\t\u20140.69\n4.20\t6.81\n9.00\t12.82\n\u2014 3.06\t3.82\n21.20\t6.89\n7.50\t11.66\n\u2014 1.66\t9.98\n1.42\t10.00\n20.00\t18.88\n2.63\t12.28","page":87},{"file":"p0088.txt","language":"en","ocr_en":"88\tWalter W. Davis,\n39\tIV\tphlegmatic.\t\u2014 5-31\n40\tV\tmot. nerv.\t10.15\n41\tI\tnervous.\t5.21\n42\tII\tmot. phi eg.\t0.78\n43\tIII\tmotor.\t10.68\n44\tIV\tnerv. mot.\t9.82\n45\tV\tmotor.\t15.70\n47\tV\tmotor.\t2.78\n48\tII\tmot. nerv.\ti.61\n49\tIII\tnervous.\t5-21\n5\u00b0\tIV\tphlegmatic.\t3.20\n\tAverage,\t\t6.05\nAverage of ist and 2d finals,\n-2.6s\n26.81\n\u20141.04 9-37 2S-38 12.50 1421 0.24 4.83 6.25\n10.74\n8-39\nmotor or phlegmatic would more often than otherwise possess those secondary characteristics attributed to his type. It is quite probable too, that although the classification was based, primarily on the celerity of movement exhibited by the subject yet it might easily have been affected by the influence, either conscious or unconscious, of the secondary considerations.\nThe results of the experiments of the preceding section were studied in reference to temperament. It only needs to be explained how the individual determination of temperament was made. This was done by the directors of the two gymnasiums. This gave due prominence to the consideration of muscular reaction. It is believed, too, that teachers of gymnastics have a most excellent opportunity to become thoroughly acquainted with a student\u2019s characteristics. The determination of the subjects\u2019 temperaments was made before, not after, the beginning of the experiment.\nTable XIII. presents the subjects, the group in which each practiced, the type of temperament under which each was classed and the percentage of gain in development each made. The gains shown in the table are those made by the hand practiced. In Group V. an average was made of the gains made by the two hands, since both were practiced.\nThe table shows that the men gained 6.94% at the first final, 7-4 at the second final. The women gained 6.05% at the first and 10.74$ at the second. By averaging the gains of the two final tests it is found that the men gained 7.17%, the women, 8.39%. The average de velopment for men and women was 7.78%.\nWe notice a very great individual variation among the subjects. -1 _ largest gain was made by No. 40, who gained 26.81%. This subject 1 of a nervous-motor temperament and practiced both hands lightly Among the men, two subjects, 6 and 20, gained more than 20% > 0","page":88},{"file":"p0089.txt","language":"en","ocr_en":"Researches in cross-education.\n89\nthese are of phlegmatic temperament and practiced vigorously. Among the women, No. 43 gained 25.38%. Her temperament is motor,\npractice light.\nThe men gave six minus results put of a total of 40 ; the women ve y minus results out of a total of 46. If all those minus results secured from practice with the cylindrical stick are cast out, then all the others, with but two exceptions, one for men and one for women, were the results of two methods of practice ; (a) phlegmatic subjects practicing lightly and (b) nervous subjects practicing vigorously. The two exceptions were No. 19, motor, and No. 35, nervous motor, both practicing lightly with both hands. So that if we consider, outside of Group IV., only those subjects who were classed as strictly nervous or phlegmatic, then losses were recorded only for those phlegmatic subjects who practiced lightly and those nervous subjects who practiced\nvigorously.\nAs in Table VII., this new arrangement of results (Table XIII.) shows the effect of fatigue, that decreases in the period of time between the two tests. The fact is more marked among the women than among the men.\nTable XIV.\nTo show conditions favorable to gain in strength.\nSubject.\tGroup.\tPractice.\t\tTemperament.\tFirst final.\tSecond final*\n6\ti\tvigorous.\tphlegmatic.\t26.48 %\t\n7\t11\tlight.\tnervous.\t12.05\t15-06 %\n12\tin\tlight.\tnervous.\t3-45\t5-52\n20\ti\tvigorous.\tphlegmatic.\t20.10\t25.92*\n22\thi\tlight.\tnervous.\t9-39\t\n\t\tAverage,\t\t14.29\ti5-5o\n\t\tAverage for both finals,\t\t\t14.89\n\t\t\tII Women.\t\t\nSubject.\t\t\t\t\tGain.\n\tGroup.\tPractice.\t\tTemperament.\tFirst final.\tSecond final.\n31\ti\tvigorous.\tphlegmatic.\t9.00 %\t12.82 %\n37\th\tlight.\tnervous.\t20.00\t18.88\n49\thi\tlight.\tnervous.\t5.21\t6.25\n\t\tAverage,\t\tII.40\t12.65\n\t\tAverage for both finals,\t\t\t12.02\n\t\tAverage for men\tand women,\t\t13-45","page":89},{"file":"p0090.txt","language":"en","ocr_en":"9\u00b0\nWalter W. Davis,\nTable XIV. was arranged to show the results of training when the -was a combination of conditions favorable to the development of strength Only the records of nervous and phlegmatic subjects are shown ; m0re over the nervous subjects must have practiced lightly and the phlegmatjc ones vigorously.1\nThe results prove very conclusively that the conditions here present were favorable to the development of strength. There were no minus results obtained ; the gains were all fairly large and the averages well above the general averages in Table XIII. The gain per cent, for men was 14.89 fo, more than twice as much as the general average. The ratio in the case of the women is 1 : 1.4. The ratio for men and women between the average gain and the gain made under favorable conditions, as shown in Table XIV. is 1 : 1.7.\nThe results of training will now be noted when there was a combination of conditions tmfavorable to the development of strength. Here are included only those results secured from nervous persons exercising vigorously and phlegmatic persons exercising lightly. Table XV. shows the individual results and the averages.1 Among a total of ten records\nTable XV.\nTo show conditions unfavorable to the development of strength. Men.\nGain.\nSubject.\tGroup.\tPractice.\tTemperament.\tist final.\t2d final.\ni\ti\tvigorous.\tnervous.\t0.48%\t2.88%\n16\tii\tlight.\tphlegmatic.\t\u20140.47\t1.89\n17\thi\tlight.\tphlegmatic.\t\u20142.08\t3-12\n\tAverage,\t\t\t\u20140.69\t2.66\n\tAverage for both finals,\t\t\t\t0.98\n\t\t\tWomen.\t\t\n\t\t\t\t\tGain.\nSubject.\tGroup.\tPractice.\tTemperament.\t1st final.\t2d final.\n32\tI\tvigorous.\tnervous.\t\u20143-\u00b06%\t3-82%\n4i\tI\tvigorous.\tnervous.\t5-21\t\u2014 1.04\n\tAverage,\t\t\t1.07\t1-39\n\tAverage for both finals,\t\t\t\ti-23\nAverage for men and women,\tI*10\nthere were four minus results. The greatest gain is 5.21 % which is ^ than the general average (Table XIII. ). Moreover Table XIV. shows on 1 one gain per cent, that is less than the greatest gain per cent, found 1 Table XV.\t_____-\u25a0\n-----------------------------------------------------------------\u2014r a xv. f\u00b0r\n1 Physically trained men and women were excluded from Tables XIV. ana -reasons shown on pages 92 and 93.","page":90},{"file":"p0091.txt","language":"en","ocr_en":"Researches in cross-education.\n91\nThe average gain under unfavorable conditions for men and women is I0^ The ratio of this gain to the general average gain for men and women (Table XIII.) is 1:7 ; and to the average gain under favorable onditions (Table XIV.) is 1:12. That is, there is a probability that there will be twelve times as much development in a nervous person exercised lightly, than if he exercised vigorously. The reverse may be said of the plegmatic subject.\nIt was noted that if subjects of the motor or phlegmatic type had had considerable previous physical training they required light exercise to secure large gains in development of strength. It seemed as if physical training had modified their temperament in so far at least as the time of their reaction to the specific stimulus of exercise was concerned. Table XVI. presents the fact very clearly. In arranging the tables only motor and phlegmatic types were included and only those subjects that had had a somewhat extensive physical training previous to the beginning of the experiment. Another necessary requirement was light practice during the experiment.\nTable XVI.\n\tTo show the effect of previous physical\t\t\ttraining on\ttemperament.\t\n\t\t\tI. Men.\t\t\t\n\t\t\t\t\tGain.\t\n\t\t\t\tPrevious\t\t\nSubject.\tGroup.\tPractice.\tTemperament.\ttraining.\t1st final.\t2d final.\n3\tIll\tlight.\tphlegmatic.\ttrack.\t8.41%\t10.28%\n5\tV\ttt\tphi eg.-mot.\ttt\t\t7-75\nVA\tIII\ttt\tphlegmatic.\ttt.\t10.20\t4.90\n9\tV\t\t\u201c\tgeneral.\t11.OO\t7-15\nII\tII\t\t\tit\t12.30\t1053\n23\tV\t\tmotor.\ttt\t6.06\t7-03\n24\tII\t< t\tt t\ttrack.\t17-39\t18.63\n\t\tAverage,\t\t\t10.89\t9-75\n\t\tAverage for\tboth finals,\t\t\t10.32\n\t\t\tII. Women.\t\t\t\n\t\t\t\t\tGain.\t\nQ..L-\t\t\t\tPrevious\t\t\n\tGroup.\tPractice.\tTemperament.\ttraining.\t1st final.\t2d final\n27\tII\tlight.\tphlegmatic.\t4 yrs.\t\t39.06%\n43\tIII\ti f\tmotor.\t4 ys.\t10.68%\t25.38\n45\tV\t( t\t<<\t3 yrs.\t15-75\t14.21\n47\tV\tit\t\u00ab\t7 yrs.\t2.88\to-37\n\t\tAverage,\t\t\t9-77\t19-75\n\t\tAverage for\tboth finals,\t\t\t14.76\n\t\tAverage for\tmen and women,\t\t\t12.54","page":91},{"file":"p0092.txt","language":"en","ocr_en":"92\nWalter W. Davis,\nThe final averages are considerably above the general averages (Table\nXIII.); 12.54% as compared with 7. 76%. The gains made by the subjects of Table XVI. become significant when compared with the gain of subjects working under unfavorable conditions (Table XV.), 12.54^ to 1.10%. The fact is illustrated again in Table XVII.\na\nb\nTable XVII.\nEffect of previous training on tei?iperament.\nTemperament.\nphlegmatic.\nphlegmatic.\nPractice.\nlight.\nlight.\nGain.\nPrevious ---------------------------\ntraining. ist final. 2d final,\nconsiderable. 10.48%\t14.36%\nnone.\t\u2014 1.27\t2.50\nAverage.\n12.42%\n0.61\nIn arranging this table only phlegmatic subjects were included and the practice was, in all cases, light. But the subjects in line a. had had considerable previous physical training ; those in line b. had had none. The ratio between the average results, 12.42 and 0.61 is 20:1. That is, those phlegmatic subjects who were physically trained men and women made 20 times as great a development of strength as those who were not so trained, both classes practicing lightly. It is evident, therefore, why those phlegmatic subjects who were trained men and women physically were excluded from Tables XIV. and XV.\nWhat has just been said about the effect of previous training is probably only a specific effect. This effect is analogous to that produced on the neuro-muscular system as the result of training in quickness of simple reaction. A decrease in simple reaction time results only when all those physiological elements which are concerned in converting a stimulus into muscular movement learn to respond more quickly to that stimulus. So exercise must be considered a stimulus to development since it accelerates the activity of those organs whose activity is necessary to the building up of muscular and nervous tissue. If a phlegmatic subject has had a motor training his physical system has gained the power or habit of reacting more quickly to the stimulation of light exercise and rapid growth follows more rapidly than could otherwise have happened.\nTable XVIII. was arranged for the purpose of a summary and comparison of the facts brought out in this section. A embraces all subjects of whatever temperament or whatever their method of practice. The gains per cent, are general averages. B includes all the nervous subjects who practiced lightly, or the phlegmatic ones (except those affected by previous training) who practiced vigorously. Such conditions are favorable to development and a large percentage of gain was recorded for this class. In C the","page":92},{"file":"p0093.txt","language":"en","ocr_en":"Researches in cross-education.\n93\nsubjects practiced under unfavorable conditions, just the reverse of B, and the percentage of gain was small. In D are those motor and phlegmatic subjects who had had considerable previous physical training, and who, by virtue of this, made large gains in strength by light practice.\nTable XVIII.\nComparison of the effect of different conditions on the results of practice. Men and Women.\nGain.\nSubjects.\tConditions.\tTemperament.\tPractice.\tMen.\tWomen.\tAverage.\nA.\tall\tall\tall\t7-17 fo\t8-39%\t7-7 8%\nB.\tj Favorable to j\tf Nervous\t\t\t14.89\t12.02\t13-45\n\ti\tgain.\t1\tf Phlegmatic\t\t\t\t\t\nC.\tj Unfavorable to 1\tgain.\t( Nervous\t f Phlegmatic\t\t\tLight /\t0.98\t1.23\tI.IO\nD.\tj Effect of previ-\\ ous training.\tf Phlegmatic\t ^ Motor\t\t\tLight \\ \tLight]\t10 32\t14.76\t12.54\nA fact worthy of relation was noted in the case of No. 47 ; inasmuch as the result of her practice seemed to be an exception to the general principles discovered. No. 47 was classed as of motor temperament and practiced lightly with both hands. Moreover, she has had seven years of gymnastic training. Judging from the principles enumerated conditions seemed favorable to the development of strength. But the gain was slight (see Table XIX.).\nTo determine whether development could be secured by a different method of practice, two months after the completion of her final test exercise with the dynamometer was again begun. At this second period of practice, work was made much heavier, since we had concluded that a mistake had been made in classifying the subject at the first test. Work was now made suitable for the development of a phlegmatic rather than a motor person. The results of this practice were strikingly different\nTable XIX.\nEffect of different methods of practice on one individual\u2019s results.\nGain.\nSubject. Temperament. Practice. 1st final.\t2d final. Average.\n47\t?\tLight.\t2.78%\t0.24%\t1.51%\n47\t?\tVigorous. 12.04\t6.85\t9.42\nfrom the first ones. The results of both methods of practice are shown In Table XIX. The vigorous practice effected much the greater de-velopment. This substantiated our second classification of the subject as phlegmatic.","page":93},{"file":"p0094.txt","language":"en","ocr_en":"94\nWalter W. Davis,\nThe subject\u2019s phlegmatic tendency is shown, too, when a com made of the gains at the first and second finals. She did much h \u00b0 '* the first final than at the second whether the practice was r v ** vigorous. That is, there was no visible effect of fatigue present * either case. This indicates a large reserve of potential energy which1'11 a characteristic of the phlegmatic type of temperament. There is ** doubtedly for every individual a method of practice that is best suited to his peculiar characteristics. This method differs in intensity or amount from that which is best suited to any other individual. That amount of exercise must be given that will be just sufficient to stimulate physiological processes of growth but always stops short of the fatigue point.\nThere can be no precise division of individuals into classes. While we have classified all persons under one of the three types of temperament yet it must not be supposed that these three types are separated from each other by distinct lines of demarkation ; or that all persons belong absolutely to one type. The types merge into one another; a certain individual may be on the border line between two types. It was in accordance with this idea of temperament that our classification was discussed as it was. The motor temperament is only an average between the other two, simply a collection of the medium colors in the shading from the deepest phlegmatic to the faintest nervous type.\nNo attempt will be made at this time to explain completely those facts that we have demonstrated to be true in the first pages of this section. The field is a new one and too little work of an experimental nature has been done to merit any well-founded conclusions. We are warranted, however, in stating hypothetically those conclusions that seem to be supported by facts brought out by our experiments.\nWe have considered exercise as a stimulus to growth. The repeatedly contracted muscle increases in size. So must any other part of the neuro-muscular system be exercised to develop into its perfection function. By the use of any part of the body more blood is <^raWD. . that part ; worn-out material accumulates and is more rapidly ca away ; and new material is laid down faster than would otherwise hapf*-^ The metabolism is enforced. Now, if exercise is too light, the v functions are not sufficiently stimulated to work the desired change-^^ the work is too violent or too long continued the tearing down than counteracts the building up process and development of used is impossible. If the work is just right in intensity anu aI\u00ae^ ^ the anabolism provoked is greater than the katabolism and there velopment of the parts used.","page":94},{"file":"p0095.txt","language":"en","ocr_en":"Researches in cross-education.\n95\n-, of these facts makes plain what an almost endless variation A re!vlns would be necessary to make the adjustments of exercise\nj condi\u00bb011\nStable to all individuals.\nExercise must be prescribed per order just as\n\u00ebrsons may be classed into the three types of temperament in refer-A to the time of their muscular reaction to outside stimuli. Nervous lDs are nervous in\nfols from the three types, the stimulus must be varied from very strong ^ very weak. So, considering exercise as a stimulus to the activity of the vital functions, it seems hardly necessary to state the further and es-lential analogy that while a little exercise is sufficient to bring about thee changes in some persons, in others it requires a great deal. The nervous man\u2019s heart action will be accelerated to a very appreciable degree when he rises from a lying to a standing posture. An equal effect may be wrought on a phlegmatic person only after considerable work. The immediate effects of exercise may then be classed with all responses of the physical body to direct stimulation.\nWhy some persons should voluntarily or involuntarily react more quickly than others to a given stimulus, probably depends on what we may term the balance of those factors making up the neuro-muscular system. The differing effects of fatigue visible in different persons either after a daily practice, or after a long practice period point to the importance of two or three factors, whose presence in varying amounts or intensity determines the type of reaction or temperament.\nOther factors being equal the smaller muscle will react more quickly the larger one, because it can be stimulated more easily by a motor jmpulse of definite intensity. On the other hand, the large muscle con-t*lns more reserve material, and for this reason and because this reserve is more slowly used up, the larger muscle is more enduring.\nWe can apply the same principles to the motor cells of the brain. J* larger they are and the more potential energy they contain the more wly is this potential energy converted into the kinetic energy of the ^ous impulse, and, by virtue of this very reason, the more enduring\n* weir strength.\n\u00a7reater the volitional strength, the quicker and the more Wiighly can t^le motor impulse be generated from energy present in\n\u201ce brain cells.\njesery6 nervous objects seem then to be characterized by lack of much ftor 6 ener^y e>ther in muscle or nerve cell, but they are able to more \u00b0 y utilize the energy at hand. Phlegmatic subjects are slow be-\nmust be fitted to the individual.\ncnee\nthe sense of our consideration because they react\n**erSOn\u201d \u25a0 -, the stimuli of their environment. To get equally quick reac-","page":95},{"file":"p0096.txt","language":"en","ocr_en":"96\nWalter W. Davis,\ncause they have much reserve energy but cannot utilize it quickly. jn the typical motor subject the several factors are evenly and nicely balanced. More precise and carefully adjusted action should be expected of this type of persons.\nToo little experimental work has been done to merit any pronounced or well founded conclusions about the relations of temperament and training. Observation of the results of our own experiments in this direction seems to point to the truth of the following :\n(a) Nervous persons, in training for the development of strength, require light practice.\n(\u00e0) Phlegmatic persons require vigorous practice.\n(c)\tMotor persons are an average between these two.\n(d)\tPrevious physical training works such a change in the phlegmatic person that thereafter he requires less vigorous work to secure large gains in development of strength.\n(e)\tIt is probably true that the phlegmatic type of temperament is characterized by the presence of much reserve energy of muscle and nerve cell. The nervous type has less reserve energy but a greater ability to use the energy at hand.\nIt is not difficult to apply the principles stated above to practical physical training. They make necessary on the part of the trainer a personal knowledge, secured either by means of observation or experiment of the temperament of each man under his charge. The amount of work necessary in each case can than be apportioned with much greater exactness.\nIt seems quite as certain that there may also be a direct application of these principles in the realm of pedagogy. Our experiments show that, in the development of strength, mental factors are more necessary than muscular factors. In fact our conclusions relate as much to one set as to the other. If we can apply the principles to the development of will power and coordination why not to memory, association, imagination and reasoning as well. All have a physiological basis and in so far all are governed, in a given individual, by the same principles of growth.\nThere is at least a wide field here for inquiry and practical investigation. Our present system of secondary and collegiate instruction requires an equal amount of work from all pupils. All must measure up to a common standard. There can be no doubt that such a system results in much harm to many individuals.\nThe results of this section emphasize the importance of recognizing the individual in the training of either physical or mental ability.","page":96},{"file":"p0097.txt","language":"en","ocr_en":"Researches in cross-education.\n97\nIII. Experiments with the ergograph.\nThe ergograph used was similar in construction to Mosso\u2019s.1 The weight raised was 2 y2 kilos. It was lifted by the middle finger, the first and third fingers being encased in stationary brass tubes lined with felt. This arrangement enforced a simple movement of the finger used. The record was made on a recording drum in the usual way.\nFig. i.\nThe curves shown in Figs. 1 to 7 are records or the ability of Subject X. He was 26 years of age, well trained physically and of the motor temperament. The initial record for the left hand is shown in Fig. 1, the total distance through which the weight was raised being 1341\t; the inital\nFig. 2.\nrec\u00b0rd for the right hand is shown in Fig. 2, the total distance being 1316\n1 Mosso, Ueber die Gesetzt der Erm\u00fcdung, Arch. f. Anat. u. Physiol., Physiol. Ab*., 1890, 89.","page":97},{"file":"p0098.txt","language":"en","ocr_en":"93\nWalter W. Davis,\nThese records were made on March i, 1899. Every day thereafter for three weeks, with only two exceptions, the left hand was practiced' This practice consisted in completely fatiguing the hand once each dav by pulling at the ergograph. A record of each day\u2019s work was preserved\nFig. 3.\non smoked paper. On March 23d final records were secured for both hands. These records are shown in Figs. 3 and 4. The record for the left hand after three weeks of vigorous practice shows (Fig. 3) a total distance of 1488 mm the gain over the initial record for the left hand being\nFig. 4.\nii cf0. The record for the right hand after three weeks 01 vigorous p ^ tice of the left shows (Fig. 4) a total distance of 1492 mm, the gain the initial record for the right hand being 13%.","page":98},{"file":"p0099.txt","language":"en","ocr_en":"Researches in cross-education.\n99\nThe results secured from this practice were not satisfactory. It seemed \u2022hat larger gains in development of strength should have been secured. Therefore on April 1, after a rest of one week, practice was again begun l)Ut was made light instead of fatiguing. This practice was continued\nFig. 5.\nfor seven weeks, the left middle finger alone being exercised as before. Then two final records were taken. These are shown in Tigs. 5 and 6.\nThe record of left hand (Fig. 5) five weeks after that in Fig. 3 shows a total distance of 175 7mm, the gain over that shown in Fig. 3 being\n18% \u25a0\nFig. 6.\nhe record of right hand (Fig. 6) five weeks after that in Fig. 4 shows 1541\u2019\"\u201c, the gain over that in Fig. 4 being 3%. tice Percentages of gain both from the heavy and from the light prac-are shown in Table XX. The short time of vigorous practice\na total distance of The","page":99},{"file":"p0100.txt","language":"en","ocr_en":"IOO\nWalter W. Davis,\nbrought about results in development similar to the average results from the practice with the dynamometer. The effect of fatigue ^se^\nTable XX.\nThe development secured from practice with the ergograph.\nLeft hand. Right hand.\n\u00a3 \u2022-<U TJ\ncn in X cj\nP \u00a3 1341 1316\n\u2022E \u00ab > <\nI s s\no\nI488\n1492\n6 2\n.b\u00a3\nO\n5 P\ncs ifl\nflsi\n\u00a7 s\ns c is S\n11\n13\n1757\n1541\ne\n<0\nN\n0 s\nO\u00ab\n\u2022a\nu\n\u00ab8 % 3%\nin the greater gain of the right hand which was not practiced.\nA marked difference is seen between the results secured from the two periods of practice. The right hand made very little gain from the \u2022 second period. It is not certain however that this difference resulted from the difference in the methods of practice. It is extremely probable, rather, that the subject had reached a point in his development when the effects of practice were not transferred in any marked degree to the unused side of the body. Let us examine the method of practice and results of this subject with this idea in view.\nIn his daily practice his left hand was required to do nearly as much work as in the first practice but the work was done between intervals of rest. For example on April 11, the left finger made 35 full contractions but made them in three periods with two short rests between the periods.\nThe final records of Subject X. shows that the left hand had gained 18 \u00b0/o over its record made at the end of the first practice ; the right, only 3 %. This fact, if it is considered in connection with all the other facts noted in the previous sections, can be explained in only one way. The left hand, after over 8 weeks of light and heavy work, was at the end of that time getting all of the benefits of exercise. The ng^ was getting none. This fact proves that the unused side does not ways get a share in the benefits of exercise. One side, by long ^ ^ tinued practice, may become over-developed while the strength 0 symmetrical muscles on the other side may even be diminished.\npossible that the failure of some of the subjects to make a gain in\nThis principe\nnletely-\nmometric strength may be explained in the same way.\nwould be an interesting one to investigate thoroughly and comp At present we can assert only hypothetically that long contin cise of one member causes its development out of all proportion of the symmetrical member on the other side of the body-","page":100},{"file":"p0101.txt","language":"en","ocr_en":"Researches in cross-education.\nioi\nFig.","page":101},{"file":"p0102.txt","language":"en","ocr_en":"102\nWalter W. Davis,\nThe curves shown in Figs. 7 and 8 illustrate a fact noted in the curves of all of the subjects : that the right and left hand curves of any individual are very similar in form. Subject J. was left-handed. Both curves exhibited the same general form of outline. Both are rather irregular, growing more regular toward the last. In both, the first contractions are short, then there is an increase for several contractions and finally a gradual decrease.\nIn the same connection should be examined the curves shown in Figs. 2 and 9. Both are records of Subject X. ; Fig. 2, the right initial, Fig. 9, the third practice of the left hand. The outlines of the two curves are almost precisely the same. These observations indicate the paramount importance of the central influences affecting the strength of muscular contractions.\nSubject X. was able to completely exhaust his store of energy. Subject J. did not have this ability. The fact is shown in the abrupt endings of his curves. The curves in Fig. 7 and 8 end more gradually. Tem-\nFig. 9.\nperament and training both have an influence here. X. is motor in temperament and has had an excellent training in athletic sports. J-is phlegmatic and has had very little physical training. We have already said that a characteristic of the phlegmatic temperament was the lack of ability to command the use of the energy stored in muscle and nerve cells. It is equally as certain that a training in athletics increases this ability. J.\u2019s curve for the left hand (Fig. 7) was cut short for want of space. With the contractions as short as the last ones the work mighf have been kept up almost indefinitely. Still J. said that he was exerting his power of contraction to the utmost. He did not have the ability to tire himself out. An athlete of the motor temperament has this ability par excellence.","page":102},{"file":"p0103.txt","language":"en","ocr_en":"Researches in cross-education.\n103\nThere is a noticeable increase in the regularity of the fatigue curves of Subject X. from the beginning of the practice until the last record. Compare Figs. 1 and 5, both of the left hand. Curve 5, however, was taken after a long practice. The increase in regularity is marked. We may thus conclude that practice perfects muscular control.\nOur observations from the study of ergograph curves may be summed up as follows :\n(a) Long continued practice of one side of the body may develop that side in much greater degree than the unused side is developed. If continued long enough such practice may even detract from the strength of the side not used.\n('b) The similarity of right and left hand curves proves and illustrates the paramount importance of the influence of the central nervous system on muscular contraction.\n(c)\tThe long drawn out fatigue curve is caused by the inability of the subject to command the instant use of his nervous energy. Herein lies a chief difference between the phlegmatic and motor or nervous temperaments. It exhibits a difference too between physically trained and untrained men.\n(d)\tPractice improves regularity of muscular contractions. This improvement is due, presumably, to better coordination of mind and muscle.\nIV. General Considerations.\nThe meaning and scope of cross-education were stated in my first series of researches.1 The conclusions drawn there will need modification in the light of recent investigation, although it may be said in general that their essential features are more firmly established than before. The main conclusions were :\n\u201c(a) The effects of exercise may be transferred to a greater or lesser degree from the parts practiced to other parts of the body. This transference is greatest to symmetrical and closely related parts.\n\u201c(b) There is a close connection between different parts of the body through nervous means. This connection is closer between parts related in function or position.\n\u201c(c) Will power and attention are educated by physical training. When developed by any special act they are developed for all acts. \u2019 \u2019\nIt seems necessary in the consideration at hand to determine precisely where fatigue first appears, whether in the central or peripheral organs. Most observers contend that fatigue, when it is considered as inability to do further work, is due essentially to losses in the central\n1 Davis, Researches in cross-education, Stud. Yale Psych. Lab., 1889 VI 16.","page":103},{"file":"p0104.txt","language":"en","ocr_en":"104\nWalter W. Davis,\nnervous system. Hodge1 2 has shown by experiment that the normal fatigue of the day is associated with loss of substances in the central ganglion cells. Waller 2 asserts that the central part of the neuro-mus-cular mechanism tires first, and hence a protection is afforded to the muscles and end organs. The investigations of Lombard,3 Mosso,4 and Fechner5 all point in the same direction. The facts of cross-education are explained much more easily on such an hypothesis.\nIn 1894, Koch6 reaffirmed the statements of Mosso and Lombard, that, in general, central fatigue sets in earlier than muscular fatigue. He also states that, after fatigue, the nervous matter regains its normal function more quickly than the muscles. He studied the effect on the ergographic curve of drinking water and of the injection of cocaine and caffeine. He found that changes in the ergographic curve were caused much more readily by central than by peripheral factors. Nevertheless several peculiarities in the caffeine curve, its gradual increase and in general the entire curve points perhaps to a direct effect on the muscle itself.\nJoteyko, 7 by an investigation in which the ergograph and the dynamometer are used alternately, has reached conclusions that bear directly on \u2018 \u2018 transference \u2019 \u2019 ; and also indirectly since they are an addition to our knowledge of the relations of central and peripheral fatigue. Her method of experiment was : (1) to secure records on the dynamometer for both right and left hands ; (2) immediately thereafter,\n\u25a0Hodge, Some effects of stimulating ganglion cells, Amer. Jour. Psych., 1888 I 479-\nHodge, Some effects of electrically stimulating ganglion\tAmer. Jour. Psych.,\n1890 II 37b.\nHodge, The process oj recovery from the fatigue occasioned by the electrical stimulation of cells of the spinal ganglia, Amer. Jour. Psych., 1890 III 530.\n2\tWaller, The sense of effort, Brain, 1891 XIV 218.\n3\tLombard, The effect of fatigue on voluntary muscular contractions, Amer. Jour, Psych., 1890 III 24.\nLombard, Some of the influences which affect the power of voluntary muscular contractions, Jour. Physiol., 1892 XIII 1.\nLombard, Alterations in the strength, which occur during fatiguing voluntary muscular work, Jour. Physiol , 1893 XIV 97\n\u25a0 Mo,so, (Jeher die Gesetze der Erm\u00fcdung, Arch. f. Anat. u. Physiol., Physiol. Abth., 1890 89.\n5 Fechner, lieber den Gang der Muskeliibung, Ber. d. k. s\u00e4ch. Ges. d. Wis., math.-phys. Klasse, 1857 IX 113.\n6 Koch, Ergographische Sudien, Marburg 1894.\n\u2019Joteyko, II Effort nerveux et la fatigue, Arch. ital. de Biol., 1899 XVI.\nJoteyko, Rech. expie, sur la fatigue des centres nerveux par V excitation \u00e9lectrique, Soc. de Biol, de Paris, 1899 834.\nJoteyko, Rech. expir, sur la fatigue des organes terminaux, Soc. de Biol. Paris. 1899 386.","page":104},{"file":"p0105.txt","language":"en","ocr_en":"Researches in cross-education.\t105\nto fatigue the right hand by exercise with the ergograph and then (3) finally to again secure records of dynamometric pressure for the right and left hands. She found that the work done by the right hand with the ergograph decreased the dynamometric pressure on the left hand. This decrease was about 20%. She concludes that the decrease in power in the unused hand was caused by the loss of energy in the cerebral centers. Under ordinary conditions however it was found that when the work was not pushed to the limit of endurance, peripheral fatigue appeared first and apparently, therefore, prevented central fatigue. It was only when by an effort of- the will the subjects prolonged the physical work in spite of the feeling of weariness in the muscles, that the motor excitation of the muscles increased the fatigue of the nerve cells rather than that of the muscles themselves.\nIn connection with Joteyko\u2019s article it is necessary to distinguish between the fact of fatigue and the feeling of fatigue. They have been considered as something entirely distinct and separate. Sensations of fatigue are very deceptive, and should be no criterion for the estimation of the fact of either mental or bodily fatigue. Fatigue1 is defined as the decrease in the capacity for work ; fatigue in this sense may or may not have definite relations to the peculiar sensation known as the \u201c feeling of fatigue.\u201d This is probably true whether said of mental or of physical work. \u2018 \u2018 The 2current ideas about the fact and the feeling of mental fatigue, and the relation between them, are na\u00efve abstractions based on a simple minded analogy, a failure to carefully analyze certain mental states, and a confusion in the case of experimental investigations between lack of desire and lack of ability to work.\u201d There is always danger, too, of mistaking the location of fatigue. While it might seem that the conditions causing the feeling of fatigue from muscular work arise in the muscles themselves, yet it is probable that those very conditions are the result of changes taking place in the brain.\nWoodworth3 carried out some experiments with various forms of the graphic method, movements being made at any desired speed or interval. Some of his conclusions bear directly on \u201ctransference.\u201d \u201cPractice of the left hand helped the right also. Before the series with the left hand began, and again after it was completed, a single experiment was made with the right hand. The right hand showed a decided improvement at the rate for which the left had improved but no appreciable improvement at the rates for which the left had not improved.\n1\tScripture, The New Pschology, 247, London 1897.\n2\tThorndike, Mental Fatigue, Psych. Rev., 1900 VII 482.\n3\tWoodworth, The accuracy of voluntary movement, Psych. Rev. (Monograph Supplements), 1899 III 105-106.","page":105},{"file":"p0106.txt","language":"en","ocr_en":"io6\nWalter W. Davis,\nThese results show (i) that the transferences of the effects of practice from one side of the body to the other\u2014a transference which has been established in other investigations as taking place from the right side to the left\u2014also takes place from the left side to the right1; and (2) that it is not the mere practice that has this transferred effect but only successful practice. \u201d If at any particular speed the left did not gain then the right did not. \u201cWhen the left hand does gain the right shows the benefits in almost equal measure. \u2019 \u2019\nThe fact noticed by Woodworth that the effects of practice were transferred only when such practice was successful, may probably be stated as a general truth. Individual cases however may show an increase in the ability of the unpracticed side even though the practiced side makes no gain whatever. \u2019 \u2019 This fact was especially marked in the case of Subject E. in the tapping test.2 3 There was a loss in the right foot (practiced) of 4(Jo and a gain of 38% in the left foot (not practiced).\nThe experiments of Wissler and Richardson 3 show to how great an extent motor impulses to action may spread into muscles that are related to the one directly concerned with a certain movement. The subject\u2019s hand was put into a light clamping apparatus and tambours placed on the abductor indices, the forearm and the biceps, so that any contraction made by any one of the muscles could be recorded on the kymograph. The object was to determine whether as a result of the primary contractions of the abductor indices, there was any secondary contractions of the muscles of the arm. It was found that there was such a secondary contraction, showing that there was an overflow or diffusion of the motor impulse into adjacent muscles.\nIt was found also that by the training of the left biceps in strength, definite gains in strength were made by the left abductor, right abductor, left forearm, etc. \u201cIt seems certain that the exercise of any muscle reacts upon all related muscles, which is to say that diffusion takes place in both inward and outward directions. \u2019 \u2019 4\nThe following hypotheses are then put forward :\n(a) That the exercise of an accessory muscle has a greater reactionary effect upon the adjacent fundamental muscles than upon the more remote.\n1\tThis fact was proven, independently of Woodworth\u2019s work, by an investigation with the ergograph which I carried on during March and April, 1899. The results were not published then but appear in this paper now for the first time. (See Section III, p. 97 and also p. 100.)\n2\tDavis, Researches in cross-eduction, Stud. Yale Psych. Lab., 1889 VI II-\n3\tWissler and Richardson, Diffusion of the motor impulse, Psych. Rev., 1900 VII 29.\n4\tSame, p. 35","page":106},{"file":"p0107.txt","language":"en","ocr_en":"Researches in cross-education.\n107\n(b') That an accessory muscle of one arm gains as much from the training of the corresponding muscle of the opposite side as from the training of the fundamental muscle of the same side. In terms of motor discharge this indicates that these centers occupy the same diffusion level.\n(c) That the reactionary or secondary gain of the fundamental muscles from the exercise of the accessory arm muscles is less than when the conditions are reversed\u2014i. e., the fundamental muscles practiced and the accessory muscles reacted upon. This is in harmony with the accepted order of motor development.\nThe theory of the spreading of impulses so clearly proven by Wissler and Richardson had been stated before by Exner1 and Urbant-schitsch.2 Damsch3 explained this diffusion as due to the close connection of all motor centers. Fibers from all motor centers come together and are intimately connected in a central ganglion of the brain. The diffusion of an impulse is hindered by an inhibiting apparatus which prevents it from going the wrong way. \u201cThis apparatus is much improved by practice. In the young and in certain nervously disordered persons it is deficient.\u201d\n\u201cIt was noticed in the tapping experiment that there was a tendency for the subject\u2019s left foot to make movements to accompany those made by the right. In learning an act that involves fine coordination it is very obvious that the pupil executes many movements that are entirely unnecessary. \u2019 \u2019 4 Nearly all the subjects in the experiment with the dynamometer5 would unconsciously clench the empty hand as well as the one in which the dynamometer was placed.\nThe consideration of the above facts would seem at first glance to explain \u201ctransference\u201d as due to the unconscious indirect exercise of those motor centers, nerves and muscles that are not necessary to the movement that is being performed. It is true that the unused symmetrical or closely related muscles may grow in size as a result of another muscle\u2019s exercise. This was shown quite definitely in my first research. But there is a question whether this new substance that has been added to the muscle is a factor in the increased strength, rapidity or endurance\n1 Exner, Zur Kentniss von der Wechselwirkung der Erregungen im Centralnervensystem, Arch. f. d. ges. Physiol (Pfl\u00fcger), 1882 XXVIII 487.\n1 Urbantschitsch, \u00dceber den Einfluss von Trigeminus-Reizen auf die Sinnesempfindungen, insbesondere auf den Gesichtssinn, Archiv, f. d. ges. Physiol. (Pfl\u00fcger), 1883 XXX 129.\n3\tDamsch, Ueber Mitbewegungen in symmet. Muskeln an nicht-gel\u00e4hmten Gliedern, Zt. f. klin. Med., 1891 XIX 170.\n4\tDavis, as before, p. 49.\n5\tDavis, as before, p. 24.","page":107},{"file":"p0108.txt","language":"en","ocr_en":"io8\nWalter VP. Davis.\nof the unused muscle. The facts observed there1 2 seem to point to the conclusion that the substance added to the unused muscles is not a factor in the increased endurance, and, in so far as so few observations can, seem to eliminate the muscular factors altogether from the question of the causes of cross-education.\nScripture 2 in a recent article has stated the three facts of cross-education as follows :\n1.\t\u201c The principle of cross-education has been proved beyond question.\u201d\n2.\t\u201cThe gain by practice consists in a development of higher nerve centers connected with the two sides of the body. \u2019 \u2019\n3.\t\u201cThe effects of practice are extended to different parts of the body.\u201d\nFinally he believes that \u201c sooner or later we shall be able to establish the fact that development of those forms of the will involved in simple muscular activities does also develop the more complicated forms that express themselves in acts of a mental nature. \u2019 \u2019\n1\tDavis, as before, p. 23.\n2\tScripture, Cross-education, Popular Science Monthly, 1900 LVI 589.","page":108}],"identifier":"lit28757","issued":"1900","language":"en","pages":"64-108","startpages":"64","title":"Researches in cross-education (second series)","type":"Journal Article","volume":"8"},"revision":0,"updated":"2022-01-31T13:30:07.349077+00:00"}