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{"created":"2022-01-31T12:38:55.029348+00:00","id":"lit25269","links":{},"metadata":{"alternative":"Studies from the Yale Psychological Laboratory","contributors":[{"name":"Scripture, Edward W.","role":"author"}],"detailsRefDisplay":"Studies from the Yale Psychological Laboratory 4: 12-26","fulltext":[{"file":"p0012.txt","language":"en","ocr_en":"RESEARCHES ON REACTION-TIME.\nBY\nE. W. Scripture.\nFrom time to time various problems present themselves in connection with the study of the time of mental processes. It has been my custom to assign some of these problems to special students. The work is done under my personal direction, and, almost without exception, I serve as the subject or the experimenter.\nInfluence of a constant electric current through the head.\n(John L. Burnham.)\nThe city supply (no volts, direct) was used as the source of current. One wire was led to the binding post of a graphite resistance which regulated the amount of current. This graphite regulator comprised a plate of ground glass sliding in a grooved frame. Lines of different thickness were drawn with a lead pencil on the glass. By moving the glass any one of these lines could be placed under the springs connected with the two binding posts, whereby a resistance of any desired amount could be introduced into the circuit.\nThe current was made to pass through an Edelmann milliamp\u00e8re-meter indicating directly the quantity of current used. The poles were two sponge electrodes., A commutator permitted the change in direction of the current and a liquid resistance rendered it possible to gradually apply or remove the current without shock, and without the knowledge of the subject.\nIn all the experiments where electricity was used, the records were so divided that the experiments without electricity (with the electrodes still in place but no current on) were interposed between two sets of the records of electricity, or else the start and finish would be made without electricity while the current was used for the middle records. Thus any lingering effect of the stimulus or any mental disturbance from the electrodes was neutralized. These experiments were conducted during the month of February, 1896.\nThe tests for the effect of the current were : simple reaction-time and complex reaction-time. The shutter of the pendulum chronoscope ex-\n12","page":12},{"file":"p0013.txt","language":"en","ocr_en":"Researches on reaction-time.\n\u00ab3\nposed a colored disc and the subjected reacted by pressure on the knob at the back of the instrument1. For complex reaction-time one of two colors was exposed, the subject, being required to react to one and not to the other.\n\t\t\t\t\tTable I.\t\t\t\t\t\t\t\n0\tF\tvia\t5\td\t\u25a0Se\td\tn\tc\td\ta\td\tn\nS. head\tI\t1.0\t143\t11\t\u00ab43\t\u00ab5\t7\t\t\t\t\t\nit\tll\t3\t1.0\t146\t\u00ab5\t\u00ab37\t7\t7\t\t\t\t\t\n((\tit\t3\t\u2022 1.6\t\t\t\t\t\t281\t49\t274\t45\t10\nil\t((\t3\t4.0\t\t\t\t\t\t\t\t239\t28\t8\nn i* a.,\ti\t1.0\t194\t52\t\u00abS3\t34\t10\t\t\t\t\t\na a\t3\t1.0\t143\t23\t\u00ab35\t9\t7\t\t\t\t\t\na a\tS\t0.2\t143\t\u00ab5\t129\t6\t10'\t312\t56\t270\t60\t. 5\na a\t13\t1.8\t\u00ab43\t18\t129\t\u00ab5\t10\t260\t9\t256\t25\t5\na a\t15\to-3\t127\t\u00ab9\t121\t10\t10\t\t\t\t\t\nSm., \u201c\t5\t0.2\t132\t12\t121\t18\t10\t\t\t\t\t\nT.,\t\u201c\t2\to-3\t140\t8\t140\t9\t10\t\t\t\t\t\nit\tit\t12\ti-3\t186\t23\t161\t21\t10\t320\t34\t235\t4\u00ab\t5\na a\t13\t1.0\t149\t10\t\u00ab39\t\u00ab4\t10\t287\t29\t304\t53\t5\nD. \u00bb\ti\t0.5\t136\t29\t\u00ab57\t23\t5\t264\t66\t272\t60\t5\nit\tti\t5\t1.2\t136\t11\t128\tII\t5\t290\t36\t249\t54\t5\nit\tit\tS\t7.0\t142\t10\t117\ts\t5\t279\t\u00ab9\t275\t27\t5\nil\til\t12\to-3\t\u00ab44\t27\t\u00ab5\u00b0\t\u00ab4\t5\t330\t54\t323\t36\t5\nUnit, thousandth of a second.\t\t\t\t\t\tC, complex\t\treaction-time without\t\t\t\telec-\nO, subject of experiment.\nF, date in February, 1896. ma, milliamp\u00e8res.\nS, simple reaction-time without electricity.\nSe, simple reaction-time with electricity.\ntricity.\nCt, complex reaction-time with electricity.\nit, mean variation.\nn, number of experiments in each set.\nA glance at the above table will show an almost universal quickening of both the simple and complex times under the stimulus of the electric current. A general quantitative statement of the amount is not possible, owing to variations in the conditions of different experiments.\nIt will be noticed that in the table there are some negative results with the moderate currents. Again, the effect of the electric current varies greatly on different people and seems also to affect the same person to different degrees at different times. For example, subject D., who took 7 milliamp\u00e8res on February 5, with no hesitation, felt that he was being\n1 ScRirTURE, Some new apparatus, Stud. Yale Psych. Lab., 1895 III 98.","page":13},{"file":"p0014.txt","language":"en","ocr_en":"14\nE. IV. Scripture,\nhurt with less than half that amount a week later and was willing to perform the experiment with only 0.3 of one milliamp\u00e8re.\nHowever, in viewing all the results, the few conflicting records are lost sight of and the conclusion seems to be clearly indicated that the electric current shortens both the simple reaction-time and the complex time. Beyond this, by the introspective testimony of several of the subjects, there was a decided feeling of refreshment after the application of the electric current, the person feeling better at the close than at the beginning of the experiment. In only one case, where a high current of 9 milliamp\u00e8res was used (no reliable records could be taken), vertigo, double vision and the peculiar metallic taste were noticed by the subject.\nFrom these experiments we might perhaps conclude that the brain was directly stimulated and quickened in its processes. Nevertheless, in consideration of the unusual character of the case, we prefer at the present time not to go beyond the statement that for some unknown cause the reactions were quicker with the electrical current than without it.\nInfluence of fatigue.\nThe term \u201c fatigue\u201d is used in different senses. It may mean the condition of body and mind resulting from the presence of certain toxic products in the blood. This kind of fatigue may arise from the activity of the organism itself in mental or bodily work, or it may arise by the transfusion of blood from an already fatigued organism.1\nFatigue is also used to mean a direct deterioration in the functional activity of the whole organism or of some part of it. When the just perceptible difference is being repeatedly measured in succession under the most favorable circumstances, its size may change with the progress of the series of records. A change toward a decreased difference, or finer sensibility, is called \u201cachange due to practice a change toward an increased difference, or lesser sensibility, is called \u201ca change due to fatigue.\u201d\nLikewise a lengthening of tfie tap-time or reaction-time in a steadily repeated series\u2014all other conditions remaining the same\u2014would be called \u201ca change due to fatigue.\u201d It would seem better to name it directly the \u201cfatigue in tap-time, in reaction-time, etc.,\u201d because such expressions as \u201cdue to fatigue,\u201d \u201cdue to practice,\u201d etc., convey the impression of an explanation where none is present.\n\u201c Fatigue \u201d is also used to indicate a complexity of sensations usually but not necessarily connected with toxic or functional fatigue.\n1 Mosso, lieber die Gesetze der Ertniidung, Arch. f. Physiol. (Du Bois-Rcymond), 1890, 89.","page":14},{"file":"p0015.txt","language":"en","ocr_en":"Researches on reaction-time.\n15\nThere are thus three different phenomena denoted by the term \u201cfatigue:\u201d (1) a chemical change in the constitution of parts of the organism ; (2) a diminution in functional activity ; (3) a group of sensations. These three are usually connected. Thus the connection of the amount of work done (and the consequently available energy for further work) with the change in the nerve cells has been demonstrated by Hodge.1 The connection between the amount of work done and the sensation of fatigue is familiar to every one. The connection between the sensation of fatigue and the actual exhaustion of the organism is not always maintained ; thus, neurasthenia is treated by Cowles2 as an exhausted condition of the nervous system accompanied by an\u00e6sthesia for fatigue.\nIn the following investigations on reaction-time no regard is paid to the sensation of fatigue ; the problems are : ( 1 ) What are the characteristics of special fatigue in reaction-time? (2) Are these characteristics observable also in cases of general fatigue ?\nSpecial fatigue in reaction-time.\n(A. E. von Tobel. )\nIn several different measurements closely related to those of reactiontime, e. g., tap-time3, accommodation-time4, fatigue has been observed. This fatigue may be a fatigue in length whereby the average time becomes longer, or it may be a fatigue in regularity whereby the mean variation becomes larger. The two kinds of fatigue do not follow the same course ; in the experiments of both Bliss and Moore the average time of tapping is lengthened long before any noteworthy change appears in the mean variation.\nIn the usual experiments on reaction-time an interval of about 10s rest follows each experiment and longer intervals follow groups of 10 or 20 experiments. In this way fatigue is usually avoided. If, however, the experiments are repeated in close succession there is no possibility of\n1\tHodge, A microscopical study of the nerve cell during electrical stimulation, Journal of Morphology, 1894 IX 449.\n2\tCowles, Neurasthenia and its Mental Symptoms, Shattuck Lecture, Boston, 1891.\n3Dresslar, Some influences which affect the rapidity of voluntary movements, Am.\nJour. Psych., 1891 IV 514.\nBliss, Investigations in reaction-time and attention, Stud. Yale Psych. Lab., 1893 I 45-49-\nMoore, Studies of fatigue, Stud. Yale Psych. Lab., 1895 III 92.\n\u2018Moore, Studies of fatigue, Stud. Yale Psych. Lab., 1895 III 87.","page":15},{"file":"p0016.txt","language":"en","ocr_en":"i6\nE. W. Scripture,\nrest. Series of such experiments have been made by Patrizt.1 The stimulus occurred at intervals of 2s and the subject was to react as quickly as possible each time. The same characteristics were found as in tapping and accommodation, namely, a lengthening of the average time and an increase in the mean variation.\nIt was determined to carry the problem further, and, in reference to certain observations on methods of inducing hypnotic sleep, to determine in what particular part of the process the fatigue arose. It was proposed, therefore, to investigate the fatigue in the case of repeated flashes of light, and to determine whether it is due to the muscles of accommodation and convergence, to attention or to both muscles' and attention.\nThe flash was produced by a small Geissler tube, connected with a spark coil in the adjoining room. The primary circuit of the coil passed through a modified Wundt contact-apparatus.2 This was so arranged that a revolving arm made contact at definite points with brass blocks in such a way as to illuminate the tube at regular intervals.\nThe tube was placed on a table in the isolated room and the subject was seated before it. The room is so constructed that neither light nor sound can enter from the outside.3 The room was supplied with fresh air by a blower, operated from the floor below.\nA telegraph key in the isolated room was arranged in a circuit with a DEPREZ-marker which wrote on the drum of a kymograph. A subject was told to press the key in response to each flash ; nothing was said about removing the pressure. The pressing of the key caused a downward movement in the point of the marker and the release of the key a movement back to the original position. We thus have two mental phenomena recorded: the first is the reaction-time from the moment of the flash to the pressure on the key ; the second is the length of time during which the subject chooses to hold the key down.\nThe experiments were continued during a long interval. Records were taken for a number of times at the beginning and then for a number of times at the end. Mr. von Tobel, a college senior, was the subject of the experiments.\nAfter a sufficient number of records had been taken, the drum was allowed to revolve without being moved axially; the reactions continued as before, but the records overlapped and were not regarded.\n> Patrizi, La graphique psychom\u00e9trique de I attention, Archives ital. de biologie, 1894 XXII 187.\n2\tWundt, Physiologische Psychologie, II 424, Leipzig, 1893.\n3\tBliss, Investigations in reaction-time and attention, Stud. Yale Psych. Lab., 1893 I 2.","page":16},{"file":"p0017.txt","language":"en","ocr_en":"Researches on reaction-time.\n17\nAfter the desired interval the drum was again moved axially and the records were separated. The reaction-times were longer and very irregular. The time of holding was enormously lengthened. As nothing had been said to the subject concerning releasing the key, it was done semi-con-sciously. The time of holding was sometimes so long that the subject was apparently not fully awake. In fact, various statements of the subject showed that on some occasions he had fallen into a half-dazed condition resembling the first stage of passage toward hypnotic sleep.\nThe further details of the apparatus were the usual ones. The drum was timed by the Jacquet chronometer. The records were read in hundredths of a second'; the next decimal arising in the averages was retained.\nIn the first series of experiments the room was kept dark. Both eyes were open and relaxed. The appearance of the flash caused both convergence and accommodation. In the next series one eye was bandaged in order to reduce the convergence ; it is an easily demonstrable fact that the closed eye only partially performs the movement necessary for convergence. In a third series one eye is bandaged as before, but a light is turned on in the room ; as the subject looks constantly at the tube all the time, the condition of accommodation is a steady one. In all three cases the mental condition known as \u201cattention\u201d is present; in the third there is no noticeable muscular effort in the eyes ; in the second there is at each flash a definite change of accommodation with imperfect convergence and in the first there are definite acts of both accommodation and convergence.\nThe first record was as follows: No light in the room ; both eyes open ; flashes once in two seconds\u2014\n\tReaction-time.\tMean Variation.\tHolding-time.\nAt start\t195*\tH<r\t319\u00b0-\nAfter 5m\t300\t43\t7S3\nFatigue\ti\u00b05\t32\t434\nHere we see that after five minutes, or about 150 flashes, the time of reaction was increased about 60%, the time of holding down the key was lengthened about 130%, and the irregularity was four times as great. The ^subject states: \u201cDuring the experiment I felt a strong sense of contraction between the eyes. I also found that it required great effort to keep the attention fixed on the tube. It seemed to float around and move upward.\u201d\n2","page":17},{"file":"p0018.txt","language":"en","ocr_en":"i8\nE. H'. Scripture,\nThe next record was taken under exactly the same conditions, but was continued for xom\u2014\n\tReaction-time.\tMean Variation.\tHolding-time.\nAt start\t224 <r\ticxr\t163^\nAfter lom\t304\t32\t837\nFatigue\t80\t22\t674\nThe reaction-time increased about 35%, the holding-time over 400%, and the irregularity 300%. \u201cThe bodily effects were much the same as before, only more intense. Tears flowed freely from the eyes, the feeling of contraction between the eyes became almost painful and there was a sort of general lassitude and disinclination to move.\u2019\u2019\nFor the third record all conditions were the same as before, except that one eye was bandaged. In this set a series of records was taken after an interval of 15 minutes also. The results were as follows\u2014\n\tReaction-time.\tMean Variation.\tHolding-1\nAt start\t241\u00b0'\u2019\tI3<r\t404c\nAfter 5\u201d\t328\t33\t758\n\u201c IOm\t297\t25\t859\n\u201c 15\u201c\t337\t34\t593\nFatigue at 5m\t87\t20\t354\n\u201c\t<< I0m\t56\t12\t455\ntt\tu\t96\t21\t189\n\u201c In this series I felt much greater effects than in any of the others and seemed to approach nearer a hypnotic state. There was a general feeling of fatigue all over the body, accompanied by a slight stiffness of the joints, also a feeling of floating off in the air or of dropping off to sleep.\u201d\nThe last set of experiments was taken with only one eye open and with a light in the room, thus eliminating the acts of accommodation and (practically) of convergence. The results were as follows:\n\tReaction-time.\tMean Variation.\tHolding-ti\nAt start\t2671T\t24<r\t176^\nAfter 5\u201c\t278\tIO\t184\n\u00ab\t10m \u25a0\t296\tIO\t652\nFatigue at 5\u201c\tII\t-I4\t8\n<<\tit jQtn\t29\t-I4\t476\nThe results apparently show that fatigue of attention alone produces \u2014at least within the first iom\u2014very little lengthening of reactiontime. The increased regularity\u2014\u201cpractice\u201d\u2014continues. The ten-","page":18},{"file":"p0019.txt","language":"en","ocr_en":"Researches on reaction-time.\n19\ndency of the subject to finally \u201cfall asleep\u201d over his work is shown in the greatly increased holding-time in the last case.\nA comparison of all the results seems to indicate the following conclusions :\nX. The fatigue in reaction-time increases with the complexity of the adjustments required for perceiving the stimulus. There is least fatigue when only an effort of attention is involved, more when the act of accommodation is added and still more when the act of convergence is also added.\n2. The tendency of the subject to fall into a condition of daze, as indicated by the holding-time, depends on the fact of repetition of the stimulus (fatigue of attention ? ) as well as on the fatigue from the adjustments.\nThe application of these results to the common methods of hypnotizing requires no remark.\nGeneral fatigue and reaction-time.\n(John L. Burnham.)\nExperiments on simple and complex reaction-time were made with the chronoscope in the manner previously described (p. 12). The morning records were made at 8:30, just before the duties of the day began, i. e., just after breakfast and before the first recitation in college. The afternoon records were made at 5:30, after the day\u2019s work had closed with a two hours session of laboratory work. The results of several series of experiments are given in Table II.\nTable II.\nSubject.\tS\td\tMorning. n\tC\t\td\tn\t5\td\tAfternoon. n\tC d\t\tn\tDifference. S C\t\nSmith\t119\t10\t60\t263\t38\t60\t127\t16\t60\t3\u00b09 34\t60\t8\t46.\nv. Tobel\t146\t16\t20\t281\t43\t20\t149\t10\t20\t281\t29\t20\t3\t0\nBurnham\t128\t13\t80\t256\t29\t80\ti4i\t15\t80\t278 27\t80\t13\t22\nUnit, thousandth of a second.\tC, complex reaction-time.\nS, simple reaction-time.\td, mean variation.\nThe bearing of this table of results is evident. The table shows an average lengthening of the afternoon records over those of the morning by 19V in simple and 24* in complex time. This is a loss of 15y2\u00b0Jo in one case and of 17 \u00b0}o in the other.","page":19},{"file":"p0020.txt","language":"en","ocr_en":"20\nJS. IV. Scripture,\nIt will be noticed that general fatigue has a very small influence on reaction-time as compared with special fatigue.\nIt may be interesting to add that at the end of these afternoon records a few records were sometimes taken under the electrical stimulus. This resulted in a shortening, but never enough to bring the time down to that of the morning. This seemed to indicate that the fatigue of the mind by a day\u2019s work is greater than can be overcome by the stimulating action of the electrical current, at least as used in these experiments.\nInfluence of tension on the reacting finger.\n(John L. Burnham.)\nThe problem was suggested by the consideration that there might be some relation between the time of reaction and the energy of reaction.\nThe first set of experiments took the form of a constant tension applied to the reacting finger just before and during the experiment, whereby the reaction involved the moving of a weight. For this purpose a set of pulleys was arranged with a cord running over them. At one end the cord passed through a tape around the index finger of the reacting hand and at the other a iooo8 weight was attached. When the hand was put in position for reacting, the weight swung free. Thus there was a tension 01 iooo8 on the finger at the start and the whole mass must be raised by the finger as it pushed the key in reacting.\nThe first three records were taken on February 15 and 19, 1896. The results were so unexpected in various ways that the experiments were repeated for the observer E. W. Scripture at a later date, April 29, 1897, with the results as shown in the last record of the table.\nTable III.\nSubject.\tR\td\tLight. Rk\nJ. B.\t127\t9\t127\nJ. D.\t120\t28\t107\nE. W. S.\t152\t26\t128\nE. W. S.\t127\t12\tno\nWeighted mean\t132\t19\t118\nUnit, thousandth of a second. R, reaction without weight. Ri,, reaction with weight.\nB, shortening due to weight.\nd\tB\tR\td\tSound. jRk\td\tB\n6\t0\t>3\u00ab\t9\t123\t8\t8\n6\t\u00bb3\t108\t8\t101\t7\t7\n11\t24\t172\t3\u00b0\t136\t16\t36\n10\t\u00ab7\t132\t9\t122\t8\t10\n8\t14\t136\t14\t121\t10\t>5\nd, mean variation.\nEach figure is the average for ten experiments.","page":20},{"file":"p0021.txt","language":"en","ocr_en":"Researches on reaction-tune.\n21\nThe shortening of the time is evident. Another noteworthy fact is the-increase in the regularity of the reactions as indicated by the decrease in the mean variations. When errors of the apparatus and method are eliminated, the mean variation is a mental quantity expressing the subject\u2019s definiteness of perception and response.1 This definiteness makes up a large part of the vague group of phenomena which goes under the name of \u201cattention.\u201d\nThe following conclusions seem justifiable :\nX. Increased definiteness of the act to be performed shortens the time required to begin it. In the case of the experiments with sound the action of the weight lay mainly or entirely in forcing \u201cattention\u201d to the finger to be moved. This was distinctly felt by the subject. When the weight was removed, the subject noticed the increased difficulty of attending to the movement. The shortening in time was 8\" in the case of sound.\n2.\tIncreased definiteness of the expectant image of the sensation shortens the time required for responding to it. In the experiments on sight the stimulus was just above the finger and any increased attention would include it also. It could be directly observed introspectively that the strain on'the finger forced attention to the place just behind it where the signal was to appear. The decreased ease of attention when the weight was removed was noticed here also.\n3.\tThe reaction-time decreases as the mental tension increases. This follows from the preceding conclusions. It is still more strongly brought out by the following facts :\na. Reactions with the pendulum chronoscope are always quicker than with other methods. This can be seen by comparing these figures with those obtained (p. 17) by use of the graphic method and the isolated room. This fact has been repeatedly noticed on various persons. An example of the short time required is seen in the average of i79<r for 19 students (p. 10). A similar statement is true of Gilbert\u2019s results with his reaction-board.2 The explanation is not hard to find. When the subject is placed in a quiet room away from all excitement,\n\u2018This view, definitely advocated and explained in The New Psychology, London, 1897, has for several years been part of my regular teaching. It is implied in the calculations published by Gilbert in Stud. Yale Psych. Lab., 189+ II 77 etc., and by Moore in the same, 1895 III 76. Definite explanations of the meanings and relations of what I have termed the \u201c individual mean variation,\u201d and the \u201c statistical mean variation\u201d arc given in the Zt. f. Psych, u. Physiol, d. Sinn., 1896 X 163 ; see also the summary to Naoler\u2019s article on p. 8 above.\n2 Gilbert, Researches on the mental and physical development of school-children, Stud. Yale Psych. Lab., 1894 II 78.","page":21},{"file":"p0022.txt","language":"en","ocr_en":"22\nE. IV. Scripture,\nthere is nothing for him to do but to sit at ease till the warning for work arrives, and he falls into a more or less comfortable or relaxed condition of mind and body which is decidedly contrasted with that experienced with the apparatus and experimenter at his very face. The tense condition of mind under such circumstances is very evident to every one who reacts at the chronoscope.\nb. The shortening of the reaction-time becomes especially marked in reactions to sight. The presence of the sight-shutter just above the reacting finger is conducive to the strictest attention. The reactions to sound do not gain in a similar manner, and thus it frequently results that a subject\u2019s reaction to sight is shorter than that to sound.\nInfluence of the amount of effort.\n(Gerry R. Holden.)\nThe experiments with the strain on the finger, reported in the preceding section, had been planned for the purpose of solving the problem of the influence of the amount of effort on the time required for reacting. The records proved from the start just the reverse of what was expected, and it soon became clear that the constant strain on the finger produced an increase in attention which entirely overbalanced any effect of the increased effort.\nExperiments were now planned in which there was no strain on the finger before the reaction and in which the subject was placed in the isolated room utterly away from the apparatus. Both factors of the increased attention in the previous experiments were now eliminated.\nThe reaction-key was made from a double contact telegraph key by lengthening the rear arm of the lever. A cord was attached to the lever and weights could be hooked at the end. The back contact of the key supported the weight until the knob was pressed. Pressure on the knob broke the contact, and lifted the weight at the same moment.\nThe graphic method of recording by means of the multiple key was used.* 1 Pressure on the multiple key in the experiment room closed a sounder circuit, broke the primary circuit of a spark coil and immediately closed it again. A spark was thus made on the time-line of the dnim at the moment of sending the current through the sounder, which, with a correction for the latent time, gives the moment of the sound in the isolated room. The subject broke the same primary circuit and made a second spark on the time-line.\n'Bliss, Investigations in reaction-time and attention, Stud. Yale Psych. Lab., 1893\nI 10. The latest model of this key is described below among the new apparatus.","page":22},{"file":"p0023.txt","language":"en","ocr_en":"Researches on reaction-time.\n23\nThe subject\u2019s finger rested upon the key with no exertion and no tension of the muscles. Experiments were made at intervals of 15*. Each experiment was preceded, as usual, by a warning. An interval of about io1\" (during which the ventilating blower drove fresh air into the room) was taken for rest after each set of 25 or 30 experiments. Smaller rest intervals occurred as the weight was changed. Practice and fatigue were compensated in the usual way by the order of the experiments.\nEach set of records for any one weight was preceded by experiments (not recorded) with the same weight in order to produce in the mind of the subject a definite idea of the effort to be exerted.\nTable IV.\n\t100\u00ab\t\t\t\t200\u00ab\t\t\t5005\t\tIOOOS\t\t\t\t1500s\t\n\tR\td\t11\tR\td\t11\tR\td\t11\tR\td\t11\tR\td\t11\nHolden\t168\t17\t47\tI7t\t13\t19\t191\t22\t21\t173\t12\t34\t166\t15\t>9\nScripture\t179\t12\t14\t232\t2\t2\t218\t35\t9\t260\t45\t7\t203\t19\t15\nSeashore\t165\t24\t6\t\t\t\t\t\t\t\t\t\t187\t22\t8\nUnit, thousandth of a second.\t1 d, mean variation.\nR, reaction-time.\t|\t\u00ab, number of measurements.\nThe conclusion to be drawn is different from the one expected. No definite relation is to be found between the amount of effort and the time of reaction, the results being irregular and contradictory. Careful observation showed the source of the irregularity. The finger being in a passive condition, it was necessary for the muscles and joints to do considerable work before the movement began. Moreover, the soft tissues at the end of the finger would yield considerably before the key would move. Not only was time consequently lost, but the complicated adjustments, especially for the heavier weights, rendered the records irregular. Thus, although the method of obtaining the definite effort had been found, the method of recording the result was not adequate for the purpose for which the work was undertaken. The figures, however, prove one very important fact, namely, that the tension of the spring of the telegraph key alters the record for the reaction-time. Some definite standard tension must be adopted if results by different observers and on different occasions are to be comparable. The tension of o would appear to be the best for adoption. This is the case in the slide reaction key' and in a telegraph key adjusted so that the back contact rests in place with little or no tension of the spring.\n1 Scripture and Moore, A new reaction-key and the time of voluntary movement, Stud. Yale Psych. I.ab., 1893 I 88.","page":23},{"file":"p0024.txt","language":"en","ocr_en":"24\nE. IV. Scripturei\nThe next step was to eliminate the effect of strain on the finger. This was done by having the subject always react with a key of no tension ; the telegraph key was used in order not to introduce any further change. \u2022 The finger necessarily remained passive, as the key responded to the slightest movement. The subject reacted in alternate sets with two degrees of voluntary effort. The degrees were defined as \u201clight\u201d and \u201cstrong; \u201d the intention was to make the effort correspond somewhat to the extremes of o and the heaviest weight in the previous set, but no measurements were made on the actual energy of effort.\nThe results are given in Table V.\nTable V.\nSubject.\t1 ,ight effort.\t\tStrong effort.\t\t\n\tR\td\tn\tR\td\tn\tD\nHolden\tl5S\tIO\t26\t143\t8\t27\t15\nScripture\t179\t16\t17\t154\t19\t18\t25\nSeashore\t168\t15\t9\t137\t21\t6\t31\nFisher\t626\t25\tS\t375\t4t\t6\t241\nUnit, thousandth of a second.\t\u00ab, number of measurements.\nR, reaction-time.\tD, decrease in R for strong as compared\nd, mean variation.\tj with light effort.\nThe figures for the colored janitor, Fisher, are interesting. Having been accustomed for several years to serve as subject in exercises and investigations, he is perfectly at home in the work and yet has no interest or concern in the experiment beyond carrying out the instructions ; these facts make his record very reliable. His unusually long reaction-time has been observed for several years.\nThe problem has thus found a definite solution : the intensity of the effort affects the reaction-time, making it shorter for the greater intensity.\nSimple and cortical reaction-time.\n(Howard F. Smith, M.D.)\nThe determination of the time of a motor response to a direct stimulation of the cerebal cortex and a comparison of this time with the simple reaction-time of the subject would apparently lead to certain conclusions concerning the relation between mental and cerebral processes. The attempt has been made in the following manner. .\nA cat was held quietly in the hands of an assistant. A double pointed platinum electrode was rested against the skin at a suitable point. A","page":24},{"file":"p0025.txt","language":"en","ocr_en":"Researches on reaction-time.\n25\ntouch key' was rested against the same member in such a way that a movement would break an electric circuit. The electrode was connected with the secondary coil of an inductorium ; an interrupted current was sent through the primary coil. The inductorium was so connected with the chronoscope that the electrodes stimulated the skin as the index passed the zero point. The touch key was connected with the magnets that stop the index. Thus, when the pendulum was released, a moderately noticeable (but not painful) electric shock was given to the foot or the lip, and the consequent reaction by withdrawing the leg or raising the head broke the circuit of the touch key and made a record on the chronoscope.\nThe first experiments were made on a cat weighing nearly three kilograms. The stimulus was applied ( i ) to the right fore foot with the key against the elbow; (2) to the right hind foot, with the key pressed against the heel; (3) to the upper lip with the key on the top of the head. The results were id, mean variation ; n, number of experiments) : right fore foot, 96^\t= 0.00T, d= 26\u00b0\u2019, n = 7) ; right hind foot,\n116\" (d = 38\", \u00ab = 4) ; lip, 6^ (d= 9*, \u00ab= 7).\n'1 he next experiments were made with a cat weighing four kilograms. The results were: right fore foot, 41er (d = 2\u201d, n = 3) ; right hind foot, 62* id\u2014 o, // = 4) ; lip, 62\u00bb (d= 8% n = 5).\nWith the second cat we proceeded to a determination of the cortical reaction-time by etherizing the animal in the usual way.\nBefore the operation was begun but after the etherization (surgical degree) had been effected, the experiments on sensory-motor reaction were again tried with the same intensity of stimulation. No response was received anywhere except from the ear, 57er (d = 8er, n = 2).\nIt is a curious fact that the muscle here involved, the Retrahcns aurem, is one which man has practically lost the use of. When the temporal muscle was laid bare by the operation, it was found to respond, when-stimulated directly, with a time of 63* (d = n<r, \u00ab= 3).\n1 he cortex was then exposed by the usual surgical procedure. The motor centers were found by the electrode and the key was applied in such a manner as to record the movements. The movements produced, however, were not quite the same as those used for the sensory-motor reaction. The results were: supination of right fore leg, 184^ (\u00ab'=7*, \u00ab=2); advance of right hind leg, 161^ {d= 26er, n= 6); raising of head> 33\" (^=17\u00b0', n= 2); elevation of right side of upper lip, 37*\n(d=(\", n=6) ; closing of right eye, 61* (rt^n*, \u00bb=3).\nWe notice, first, the remarkably quick reaction of the cat, being as quick\n\u2018Scripture, Some new apparatus, Stud. Yale Psych. I.ab., 1895 III 108.","page":25},{"file":"p0026.txt","language":"en","ocr_en":"2\u00d6\nE. IV. Scripture.\nas 4ia for the right fore foot. This may be compared with that of 89* for a dog about twice as large as the cat1 2 * * ; it is far below the time for human beings, which rarely falls as low as too'7. We next notice that the second cat, though larger, was much the quicker in each kind of reaction. In both cases the hind foot was 20\" slower than the fore foot. This is analogous to results obtained by Cattell and Doi.ley for human beings.*\nEtherization destroys the reactions, presumably by cutting off the sensory half. It seems, also, that it seriously affects the motor centres, as the cortical reaction for the hind leg was ioo<r longer even than the complete reaction before etherization. It would be difficult to draw any conclusion concerning the relative portion of the complete reaction-time, which is used by the cortical reaction. Even if we assume that the cortical time is one-half of the complete time (probably by far too great a proportion), we have 33\u00b0' x 2 = 66er for the head-movement corresponding to the lip stimulation with raising head, which yielded only 410'. The discrepancy is undoubtedly due to the retardation caused by the use of ether.\nIn conclusion we may point out the peculiar importance of such researches as these for physiological psychology. For experimental psychology as applied to man the simple reaction-time consists of a process 01 sensation (perception) and one of volition. For physiology the reaction consists in transmission of the irritation to the brain, various processes in . the brain and transmission of an impulse to the muscles. What is the relation between the two sets of simultaneous phenomena? As an example of some of the problems that present themselves in this respect, we may mention that of the character of the \u201cmotor centers\u201d of the cortex. Are they truly motor centers governing the muscles directly or are they, rather, sensory centers from which impulses proceed to motor centers at lower points in the brain ? In terms of time are they connected with earlier or later processes in the reaction ? We may hope some day to answer the question by experimental means.\nPerhaps the most important bearing, however, of these experiments is to be found in the fact that, following Weyer\u2019s investigation, they show the possibility of applying some of the psychological methods to the study of animals. It is the firm belief of the editor of the Studies that a quantitative science of comparative psychology can be established by the proper development and modification of the methods of experimental psychology.\n\u2019Weyer, Some experiments on the reaction-time of a dog, Stud. Yale Psych. Lab., 1895 III 96.\n2 Cattell and Doi.i.ky, On reaction-times and the velocity'of the nervous impulse,\nMemoirs of the U. S. Nat. Acad, of Sciences, 1896 VII 404; previously summarized\nin the Psych. Rev., 1894 I 159.","page":26}],"identifier":"lit25269","issued":"1896","language":"en","pages":"12-26","startpages":"12","title":"Researches on reaction-time","type":"Journal Article","volume":"4"},"revision":0,"updated":"2022-01-31T12:38:55.029354+00:00"}