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{"created":"2022-01-31T12:47:48.690351+00:00","id":"lit28734","links":{},"metadata":{"alternative":"Studies from the Yale Psychological Laboratory","contributors":[{"name":"Scripture, Edward W.","role":"author"}],"detailsRefDisplay":"Studies from the Yale Psychological Laboratory 4: 69-75","fulltext":[{"file":"p0069.txt","language":"en","ocr_en":"RESEARCHES ON VOLUNTARY EFFORT.\nBY\nE. W. Scripture.\nWe may suppose that in primitive times quantities were measured according to mental scales ; thus distances would be established by the eye or paced off by walking, weights would be judged by the effort required to lift them, etc. In most cases later civilization has, by the method of maximum agreement,1 established successively finer methods wherein the disagreements due to the personal and instrumental differences are reduced to extremely small quantities. These are the so-called \u201c physical \u201d or \u201c instrumental \u201d methods. Thus by instrumental methods a scale for space is developed from the standard meter bar, or a scale of mass from the standard kilogram. With such scales in our possession the problem arises: how do our mental scales compare with the instrumental ones? The solution of this problem in regard to the voluntary efforts used in compressing the fingers was attempted in the following way.\nApparatus.\nThe dynamometer. Experience with various dynamometers led to the construction of a new one. Two spring-steel rods are inserted into a brass block so that they extend from one side. Flat hard-rubber knobs are fastened at the appropriate distance from the block ; when pressure is applied to these knobs, the rods bend inward after the manner of sheep-shears. A light plate is attached to the end of one rod ; the end of the other rod is pointed to serve as an index. The amount of the pressure exerted on the knobs is measured by the deflection of the rods, and this is indicated by the distance through which the index passes over the plate. The physical scale is established by resting the dynamometer on one knob and placing weights on the other knob ; the position of the index for each weight is scratched on the plate. The knobs may be placed at any desired point along the rods. As they are placed nearer to the block, the apparatus becomes less sensitive and the movement less ; as they are moved toward the ends of the rods, the apparatus becomes more sensitive. In the present investigation they are so placed that the maximum force usually exerted makes the index pass over the entire scale.\n\u25a0Scripture, New Psychology, ch. Ill, I-ondon, 1897.\n*\t69","page":69},{"file":"p0070.txt","language":"en","ocr_en":"7o\nE. IV. Scripture,\nThe instrument is graduated for one position of the knobs and must then be left unaltered. These dynamometers are so readily made that it is preferable to have a separate one for any special problem rather than to alter the knobs and change the scale.\nThe dynamometer is used by holding it up between the ends of the thumb and one of the fingers. The other fingers are kept away from the one used. The metal block may be allowed to rest lightly on the palm of the hand.1\nThe dynatnograph. The dynamometer is turned into a dynamograph by means of a piston recorder or a recording capsule. The particular one used in the following experiments was made by fastening one of the extra glass cylinders of a H\u00fcrthle piston recorder to one of the steel rods while the piston was fastened to the other rod. Pressure on the knobs caused the piston to descend in the cylinder and the air to pass through the rubber tube to the recorder. The cylinder is adjustable to any point on the rods ; this regulates the amount of movement in the piston.\nThe recording point is rested against any smoked surface in the usual way. It repeats the movement of the piston on the dynamometer and consequently indicates the pressure exerted. To graduate the record the dynamometer is placed in a vise or a clamp and is subjected to pressure so that its index reads i, 2, 3, etc. on the scale ; the position of the recording point at each of these readings is marked on the smoked surface.\nScale for the thumb and finger.\nTwo points are to be determined for our scale of voluntary effort : 1, the relation of its units to the weight units ; 2, its regularity.\nThe subject of the experiment takes the dynamometer in his hand. At the command \u201cOne\u201d he exerts a light pressure ; at the command \u201cTwo\u201d a pressure intended tobe twice as great ; at \u201cThree\u201d three times as great ; etc. At each pressure the recording point marks its excursion on the smoked surface ; between records the surface is moved so as to keep the marks separate. The experiment is.repeated several times. Then the dynamometer is placed in the vise, which is screwed up until the index indicates a pressure of ik8 ; a turn of the drum inscribes the line for ik8 on all records. This is repeated for 2k8, etc. The records are then read in tenths of a kilogram.\n1 This dynamometer and the dynamograph are pictured in Scriiturk, New Psychology, Figures 4 and 24, London, 1897.","page":70},{"file":"p0071.txt","language":"en","ocr_en":"Researches on voluntary effort.\n71\nThe following is a specimen record ; the figures in the top line give the relative intensities of the efforts as intended, while the actual results of five experiments are recorded below them. The unit is the kilogram.\nI\t2\t3\t4\no-5\t1.0\ti-7\t3-3\n0.4\t1.0\t1.6\t2.8\no.S\t1.0\t1.6\t2-5\n0.8\t1.6\t2-5\t3-7\n0.9\t2.1\t3-2\t41\nThe question arises concerning the proper method for computing the results. If the values in each column represent identical processes, they should be added directly. This is the method which I have followed in reporting the results in the New Psychology (p. 218). Further consideration leads me to modify the procedure. The values for effort 1 are not intended to be one particular effort, but any convenient light effort to start with. Likewise the values for effort 2 are not attempts at a certain definite effort, but are attempts to double effort 1, which may be different for different experiments, etc. The proper procedure seems, therefore, to lie in measuring efforts 2, 3 and 4 by effort 1, as a unit ; this is done by dividing all four records by the record for effort 1 in each experiment separately. The specimen record then takes on the following form :\nI\t2\t3\t4\nI\t2.0\t3-4\t6.6\nI\t2.5\t4.0\t7.0\nI\t2.0\t3-2\t5-0\nI\t2.0\t3-1\t4.6\nI\t2.3\t3-6\t4.6\nThe averages and mean variations are then computed in the usual way. The results for several observers are given in the following table :\nSubject.\ti\tttx\t2\tTable I. <4\t3\t'4\t4\t<4\t\u00ab\nI\ti\t29%\t2.1\t9%\t3-5\t7%\t5.6\t2%\t5\nII\ti\t14%\t2.0\t\u00bb%\t3-3\t21%\t7-1\t19%\t5\nIII\ti\t25%\t30\t27%\t5-7\t33%\t11.4\t14%\t4\nIV\ti\t22%\t2.2\t14%\t3-1\t29%\t4.6\t24%\t4\ndlt d.lf dZi dv mean variations.\t\t1 \u00bb.\tnumber of experiments.\t\t\t\t","page":71},{"file":"p0072.txt","language":"en","ocr_en":"72\nE. IV. Scripture,\nScale for forearm and hand.\nThese experiments were made with a dynamometer constructed by Dr. Seashore (p. 60, above). A light wooden rod was hinged at one end to an upright ; a coiled spring supported the rod in a horizonal position. Pressure on the rod at a given point deflected it downward ; this point was chosen very near to the axis in order to make the movement a minimum. An index at the movable end of the rod passed over an arc graduated in grams.\nThe subject was seated with the hand and arm extended horizontally. At the signals he executed downward pressures intended to be in the relations ot i, 2 and 4. The results are given in the following table. The experiments were all made by me on Dr. Seashore on the same day in successive groups.\nTable II.\nI\t*1\t2\t4\t4\tA\t71\nI\t12%\t2.2\t9%\t3-8\tn%\tIO\nI\t17%\t2-3\t24%\t3-9\t23%\tIO\nI\t23%\t2.4\t13%\t4.2\t17%\tIO\nI\t26%\t23\t20%\t41\t28%\tIO\nI \u2022\t19%\t2.1\t15%\t3-3\t14%\tIO\nMean\t1\t19%\t2-3\t16%\t3-9\t21%\t5\u00b0\nd\u201e it.,, </,, mean variations.\t\t1\t\u00ab, number of experiments.\t\t\t\nConclusions concerning the scales.\nThe mental scale of exertion is a fairly definite affair. It varies considerably in different individuals, but is fairly constant for the same individual on a given occasion.\nThe question of how these scales are established by past experience is not touched upon ; the problem for the experiments related to the actually existing scale.\nRepeated voluntary efforts.\n(Henry E. McDermott.)\nThe purpose of these experiments was to measure, not the fatigue of maximum pressure, but the fatigue resulting from many repetitions of a moderate pressure, thus showing the fatigue of the finger muscles under control of the will involving concentrated attention.","page":72},{"file":"p0073.txt","language":"en","ocr_en":"Researches on voluntary effort.\n73\nThe instrument used was the dynamometer described above (p. 69). The first person experimented on, A. G., was a High School student. I allowed him to give a desired pressure and then told him to relax the grip, and with the eyes closed to give the same pressure as before. His results expressed in dekagrams were as follows : 78, 75, 80, 76, 85, 85, 85, 85, 83, 80, 84, 85, 90, 85, 85, 86, 82, 85, 80, 83, 83, 83, 84, 84, 85, 86, 90, 89, 90, 90, 90.\nAt 90 the pointer touched the extreme of the scale and continued to do so for several seconds. In this set we see a tendency to gradually increase the grip.as it is repeated ; this is exactly the opposite of what was expected. The results fluctuate for a time and then for a few seconds become regular. On the average, however, they slowly, yet constantly, increase in strength.\nThe second person experimented on was also a High School student, F. C. His results were 55, 70, 65, 70, 70, 75, 74,\t76,\t80,\t80,\t80,\t82,\n74,\t80, 83, 82, 86, 85, 85, 85, 85, 83, 84, 82, 81,\t78,\t82,\t85,\t86,\t83,\n80, 82, 82, 83, 83, 82, 83, 85, 85, 81, 76, 77, 79, 80, 80, 73, 74,\n75,\t80, 78, 80, 80, 85, 90, 90, 88, 90, 88, 90, 90, 90, 90, 90, 90, 90, 90, 88, 89, 90, 90, 85, 89, 89, 88, 88, 90, 90, 90. In this set we see nothing very different from the first, except that there was greater regularity at the start and that the difference between beginning and end was greater because the starting point was lower.\nThe third person experimented on was also a High School student, N. B. His results were, 30, 34, 32, 33, 32, 29, 32,\t29,\t30,\t30,\t32,\t30,\n34,\t33, 3G 29> 29, 29> 29> 31, 31, 32> 29> 33, 35,\t32>\t35,\t4\u00b0,\t45,\t35,\n39, 38> 40, 38, 39, 41, 40, 36, 32, 40, 40, 35, 36,\t34,\t30,\t38,\t35,\t35,\n35,\t35, 36, 34, 36, 4\u00b0, 4\u00b0, 35, 4\u00b0, 4\u00b0, 42, 4\u00b0, 39,\t4\u00b0,\t5\u00b0,\t5\u00b0,\t48,\t45,\n50, 50, 48, 44, 45, 44, 40, 40, 43, 44, 45, 44, 41, 40. In this set we have a remarkable constancy of exertion. However, the tendency to increase is noticeable, as almost all the later results are greater than earlier ones. The greatest difference is 20, in contrast with 26 of A. G. and 35 of F. C. ; both of which would have been even greater had the scale been longer.\nThe fourth subject was a college student, J. R. N. His results were 47, 55, 5\u00b0, 51, 55, 6o> 6z> 56, 60, 64, 66, 65, 71, 65, 72, 68, 68, 70, 66, 65, 68/75, 76- In this set we have an almost constant increase up to a maximum of 29, which is large considering the shortness of the experiment.\nThe fifth subject was D. J. R., a carpenter. His results were 55, 53, 54, 65, 66, 68, 65, 66, 77, 75, 73, 72, 78, 78, 80, 82, 85, 85, 87, 85, 82, 83, 80, 82, 81, 85, 87, 90, 85, 87, 90, 90, 90, 90. At 90 the","page":73},{"file":"p0074.txt","language":"en","ocr_en":"74\nE. IV. Scripture,\npointer touched the extreme of the scale. , Here we see the same steady increase up to the limit of the instrument.\nThe sixth subject\twas\ta young lady, Miss\tF.\tHer\tresults were 45,\t47,\n36, 42,\t45,\t50,\t50,\t44,\t43,\t51,\t55,\t56,\t55,\t46,\t40,\t47, 52,\t54, 60,\t54,\n56, 40,\t49,\t53,\t47,\t49,\t48,\t54,\t45,\t56,\t58,\t57,\t60,\t60, 54,\t61, 65,\t70,\n74> 74,\t74,\t72,\t59,\t52,\t58,\t66,\t55,\t70,\t71,\t72,\t68,\t70, 70,\t64, 68,\t65.\nHere we have the same general result, except that it is more irregular than the previous ones.\nThe preliminary experiments seemed to point to something definite, so for seven successive days at about 6.30 P. M. I made sixty experiments on D. J. R. to determine his average progressive error and mean variation. He is a carpenter, 24 years of age, 5 feet 11 inches (i8o.6\u00b0m) in height and weighs 175 lbs. (79450s). He uses his hands in hammering, sawing, planing and so on ; he is therefore not easily fatigued, and at the same time his judgments by the \u201cmuscle sense\u201d should be accurate because of this training.\nIn the following table the lines across the page give the averages for the experiments of the seven days. The first line gives the serial number of the contraction ; the second line gives the difference\u2014\u201c progressive error\u201d\u2014between each contraction and the initial contraction of 20 dekagrams. The third line gives the mean variations.\nSerial number\tI\t2\t345\t6\t7\t8\t9\tIO\tII\t12\nProgressive error\to\to\t0.3 o.l 1.3\t1.9\t2.3\t1.9\t1.9\t2.6\t2.0\t3.9\nMean variation\to\t1.7\t2.3 2.7 2.9\t2.8\t3.8\t4.4\t5.2\t4.8\t3.7\t4.2\n13\t14\t>5\t16\t17\t18\t19\t20\t21\t22\t23\t24\n2.7\t3-6\t3-6\t4-3\t3-7\t3-0\t4.1\t3-7\t4.0\t3-1\t3-9\t4-3\n3-6\t4.2\t4-7\t70\t5-4\t4.9\t5-o\t4-4\t5-4\t6.2\t5-2\t5-0\n25\t26\t27\t28\t29\t3\u00b0\t31\t32\t33\t34\t35\t36\n5-6\t5-4\t5-4\t4.6\tS-i\t5-9\t4-7\t5-3\t5-3\t5-4\t5-6\t6-3\n7-4\t8-3\t8.0\t7-7\t8.2\t7.2\t8.2\t7-8\t9.0\t7.2\t8.0\t8.8\n37\t38\t39\t40\t41\t42\t43\t44\t45\t46\t47\t48\n6.6\t4-9\t5.6\t5-7\t5.6\t6.4\t6.0\t4.6\t5-0\t4-4\t4-4\t4.6\n9-7\t7.8\t7-7\t7.6\t8-3\t7-7\t7-1\t6.7\t7-i\t6.9\t7-1\t6.1\n49\t5\u00b0\t5\u00ab\t52\t53\t54\t55\t56\t57\t58\t59\t60\n3-4\t4.0\t4-3\t6-3\t6-3\t47\t3-7\t3-7\t4-3\t7.0\t7-0\t6.4\n6.7\t7.0\t5-7\t6.7\t6.0\t6.2\t5-7\t7-1\t8.9\t8-3\t8.1\t7-7\nThese results are exhibited in Figure 5.","page":74},{"file":"p0075.txt","language":"en","ocr_en":"Researches on voluntary effort.\n75\nUsing \u201cfatigue\u201d to mean a decrease in functional activity as defined on p. 14, we can consider both the progressive error and the mean variation in the preceding experiments to be phenomena of fatigue. Although\nHorizontal axis, serial number of ex- I /\u2022', course of progressive error, p\u00e9riment.\tM, course of mean variation.\nVertical axis, number of grams.\nthe actual force exerted increased as the efforts were repeated, yet, since they were intended to be equal to the first one (or to the preceding ones), they became steadily less accurate. This increasing inaccuracy of judgment is properly a phenomenon of fatigue. Likewise the increasing uncertainty, as measured by the mean variation, is a constantly recurring phenomenon of fatigue.","page":75}],"identifier":"lit28734","issued":"1896","language":"en","pages":"69-75","startpages":"69","title":"Researches on voluntary effort","type":"Journal Article","volume":"4"},"revision":0,"updated":"2022-01-31T12:47:48.690356+00:00"}