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{"created":"2022-01-31T15:50:08.742207+00:00","id":"lit25272","links":{},"metadata":{"alternative":"Studies from the Yale Psychological Laboratory","contributors":[{"name":"Slattery, M. D.","role":"author"}],"detailsRefDisplay":"Studies from the Yale Psychological Laboratory 1: 71-79","fulltext":[{"file":"p0071.txt","language":"en","ocr_en":"ON THE RELATION OF THE REACTION-TIME TO VARIATIONS IN INTENSITY AND PITCH\nBY\nMorris D. Slattery, M.D.\nMethod of experimenting.\nThe plan followed was to place the person experimented on in an isolated room to which all stimuli were sent through wires from a distant room, and from which other sets of wires conducted the currents making electric registration in still another room.\nThe first requirement was thus a room free from disturbing lights and sounds ; this was met by the construction of the isolated room. The isolated room is a small room built inside of another room ; four springs of rubber and felt are the only points in which it comes in contact with the outer walls. The space between the walls is filled with sawdust as in an ice box. The room is thus proof against sound and light, and affords an opportunity of making more accurate experiments on the mental condition than yet attempted. This was the final construction of the room, adopted after numerous experiments. As such a room may prove valuable in physiological and medical work where freedom from disturbing sights and sounds is desired, it may be well to point out some of the difficulties to be overcome and erors to be avoided. The first requirement is a wall-surface impervious to sound. Owing to the great expense involved, such materials as asbestos, heavy tough hair-felt, lead, etc., could not be used ; soft wood with outside packing of sawdust was finally chosen. The next requirement is that the sound waves from the building should not be transmitted to the frame work of the inner room, i. e. it must not be connected to the outer room. The nearest approach to the satisfaction of this requirement was made by supporting the inner room on pieces of soft rubber and avoiding all other connection with the walls of the outer room. The sound waves in the building are thus almost hindered from passing to the inner room. The vital importance of these precautions can be shown by simply laying a pencil across from the wall of the outer to that of the inner room ; the various sounds are at once carried across and are heard in the inner room almost as loudly as if none of the other","page":71},{"file":"p0072.txt","language":"en","ocr_en":"72\tReaction-time in relation to intensity and pitch.\nprecautions had been taken. The third requirement is the means of ventilation without sound conduction. After several trials a peculiar ventilator has been invented in which the air is made to pass back and forth through a tortuous passage, the walls and partitions in which are made of hair-felt. Sound waves can pass through bent tubes only by reflection from the walls and refraction around the angles; in the ventilator all reflection is killed by the non-elastic felt and the amount of sound transmitted by refraction through such a tortuous passage is so small that a person shouting into it at one end can barely be heard at the other.\nThe records were made by the graphic method, the usual chrono-scope method being rejected as cumbersome and inaccurate. The counting of the fork-vibrations by the graphic method takes a somewhat longer time than the reading of the chronoscope records but in measurements of simple reaction-time this extra work is more than compensated by the saving on the laborious adjustment of the chronoscope and the necessary re-reckoning of the results. The new method of making graphic records, which was invented in the laboratory and used in the later experiments, not only greatly increased the accuracy of the records but made the work much less than that of taking chronoscope records. The apparatus used for recording was the same as that described by Bliss on pages 10-16.\nIn my investigations the multiple-key was connected with the isolated room and the apparatus in the following ways. The circuit from the tuning-fork through the time-marker was connected at one side to P and at the other to B, so that when P and B were in contact they short-circuited the current. This, of course, stopped all action of the marker while the contact was made, but as soon as the knob G was pressed the marker started. The circuit to the other marker was passed through the lever I to O and the platinum point, and out through Z and W, then to the reaction-room and through the reaction-key. As soon as the point of E touched TJ the lever I would break its contact at Z and immediately make it again at W, thus making a nick in the line of the second marker. As the stimulus circuit is closed at the moment E touches U this nick gives the moment of the stimulus. Since the current is immediately closed at W the marker is ready to make another nick as soon as the person reacting presses his key. The time-marker connected with the fork was set vibrating as soon as the knob G was touched, so that the curve was already being drawn before the record began. When the spark-coil is used the primary circuit is run over the same line as the","page":72},{"file":"p0073.txt","language":"en","ocr_en":"Reaction-time in relation to intensity and pitch.\t73\ncircuit used for the second marker ; the secondary circuit has its poles in the drum and in the lever of the marker connected with the fork. Any movement at Z or of the reactor\u2019s key, produces a spark. Three different arrangements had to he adopted for the three variations of the stimuli to be used. These will he described in the appropriate sections.\nExperiments with different intensities of tone.\nIn all the experiments on tones they were produced hy electric forks in a distant room. The sound thus produced was sent from the primary circuit of a telephone transmitter, which was placed near the fork, through ,wires to the multiple-key. The secondary circuit of the transmitter was connected directly with the reacting telephone in isolated room. In investigating the relation to intensity of tones a fork of 250 complete vibrations per second was placed in the distant room. For producing variations in the intensity, a resistance-box was placed in the primary circuit of the transmitter ; by this means a resistance of 100 ohms could he introduced, giving a weak tone, or 50 ohms, giving a medium tone or zero, giving a loud tone.\nThe first person experimented on was E. W. Scripture. With everything in readiness for the experiments the person entered the isolated room, closed and fastened the door, and, holding the reacting telephone close to his ear, waited for the stimuli to which he would react by pressing on the knob of the reacting-key. Thirty experiments were made in series of 5 to 10 with each grade of intensity, the order being varied to eliminate influences of practice and fatigue. After each series an intermission of at least 5 minutes was given. Preceding the sending of each stimulus a warning was sent to the reactor to call his attention to the expected sound.\nAfter the first evening\u2019s experiment, the person experimented on made the following statement. \u201c Left arm resting, with telephone in hand close to ear. Loudest sound, quite loud. Reacting hand at rest except index-finger which is held upon key-knob. After the warning, attention was directed entirely to expected sound. Eyes were closed and while waiting for sound were turned strongly toward the left. General condition slightly fatigued.\u201d\nThe next person experimented on was D. O\u2019Keefe, the experiments being performed in the same manner as the preceding ones. His statement after the experiments was, \u201c Left arm resting with telephone in hand close to ear. Loudest tone quite loud, the weak-","page":73},{"file":"p0074.txt","language":"en","ocr_en":"74\tReaction-time in relation to intensity and pitch.\nest tone being just perceptible. Reacting hand at rest except middle finger which was held upon key-knob. After receiving the warning, attention was turned entirely to expected sound. Eyes open and turned toward the left. General condition good.\u201d Before making the statement he asked, \u201c if there was any trouble with the apparatus as the tone changed in intensity at different intervals.\u201d He was not aware of the fact that the intensity was to be var^pd. The results of the experiment are summed up in table I.\nTABLE I.\nUnit of measurements 1CT= .001 second.\n\tS'\tMV\tn\tS\"\tMV\tn\tS'\u201d\tMV\tn\nE. W. S.\t282\t68\t14\t287\t61\t17\t299\t72\t15\nD. 0. K.\t249\t67\t84\t212\t70\t29\t218\t68\t10\nThe first column gives the person experimented on, the second the reaction-time to the strongest tone, the third the mean variations from the average, the fourth the number of experiments, the fifth, sixth and seventh give the data for the medium tone, the eighth, ninth and tenth those for the weakest tone. ^\nIt will be seen from the results that for the loudest sound, in the case of E. W. S., we have a reaction-time of 282ff ; for the medium intensity the reaction-time was 287'7, for the tone of weak intensity the reaction-time was 299\u00b0. The absolute differences for different intensities were small and were much less than the amount of the mean variation. We can therefore conclude that they are practically equal and that within the limits of intensity used in these experiments the reaction-time does not vary with the intensity to any degree that can be detected.\nIn the experiments on D. O. K. it will be seen that the differences in the reaction-time are reversed but are also small ; with sound of greatest intensity the reaction-time was 249er, with the sound of medium intensity the reaction-time was 212er, with sound of weak intensity it was 218\u00b0. From these results the same conclusion is to be drawn as from the previons ones.\nSimilar experiments had been previously begun in March, 1892, by Dr. Scripture at Clark University on F. B. Dresslar, but were not carried to completion. The sound was produced by a secondary coil","page":74},{"file":"p0075.txt","language":"en","ocr_en":"Reaction-time in relation to intensity and pitch.\t15\nconnected with a telephone and placed over a primary coil through which passed a current interrupted by the vibrations of a 250 tuning-fork. The angle which the axes of the two coils made with each other regulated the intensity of the sound, which was in all cases weak. Five steps with coils at angles of 110\u00b0, 125\u00b0, 140\u00b0 and 155\u00b0 were taken. The records of March 22 were handed to me by Dr. Scripture to he used, if I saw fit, in comparison with my experiments. They were counted and the results will he found in table II.\nTABLE II.\nUnit of measurement== .001 second.\nS'\tMV\tn\tS\"\tMV\tn\tS'\"\tMV\tJl\tS\"\"\tMV\tn\n288\t26\t30\t239\t18\t28\t224\t25\t29\t268\t15\t30\nThe columns refer to the same subjects as in the previous table, but four grades of intensity were used. The strongest sound is placed first. The reactor, Mr. Dresslar, said in a note at the end of the experiments, \u201c that he perceived no difference in the intensity of the various sounds, i. e. to his consciousness the different sounds appeared to him to he of equal intensity.\u201d While actually there was a difference in the intensity of the tone, it must have been very slight. A comparison of the reaction-times of the four steps taken shows such a slight difference that the only conclusion to he drawn from the experiments is the same as in the previous case.\nThat other observers have obtained very long reaction-times for very weak noises might be explained by the fact that when the warning signal is used shortly before the stimulus is to be produced there is a natural tendency to revive an image of the sound in the mind. In the case of loud sounds the image would give rise to no confusion, hut in the case of very weak sounds the observer might well he in doubt as to whether a sound apparently heard was such a memory or was actually produced by a stimulus. Some experiments on the border line between sensation and hallucination indicate such an explanation.\nIn the table of results obtained from experiments performed by Wundt,1 from which he concludes that the reaction-time decreases constantly with an increase in intensity of the stimulus, it will he seen that his figures do not hear out the statement. In his experiments the sound was produced by a hall falling from different\n'Physiologische Psychologie, 2 ed., II 238.","page":75},{"file":"p0076.txt","language":"en","ocr_en":"76\tReaction-time in relation to intensity and pitch.\nheights ; as the height increased, the noise became louder. His figures for successively louder sounds are 217\u00b0', 146er, 132er, 135er, 161er, 176er, 159er, 94er. It is at once apparent that with the exception of the weakest sounds, the results are in direct contradiction to the statement. It is but fair to add that these results are omitted from the later editions of the Physiologische Psychologie.\nThe experiments of Mabtius1 on tones and noises gavejpegative results, i. e., the reaction-times of the various experiments wer\u00e9 nearly equal or showed slight and inconstant relations to each other. He drew the following conclusions : \u201c There is no constant decrease in the reaction-time with an increase in the strength of the stimulus. Differences in the times occur only when very great differences in the strength of the stimuli exist, as for instance between a very weak and a very loud sound. The lengthening of the time with very weak stimuli can be accounted for by difficulty of perception.\u201d\nMy experiments on tones lead to these conclusions :\nFirst\u2014The law that the reaction-time decreases with increasing intensity of stimulus does not hold good for the sense of hearing, i. e. the reaction-time to tones is nearly the same for all moderate intensities.\nSecond\u2014The longer time registered for very weak tones or noises by som,e observers is probably not due to any conscious change, but is caused by hesitation as to the actual hearing of the stimulus.\nExperiments with tones op diff\u00e9rent pitch.\nIn using tones of different pitch the arrangement was nearly the same as in the previous case. Three forks were all kept ready so that in the few minutes of rest between the sets of experiments a change could be made from one to the other. The resistance was kept in the circuit and by preliminary trials the amount of resistance to be used for each tone was determined, so that all the tones seemed to he of the same intensity. This was quite necessary as it is impossible to adjust an electric fork so as to give the same intensity on different occasions. Similar precautions as to practice, fatigue, etc., were taken as in the previous case. The reactor seated in the isolated room heard the tones through the reacting telephone as before. The pitch of the tones was changed by changing the forks. Since the\n1 Martius, Ueber den Einfluss der Intensit\u00e4t der Reize auf die Reactionszeit der Kl\u00e4nge, Phil. Stud. 1891 VII 469.","page":76},{"file":"p0077.txt","language":"en","ocr_en":"Reaction-time in relation to intensity and pitch. .77\ntones were adjusted so as to be of the same apparent intensity it would naturally be expected from the experiments of the preceding section that the reaction-times would be the same. The actual results are given in the following table :\nTABLE in.\nUnit oi measurement=lff= .001 second.\nF\tMY\tn\tF'\tMV\tn\tF\"\tMY\tn\n240\t38\t46\t179\t28\t60\t163\t20\t60\nP', P\" and P'\" denote the tones 100, 250 and 500 respectively. It is at once seen that the reaction-time decreases with the rise in pitch, a result which agrees with that of Martius. The natural inclination is to explain this difference in the reaction-times by the supposition that 10 to 15 vibrations are required before the tone is perceived. If this supposition be true we should obtain the same reaction for all the tones by deducting the perception-time of each from its reactiontime. Suppose we take ten vibrations as representing the inertia of the sense organ ; this would give us the perception-times, 100\u00b0, 4 O'1 and 20ff for the three tones 100, 250 and 500 respectively. Subtracting these perception-times from the total reaction-times given in the table, 240\u00b0, 179CT and 16317, we get the remainders 140er, 139er and 143\u00b0. These remainders fall within the limits of variation and are to be regarded as the same. My results are thus in harmony with the supposition mentioned. Martius obtained results which agree with mine in the fact that the reaction-time decreases with a rise in pitch, but this decrease could in no way be brought into harmony with the supposition that a constant number of vibrations was used up in the latent time.\nThe conclusions to which my experiments lead are as follows :\nFirst\u2014The reaction-time to tones decreases as the pitch rises.\nSecond\u2014The view held by Exner, von Kries and Auerbach and rejected by Martius,\u2014namely, that about 10 vibrations are necessary to the perception of a tone, no matter what its pitch,\u2014is sufficient to explain the differences in the reaction-times for different tones.\nExperiments with electrical stimuli op different intensities.\nIn using electric stimuli the current of the primary circuit after passing through the inner coil was sent through one of the prongs of a fork, kept vibrating electrically, by which it was interrupted at","page":77},{"file":"p0078.txt","language":"en","ocr_en":"78\tReaction-time in relation to intensity and pitch.\neach vibration. From the fork it was sent through a rheochord composed of seven lengths of wire. Hence it passed to binding posts 2 of the multiple-key mentioned above. The other pole of the battery was connected to binding post 3. When the key is pressed, the circuit is completed. The secondary coil was connected with two electrodes in the reaction-room. One electrode was of zinc covered with cloth, the other of sponge ; both were moistened with a solution of common salt. The other arrangements were the same as in the previous cases. In these experiments the spark-coil was used and the same precautions as observed in former experiments were adopted.\nAs soon as the multiple-key is pressed the current passes through the primary circuit, being all the time interrupted 100 times per second by the electric fork. This causes a current to pass through the secondary circuit and the person in the isolated room receives 100 shocks per second. As soon as he perceives the shocks he is to react in the usual way. The time is measured between the moment of closing the primary circuit and that of reacting. The intensity of the stimulus can be regulated either by moving the secondary coil nearer to or further from the primary or by weakening the primary current. The former method was not suited to the single experiments but was used to regulate the shock permanently to any desired intensity. Then the different intensities were produced by adjustment of the amount of wire introduced on the resistance-board.\nDuring the experiments six steps of different intensity were taken. The greatest intensity was obtained by shoving the secondary coil sufficiently near to the primary coil until a shock was produced which was not strong enough to startle the reactor and thereby interfere with the reaction-time. When a variation in the intensity of the stimulus was desired, the clamp was transferred to another wire on the resistance-board, causing an increase of resistance of two feet of the wire with each step. When the clamp was on wire No. 6, a resistance of 12 feet of fine German silver wire was thus inserted and a very weak shock was produced.\nThe experiments were performed in the same manner as the preceding ones. A warning was given previous to each stimulus. The reactions were repeated at intervals of 15 seconds, until a record of 30 reactions was taken, after which a rest of five minutes was given to the reactor. The person experimented on was E. W. Scripture.\nThe results are seen in table IY.","page":78},{"file":"p0079.txt","language":"en","ocr_en":"Reaction-time in relation to intensity and pitch.\t7 9\nTABLE IV.\nS'\tMV\tn\tS\"\tMV\tn\tS\"'\tMV\tn\tSiv\tMV\tn\tS\"\tMV\tn\tgvl\tMV\tn\n137\t21\t19\t135\t26\t15\t155\t29\t17\t180\t46\t26\t220\t61\t24\t210\t61\t22\nS' is the shock of greatest intensity ; S\u201c, SIil, Slv, S\", ST| represent shocks of lesser intensity, Svi being the weakest ; otherwise the abbreviations are the same as used in previous tables.\nIt will be seen that there is a slight but constant decrease in the reaction-time with an increase in the intensity of the stimulus. These results coincide with those obtained by other observers.\nThe conclusion to be drawn seems evident, namely, that in the domain of tactile stimulation by electricity the reaction-time decreases with the increase in the intensity of the stimulus.","page":79}],"identifier":"lit25272","issued":"1892-1893","language":"en","pages":"71-79","startpages":"71","title":"On the relation of the reaction-time to variations in intensity and pitch","type":"Journal Article","volume":"1"},"revision":0,"updated":"2022-01-31T15:50:08.742212+00:00"}