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{"created":"2022-01-31T14:50:42.520012+00:00","id":"lit28688","links":{},"metadata":{"alternative":"Studies from the Yale Psychological Laboratory","contributors":[{"name":"Scripture, Edward W.","role":"author"}],"detailsRefDisplay":"Studies from the Yale Psychological Laboratory 3: 98-109","fulltext":[{"file":"p0098.txt","language":"en","ocr_en":"SOME NEW APPARATUS.\nBY\nE. W. Scripture.\nThe constant activity of the laboratory workshop during the two years since its first productions were described1 has resulted in over fifty new pieces of apparatus for the purposes of research and demonstration. Of these I have selected for description only a few whose fundamental ideas may be serviceable to the investigator.\nPendulum chronoscope.\nThe spark method previously described2 has reduced the labor of making records of reaction-time to a point lower than obtainable by any other method recording accurately in thousandths of a second. The apparatus, however, is not portable. We set ourselves, therefore, to produce an apparatus fulfilling the following requirements : 1, accuracy to the thousandth of a second ; 2, ease in transport ; 3, readiness of setting up ; 4, quickness in reading ; 5, availability for many kinds of experiments on time. These requirements were met after eight months of labor by the first pendulum-chronoscope. Two chronoscopes were built later, but the model remained essentially the same.\nThe pendulum-chronoscope contains in the first place an accurately adjusted double-bob pendulum. This pendulum is held by a catch at the right hand side. In making an experiment this catch is pressed noiselessly and the pendulum starts its swing. It soon reaches a light pointer held in position by a delicate spring and carries it along. At exactly the moment it takes up the pointer it presses a delicate catch which releases the mechanism beneath the base. This mechanism is adjusted to do several things ; one of them is to drop a shutter which covers an opening in a metal plate at the back of the chronoscope. The person experimented upon is seated at the back ; owing to the curtain, he can see nothing but the metal plate\n1 Scripture, Some new apparatus, Stud. Yale Psych. Lab., 1892-93 I 97.\t^\n5 Bliss, Investigations in reaction-time and attention, Stud. Yale Psych. Lab., 1892\nI 7.","page":98},{"file":"p0099.txt","language":"en","ocr_en":"Some new apparatus.\n99\nwith the covered opening. He finds before him a rubber button like that on a telegraph key. He is to press this button as soon as be sees the shutter move. He does so, and apother mechanism releases a horizontal bar running behind the scale. The pointer swings between this bar and the scale and is consequently stopped when the bar snaps against the scale. The pointer starts to move\nFig. 15.\nwhen the shutter starts to fall and consequently any time that elapses thereafter will be indicated by the distance through which the pointer travels before being caught. The connection of the pointer with the pendulum is so light that it continues its swing (fig. 15) and is finally caught on the other side.\nThe scale in front is graduated by actual comparison with tuning-fork records made by the finest graphic methods. Special electrical contacts are arranged so that the units of the scale indicate always","page":99},{"file":"p0100.txt","language":"en","ocr_en":"100\nE. TF. Scripture,\nthe elapsed time between the starting of the shutter and the pressing of the button. That is to say, all lost time in the action of the mechanism is taken up in the scale. All irregularities of the instrument would also appear in the records. The vital point of the construction is, therefore, accurate adjustment ; this has been so successfully attended to that the mean variable error of the instrument does not exceed 0.0023. The scale is marked in hundredths and half hundredths ; the latter space is readily divided by the eye into fifths, thus giving records in thousandths of a second.\nFor reaction to light, colored cards are inserted into a holder just behind the shutter, or a reflecting surface at this point receives light coming from the side and sends it through colored glass or gelatine. When several different colors are to be used, a wheel containing them is placed just behind the shutter. This wheel was left off the chrono-scope shown in the figure, but considerable experience has proved that the state of mind of the person experimented upon differs greatly according as he supposes the order of presentation of colors to be left to chance or to the experimenter. To present them by chance all the compartments in the wheel are filled with two, three, or more colors as desired ; the wheel is given a twirl and is stopped without any knowledge of what particular color is ready for exposure.\nThe reactions to light are not disturbed by noises, as the pendulum makes no noise either at release or during its swing and the shutter makes only a faint sound.\nFor reactions to sound without further apparatus the shutter is arranged to strike with a noise. In this case a constant quantity is subtracted from the shutter as read. For sound-reactions it is generally preferable to insert a telephone either with or without a battery in circuit with the platinum contact about to be described.\nThe shutter rests against a platinum point in such a way that its movement can be used to break an electric circuit ; this can be used for producing lights, sounds, electric shocks, etc. A strong electromagnet is placed beneath the base in such a way that it can take the place of the button ; thus the pointer can be caught by the movement of a key in the hands of a distant person. An arrangement is also provided whereby the pendulum itself is released electrically. Still further mechanisms are added for various purposes.\nI may add that the chronoscope has fulfilled all expectations ; in particular, the fact of its constant readiness for use without a moment s delay has been a great inducement for employing it in research and demonstration.","page":100},{"file":"p0101.txt","language":"en","ocr_en":"Some new apparatus. Standard drum.\n101\nFor records where great constancy of revolution is desired we use the standard drum, fig. 16. This consists of a very heavy wheel revolving on a vertical axis. The sliding carriage to the right is arranged to carry a fork or a marker. On the top of the drum there is an automatic break. A rigid arm projects from the axle ; as it passes a certain point, it trips a lever and breaks an electric circuit.\nIn using the automatic break the drum is turned slowly till the arm just touches the lever. The marker is then run vertically downward so that its trace, the zero line, shows the true position of its point when the circuit is broken.\nFig. 16.\nWhen the drum is used for reaction-times, the stimulus, e. g. light, sound, etc., is produced by the break either in direct circuit or shunt as the case may require. The drum is run at any desired speed, and the marker or fork draws the time line. The distance between the zero line and the reaction spark gives the elapsed interval.\nThe automatic break has a special, very important use in finding the latent times of markers, spark-coils, etc. For markers this must be done separately for make and break on every occasion. For spark coils used in the way described it is necessary to do this only","page":101},{"file":"p0102.txt","language":"en","ocr_en":"102\nJE. W Scripture,\nonce. One reason is that when the multiple key1 is used, the latent time at each end of the record will unquestionably be the same, and so disappears. Another reason appears in the results of the following experiments. The automatic break was inserted in the primary circuit of the spark coil, (1 inch Ritchie with condenser around the break) with 4 amperes of current ; the secondary circuit was arranged to make a spark off the point of the time marker, vibrating 100 times per second.\nFig. 17.\nThe exact position of the automatic break was marked on the paper ; this could be determined within an error of less than 0.1mm. The drum was then revolved at high speed and a record was taken with a spark produced by the break. The speed of the drum was so great that an interval of 0.01s occupied 28mm; the great regularity of the drum enabled us to treat the interval as constant throughout. The lag of the spark was measured in tenths of a millimeter. The quotient of the lag divided by the length of the wave gave the time\n'Scripture, Some new apparatus, Stud. Yale Psych Lab., 1892-93 I 97.","page":102},{"file":"p0103.txt","language":"en","ocr_en":"Some new apparatus.\n103\nof lag. The result of six measurements gave : mean time of lag, 0.00014s ; mean error for the series, 0.000015s ; mean error for a single experiment, 0.00009s ; largest error occuring in our determination, 0.00032s.\nThe mean time of lag is so small that it is quite negligible except where accuracy to the ten thousandth of a second is required, e. g. in graduating a cbronoscope. The mean error completely disposes of an objection seriously urged against the spark-method, namely, that the spark jumps irregularly through the paper ; with the paper used in this laboratory (glazed paper for covering pasteboard boxes) the extreme error was only one-third of a thousandth of a second.\nElectric color wheel with speed indicator.\nA small series-wound motor is mounted on a very heavy iron base. A suitable arbor to hold the color discs is placed on the front of the axle. A prolongation of the axle to the rear carries two arms like those of an engine governor, which diverge from the axle according to the speed of the motor. By an attachment to a pointer this divergence can be read off on a scale. By an electric contact in combination with the spark method, this scale is graduated in revolutions per second. The speed of the motor depends on the amount of current sent through it and can be regulated at will. The apparatus is shown in fig. IV.\nIt also affords the means for investigating the flickering-point under various conditions.1\nColor sight tester.\nThe usual tests for color-blindness fail to detect those who are color-weak, although these persons are really color-blind for objects at a distance. For examinations of railroad employes and sailors I have invented a convenient instrument which not only detects the color-blind with rapidity and accuracy but also detects the color-weak.\nThe use of different intensities of light for the purpose of a quantitative determination of color-blindness was, I believe, first made by Donders. In the form of a very cumbersome lantern by Enn-ridge Green it is now, I understand, officially adopted by the English Board of Trade.\n1 Marbe, Zur Lehre von den Gesichtsempfindungen, welche aus successiven Reizen resul-tiren, Phil. Stud., 1893 IX 384.","page":103},{"file":"p0104.txt","language":"en","ocr_en":"104\nJE. W. Scripture,\nFig. 18.\tFig. 19.\ncalls off the colors seen at the windows. The windows, 1, 2, and 3 are, however, fitted with gray glasses. No. 1 carries a very dark smoked glass ; all colors seen through it will be dark. No. 2 carries a piece of ground glass, showing all colors in full brightness. No. 3 carries a light smoked glass. There are thus thirty-six possible combinations of the colors. The twelve glasses are, however, mainly reds, greens and grays.\nIn general appearance the color sight tester resembles an ophthalmoscope. On the side toward the person tested, fig. 18, there are three circles of glass one-quarter inch in diameter, numbered 1, 2 and 3 respectively. The opposite side of the tester, fig. 19, consists of a movable disk carrying twelve glasses of different colors. As this disk is turned by the finger of the operator the various colors appear behind the three windows. At each movement of the disk the subject","page":104},{"file":"p0105.txt","language":"en","ocr_en":"Some new apparatus.\n105\nA suitable arrangement of tbe colors gives direct simultaneous comparisons of reds, greens, and grays of different shades. The well-known confusion by color-blind persons of dark greens with reds, greens with gray, etc., are exactly imitated, and the instrument gives a decisive test for color-blindness. Its peculiar advantage, however, lies in the fact that it presents reds, greens, and grays simultaneously in a large number of different shades of intensity. The light of a green lantern, as it appears to a color-weak person at different distances, is simulated by the red behind the different grays ; at the same time a white light is also changed. The color-weak person to whom weak green is the same as gray (white at a distance) is utterly confused and thinks that the weakened green is gray (white) and the dark gray is green.\nThe actual test is performed in the following manner : The tester is held toward a window, but not in the bright sunlight, at about 2^ feet from the person tested. The operator begins with any chance position of the glasses, and asks the person tested to tell the colors seen through the three glasses, Nos. 1, 2, and 3. He answers, for example, \u201cNo. 1 is dark red ; No. 2 is gray ; No. 3 is green.\u201d The operator records from the back of the tester the letters indicating what glasses were actually used. Suppose he finds that A, D, and G were opposite the glasses Nos. 1, 2, and 3 he records : A 1, dark red ; D 2, gray; G 3, green. The disk is then turned to some other position, the colors are again named, and the operator records the names used. For example, the result might be : \u201cNo. 1 is dark green ; No. 2 is white ; No. 3 is red.\u201d and the record would read: G 1, dark green ; J 2, white ; A 3, red. Still another record might give ; J 1, dark gray ; A 2, red ; D 3, medium gray. Similar records are made for all combinations. Of course, the person tested knows nothing concerning the records made. The blank thus filled out is forwarded to the chief inspector for railway or marine service. A comparison with a table containing the true colors for each position determines whether the test has been passed or not.\nThe records can be taken by any one, and, on the supposition that the record has been honestly obtained and that the instrument has not been tampered with after leaving the central office, the comparison is likewise mechanical. There is none of the skillful manipulation required in the wool test and none of the uncertainty attaching to its results. The only instruction given to the subject is, \u201cName the colors \u201d ; the results render the decision with mechanical certainty.","page":105},{"file":"p0106.txt","language":"en","ocr_en":"106\nE. W. Scripture,\nThe three records just cited were all obtained from the red glass A, the gray glass D, the green glass G, and the white glass J, in combination with the dark gray No. 1, the clear No. 2, and the medium gray No. 3. Those familiar with color blindness will notice that these combinations place side by side the colors most confused. More important still is the fact that red, green, and white are made to undergo changes that detect the color-weak. Another set of colors includes red, white, green, and blue-green, subject to all the combinations. For green I use the ordinary green glass common on most railways ; the blue-green is known to dealers as \u201c signal green,\u201d and is frequent on the water. The third set of colors is an additional test. It includes orange-brown, green, blue, and violet. These colors are confused in many cases of color-weakness and color-blindness.\nThought and action apparatus.\nOn a horizontal rod 1 meter long, fig. 20, there are placed three metal blocks, A, B, C, adjustable at any distance apart. The block A carries a signal and is arranged so that a movement of the signal\nFig. 20.\nbreaks an electric circuit at a. The blocks B and C carry light bamboo rods held in small revolving clamps. On touching one of these rods it falls and in doing so it makes electric contact for an instant at e or i. By connection with the spark coil records are obtained on the drum for each of the three movements.\nLet it be required to determine the length of reaction-time in relation to the intended extent and velocity of movement. The finger is placed lightly against C and upon a signal from A it is to be moved past B. The time between the sparks from A and C is the reaction-time ; the time between those for C and B is the time of movement. By varying the distance between B and C and the time of movement the problem can be answered in all its forms.\nBy omitting B the instrument serves as signal and reaction-key. By reacting to a movement of A in one direction and not in the other it is used for discrimination and choice. By using B and C alone it is an apparatus for repeating and extending the investigations1 on the time and extent of movement.\n1 Fullerton and Cattell, On the perception of small differences, 103, Philadelphia 1892.","page":106},{"file":"p0107.txt","language":"en","ocr_en":"Some new apparatus.\n107\nPistol hey.\nThis serves for investigating the reaction-time in starting to run. The blast from the pistol barrel a, fig. 21, moves the fan /so that contact is broken at d for an instant, the lever being drawn back by a spring. Only a few experiments have been made with the apparatus. These, however, have brought to notice the following facts : 1. the reaction-time is about one-third shorter for short-distance runners, who are trained\tFig. 31.\nto start quickly, than for long-distance runners ; 2. the reactiontime for movements of the whole body is longer than for movements of a single member.\nVoice hey.\nThe voice key, fig. 22, is intended for experiments on the time of associating ideas. It comprises a cylinder of hard rubber holding a metal plate at the end furthest from the mouth. A fine screw rests lightly against this plate. The current is sent through the point of contact between screw and plate ; it is interrupted by the vibration of the plate in response to the voice. With the spark method this produces a chain of dots on the drum while the word is being spoken.\nFig. 22,\nWith two voice-keys and a telephone connection the person experimented upon can be in a distant room, a key being placed over the opening in each transmitter.\nTouch hey.\nA long flexible spring, fig. 23, is mounted in a wooden handle and bears against a short rigid arm, also attached to the handle, so as to keep closed \u00e4n electrical circuit. The circuit is led into the handle","page":107},{"file":"p0108.txt","language":"en","ocr_en":"108\nJE. W. Scripture,\nby a pair of twined flexible cords. When the end of the spring touches the subject, it is pressed away from the short arm and breaks\nFig. 23.\nthe contact. Striking against a piece of metal above, it makes contact again immediately. In this way a spark is made and the circuit is closed ready for the reaction. For touch alone the spring carries a small rubber knob at its end ; for temperature this is replaced by a heated or cooled metal ball.\nJEleclric baton.\nThis is designed for the study of the sense of musical rhythm. A rod, fig. 24, similar to an orchestra leader\u2019s baton, is provided with a spherical ball of metal mounted upon a flexible wire. Closely surrounding but not touching this wire is a metallic ring. The tip and ling are respectively joined to the ends of a pair of flexible conductors, leading off to a recording circuit. Every change of direction of the baton makes contact for an instant and thus a spark record is made upon the drum.\nFig. 25.\nFoot key.\nThe foot-key, fig. 25,1 is designed for the study of the sense of rhythm as involved in walking. A yoke piece is arranged to clamp to the heel, provision being made for heels of varying widths. Upon this yoke is mounted a small contact key, so that the circuit is broken whenever the foot strikes the ground and made again as the foot is raised. Flexible conductors place the shoe in the recording circuit.\n1 Figures 22, 24 and 25 are from Scripture, Thinking, Feeling, Doing ; Meadville, 1895.","page":108},{"file":"p0109.txt","language":"en","ocr_en":"109\nSome new apparatics.\nVolt reducers.\nWhen the city current is at hand in the laboratory, it is very desirable to use it for forks, spark coils, telegraph keys, etc. This cannot be conveniently done on account of the high voltage of the current which arcs across the keys, burns out the platinum contacts, etc. With a battery current Helmholtz1 used a zigzag of resistance wire connected in parallel with the cup of the tuning fork in which he wished to suppress the spark. This idea has been developed by our laboratory mechanician, J. J. Hogan, into an arrangement by which the dynamo current of high voltage can be manipulated just as a number of galvanic cells. With the cells the current is altered in potential and intensity by the use of more or less of them and by their arrangement in parallel, in series or in combination. With the volt reducer the amount of current drawn from the dynamo is regulated by incandescent lamps. This current passes to a pair of binding-posts by way of the apparatus in which the current is desired, and by way of one or more coils of wire. The particular arrangement of the coils depends on the insertion of various plugs. In this way the current drawn from the binding-posts can be made of any potential from 1 volt to 10 volts and of any intensity within the limits of the particular volt-reducer. The current acts under varying circumstances exactly like that of a battery of the same potential and internal resistance.\n! Helmholtz, Die Lehre von d. Tonempfindungen, 632, 3 ed., Braunschweig, I87t.","page":109}],"identifier":"lit28688","issued":"1895","language":"en","pages":"98-109","startpages":"98","title":"Some new apparatus","type":"Journal Article","volume":"3"},"revision":0,"updated":"2022-01-31T14:50:42.520018+00:00"}