A green line moved rapidly to the bottom. I saw two successive positions intermediate to the beginning and final stages. These lines were fairly clean-cut and saturated (C, 75). A green horizontal extent appeared in the visual field; then a moment later another green line somewhat like the first (chroma less) beneath it. Finally, a red line appeared a little lower down in a horizontal position (Y, 75). Results; Series 17-32.-Here we used the stronger and the weaker lights. One light was given of an intensity sufficient to outline clearly the colored line upon the field. The fields were white, blackish, red, green and yellow. Upon the first two we drew red and green lines; upon the red we placed green lines; and upon the green and yellow, red lines. The stronger light was intense enough to wipe out the weaker. In serial exposition, the stronger light was turned on and off at periods of one second. The increase in brightness did not seem to disturb the observer. Just as in the previous series we find here that the use of dissimilar hues brings out more reports of partial movement, although movement might be wholly optimal. The latter was especially true under serial exposition. Likewise the field of movement was partially or wholly covered with either red or green with a mixture of yellow. Again we find the presence of various intermediates of the hues of the moving object. Finally, we observe that the clearest kind of movement may be had even where the field is entirely that of the background. We cite the following reports to give some notion of the movement under these conditions. A red oblique appeared upon a greenish-yellow background for a moment and then disappeared; and at the same instant a greenish line seemed to start just below and move down and come to rest as a horizontal line upon a brighter field of red. There was a distinctly greenish tinge over most of the sector although the red of the background was visible through the green overlay. The color of the moving line was spread over the ground much on the order of a varnish (C). A green line appeared on a red field of medium chroma. Then the whole field suddenly brightened and I saw another green extent below. Then I saw an upper green line again in the first position. This happened five times. I saw a green line move from an upper position to a lower position, then up, then down, etc. Cloud-like greenish haze over part of the field (Y). A red bar moving continuously up and down. The field is red over the upper and the lower. The middle is exactly like the black background. I compared the two very carefully. Movement is over the whole field regardless of this gap. The field alternately grew lighter and darker (C). A green line appeared in an oblique position. It disappeared by moving to a horizontal position. Movement was uniform and continuous although visually the background of red was observable over most of the field. Just above the final position of the line the field was greenish (C). A bluish-red line at angle on yellowish field; then a more saturated and similar line on a high-chroma yellow field. I saw a bluish-red line move downward over part of the field (Y). I saw absolutely continuous movement of a red line up and down with the impression that the red line was in some way detached from the green field. I got the red line outlined at various stages of movement between the end-positions. The field of movement is not the same as the background; it has a reddish tinge over it. I see the green shine through the reddish overlay (C). A rather significant fact came out of these series (17-32) where, through the use of the dissimilarly colored members, O could discriminate more sharply between the two objects. Frequently it was not the first object which moved across the field to the position of the second. Rather it was the second object of a different hue which travelled away from the position occupied a moment earlier by the first. Wertheimer, as we know, claims that the temporal disjunction of the two objects provides for the completion of the neural process underlying visual movement; and Koffka represents in a simple diagram the way in which the cortical flow which is assumed to serve as the neural substratum of optimal movement spreads out. Let us assume a point in the cortex excited by the first object, followed a short time later by a second point corresponding to a second object. If the second cortical region is aroused when the neural excitation from the first has reached a point such that the two neural processes coincide near the second, the observer sees the first object move to the second. But here we get a weaker red or green object presented for a time; then a stronger green or red object is given. And under these conditions O may actually see the second assume its final position by moving over the field from the region of the first. The use of the type of object employed in this series gave us an opportunity closely to compare our reports with those of Dimmick. Where we used the whitish background we had a total of 42 per cent. of reports of a grey lying somewhere between the lines or colored end-areas. But where we used the black, red, green and yellow cards we did not obtain a single report of a grey such as Dimmick describes. This fact is all the more striking because we started the series with the white cards and O reported the greys. Then after we changed to the other cards O (Y particularly) remarked that "I no longer see the grey filling which I observed a short time ago." The intermediate grey appeared as a darkening of the field. When O was asked to describe it he reported that it was a "slight decrease in the brightness of the field, just as if the field had been slightly shaded." There is then a possibility, where a greyish field is used with colored stimulus objects, that O will see a grey somewhere between the lines; but where colored and black grounds are used the chance of such a grey occurring is negligible. This visual grey appears partly as a function of certain particular physical conditions without any outstanding significance for the movement experience in general. It is, as we now see, but one of various kinds of visual filling and cannot possibly be set up as of special importance. Conclusion.-We find that the hue of visual movement perceived under the present conditions is absolutely dependent upon the hues of the stimulus objects. If red objects are employed the movement is always of red objects, although no color may be observed covering the total extent of the movement field. When green lines are used the movement is always of a green object. When unlike hues are employed the movement may be of one or both members but there is always an object-meaning. O can definitely say that it was not that object of that hue which moved but this object of this hue. Again we must agree with Wertheimer that movement may be perceived without any precise filling of a visual character being present at all stages to carry the movement. In this way we get the 'illusion' in its most striking form. But always, even across these "visual gaps," there is the meaning that it is an object of a certain hue which moves. Movement is not in any sense to be cut away from the hue of the object. It is here that we are unable to agree with Wertheimer. Movement as we see it is always possessed of objective characteristics. From our study we can say furthermore that a mere change in hue is sufficient to change the character of the movement apprehended; objects of unlike hue giving fewer cases of optimal movement. This fact is of importance and must be seriously considered in any final explanation of visual movement. It may mean that a mere loss of identity between the two members interrupts the continuity of movement. To the three factors of intensity, distance and time, which, according to the Gestalttheorie, determine the nature of perceived movement, must be added that of quality, and while it is not so difficult to understand in terms of the doctrine the claim that the intensity of the stimulus, the spatial separation of the objects, and the temporal disjunction of the members, effect the total character of the movement seen, it is, according to the same way of thinking, extremely difficult to understand the particular rôle that quality plays in the whole matter. Finally, we can state with the highest degree of assurance that the existential correlate of visual movement under discrete retinal excitations with colored stimulus objects cannot be said to be a grey. That such a claim is not sustained by experiment is a sufficient warrant for its denial. A MODIFICATION OF THE LIPPS-MEYER LAW1 BY PAUL R. FARNSWORTH In a recent article2 the writer summarized the work of Meyer on tonic endings in melodies, and added further facts on atonic endings which considerably extended the scope of the Lipps-Meyer Law (Law of the Number 2). In the present article, still more conclusive evidence will be given for the need of modifying this law. Let us think of the tonal relationships in a scale where c has been made the tonic. This is done by playing the scale of c a number of times until the tone c is felt as the important tone of the scale. The scale ratios are then usually understood It can be readily seen that the extraction of the powers of 2 does not alter the existing relations. The following series of ratio symbols then appears Bb in this system would be 7. The tone which bears the ratio-symbol 2, the tonic, has the property of being preferred over all other tones as the melody ending. This is the substance of the Lipps-Meyer Law. If g is made the tonic, the ratio-symbols shift so that g is ratio-symbol 2, d is 3, a is 9, etc. In the previously mentioned article, the writer found that when the tonic is absent, the ratio 3 is preferred most extensively as the point of ending for a melody. The ratio-symbol 1 This paper was read in part at the Berkeley meeting of the Western Psychological Association, August, 1925. The experiments were carried out in the Psychological Laboratory of Ohio State University. P. R. Farnsworth, Amer. J. Psychol., 1925, 36, 394–400. |