was just barely learned, and 'backward associations' were apparently formed. The logical material in the present experiment was greatly overlearned, and there was on the whole an inhibition of backward associations. These facts are definitely opposed to the theory of backward association. INTERPRETATION OF RESULTS Probably the most reliable conclusion that can be drawn from the results of the experiments described in Parts I and II is that certain factors influence the learning process in such a way that the chances are practically equal of obtaining evidence in favor of or opposed to the theory of backward association. Although the variability of the results is important from a practical point of view, this does not exclude the possibility that some general principle may be at work. We have already attempted to show that the tendency in favor of backward association, when rote material is used, is the result of an inability to control the learning process. We have still to explain the apparent inhibition of backward associations with the logical material.10 Let us suppose that the 200 words in Table XII are numbered consecutively. Then the 10th B-list, for example, will be made up of the items 10-9-8-7-6-5-4-3-2-1; and the 10th S-list will be made up of the items 191-171-151-131-III91-71-51-31-11. Now when the material in the second part of the procedure is practiced and learned in the forward direction, an association is formed between each item and the item immediately following, i.e., from 1 to 2, from 2 to 3, etc., throughout the series. These associative tendencies persist of course in all of the items of the B- and S-lists when these lists are relearned in the third part of the procedure. We may set down the items of the 10th B- and S-lists in large numerals, with the associative tendencies of the items in small numerals, as follows: B: S: 10-11 9-10 8-9 7-8 6-7 56 4-5 34 2-3 -92 51-52 31-32 11-12 10 Cf. G. Frings, Ueber den Einfluss der Komplexbildung auf die effektuelle und generative Hemmung, Arch. f. d. ges. Psychol., 1914, 30, 415-479; F. Nagel, Experimentelle Untersuchungen über Grundfragen der Assoziationslehre, Arch. f. d. ges. Psychol., 1912, 23, 156-253; E. Claparède, L'association des idées, 1903, 141-150. The first syllable in the B-list (no. 10), for example, has a tendency to arouse syllable no. II; the second syllable in the S-list (171) has a tendency to arouse syllable 172, etc. These associative tendencies will interfere with the relearning of both the B- and S-lists; but the inhibition will be greater for the B-list. In the 10th S-list, shown above, all of the associative tendencies (192, 172, etc.) were aroused in next to the last list which the subject learned before learning this list, since the B- and S-lists were learned in the order 1B, IS, 2B, 2S, etc. In the B-list, however, the associative tendencies immediately precede the syllables, so that when the subject reaches the second syllable (9), for example, he tends to go back to the first syllable (10); when he reaches the third syllable (8) he tends to return to the second (9), etc. In the B-list, the associative tendency (preceding syllable) is quite 'prominent' because it has just been seen and named. The recent arousal of syllable 10 facilitates the recall of this syllable when syllable 9 is reached. The presence of these associative tendencies in the B-list not only interferes with the practice of this list but also with its final reproduction. The inhibiting tendency to shift backwards in the series should theoretically be greater in a B-list than in any other arrangement of the items. The associative tendencies in the S-list have not been aroused so recently; they are not so active or so prominent, and they do not tend to make the subject turn backwards in the series. When the subject reaches syllable 9 in the B-list, he tends to go back to 10, because he has just looked at it and named it. But when he reaches 171 in the S-list, he does not tend to go back to 191, but rather to 172. Several minutes have elapsed since 172 was aroused, and the tendency from 171 to 172 is not as strong as the tendency from 9 to 10. It appears therefore that the associative tendencies from learning the prose passage inhibit the later learning of the B-lists more than the S-lists. But since the S-lists represent a zero base of learning, or a base of learning slightly below zero, a conclusion against the theory of backward association is justified. The act of learning the series 1-2-3-4-5, instead of establishing backward associations, forms inhibiting associations which interfere with the later learning of the same items in the order 5-4-3-2-1. The negative results of our study of backward association harmonize with the well-established physiological law of forward conduction across the synapse. Our results, however, do not agree with the results of the few other investigators who have studied this problem, Ebbinghaus, Müller and Schumann, Wohlgemuth and others. We shall not make a detailed comparison of the various results which have been obtained, but limit our remarks to pointing out one error in interpretation which several writers have made in regard to learning "paired associates." When responses A and B are connected, the practice is frequently from A to B and also from B to A. If such is the case, A will evoke B, and B will also evoke A. The two responses have been integrated." Some would say that they have combined. It is important to note, however, that the practice has been in two directions, and two associations have been formed.12 The conditions obtaining when paired associates are learned are not suitable for testing the theory of backward association.13 Some writers have erroneously assumed that the use of a memory exposure apparatus adequately controls the subject's thinking processes. Nevertheless, the subject can, and frequently does, think about an item in a series, even though the item is not visible at the time. SUMMARY In order to test the theory of backward association a procedure with forward, backward, and separated lists was devised, in Part I, and nonsense syllables and short familiar "Müller and Schumann (op. cit.) claimed that, when two consecutive syllables form a part of the same rhythmical measure, the second has a slight tendency to evoke the first. 12 Cf. E. Claparède, L'association des idées, 1903, 128-130. 13 Cf. especially A. Wohlgemuth, On memory and the direction of associations, Brit. J. Psychol., 1913, 5, 447-465; Ueber die Richtung der Assoziationen, Ber. über d. V. Kongress f. exper. Psychol., 1912, 284–287. words were used as learning material. It is apparently im✓ possible to limit the learning processes to the formation of associations in the forward direction when rote material is used. The various fluctuations and irregularities which occur in the learning process support the belief that when a series is being learned to all appearances in the forward direction, some practice is also taking place in the backward direction. The objective results show that when an effort is made to control the forward learning of rote material in a laboratory situation, some backward associations are formed in about 2 cases out of 3. Although the theory is true as a practical proposition under these conditions, the results give no justifi-cation for the belief that it will apply to all learning situations and to all types of material. In Part II the subjects learned a logical prose passage and tests were given on later occasions to determine whether backward associations were also formed. It was found that the learning of logical material, instead of establishing backward associations, actually forms inhibiting associations which interfere with the later learning of the same items in the reverse order. The conclusion against the theory of backward association is further supported by the fact that the conditions of learning logical material can be controlled very satisfactorily. The results emphasize the specific nature of the learning process when associations are being formed between the items of a series. The results of the present experiment on backward association should be considered in connection with a later experiment on remote forward association, since the two experiments deal with different aspects of the problem of remote association. The general significance of the results for the psychology of learning will be discussed in the later paper. APPARENT VISUAL MOVEMENT AND THE GESTALT BY GLENN D. HIGGINSON University of Illinois I. NINE OBSERVATIONS WHICH STAND AGAINST The Gestalttheorie originated in the field of perception. In the apprehension of visual motion, as Wertheimer and others have maintained, lies the secret of many of our major psychological problems. An adequate understanding of this perception furnishes, as they think, a key to the comprehension of a wide range of experiences. Now theories are easy to formulate but difficult to sustain. The final test of any scientific assumption is experimental verification. If the facts of extended observation fail at substantiation, a doctrine can have little worth. We wish to indicate certain phases of the Gestalt which seem to possess limited scientific value because of an apparent conflict of theory with the facts of observation. Since the doctrine owes both its origin and its fullest expression to the study of apparent visual movement, we contend that the clearest understanding of its weaknesses as well as its strength may be had through a brief survey of the facts there alleged. An individual never outlives his history; and as much may be said for a theory. When a doctrine will not hold for the facts wherein it took its beginnings, it is immediately open to suspicion on that score; and where a theory has been mis-stated scientific interest demands an exposition of its exact significance shorn of its inadequacies. The inadequacies in the Gestalttheorie are most apparent in the treatment of visual movement. Let us consider some of them. I. Simultaneous apprehension of movement in different directions over identical regions.—Visual movement has been ex 228 |