Adaptation in motion perception: Alteration of induced motion

Prolonged exposure to a condition that causes induced motion was found to diminish this effect. The extent of a horizontal induced motion was measured by obtaining estimates of the direction of the apparent oblique path that resulted when a spot was visible on a horizontally moving pattern and was therefore in horizontal induced motion and, at the same time, moved vertically. Because the horizontal component of the perceived motion path represented the induced motion, the slope of the path measured the extent of the induced motion. After a 10-min exposure to induced motion, the apparent motion path was steeper; the mean change corresponded to a 15% smaller extent of the induced motion. Results were obtained that argue that this effect is not due to a diminished horizontal motion of the pattern but amounts to a smaller motion-inducing effect. The experiments were meant to support the view that the perceptual process that underlies induced motion is learned.     

Der mikrophyfikalifche Vitalismus

Ohne ZusammenfassungDie folgenden Darlegungen bilden den Inhalt eines Vortrages, den ich auf freundliche Einladung des Ausfchuffes des Zweiten internationalen Kongreffes für Einheit der Wiffenfchaft, Kopenhagen 1936, halten wollte; ich war jedoch verhindert, an der Tagung teilzunehmen.     

Ueber die Methoden der Physik

Ohne Zusammenfassung     

Effects of inbreeding on mental-ability factors

The differential effects of inbreeding on 11 subtests of the WISC, in a Japanese (Hiroshima) population, are related to the factor structure of the tests. The degree of inbreeding depression on mental abilities is most strongly correlated with the subtests' loadings on the General factor, g, which is common to all of the subtests. Loadings on the Verbal factor are also positively correlated with inbreeding depression. The (non-verbal) Performance factor, however, is slightly enhanced by inbreeding. One possible inference from these findings is that at least the General factor shows genetic dominance, which is theoretically consistent with natural selection for g in the course of human evolution. It is also noted that the factor structure of the WISC in the Japanese population is highly similar to that of the U.S. standardization sample.     

FORMAL OPERATIONS AND LANGUAGE

Un individu dont le savoir linguistique est très pauvre peut-il atteindre le stade des opérations formelles? Comment les opérations formelles sont-elles liées au langage? Pour répondre à ces questions, on compare la performance d'un échantillon d'adolescents sourds à celle d'adolescents normaux de milieux socio-économiques différents. Dans une tâche de symbolisation logique, on constate de grandes différences: 28% des sujets sourds et 53% des sujets de milieu défavorisé atteignent le stade formel après 5 semaines d'entraînement, alors que 75% des sujets de la classe moyenne atteignent ce résultat après une semaine d'entraînement. Mais pour deux autres types de tâche, les performances sont comparables: dans une tâche de prédiction probabiliste, 45% des adolescents sourds réussissent les opérations formelles et dans une tâche de combinatoire, 76 % réussissent. d'après les données d'ensemble aussi bien que d'après L'étude des cas individuels, on constate que les opérations formelles fonctionnent chez des sujets dont la performance linguistique n'est pas suffisante pour manier les propositions du discours. Les AA. se basent sur ces résultats, ainsi que sur la théorie de Piaget, pour dire qu'un langage social n'est ni une condition nécessaire, ni une condition suffisante du développement opératoire. Des résultats antérieurs, qui sont ici brièvement résumés, montrent que le langage, au mieux, a un effet indirect de facilitation sur les opérations concrètes. Pour certaines opérations formelles, le langage, associé à certains autres facteurs sociaux, peut avoir un effet direct de facilitation; il peut fournir à la fois L'occasion et le support figuratif pour que fonctionnent les opérations formelles.     

Serial rote-learning: Incremental or all-or-none?

If the associative connections in a serial list are acquired in an all-or-none fashion, rather than gradually with every trial adding an increment of associative strength, then changing the serial order of the middle items in the list during the course of practice should have no effect on the rate of learning the list as a whole or even of the particular items that have been interchanged. Thirty subjects learned a serial list by the anticipation method. The middle items of the list were reversed in serial order approximately half-way through the number of trials required for mastery. The subjects took no longer to learn the list and made no more errors than did 30 control subjects for whom there was no change in serial order. The serial-position curves of the two groups were almost identical. It was also shown that the learning “curves” of single items in the series, when plotted for individual subjects do not reveal a gradually increasing probability of the correct response, but show instead a sudden jump on one trial from the chance guessing level to a level close to 100 per cent, correct responses. The results are consistent with a non-incremental theory of serial learning.     

Stimulus aspects of aversive controls: the retention of conditioned suppression

Three years ago a tone ending in unavoidable electrical shock was periodically presented to pigeons while they pecked a key for food. When pecking was disrupted by tone, shock was disconnected and the training tone as well as tones of different frequencies were presented. At first, all tones caused a reduction in the rate of pecking, but as testing proceeded, suppression began to extinguish and the gradient narrowed. In the present work, testing was resumed after a 2½-yr interruption. Analysis of the gradients obtained just before and just after the interruption yielded no evidence of changes with the passage of time. As testing proceeded, however, extinction of suppression continued and the gradient all but disappeared. In subsequent experiments with these subjects (Ss) it was found that the presentation of free shocks caused a reappearance of the gradient and that this effect persisted in reduced amount for several sessions after the shock condition was terminated.