The relationship between memory performance and the number of rehearsals in free recall

The purpose of the present study was to examine the relationship between the number of rehearsals and long-term recall performance by means of an overt rehearsal procedure. Subjects were induced to concentrate their rehearsal activity on specific items in free recall tasks. In Experiment 1, both the primacy and the recency items that had received additional rehearsals were recalled with higher probability than were the ordinarily rehearsed items in immediate recall but not in final recall. Experiment 2 was designed to extend the occasions for subjects’ rehearsal by manipulating the rate of item presentation. The overall pattern of resulting data shewed that for neither recency items nor primacy items does the additional overt rehearsal reliably lead to facilitative effects on long-term recall performance. The possibility of a qualitative change in rehearsal is discussed.     

Separate neural sites for d-amphetamine suppression of mouse killing and feeding behavior in rats

The present study was conducted to investigate several possible neural sites for d-amphetamine's effect on mouse killing and feeding behaviors. d-Amphetamine (10, 20, and 30 μg) injected into each lateral ventricle, suppressed mouse kiling, food, and water intake in a dose-dependent manner. Bilateral adminstration of d-amphetamine (20 μg) into the central amygdaloid nucleus abolished mouse killing behavior but did not affect feeding and drinking. By contrast, bilateral amphetamine injections into the substantia nigra, or into the ventral region of the caudate nucleus, did not suppress mouse killing behavior, but significantly decreased food and water intake. The lateral hypothalamus was sensitive to d-amphetamine injections, which suppressed mouse killing and food intake as well as water intake. d-Amphetamine injections into the nucleus accumbens produced inconsistent effects on mouse killing and feeding. Our observations suggest a differentiation of the neural sites that mediate feeding from those underlying mouse killing behavior.     

Evidence for the correcting-mechanism explanation of the Kanizsa amodal shrinkage

An object phenomenally shrinks in its horizontal dimension when shown on a 2-D plane as if the central portion of the object were partially occluded by another vertical one in 3-D space (the Kanizsa amodal shrinkage). We examined the predictions of the correcting-mechanism hypothesis proposed by Ohtsuka and Ono (2002, Proceedings of SPIE 4864 167-174), which states that an inappropriate operation of the mechanism that corrects a phenomenal increase in monocularly visible areas accompanied by a stereoscopic occluder gives rise to the illusion. In this study we measured the perceived width (or height in experiment 3) of a square seen behind a rectangle, while controlling other factors which potentially influence the illusion, such as the division of space or depth stratification. The results of five experiments showed that (a) the perceived width was not influenced when the occluder had a relatively large binocular disparity, but was underestimated when the occluder did not have disparity, and (b) the shrinkage diminished when the foreground rectangle was transparent, was horizontally oriented, or contained no pictorial occlusion cues. These results support the hypothesis that the correcting mechanism, triggered by pictorial occlusion cues, contributes to the Kanizsa shrinkage.     

Compound self-motion perception induced by two kinds of optical motion

Two kinds of flow patterns consisting of random dots were presented simultaneously to subjects to investigate whether or not two kinds of vection occur simultaneously. One pattern induces vertical linear self-translation, whereas the other induces self-rotation around a vertical axis (when either pattern is presented alone). Three sets of conditions were tested. The first condition was one in which random dots moved in a summed direction of both flow vectors. In the second condition, both flow patterns were simply overlaid, whereas in the third condition, the two kinds of flow patterns were overlaid with a depth separation produced by binocular disparity. The subjects perceived both kinds of vection simultaneously in directions opposite to those of the corresponding flow components under the first condition, whereas either vection occurred mainly under the second condition. Under the third condition, both of the flows induced each kind of vection simultaneously, despite there being no physical vector summation of dot motion. The background flow induced vection in a direction opposite to the flow direction, whereas the foreground flow induced vection in the same direction as the flow direction. These results show that induced self-translation and induced self-rotation can occur simultaneously in two ways.     

Reliability and validity of a Japanese version of the Eating Disorder Inventory

The rapid increase of patients with eating disorders in Japan has male necessary the reliable and valid measurement of psychological factors in eating disorders. The purpose of this study was to examine the reliability and validity of the Japanese version of the Eating Disorder Inventory. 766 females without eating disorders and 139 female patients with eating disorders responded to the Eating Attitude Test and the Eating Disorder Inventory. Principal factor extraction with promax rotation isolated 9 interpretable factors with satisfactory internal consistency (Cronbach alpha range=.74-.90). Compared with controls, patients scored significantly higher on all factors after minimizing the influence of Body Mass Index. There were strong correlations among factor scores and scores on the Eating Attitudes Test, particularly among patients. These results indicate the Eating Disorder Inventory as showing psychometrically sound internal consistency and concurrent validity.     

Relationship between vection and motion perception in depth

This study examined the effects of cues to motion in depth – namely, stereoscopic (i.e., changing-disparity cues and interocular velocity differences) and changing-size cues on forward and backward vection. We conducted four experiments in which participants viewed expanding or contracting optical flows with the addition of either or both cues. In Experiment 1, participants reported vection by pressing a button whenever they felt it. After each trial, they also rated the magnitude of the vection (from 0 to 100). In Experiments 2 and 3, the participants rated the perceived velocity and motion-in-depth impression of the flows relative to standard stimuli, respectively. In Experiment 4, the participants rated the perceived depth and distance of the display. We observed enhancements in vection, motion-in-depth impression, and perceived depth and distance when either or both types of cues indicated motion-in-depth, as compared to those when the cues did not (Experiments 1, 3, and 4). The perceived velocity changed with cue conditions only for the high velocity condition (Experiment 2). Correlational analyses showed that the vection can be best explained by the motion-in-depth impression. This was partially supported by the multiple regression analyses. These results indicate that the enhancement of vection caused by cues is related to the impression of motion-in-depth rather than the perceived velocity and perceived three-dimensionality.     

One percent ability and ninety-nine percent perspiration: a study of a Japanese memorist

In 1987, Hideaki Tomoyori, a Japanese memorist, set a world record for reciting the first 40,000 digits of pi. The authors report results from a series of tests that give a view of Tomoyori's memory performance compared with that of a control group, matched for age and educational level. He showed very good scores on tasks with digits, such as digit memory span tasks and 5 x 5 number matrix learning, although some of the control participants were nearly as good. In contrast, his performance was not particularly good for learning word lists and story recall. Overall, his performance on the tasks does not suggest that he has superior cognitive abilities. We believe that his extraordinary memory performance in reciting the digits of pi results from his effective use of a combination of digit-syllable transformations and imagery mnemonics developed from extensive practice. These results are consistent with the skilled memory framework.     

Experimental study on co-evolution of categorical perception and communication systems in humans

In this paper, we present an experiment that integrates a semiotic investigation with a dynamical perspective on embodied social interactions. The primary objective is to study the emergence of a communication system between two interacting individuals, where no dedicated communication modalities are predefined and the only possible interaction is very simple, non-directional, and embodied. Throughout the experiment, we observe the following three phenomena: (1) the spontaneous emergence of turn-taking behaviour that allows communication in non-directional environments; (2) the development of an association between behaviours and perceptive categories; (3) the acquisition of novel meaning by exploiting the notion of complementary set theory.     

Intergroup retaliation and intra‐group praise gain: The effect of expected cooperation from the in‐group on intergroup vicarious retribution

Intergroup vicarious retribution is the phenomenon whereby, after an out‐group member attacks an in‐group member, a member of the victim's group retaliates against a member of the perpetrator's group. This study examined the effect of expected cooperation from the in‐group on intergroup vicarious retribution through intra‐group reputation based on praise gain and exclusion avoidance. In the experiment, we conducted a one‐on‐one match in which, after participants learned that an out‐group member (as the winner) had imposed a fine on an in‐group member (as the loser) in a previous round, winning participants were allowed to impose an arbitrary fine on the other losing out‐group member. As a result, participants imposed a larger fine on their out‐group member opponent in retaliation when they were expected by in‐group members to cooperate than when such cooperation was not expected. Furthermore, participants regarded a fine as intra‐group cooperation. Since a path analysis revealed a mediating effect of praise gain, but no mediating effect of exclusion avoidance, expected cooperation from in‐group members facilitated vicarious retribution because those involved in retribution sought praise from other in‐group members. These findings suggest that the intra‐group reputation dynamics of expected cooperation and praise gain escalate intergroup conflict.     

Young children's awareness of socially mediated rejection of food: Why is food dropped at the table “dirty”?

We sometimes drop food at mealtimes. Once dropped, the food becomes dirty or inedible not only in a physical but also in a social sense. Even without physical contact with contaminants, we may not eat fallen food in some social contexts, e.g., a high-quality restaurant. Such thinking is referred here as “socially mediated rejection.” In Study 1, Japanese children were observed during mealtimes at home and at school. Even 2-year-olds reacted to fallen food differently between at school and home. In Study 2, 4- and 6-year-olds and adults were presented several stories in an experiment, and were asked to predict the story character's bodily and emotional reactions to eating fallen food. Preschoolers noticed that physically contaminated food would cause bodily harm more than socially rejected food.