Relative sensitivity of the mutual exclusivity and novel-name-nameless category assumptions

The mutual exclusivity (ME) assumption states that children affix a novel label to only one unfamiliar object, while the novel-name-nameless category (N3C) assumption states that children affix a novel label to multiple unfamiliar objects. To compare the relative sensitivity of the two assumptions, two types of tasks, with two trials in each, were given to 5-year-olds. In the first trial of each task, all children selected only the unfamiliar object for a novel label, which was consistent with the ME assumption. For the task which did not have the same unfamiliar object in the two trials, 94% of the children selected the object with the same shape but black-white reversed image in the second trial, which was consistent with the N3C assumption. For the task which had the same unfamiliar object in the two trials, 43% of the children selected the same object in the second trial, which was consistent with the ME assumption, and 48% of them selected the object with the same shape but reversed image, which was consistent with the N3C assumption. The findings suggest that the ME and N3C assumptions can be flexibly applied to children's word learning.     

Emotional attention modulates microsaccadic rate and direction

Involuntary microsaccades and voluntary saccades reflect human brain activities during attention and cognitive tasks. Our eye movements can also betray our emotional state. However, the effects of attention to emotion on microsaccadic activity remain unknown. The present study was conducted in healthy volunteers to investigate the effects of devoting attention to exogenous emotional stimuli on microsaccadic response, with change in pupil size as an index of sympathetic nervous system activity. Event-related responses to unpleasant images significantly inhibited the rate of microsaccade appearance and altered pupil size (Experiment 1). Additionally, microsaccadic responses to covert orienting of attention to emotional stimuli appeared significantly in the anti-direction to a target, with a fast reaction time (Experiment 2). Therefore, we concluded that attentional shifts induced by exogenous emotional stimuli can modulate microsaccadic activities. Future studies of the interaction between miniature eye movements and emotion may be beneficial in the assessment of pathophysiological responses in mental disorders.     

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Microstructural investigations have been carried out on a fully lamellar Ti₄₉Al₄₇Cr₂Nb₂     

Load Perturbation Facilitates Interpersonal Error Compensation in a Dyadic Force Production Task

The present study tested the hypothesis that a load perturbation facilitates interpersonal compensation for force error. Ten groups performed both control and perturbation conditions. In the control condition, a target discrete peak force was the sum of 10% of the maximum voluntary contraction produced by two participants. In the perturbation condition, two cooperative participants a and b produced the same target force as the control condition, and the force produced by a non-cooperative participant c increased or decreased the total forces produced by participants a and b. The load perturbation facilitated interpersonal compensation for force error but negatively affected performance during joint action. The participants further learned to improve the error compensation over experimental blocks in the perturbation condition.     

Recovery from object substitution masking induced by transient suppression of visual motion processing: a repetitive transcranial magnetic stimulation study

Object substitution masking is a form of visual backward masking in which a briefly presented target is rendered invisible by a lingering mask that is too sparse to produce lower image-level interference. Recent studies suggested the importance of an updating process in a higher object-level representation, which should rely on the processing of visual motion, in this masking. Repetitive transcranial magnetic stimulation (rTMS) was used to investigate whether functional suppression of motion processing would selectively reduce substitution masking. rTMS-induced transient functional disruption of cortical area V5/MT+, which is important for motion analysis, or V1, which is reciprocally connected with V5/MT+, produced recovery from masking, whereas sham stimulation did not. Furthermore, masking remained undiminished following rTMS over the region 2 cm posterior to V5/MT+, ruling out nonspecific effects of real stimulation and confirming regional specificity of the rTMS effect. The results suggest that object continuity via the normal function of the visual motion processing system might in part contribute to this masking. The relation of these findings to the reentrant processing view of object substitution masking and other visual phenomena is discussed.     

Reconciliation and variation in post-conflict stress in Japanese macaques (Macaca fuscata fuscata): testing the integrated hypothesis

Reconciliation in primates, a post-conflict affiliative interaction between former opponents, appears to have two functions: (1) to repair relationship damaged by aggression such that animals who share more valuable relationships are more likely to reconcile, and (2) to reduce the post-conflict uncertainty and stress of former combatants. The 'integrated hypothesis' of reconciliation links these functions by arguing that the disturbance of a valuable relationship by aggression should result in particularly high levels of stress, which in turn should facilitate efforts to reconcile and thus gain relief from post-conflict stress. A key prediction of the integrated hypothesis is that victims of aggression suffer more stress following conflicts with individuals with whom they share a valuable relationship. In this article, we test the integrated hypothesis by observing the post-conflict behaviour of victims among a free-ranging provisioned troop of Japanese macaques (Macaca fuscata fuscata) living in Shiga Heights, Nagano, Japan. In this troop, monkeys reconciled roughly one in seven conflicts. The only factor that we could significantly relate to the occurrence of reconciliation was kinship; kin reconciled more frequently than non-kin did. Receiving aggression increased and reconciliation reduced the probability of being re-attacked after aggressive interactions, supporting the hypothesis that reconciliation repairs relationships. Victims' self-directed behaviour (SDB) – a behavioural index of stress comprising increases in scratching, self-grooming, and body-shaking – was elevated following aggression but decreased rapidly following reconciliation, supporting the idea that reconciliation functions to reduce post-conflict stress. Post-conflict SDB varied as follows: (1) victims showed a higher level of stress following aggression with kin than with non-kin, and (2) juvenile victims were less distressed than adults. The level of post-conflict SDB performed by juveniles following conflicts with kin was indistinguishable from that performed by adults but was greatly reduced following attacks from non-kin. These results indicate that post-conflict SDB keenly reflects the value of relationships between opponents, and that the post-conflict behaviour of free-ranging Japanese macaques fits the predictions of the integrated hypothesis. Accepted after revision: 11 September 2001 Electronic Publication     

Failure of Retrospective Inference in Rats' Taste Aversion

Three experiments explored the possibility of retrospective inference in the rat. Experiment 1 revealed that poisoning of an element of a taste compound after single compound poisoning enhanced aversion to the other element, and that presentation of an element without poison after the compound poisoning reduced aversion to the other element. These results were opposite to those predicted by retrospective inference. Experiment 2 eliminated some confounding variables and examined the effect of element poisoning after compound poisoning. The result again was opposite to what the retrospective view predicts. The results, however, accorded with the idea that within-compound learning was established during compound presentation, and subsequent poisoning or nonpoisoning of one element affected response to the other element via the within-compound learning. In Experiment 3, the possibility of within-compound learning was reduced by using sequential presentation of tastes, but there was no indication of retrospective inference even under this condition.     

The neural correlates of driving performance identified using positron emission tomography

Driving is a complex behavior involving multiple cognitive domains. To identify neural correlates of driving performance, [15O]H2O positron emission tomography was performed using a simulated driving task. Compared with the resting condition, simulated driving increased regional cerebral blood flow (rCBF) in the cerebellum, occipital, and parietal cortices. Correlations between rCBF and measurements of driving performance were evaluated during simulated driving. Interestingly, rCBF in the thalamus, midbrain, and cerebellum were positively correlated with time required to complete the course and rCBF in the posterior cingulate gyrus was positively correlated with number of crashes during the task. These brain regions may thus play roles in the maintenance of driving performance.     

Repeated writing facilitates children’s memory for pseudocharacters and foreign letters

In a logographic language culture,repeated (hand)writing is a common memory strategy for learning letters and Chinese characters. The purpose of this paper is to determine whether this strategy facilitates children’s memory for pseudologographic characters and foreign letters. It also explores which aspect of writing, the use of stroke orders or the writing action itself, is responsible for the effect. First, third, and fifth grade Japanese children participated in the study. Results showed that, for all the subjects, characters and letters were better recalled when learned by writing rather than by looking only (Experiments 1 and 4). The advantage of writing was decreased, however, when the proper writing action prevented (i.e., when subjects were instructed to trace or write without feedback; Experiments 3 and 4) but not when the proper stroke orders were prevented (i.e., when subjects were instructed to write in reverse or random orders; Experiment 2). The results indicate that the writing action, rather than the use of stroke orders, is responsible for the effect.