Relationship between manual preferences for object manipulation and pointing gestures in infants and toddlers

The aim of this study was to measure the pattern of hand preferences for pointing gestures as a function of object‐manipulation handedness in 123 infants and toddlers (10–40 months). The results showed that not only right‐handers but also left‐handers and ambidextrous participants tended to use their right hand for pointing. There was a significant correlation between manual preferences and pointing lateralization. Further analyses showed that the correlation between these two indexes was at its strongest during two key phases of language development (i.e. vocabulary spurt and syntax improvement) and weakened to become nonsignificant in the interim. These findings support the view that humans have a specialized area for communicative gestures and language in the left cerebral hemisphere that may be independent of the system controlling the purely motor functions of hand use.     

Prenatal testosterone treatment potentiates the aggression‐inhibiting effect of the neurosteroid dehydroepiandrosterone in female mice

The neurosteroid dehydroepiandrosterone (DHEA) is a powerful inhibitor of aggression in murine models when given for 15 days and potentially may be useful in the management of inappropriate human aggression. Although the biosynthesis and metabolism of DHEA have been described, little is known about the potential effect of the steroidal environment during sexual differentiation on the subsequent response to DHEA. Whether prenatal androgen exposure influences the subsequent response to DHEA was assessed by comparing the effect of DHEA (80 μg/d) on aggression in female offspring where dams were treated with 1, 10, or 100 μg of testosterone (T) on days 15 to 18 of gestation (Experiment I) or that developed in different uterine positions (Experiment II). The results showed that DHEA decreased attack behavior in general and that the 100‐μg prenatal T treatments enhanced the antiaggressive effect of this neurosteroid. Neither the lower doses of exogenously administered T nor the uterine position led to an enhanced response to DHEA. In addition, whether DHEA produced changes in social and nonsocial activities was examined. In the 100‐μg T females, DHEA increased the duration of the former and decreased the frequency and duration of the latter, indicating that it was not a general decrement in behavioral expression that mediated the enhanced response to the antiaggressive effect of DHEA. In the second experiment, DHEA treatment led to increased frequencies of social nonaggressive and nonsocial activities. However, the uterine positions × treatment interactions were not significant, demonstrating that contiguity to male fetuses did not differentially affect the response to DHEA. Aggr. Behav. 27:130–138, 2001. © 2001 Wiley‐Liss, Inc.     

Student learning as the basis for reinforcement to the instructor

The present study reinforced the two instructors of two students with profound mental retardation first for the instructors' training behaviors, then for improved student learning in a multiple baseline across responses design. Reinforcement of the instructors' training behaviors increased their training behaviors, replicating the findings of previous studies, but had no effect on student learning. When the reinforcement for the instructors was instead made contingent upon student learning, the student learning improved and the instructors' high level of training behaviors was maintained. In addition, the instructors began to request training for themselves. These findings suggest that staff motivation programs for instructors might usefully base the reinforcers not only on the instructor's performance, but on the progress of their students.     

Mental states in animals: cognitive ethology

This article addresses the question of mental states in animals as viewed in 'cognitive ethology'. In effect, this field of research aims at studying naturally occurring behaviours such as food caching, individual recognition, imitation, tool use and communication in wild animals, in order to seek for evidence of mental experiences, self-awareness and intentionality. Cognitive ethologists use some philosophical concepts (e.g., the 'intentional stance') to carry out their programme of the investigation of natural behaviours. A comparison between cognitive ethology and other approaches to the investigation of cognitive processes in animals (e.g., experimental animal psychology) helps to point out the strengths and weaknesses of cognitive ethology. Moreover, laboratory attempts to analyse experimentally intentional behaviours such as deception, the relationship between seeing and knowing, as well as the ability of animals to monitor their own states of knowing, suggest that cognitive ethology could benefit significantly from the conceptual frameworks and methods of animal cognitive psychology. Both disciplines could, in fact, contribute to the understanding of which cognitive abilities are evolutionary adaptations.     

Simulation study of a decision-making model of squash competition, phase one: The analysis of the protocol

This study aims at specifying some of the cognitive processes underlying decision-making in squash competition. More specifically, the study focuses on the strategy of the defending player (D) when chosing among three categories of preparation (total preparation for one particular event, partial preparation in favor of one event and absence of biased preparation). D is viewed as an information processing system (IPS) placed in a problem-solving situation, the problem being what decision to reach. The results obtained in a preceding investigation about the nature of the information processed by a player to anticipate and prepare for the opponent's shot in a real game setting, are used to determine a typical protocol of the behavior of D. The analysis of this protocol allows one to formally define (in Backus-Normal-Form) the problem space of D which is also D's internal representation of the task environment. From the problem space are derived (1) the problem behavior graph depicting the search of D through his problem space for a solution, and (2) the production system (a set of conditional statements, each expressing what to do under specific conditions) defining the logic of the search. The results of this first phase of the simulation study of a decision-making model of squash competition show that the cognitive strategy of D is based upon the use of a specific preformed algorithm. This algorithm could be stored in some long-term memory and activated by the current state of information in short-term memory. Finally, the proposed model also leads to the suggestion that the cognitive strategy of the performer may be influenced by a variety of factors such as the experience of the player, the time pressure, the expectancies, the performer's confidence in his predictions and the mistakes caused by incorrect predictions.     

Some effects of congenital spasticity on fundamental frequency

5 normal speakers and 5 speakers with congenital upper motor-neuron damage repeatedly spoke a three-work sentence stressing the first, second, or third words. Fundamental frequency was measured for each word and over each sentence. Analysis showed that the spastics' mean fundamental frequency was significantly higher than the normals', regardless of utterance. Also, spastics were more restricted in their prosodic maneuvering above this average fundamental frequency. Despite this finding, the spastics were capable of producing consistent stress patterns with normal variability.     

Emotional prejudice,essentialism, and nationalism The 2002 Tajfel lecture

In explaining differences between groups, people ascribe the human essence to their ingroup and consider outgroups as less human. This phenomenon, called infra‐humanization, occurs outside people's awareness. Because secondary emotions (e.g. love, hope, contempt, resentment) are considered uniquely human emotions, people not only attribute more secondary emotions to their ingroup than to outgroups, but are reluctant to associate these emotions with outgroups. Moreover, people behave less cooperatively (in terms of altruism, imitation, and approach) with an outgroup member who expresses himself through secondary emotions. Infra‐humanization occurs for high and low status groups, even in the absence of conflict between groups. It does not occur when the outgroup target is adequately individualized, by a complete name or through perspective taking, for instance. The differential familiarity with the ingroup and the outgroup cannot explain infra‐humanization. Yet, preliminary results show that subjective essentialism and ingroup identification may mediate the effects of infra‐humanization. A connection is made between nationalism and infra‐humanization. Copyright © 2003 John Wiley & Sons, Ltd.