Neural Network Models and Mechanisms of Strategy Development

The focus of this paper is mechanisms that may be responsible for intellectual and developmental differences in the cognitive strategies of typical and atypical children, including those with mental retardation. The discussion of these mechanisms is based on behavioral experiments on external memory strategies and on a set of neural network models designed for these tasks. Following the review of the external memory research, the rationale for using neural network models, how they have been used in other research, and their specific application to intellectual and developmental differences in external memory, including the results of several simulations, are reviewed. This is followed by a discussion of the mechanisms of intellectual differences and developmental change included in the models and some challenges for this type of modeling. Neural network modeling is discussed as an asset to research on cognitive development.     

Gender role stereotyping in Australian radio commercials

Most previous research into gender role stereotypes in the mass media has concentrated on television or print. Only one content analysis (Furnham & Schofield, 1986) has examined radio content, finding patterns of bias in British radio commercials consistent with, though less marked than, those in television commercials. The present study sought to determine whether similar patterns obtain in another Western country’s radio commercials collected approximately a decade later. Over 100 Australian radio ads were content analyzed, and results very similar to those of the earlier study were obtained. The findings are discussed in terms of their implications for studies of gender role development and audience reactions to media content. We are grateful to Elyse Frankel and Jason Low for assistance in data coding and checking, and to two anonymous reviewers for constructive commentaries on an earlier version.     

Hippocampal synaptic plasticity during instrumental learning

present research examined the role of hippocampal NMDA-dependent synaptic potentiation on appetitive instrumental conditioning under a continuous reinforcement schedule. In the first experiment, low (.025 mg.kg) or moderate (.05 mg/kg) dosages of the NMDA receptor antagonist, MK801, failed to increase the number of training days required to reach acquisition criterion; number of training days required to reach criterion for extinction were also unaffected. In the second experiment, a higher dosage (.10 mg/kg) of MK801 or induction of long-term potentiation failed to alter the number of responses occurring during acquisition. These data suggest that hippocampal synaptic potentiation does not play a prominent role in instrumental learning with simple contingency conditions. It is suggested that hippocampal LTP reflects a perceptual process that contributes differentially to spatial cognition, classical and instrumental conditioning.     

THE CREDIBLE SHRINKING ROOM:

Abstract— Becoming a proficient symbol user is a universal developmental last in the first years of life, but delecting and mentally representing symbolic relations can be quite challenging for young children To test the extent to which symbolic reasoning per se is problematic, we compared the performance of 2-year-olds in symbolic and nonsymbolic versions of a search task. The children had to use their knowledge of the location of a toy hidden in a room to draw an inference about where to find a miniature toy in a scale model of the room (and vice versa) Children in the nonsymbolic condition believed a shrinking machine had caused the room to become the model They were much more successful than children in the symbolic condition, for whom the model served as a symbol of the room The symbol understanding and use.     

Deterrence, Opportunity, and Choice

Traditional studies of deterrence have focused on punishment with less regard for the rewards of both crime and noncrime. Influenced by work in economics and behavioral psychology, more recent studies have departed from tradition by incorporating rewards for crime. To this extent, they should be regarded as advances over the more traditional approaches. Notwithstanding these advances, variations in both the probability and magnitude of reward for noncrime have not been systematically included in these more recent theories of choice. In an attempt to determine whether opportunities for noncrime are either central or trivial to the criminal decision-making process, the present study fitted two alternative models to experimental data involving risk-taking: (a) the economic utility model employed by Piliavin, Gartner, Thornton, and Matsueda (1986) in their study of criminal choice; and (b) the satisfaction balance model developed by Gray and Tallman (1984). Results showed that while both models explained significant amounts of variation in the dependent variable, the Gray-Tallman model provided a substantially better fit of the data. Despite limitations inherent in experimental studies as, for example, limitations surrounding the issue of external validity, the findings strongly suggest that opportunities for noncrime are as important as rewards and costs for crime in the process by which criminal decisions are made.     

Assisting At-Risk College Students With Attributional Retraining and Effective Teaching1

Attributional retraining appears to be an effective remedial intervention for college students. However, the potential moderating effects of student and classroom characteristics have not yet been investigated systematically. In two studies, attributional retraining was provided to low- and high-risk students, followed by a videotaped lecture presented by either an ineffective or effective instructor. Attributional retraining enhanced achievement on a lecture-based achievement test only when combined with effective teaching, improving the achievement of students who had previously performed poorly (Experiment l), and of low-achieving externals (Experiment 2). The intervention provided no advantage for previously successful students and low-achieving internals. Moreover, attributional retraining induced a more internal attribution profile in students with an external locus, and increased expectations of future success in both externals and internals, but again only when students also received effective instruction. These results suggest that contextual factors related to the classroom, such as quality of instruction, and individual differences have to be considered when developing attributional retraining programs.     

A PRELIMINARY COMPARISON OF REINFORCER ASSESSMENT METHODS FOR CHILDREN WITH ATTENTION DEFICIT HYPERACTIVITY DISORDER

We evaluated the relative treatment utility of a verbal forced-choice questionnaire, child nomination, and direct observation for identifying the most potent reinforcers for children with attention deficit hyperactivity disorder. Results demonstrated that all three methods were more likely to disagree than to agree, that a forced-choice format may enhance verbal reinforcer assessment, and that further development and evaluation of verbal reinforcer-assessment methods are needed.     

The third person effect: Social distance and perceived media bias

Two studies were conducted to determine the conditions under which the third person effect (Davison, 1983) operates. It was hypothesized that the effect would be accentuated as target groups of others became more remote from the self. A second objective was to determine whether the effect operates in the absence of overtly persuasive intent in the media. Television programmes concerned with moral themes were employed as stimuli. The results further support Davison's claim that overestimation of media effects is greater when people imagine the responses of others whom they do not know than those of familar individuals. The results also indicate that the third person effect does operate in the absence of perceived persuasive intent, but is accentuated when bias is perceived by viewers.