Simulation of the filtering role of habituation to stimuli

In the context of a medium-term study designed to integrate the simulation of different types and processes of learning-such as classical, operant, and some cognitive types--one must start with other more elementary ones that are facilitators of the more complex types and processes. Of special interest is habituation, owing to the filtering out of irrelevant stimuli, which means that the simulated agent does not have to respond to them. This paper presents two difference functions constructed to computationally simulate the characteristics that define habituation. The behavior of these functions is described, as are differences arising from stimulus intensity and interstimulus intervals. Results are compared with existing empirical data.     

The immoral gene: Does it really exist?

Over the last years several European patents were opposed for protecting technology violating the morality requirement under Article 53(a) EPC. Attempts have been made by the Appeal Boards of the European Patent Office (EPO), as well as by amendments introduced into the Implementing Regulations of the European Patent Convention (EPC), to address this sensitive patentability requirement more precisely. The most recent hot topic coming up in this context is the patentability of stem cells. It is to be expected that this discussion will still go on in the field of biotechnological inventions for the next several years. An earlier version of this paper was presented at an international conference, “The Ethics of Intellectual Property Rights and Patents,” held in Warsaw, Poland on 23–24 April, 2004.     

Different effects of dual task demands on the speech of young and older adults

Young and older adults provided language samples in response to elicitation questions while concurrently performing 3 different tasks. The language samples were scored on three dimensions: fluency, grammatical complexity, and content. Previous research had suggested the hypothesis that the restricted speech register of older adults is buffered from the costs of dual task demands. This hypothesis was tested by comparing language samples collected during a baseline condition with those produced while the participants were performing the concurrent tasks. The results indicate that young and older adults adopt different strategies when confronted with dual task demands. Young adults shift to a restricted speech register when confronted with dual task demands. Older adults, who were already using a restricted speech register, became less fluent although the grammatical complexity and informational content of their speech was preserved. Hence, some but not all aspects of older adults' speech are buffered from dual task demands.     

The odd-even effect in addition: an analysis per problem type

The odd-even effect is a well documented finding in the literature on mental arithmetic, at least for multiplication. It implies that false answers with the same parity as the correct answer are rejected more slowly than false answers with a different parity. For addition, this effect is not so well documented. The study by Krueger and Hallford (1984) is the only one that investigated odd-even effects for addition. However, they did not investigate odd-even effects per problem, even though there are indications that problem type can modulate odd-even effects for multiplication (Lemaire & Reder, 1999). Therefore, we wanted to get more insight into odd-even effects for addition by investigating odd-even effects per problem type. Our results extended the findings of Krueger and Hallford. First of all, we found an interaction between split and problem type. The most important and new result of present study, however, was a strong parity effect for E + E problems. We discuss our results in terms of two alternative explanations for odd-even effects, namely use of a parity rule on the one hand and familiarity with even outcomes on the other.     

Social dominance orientation,prejudice, and discrimination: A new computer-based method for studying discriminatory behaviors

A number of studies have shown that the scale of social dominance orientation (SDO), used to measure the degree of preference for inequality among social groups, is a predictive measure of social and political attitudes toward stigmatized outgroups. However, the relationship between SDO and discrimination has received little attention. The main goal of this study was to assess the validity of a new computer-based method used to measure discriminatory behaviors in a laboratory setting. An additional goal was to test the mediating role of prejudice in the relation between SDO and discrimination. The results provide a first validation of this new method and demonstrate that the effect of SDO on discrimination is mediated by prejudice.     

A matter of facts

We discuss the justification of Bickle's “ruthless” reductionism. Bickle intends to show that we know enough about neurons to draw conclusions about the “whole” brain and about the mind. However, his reductionism does not take into account the complexity of the nervous system and the fact that new properties emerge at each significant level of integration from the coupled functioning of elementary components. From a methodological point of view, we argue that neuronal and cognitive models have to exert a mutual constraint(MC) on each other. This approach would refuse to award any priority of cognitive approaches over neuroscience, and reciprocally, to refuse any priority of neuroscience over cognitive approaches. MC thus argues against radicalreductionism at the methodological level.     

Measuring Impulsivity in School-Aged Boys and Examining Its Relationship with ADHD and ODD Ratings

Seven different laboratory measures of impulsivity were administered to a group of 165 school-aged boys. Parents' and teachers' ratings of Attention Deficit and Hyperactivity Disorder and Oppositional/Defiant Disorder were also obtained. Factor analyses of impulsivity measures revealed the existence of a strong Inhibitory Control Factor including measures derived from Stop Task, the Continuous Performance Test, the Matching Familiar Figures Test, and the Circle Tracing Task. Other forms of impulsivity like resistance to interference, the Wisconsin Card Sorting Test and efficiency in the DRL Task loaded on a second independent factor. The Inhibitory Control factor was correlated with ADHD ratings, whereas the second factor was slightly related to the presence of ODD symptoms. Discussion is focused on the relevance of inhibitory control in impulsivity and ADHD research.     

Directed forgetting in working memory: age-related differences

This study explored the effects of ageing on working memory by means of the directed forgetting procedure designed by Reed (1970). Memory for a letter trigram was compared in conditions where it was either presented alone (single-item), or followed by a second trigram to be recalled (interference), or followed by a second trigram to be forgotten (directed forgetting). The results clearly indicated that elderly participants inhibited the no-longer-relevant information less efficiently (recall in the single-item condition - recall in the directed forgetting condition), as predicted by the model of Hasher and Zacks (1988). However, the results also demonstrated that sensitivity to interference (recall in the single-item condition - recall in the interference condition) increased in the condition in which no inhibition was directly required.