Discrete dynamic choice: An extension of the choice models of thurstone and luce

The present paper deals with the extension of two well-known static discrete choice theories to the dynamic situation in which individuals make choices at several points in (continuous) time. A dynamic version of Luce's Axiom, “independence from irrelevant alternatives”, is proposed and some of its implications are derived. In the static case Yellott (J. Math. Psych. 1977, 15, 109–146) and others have demonstrated that an independent random utility model generated from the extreme value distribution exp(?e^?ax?b) becomes equivalent to Luce's Axiom. Yellott also introduced an axiom called “invariance under uniform expansions of the choice set”, and he proved that within the class of random utility models with independent identically distributed utilities (apart from a location shift) this axiom is equivalent to Luce's Axiom. These results are extended to the dynamic situation and it is shown that if the utility processes are expressed by so-called extremal processes the corresponding choice model is Markovian. A nonstationary generalization is proposed which is a substantial interest in applications where the parameters of the choice process are influenced by previous choice experience or by time-varying exogenous variables. In particular, it is demonstrated that the nonstationary model is Markovian if and only if the joint choice probabilities at two points in time have a particular form. Thus, the paper provides a rationale for applying a specific class of Markov models as the point of departure when modelling mobility processes that involve individual discrete decisions over time.     

Does reward depletion influence spatial memory performance?

If spatial memory tasks are considered as foraging problems, it can be predicted that rats' difficulty in learning a win-stay task—revisiting part of a maze where food has recently been found—should be partly overcome if the food is not fully consumed at the first visit (nondepleted reward) rather than being all eaten (depleted reward). Three experiments confirmed and further analysed this result. Experiments 1 and 2 showed that it does not depend on the amount of food initially found; nor is win-stay performance affected by the amount of food actually eaten. Experiment 3 suggested that the effects of nondepleted reward are mainly due to the animals' being interrupted while eating, and very little to the fact that uneaten food is left behind. The results are discussed with regard to their implications for learning theory, and for the application of foraging theory to learning and memory experiments.     

Contrasting cases of Italian agrammatic aphasia without comprehension disorder

This study examined the effects of different concurrent verbal memory loads on a recognition accuracy task using bilaterally presented nouns. Four different memory load conditions were examined. They varied along a size dimension of either three or six words and along a complexity dimension of either easy concrete nouns or difficult highly abstract nouns. In each of the above conditions and in one control group, order or word report was controlled and in a second control group subjects were free to report the lateralized words in any order they wished. There were 20 subjects in each of the six groups. As expected, a significant right visual field superiority for verbal processing was obtained. there were no main effects of size of memory load nor complexity of m emory load on the laterality patterns. More subtle fluctuations in the patterns were found in the form of significant interactions between memory load, order of word report, and visual field. These interaction effects suggest that words reported second in the bilateral task, are more susceptible to the interfering effects of either larger or more complex memory loads. This is particularly true for right visual field words. While these data generally support a structural model of hemispheric organization, the interaction effects suggest that modifications must be made to the basic model to account for such factors as hemispheric capacity limits and order of report in the bilateral task.     

Attentional biases and the right-ear effect in dichotic listening

Most dichotic listening experiments permit subjects to deploy attention in any way they choose. We argue that this adds uncontrolled variance to the observed right-ear advantage. In the first experiment, more robust laterality effects were obtained in an identification task with focused than with divided attention. Such differences were not found in the second experiment, when a detection procedure was used. Virtually all the laterality effect observed in the second study could be attributed to subjects who were biased attenders, in the sense that they exhibited more intrusions from the right ear to the left than vice versa. However, rather than indicating that laterality effects are simply attentional bias, this effect can be attributed to an asymmetry of perceptual discrimination.     

Conflict,learning, and Piaget: Comments on Zimmerman and Blom's “Toward an empirical test of the role of cognitive conflict in learning”

A brief historical account dealing with the concept of psychic conflict is first presented, followed by an examination of Piaget's equilibrium/equilibration model and the relevance of the concept of conflict to that model. A critical analysis of B. J. Zimmerman and D. E. Blom (Developmental Review, 1983, 3, 18–38) is then presented, after which suggestions are made regarding future directions research efforts pertaining to Piaget's conflict/learning formulation might fruitfully take.     

An observational case study of failure in social problem-solving

An observationally based assessment of social problem-solving skill was contrasted with more traditional testing methods. A preschool child with low social success was chosen for a demonstration profile analysis. The relative frequencies of the social goals, strategies, and targets shown by this child during free play were plotted in relation to that of his same-sex peer group. Parallel profiles of his relative success with specific goals, strategies, and targets were also constructed and compared to relevant group means and standard deviations. Specific social problem-solving strengths and weaknesses were identified from these profiles, using both intra- and interindividual analyses. The benefits and limitations of this approach for measurement and treatment of social problem-solving deficits were discussed.     

The relationship of mathematics self-efficacy expectations to the selection of science-based college majors

The major purpose of the present study was to investigate the relationship of mathematics self-efficacy expectations to the selection of science-based majors in college males and females. Based on results obtained from a pilot sample of college students, an instrument assessing mathematics self-efficacy expectations was developed. The items used in the mathematics self-efficacy scale included everyday math tasks, math problems, and math-based college courses. Subjects, 153 female and 109 male undergraduates, completed the mathematics self-efficacy scale, the Bem Sex Role Inventory, an adapted version of the Fennema-Sherman Mathematics Attitudes Scales, and a questionnaire concerning their college major choices. Results indicated that mathematics self-efficacy expectations were significantly related to the extent to which students selected science-based college majors, thus supporting the postulated role of cognitive mediational factors in educational and career choice behavior. In addition, the math-related self-efficacy expectations of college males were significantly stronger than were those of college females. Implications of the findings for the process of educational and career decision-making are discussed.     

Sex differences in the levels of generality of values/preferences related to work

The current literature on sex differences in values/preferences related to work appears polarized around two apparently contradictory sets of findings and conclusions. One set of studies fails to detect sex differences. The other set of studies indicates that males are more concerned about money, independence, security, and career goals, while females appear more concerned about people and environmental issues at work. Following W. D. Siegfried, I. MacFarlane, D. B. Graham, N. A. Moore, and P. L. Young (Journal of Vocational Behavior, 1981, 18, 30–42) it is suggested that level of analysis may be a crucial factor accounting for much of the prevailing confusion in the literature. This study investigated sex differences in values/preferences related to work at various levels of generality. A sample of 1081 senior high school students was administered the Work Aspect Preference Scale (WAPS). Complete-link cluster analyses were performed for males and females separately. Comparison of the two dendrograms reveals the substantial similarity of the preference patterns of males and females. However, the basic difference in the patterns focused on the Altruism and Physical Activity subscales. Females appeared more likely to associate helping others with personal achievement whereas males tended to see helping people in terms of controlling and organizing them. Females also linked physical activity with helping others and self-development whereas males tended to associate physical activity with extrinsic rewards of work. It is concluded that the use of cluster analysis techniques may provide the best procedure to effect an adequate reconciliation of the conflicting results to be found in the current literature.     

Fluid and crystallized intelligence and primacy/recency components of short-term memory

Primacy and recency recall measures, obtained from both free and probed-recall tasks, were included in a battery of tests which also contained markers for fluid intelligence, crystallized intelligence, and cognitive speed factors. Our results confirmed previous findings that for subjects within the normal range of abilities, recency recall from probed-recall tasks is more closely linked to intelligence than is primacy recall. A new finding was also obtained: that primacy recall is correlated more with measures of cognitive speed than is recency recall. These results are discussed in terms of the concept of working memory and its relation to intelligence.