A process model for Missionaries-Cannibals and other river-crossing problems

We extend a model originally developed by Atwood and Polson (1976) for the water jug task to four isomorphs of the Missionaries-Cannibals problem. Our results show that variation in cover story produced no differences in number of legal moves to solution, but caused large differences in illegal moves. A three-stage process model incorporating means-ends heuristics, assumptions about the utilization of memory, and an illegal move-detection process is able to account for both legal and illegal move data from all four versions of the problem.     

The effects of feature necessity and extrinsicity on gradedness of category membership and class inclusion relations*

Two theories of differences among natural language categories in graded membership and strength of class inclusion are contrasted. The two sets of hypotheses tested were: (1) that categories represented by features which many people believe to be necessary would have less graded memberships, and stronger class inclusion, than those represented by features which few people believe to be necessary, and (2) that categories which people believe are represented primarily by intrinsic features (i.e. features that are true of an entity in isolation; see Barr & Caplan, 1987) would have less graded structures, and stronger class inclusion, than those which people believe are represented primarily by extrinsic features (i.e. features representing relations between an entity and other entities). The findings suggest that feature necessity and feature extrinsicity have independent effects on gradedness of category membership and on class inclusion.     

Experience and backswing movement time variability : A short note concerning a serendipitous observation

Decreased variability of both response outcome and movement kinematics is generally thought to be a characteristic of skilled performance. This note reports an apparently paradoxical case in which expertise is associated with greater variability of an aspect of movement kinematics. The relative variability of backswing and downswing duration (standard deviation as a percent of movement time) was assessed for experienced and novice field hockey players performing a drive of an approaching ball. The experienced group exhibited higher relative variability of backswing duration than the novice group. It is argued that this variability is functional (in the sense that greater backswing duration variability is associated with superior task performance) and may result from the joint effects of players visually controlling movement during its execution (Bootsma 1988) and the experienced subjects' earlier pick-up of relevant information for visual control (cf. Abernethy and Russell 1987).     

Children's explanations for self‐presentational behaviour

Previous research has underestimated children's capacity to understand the self‐presentational behaviour of other people. We argue from recent research in mental‐state understanding that 8‐year‐olds should be able to attribute self‐presentational motives in order to explain others' behaviour. In the present study, children aged 6 to 11 years heard stories involving emotion‐masking displays and were then asked to explain the motivations for those displays. Results supported our prediction. Copyright © 1999 John Wiley & Sons, Ltd.     

Democracy and Fatalism in the Former Soviet Union1

Recent political events in the former Soviet Union suggest that democracy has only a tenuous hold in this region. Underlying many of these events may be psychological values and beliefs ill conducive to the development of democracy. In the 2 studies described in this paper, conducted in 1995 and 1998, 2 large and representative groups of manual workers, students, civil servants, managers, and the retired from 4 former Soviet republics completed measures of fatalism, attitudes toward democracy, and democratic participation (N= 2,672 and 925). Structural equation analyses of the data from both studies find that particular groups (in particular, manual workers and the retired) hold the strongest fatalistic beliefs, which in turn predict democratic attitudes, voting behavior, and political‐party membership. These findings are discussed in the light of possible interventions that might promote democratic participation in the region.