The essentials of a theory of mind are generally considered to be acquired around 4 years of age when the child succeeds in the standard 'Maxi task' (Wimmer & Perner, 1983). However, rational thought is not attained before 7-8 years of age in other domains of cognitive development. This study demonstrates that the mastery of mental state attribution using logical criteria is not reached before age 7-8 years when several assessments of a belief need to be coordinated. This is revealed by the dissociation between the cognitive and emotional assessments of a false belief which yield contradictory responses in most of the children who succeed on the standard task. The results were replicated in ve experiments with a total of 254 children aged 3-8 years. The analysis of this décalage focuses on the autonomy of emotional attributions and the semi-mental and semi-behavioural structure of belief understanding implied in the standard task. An increase in processing capacity leads to a rational concept of belief around 7-8 years: this concept is called here 'third-person', in opposition to 'second-person' which involves only an initial differentiation from the rst-person point of view. Second-person depends on an opposition between the self and the other in terms of a single, modular evaluation of belief, whereas third-person depends on an integration among various assessments and provides a consistent and isotropic concept of belief.Ça me fait penser à l'histoire du chien qui perdait toujours au poker parce que chaque fois qu'il avait du jeu, il remuait la queue . . . (This reminds me of the story of the dog who played poker and always lost because each time he had a good hand, he wagged his tail . . .).

This paper reports a study of a multi-agent model of working memory (WM) in the context of Boolean concept learning. The model aims to assess the compressibility of information processed in WM. Concept complexity is described as a function of communication resources (i.e., the number of agents and the structure of communication between agents) required in WM to learn a target concept. This model has been successfully applied in measuring learning times for three-dimensional (3D) concepts (Mathy and Bradmetz in Curr Psychol Cognit 22(1):41-82, 2004). In this previous study, learning time was found to be a function of compression time. To assess the effect of decompression time, this paper presents an extended intra-conceptual study of response times for two- and 3D concepts. Response times are measured in recognition phases. The model explains why the time required to compress a sample of examples into a rule is directly linked to the time to decompress this rule when categorizing examples. Three experiments were conducted with 65, 49, and 84 undergraduate students who were given Boolean concept learning tasks in two and three dimensions (also called rule-based classification tasks). The results corroborate the metric of decompression given by the multi-agent model, especially when the model is parameterized following static serial processing of information. Also, this static serial model better fits the patterns of response times than an exemplar-based model.

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Categorization researchers have tried to verify their models through laboratory experiments with simplified stimulus sets, a requirement that can rarely be met in real-world situations in which properties are often connected. Still, the targeted simplification of the material might be illusory. We replicate and extend Love and Markman's (2003) study of the nonindependence of canonical stimulus properties such as size, colour, and shape in human classification learning, in which the authors concluded that shape takes precedence over other dimensions. To support their hypothesis, Love and Markman showed that certain classifications are more difficult for participants when shape is combined to one of its putative subordinate features, size or colour, than when shape is irrelevant to the task. A data set of 290 + 50 adult participants completing one or more classification tasks was collected. The results confirm that certain combinations of shape, size, and colour can hinder or facilitate classification learning, but not necessarily in the form expected by the nonindependence postulated by Love and Markman, especially in Experiment 2 where a totally reverse pattern of difficulty is observed (shape does not take precedence over other dimensions). Also, we show that simple similarity effects in clustering retain considerable intuitive appeal and can offer an alternative account to the nonindependence of stimulus properties, especially because slight variations in the dimensions chosen make the observations of Love and Markman unstable.

From 1984 to 1988, a longitudinal study was conducted with 104 children born in 1980. This study was devoted to the development of Piagetian concrete operational thought, using 25 classical Piagetian tasks. Seven years after the end of the study, 62 children from the original sample were again examined in relation to formal thought, general intelligence and spatial and verbal abilities. This paper analyses the data obtained and the relationships between concrete and formal thought. The main results show: (i) the low average attainment in formal thought among 15-year-old adolescents; (ii) the reliable measurement of general intelligence provided by Piagetian tasks; and (iii) the strong relationship between early competence in number manipulation and later access to combinatorial and formal thought.