When using topographical maps to orient in space, people as a rule make use of the alignment principle: Upward direction on the map is made to correspond with forward direction in the perceived environment. Violations of this principle (e.g., placing misaligned floorplans) have a negative impact on spatial-orientation performances. Using a method of simulated egomotions in a virtual environment, we examined the influence of misalignment on time-and space-extended navigations. Twenty volunteers were given maps with different orientations showing paths leading from a starting point to a goal point. The maps were either aligned (0°), misaligned by 90' or misaligned by 180' . Ten subjects drew (pictorial encoding condition) and 10 subjects verbally described (procedural encoding condition) the path and the objects encountered along it. Misalignment effects were expected for pictorial but not for procedural encoding. When subjects later navigated through the virtual environment under egomotion conditions, detrimental effects on speed and accuracy were observed as the degree of misalignment increased. However, no differences were found between the two encoding conditions.In order t o move around, people need accurate knowledge of the spatial relations i n their environment. In addition t o the ability t o acquire spatial knowledge by directly exploring environments, humans have developed a n impressive cognitive capacity t o acquire spatial knowledge by secondary means, such as miniature models, floorplans, and maps (Kinnear & Wood,

No abstract

No abstract

No abstract

Ce texte présente un cadre d’analyse de l’activité issu de l’un des principaux courants de la psychologie soviétique qui vise aussi bien l’analyse des processus que l’élaboration d’une théorie du développement. A partir des travaux de Léontiev, il définit d’abord les éléments de la structure générale de l’activité, organisée autour de 3 concepts-clés : activité, action et opérations. Il se centre ensuite plus particulièrement sur les caractéristiques de l’action ainsi que sur ses conditions d’élaboration et d’assimilatIon telles qu’elles sont définies par Galpérine dans sa théorie sur la formation par étapes des actions.