Reaction to spatial novelty and exploratory strategies in baboons

Exploratory activity was examined in 4 young baboons with the aim of invest igating the type of spatial coding (purely geometric and/or by taking into account the identity of the object) used for the configuration of objects. Animals were individually tested in an outdoor enclosure for their explorat ory reactions (contact time and order of spontaneous visits) to changes bro ught about to a configuration of different objects. Two kinds of spatial ch anges were made: a modification (1) of the shape of the configuration (by d isplacement of one object) and (2) of the spatial arrangement without chang ing the initial shape (exchanging the location of two objects). In the seco nd experiment, the effect of a spatial modification of the global geometry constituted by four identical objects was investigated. Finally, in the thi rd experiment, a substitution of a familiar object with a novel one was per formed without changing the objects' configuration. The baboons strongly re acted to geometrical modifications of the configuration. In contrast, they were less sensitive to modifications of local features that did not affect the initial spatial configuration. Analyses of spontaneous exploratory acti vities revealed two types of exploratory strategies (cyclic and back-and-fo rth), These data are discussed in relation to (1) the distinction between t he encoding of geometric versus local spatial features and (2) the spatial function of exploratory activity.