Experience and geometry: controlled-rearing studies with chicks

Animals can reorient making use of the geometric shape of an environment, i.e., using sense and metric properties of surfaces. Animals reared soon after birth either in circular or in rectangular enclosures (and thus aVording diVerent experiences with metric properties of the spatial layout) showed similar abilities when tested for spatial reorientation in a rectangular enclosure. Thus, early experience in environments with diVerent geometric characteristics does not seem to aVect animals’ ability to reorient using sense and metric information. However, some results seem to suggest that when geometric and non-geometric information are set in conXict, rearing experience could aVect the relative dominance of featural (landmark) and geometric information. In three separate experiments, newborn chicks reared either in circular- or in rectangular-shaped homecages were tested for spatial reorientation in a rectangular enclosure, with featural information provided either by panels at the corners or by a blue-coloured wall. At test, when faced with aYne transformations in the arrangement of featural information that contrasted with the geometric information, chicks showed no evidence of any eVect of early experience on their relative use of geometric and featural information for spatial reorientation. These Wndings suggest that, at least for this highly precocial species, the ability to deal with geometry seems to depend more on predisposed mechanisms than on learning and experience after hatching.