Distance cues and depth avoidance on the visual cliff.

The study tested the hypothesis that depth avoidance in chicks is a specific case of general aversion to far patterns. Using a modified visual cliff, 192 male chicks less than 24 hr. old were on one side presented vertical patterns at varying distances from the centerboard and on the other side either a shallow or deep pattern. Control data indicated that, when two vertical patterns are presented on an opaque surface, chicks will descend to the nearer pattern and that this is motivated by aversion to the far pattern rather than attraction to the near one. Further data showed, however, that when a vertical pattern appeared at varying distances on one side of the centerboard and either a shallow or deep pattern appeared on the other, chicks avoided the side with depth at all distances of the vertical pattern. Depth avoidance in chicks then is not mediated by distance cues. While these may influence descent from a centerboard to an opaque surface, avoidance of depth overrides them on the visual cliff.