Chicks' maze learning reinforced by visual pitfall extending downward

The present study examined whether visually evoked fear of depth could reinforce a particular response of animals, i.e., to special maze learning. The maze was composed of four units of Y-shaped alley. In this maze, the visual pitfalls were set behind corners of the alley in place of a physical barrier. The experiments showed that eight of 13 male chicks could achieve the initial learning and that three successful ones could also achieve reversal learning. The results suggest that the visually evoked fear of depth provided by motion parallax can act as a reinforcer.