THE PIGEONS RECOGNITION OF DRAWINGS OF DEPTH-ROTATED STIMULI

Four experiments used a four-choice discrimination learning paradigm t o explore the pigeon's recognition of line drawings of four objects (a n airplane, a chair, a desk lamp, and a flashlight) that were rotated in depth. The pigeons reliably generalized discriminative responding t o pictorial stimuli over all untrained depth rotations, despite the bi rds' having been trained at only a single depth orientation. These gen eralization gradients closely resembled those found in prior research that used other stimulus dimensions. Increasing the number of differen t vantage points in the training set from one to three broadened the r ange of generalized testing performance, with wider spacing of the tra ining orientations more effectively broadening generalized responding. Template and geon theories of visual recognition are applied to these empirical results.