Pigeons Discount Continuously Changing Perspective During Action Recognition

An important challenge for animal and artificial visual systems is separating the system's own motions from the movements of other animals or events. To examine this issue in birds, we conducted three experiments testing four pigeons in a go/no-go action discrimination. The pigeons discriminated whether a digital human model was exhibiting an extended series of articulated motions or one of a set of static poses from the same video. They were required to do so while the rendering camera's perspective changed continually during each trial's 20-s video presentation. Experiment 1 found that pigeons easily discount the camera's continuous motion. Experiments 2 and 3, by testing novel sequences of the behavior, novel behaviors, silhouettes, and a form of conditional discrimination, revealed this to be a general capacity. Overall, the discrimination was predominantly mediated by global action cues, although a small contribution of image-based statistical features was detected. Collectively, the experiments reveal pigeons can readily separate and discount constantly changing perspectives while processing others' actions.