Tracking and capture of constant and varying velocity stimuli: a cross-species comparison of pigeons and humans

The mechanisms underlying tracking and capture of moving objects in non-human animals are poorly understood. This set of experiments sought to further explore aspects of anticipatory tracking in pigeons and to conduct comparisons with human participants. In Experiment 1a, pigeons were presented with two types of varying velocities (fast-slow-fast or slow-fast-slow) in separate phases. They were readily able to track and anticipate both of these motion types. To examine the effects of predictability on anticipatory tracking, Experiment 1b presented the pigeons with the same two varying velocities randomly intermixed within a session. This resulted in reduced capture success, later capture, and errors that no longer anticipated ahead of the motion, suggesting that the anticipatory mechanism had been disrupted. This implies that the mechanisms involved in pigeon tracking are different from the predictive extrapolation mechanism proposed in humans. Experiment 2 tested this by presenting adult humans with a tracking task that was similar to tasks previously received by the pigeons. The capture behavior of humans was similar to the pigeons, but the errors revealed different processes underlying their tracking behavior.