Simultaneous Discrimination of Speed is More Difficult than Simultaneous Discrimination of Size for Both Pigeons and People

Abstract

-Previous reports suggest that pigeons are highly sensitive to speed of motion (Cook, Beale, Koban, 2011;Herbranson, Fremouw, & Shimp, 2002). In contrast, we found that pigeons required more extensive training to learn speed discrimination than size discrimination (Lazareva, Young, & Wasserman, 2014). However, our results were based on a comparison of two experiments conducted in different laboratories, complicating the interpretation of the data. Here, we trained pigeons to perform size discrimination or speed discrimination in a two-alternative simultaneous discrimination task using a within-subject design. All birds acquired size discrimination much faster than speed discrimination, confirming our prior report. We further explored pigeons' sensitivity to differences in speed and size by training them to discriminate two end-point stimuli in a two-alternative forced-choice task and then presenting a wide range of testing stimuli located between the training end-point stimuli. The results again indicated weaker control by the differences in speed in comparison to size; comparable results were obtained for human participants.

Pigeons simultaneously attend to static and dynamic features of complex displays

“…There is no a-priori reason for these apparent processing differences among these four different dimensions and their values. In fact, prior to the experiment, a concern was that the speed discrimination would be too difficult, given the psychophysical evidence that pigeons have higher motion detection thresholds than might be expected from a flying bird (Lazareva & Share, 2017; Nankoo et al, 2014). Instead, this feature discrimination was easily learned and its value quickly detected.…”