Colour perception and the use of video playback experiments in animal behaviour

Ethologists have employed video and cine playback methods to study animal visual communication since the late 1960s, but in the last few years such methods have become extremely popular (reviewed in D’Eath, in press). However, there are some serious limitations to the use of video technology with animals that have not yet been adequately addressed. The distribution and spectral quality of light on a video screen and in the real world are different. Video systems rely on fundamental features of human visual processing to create a perceptual match between the video image and nature. This match will, in general, fail for nonhumans. In this paper we focus on issues related to perception of colour. Other potential shortcomings of video stimuli have been considered in detail elsewhere. These include the absence of depth cues, screen flicker, pixel size and visual acuity, the absence of interactiveness (D’Eath, in press) and the issue of correct viewing distance for the type of stimulus (Dawkins & Woodington 1997).