The selective benefits of colour in the detection of changes in naturalistic scenes
Previous experiments have shown a benefit for colour over black-and-white naturalistic scenes in a recognition-memory paradigm (Wichmann et al, 2002 Journal of Experimental Psychology: Learning, Memory and Cognition 28 509 - 519). The current study sought to determine whether this benefit for colour extends to the more direct visual task of change detection. Participants viewed displays of rapidly alternating 'original' and 'modified' scenes interspersed with blank fields (Rensink et al, 1997 Psychological Science 8 368 - 373). The scene changes were either central to the theme of the picture (CI) or incidental (MI). This classification was conducted prior to testing. For each participant half the stimuli were colour and half were black-and-white, and were presented in a random order. We found that fewer scene alternations were required to detect changes for CI than MI and that scene changes were detected faster in colour than in black-and-white. However, there was a significant interaction between scene chromaticity and thematic content. An effect shown in memory tasks now extends to 'change detection', but with a key distinction between the class of change affected. We suggest that the colour-CI benefit emerges from the processing stream proceeding to IT cortex.