Manipulation of colour and shape information and its consequence upon recognition and best-likeness judgments.

Abstract

Previous forays into the study of recognition have revealed an advantage for line-drawn and photographic shape caricatures of faces in reaction-time paradigms. When a presentation-time technique was used, photographs with enhanced colour intensity and saturation were also found to provide superior recognition accuracy to veridical images. This has provided strong evidence that distinctive information can produce a recognition advantage for famous faces in both colour and shape domains. Such a presentation-time paradigm allows the display of stimuli over a range of brief display periods. Using this paradigm, subjects recognised photorealistic target faces caricatured in shape with greater accuracy than veridical images, consistent with previous findings when reaction time was used as a measure. Subjects were also asked to identify the best likeness for individuals using photorealistic stimuli and an interactive paradigm with shape caricature, colour caricature, and contrast control varied by the user in real-time. The best likeness with shape manipulation was a slight anticaricature, while with colour-caricature and contrast-control images a mildly exaggerated image was selected as the best likeness. Thus, although images caricatured substantially in colour or shape (+40%) induce superior recognition compared to veridical images, such substantial exaggerations are not necessarily seen as best likenesses under prolonged exposure.