Colour and polarity contributions to global motion perception

The influence of the image segmentation cues based on colour and polarity o n a motion coherence task were examined. In line with previous reports, whe n the signal and noise were given unique identities thresholds were much lo wer than when they were the same, suggesting a strong influence of segmenta tion. In another paradigm extra noise elements that differed in colour or p olarity interfered despite this perceptual segmentation. We suggest that th e results when signal and noise have unique identities are attributable to the subjects' ability to attend to a particular location(s) in space. When this strategy was eliminated by presenting the stimuli in the near-peripher y or very briefly the effect of the colour or polarity information disappea rs. (C) 1999 Elsevier Science Ltd. All rights reserved.