Perceptual asymmetries for free viewing of several types of chimeric stimuli

We examined perceptual biases of right-handers on six free-vision chimeric tasks; two involving a judgement of happiness of a facial expression in photographic and cartoon chimeras, two involving a judgement of femininity in male/female photographic and cartoon chimeras, and two involving a spatial judgement of nonface chimeric stimuli. All four of the face tasks and one of the nonface tasks elicited left spatial field biases of varying magnitudes, and perceptual asymmetries on all tasks were positively correlated. However, multiple correlational analyses revealed that these tests shared differing proportions of variance with each other. Results indicate that, in addition to a common factor or set of factors contributing to lateral biases that is independent of both the nature of the stimulus and whether the stimulus engages lateralized mechanisms, there are distinct lateralized mechanisms which yield different patterns of perceptual asymmetries for different stimuli.