Evidence for a priming-based asymmetry in color identification

Performance asymmetries in colour discrimination (or detection) between visual fields (VFs) are typically examined using mean or median reaction times and have tended to yield either a left VF advantage for all colours (i.e., lower reaction times) or no difference for any colour, although a right VF advantage has also been reported. We used a novel colour identification task in which participants simply identified the colour of a laterally presented rectangle (i.e., red or blue). A measure of priming effects - but not mean or median reaction times - revealed a VF × colour interaction across a pilot study and two experiments; priming for red versus blue stimuli was greater in the left VF and priming for blue stimuli was greater in the right versus left VF. Two plausible psychological explanations of this interaction are offered, including the potential generation of approach and avoidance motivations and different emotional responses to blue versus red stimuli. Future work will be needed, but the current findings indicate that the left and right hemispheres are differentially primed by different colours - the right hemisphere is primed to a greater extent by red stimuli, and the left hemisphere is primed more by blue stimuli.