IS THERE INHIBITION OF RETURN FOR ISOLUMINANT COLORS?

Abstract

In the present study we replicate experiments of Lupiañez et al. (1997) who addressed the issue of inhibition of return with respect to the color of stimuli. In contrast to that study, using non-isoluminant stimuli, we employed two pairs of isoluminant colors varying along either the red-green or blue-yellow cardinal axes of a color space – deutan or tritan confusion lines in the CIE 1976. Participants (normal trichromats; n=8) were exposed successively to the color pairs; their task was to respond to the second (target) stimulus by key pressing, whereby simple reaction times were measured. In different trial stimulus onset asynchrony (SOA) was varied: 100, 400, 700, 1000 and 1300 ms. At no SOA inhibition of return was found; instead, facilitation of return was demonstrated, this especially pronounced at the short SOA=100 ms. We found that participants were overall faster in the invalid condition when compared to the valid condition (F=25.986, p=0.001). We hypothesized that when isoluminants colors are employed as both cue and target, Inhibition of Return can’t be establish.