Sex related biases for attending to object color versus object position are reflected in reaction time and accuracy

Processing of visual features related to objects and space relations occurs within separate cortical streams that interact with selective attention. Such separation has implications for cognitive development because the perception of 'what' and 'where' provide a neural foundation for the development of aspects of higher cognition. Thus, a small attentional bias in early development for attending to one aspect over the other might influence subsequent higher cognitive processing in tasks involving object recognition and space relations. We examined 134 men and women for evidence of an inherent sex-related bias for attending to basic perceptual features related to object discrimination versus object position. Each stimulus consisted of a circle located in one of 9 positions within a surrounding frame. Circles were one of three shades of blue or red. These stimuli were used in a match-to-sample paradigm where participants were required to match circles on the basis of color or spatial position. The first stimulus appeared in the center of the screen for 400 msec and the matching stimulus subsequently appeared for 400 msec oriented 5 degrees to the right or left of center. The same stimuli were used to test the perception of color and position, with order of testing counterbalanced across participants. Results showed significantly longer reaction times in females compared with males, with better accuracy to discriminate color when that color was tested before position. Males showed better accuracy when object position was tested before color discrimination. A second experiment employed the same procedure, but enhanced selective attention by adding an endogenous cue that predicted the right or left location for the appearance of the matching stimulus. This manipulation greatly attenuated the sex differences in reaction time and accuracy compared to Experiment 1, suggesting that the sex-related attentional biases are strongly coupled to bottom-up processing. Overall, the sex related attentional biases toward processing object characteristics versus object position location suggest a differential manifestation of biased competition between the weighted systems of dorsal and ventral stream processing. Results are discussed with how a developmental bias in the processing objects versus space relations may contribute to adult cognitive sex differences in humans and animals.