SPATIAL-FREQUENCY AND INTERFERENCE BETWEEN GLOBAL AND LOCAL-LEVELS OFSTRUCTURE

In three experiments, subjects identified local or global forms of hie rarchical stimuli that had been ''contrast-balanced''. Contrast balanc ing eliminates low spatial frequencies, so that both local and global forms must be identified based on high-spatial-frequency information. In all three experiments, response times (RTs) to global forms were sl owed fbr contrast-balanced stimuli, suggesting that low spatial freque ncies facilitate the analysis of global forms. In contrast, interferen ce between local and global forms was little affected by contrast bala ncing, suggesting that interference does not depend on differences in spatial frequency between local and global forms. Consistent with earl ier data, some evidence of a difference in interference for stimuli pr esented in the right versus left visual field was found. However, this difference was not affected by contrast balancing-a finding that is a t odds with the hypothesis that the hemifield asymmetry in interferenc e reflects a hemispheric difference in inhibitory interactions between high and low spatial frequency channels.