Proceedings of the Annual Meeting of the Cognitive Science Society

Categorical and coordinate stimulus processing were hypoth-esized by Kosslyn (1987) to be lateralized visual tasks, dif-ferentiated by task-relevant spatial frequencies. Slotnick et al.(2001) directly tested Kosslyn’s hypothesis and concluded thatthe lateralization presents only when tasks are sufficiently dif-ficult. Our differential encoding model is a three layer neuralnetwork that accounts for lateralization in visual processingvia the biologically plausible mechanism of differences in con-nection spread of long-range lateral neural connections (Hsiao,Cipollini, & Cottrell, 2013). We show that our model accountsfor Slotnick’s data and that Slotnick’s analysis does not con-vincingly explain their results. Instead, we propose that Koss-lyn’s initial hypothesis was based on an incorrect assumption:categorical and coordinate stimuli are not solely differentiatedby spatial frequencies. The results that our model capturescannot be reproduced by Ivry and Robertson’s (1998) Dou-ble Filtering by Frequency theory, which is driven solely bylateralized spatial frequency processing.