Abstract
Visual word recognition and face recognition are associated with neural mechanisms in opposite hemispheres and opposite visual field advantages. Here we tested whether simultaneously viewed words and faces can be recognized in parallel or not. If so, this would suggest that visual recognition of multiple visual objects belonging to two different stimulus classes are not subject to the same bottleneck as two objects belonging to the same stimulus class (i.e., serial processing of words and faces can happen in parallel). If not, then only one visual object can be processed at a time, implying that the two types of object recognition draw upon shared neural resources. In our study, observers viewed pairs of either words or faces, or a combination of the two. Items in each pair appeared to the right or left of fixation and were either matched (word+word or face+face) or mixed (face+word or word+face) by stimulus class. In doing so, we partially replicated a previously reported finding that visual word recognition is serial (White, Palmer & Boynton, 2018), and we extended this finding to face recognition. A slight recognition advantage was observed in the mixed condition relative to the matched. Results were otherwise largely similar between mixed and matched stimulus pairings, with the expected opposite visual field advantages occurring for both mixed and matched conditions. In an additional condition, observers were pre-cued to either the right or left stimulus location. This allowed us to show that the benefit of mixing words and faces was small relative to the benefit of cueing. Our results suggest that, despite hemispheric dissociations between word recognition and face recognition, serial processing of words and faces does not occur in parallel because shared visual processing resources are involved.