Attentional limits in visual search with and without dorsal parietal dysfunction: space-based window or object-based span?

Attentional resource and distribution are specifically impaired in simultanagnosia, also the visuo-attentional form of developmental dyslexia. Both clinical conditions conceived as a limitation simultaneous visual processing after superior parietal lobule (SPL) dysfunction (review Valdois et al., 2019). However, reduced space-based attentional window (i.e. limited eccentricity at which target object can be identified, Khan al. 2016) has been demonstrated simultanagnosia versus object-based span number objects processed each fixation, Bosse 2007) In healthy individuals, cost reaction times per item serial search tasks suggests that group is simultaneously time, but this undefined depends on complexity task. Healthy individuals patient with performed involving either symbols (made separable features) or made non-separable features, distractors were all identical dissimilar. We used moving paradigm to determine whether task was “working space” span” control bilateral SPL damage. found color comprising feature dissimilar window; window, well mean saccade amplitude displace it across display, independent set size, thus inconsistent an span. symbol feature-absent feature-present dissimilar, we observed decreased size performance could not mimicked by single diameter; instead participants seemed process fixed time (object-based span). Following lesions, IG similar normal window. contrast, her cost-per-item increased dramatically, demonstrating clear deficit perception. These results confirmed specific contribution multiple features (like letters), more dramatically when they different, explains difficulty for reading beginner case dysfunction.