Abstract
Attentional target selection is based on top-down search templates when target-defining features are specified in advance. However, little is known about how observers learn what to look for. The present ERP study investigated how known or newly learned perceptual categories affect the emergence and speed of spatially selective processing in perception (N2pc component) and working memory (SPCN component).
Adult participants had to select targets among distractors in a familiar (digits and letters) and a novel context (Chinese characters – numbers and non-numbers). On each trial, targets were specified by a preceding prime array. Identity prime arrays (two identical items) instructed participants to simply select the physically identical target item (if present) in the next search array. Category primes (two different items belonging to the same category) instructed participants to select a category-matching target in the next search array.
As expected, all targets triggered N2pc and SPCN components in the familiar context. N2pc onset was earliest when targets were specified by identity primes, demonstrating fastest target selection when targets and search templates match physically. In the novel context, targets specified by identity primes or by physically matching category primes also triggered N2pc and SPCN components, as participants could again base target selection on physical identity on these trials. However, when targets were specified by non-matching category primes, and this strategy was not available, target selection required the prior learning of the relevant category. On these trials, no lateralized ERP components were triggered during the first experimental session. Critically, a reliable SPCN was triggered by a category-primed target during the second session, demonstrating that this component is a marker of successful category learning.
Our study provides new insights into the real-time dynamics of top-down attentional selection guided by physically or categorically defined attentional templates, and into the acquisition of new perceptual categories.
Meeting abstract presented at VSS 2012