Isolated processing of geometric shapes and their corresponding shape words: Evidence from a delayed match-to-sample task

Some theorists propose a domain-specific cognitive system dedicated to processing geometric information, but existence of this system remains debatable because of challenges in isolating geometric from linguistic and semantic processing. Recently, Sturz, Edwards, and Boyer (2014) developed a delayed match-to-sample task that presented a sample of a shape, shape word, or bidimensional stimulus composed of a shape and shape word. After a delay, participants identified the sample shape or the sample word by selecting between 2 shapes or 2 shape words. An asymmetrical pattern of interference emerged such that increased response times (RTs) and errors occurred in matching shape targets but not word targets. This was interpreted as shape words activating a semantic and spatial representation of shapes, but shapes only activating a spatial representation. The present experiments attempted to replicate and extend these results by manipulating figure-ground relations to contrast the original condition with an alternative to address an explanation based upon sample shape saliency (Experiment 1), by confirming the effectiveness of the saliency manipulation (Experiment 2), and by explicitly testing the assumption that shapes did not activate a semantic representation by reversing the sample-to-target matching criteria (Experiment 3). Experiment 1 replicated the asymmetrical pattern of results for both conditions, and Experiment 2 confirmed the saliency manipulation, which together undermine a pure saliency explanation. Experiment 3 produced a symmetrical pattern of results and suggests that the reversed matching criteria forced shapes to be processed in both a spatial and semantic fashion. These results provide support for a cognitive system dedicated to processing geometric information isolated from linguistic and semantic processing.