Individual-specific versus shared cognitive states differently support complex semantic and perceptual judgments
Cognitive processes that underpin performance on a given task may vary both within and across individuals. Yet, it is unclear how individual-specific versus shared cognitive processes each support behaviour. Here, we used a functional magnetic resonance imaging (fMRI) pattern classifier approach to ask how individual-specific and shared neural cognitive states differently relate to an individual’s ability to detect consecutive repeats in semantic (story) meaning versus perceptual (artist style) dimensions of illustrations that depicted well-known stories. Both states were related to participants’ task performance overall but differently for story versus artist style behaviours: individual-specific states were related to story performance, whereas shared states were related to artist style performance. These findings suggest that behaviours relying upon prior knowledge—likely varying across individuals—may be supported by idiosyncratic versus shared states. In contrast, unfamiliar judgments associated with a smaller number of eligible strategies may be supported by a state shared across individuals.