Captured by associations: Semantic distractibility during analogical reasoning in schizophrenia

Impaired cognitive control, for instance increased distractibility in simple conflict tasks such as Stroop, is considered one of fundamental cognitive deficits in schizophrenia patients. Relatively less is known about patients proneness to distraction in more complex, longer-lasting cognitive tasks. We applied the four-term analogies with and without distraction to 51 schizophrenia patients in order to examine whether they display increased distractibility during analogical reasoning, and to test which kind of distractors (semantic, categorical, or perceptual) elicits their strongest distraction, as compared to 51 matched controls. We found that (a) both groups reasoned by analogy comparably well when distraction was absent; (b) in both groups distraction significantly decreased performance; (c) schizophrenia patients were significantly more distracted than the controls; (d) in both groups the semantic distractors were selected more frequently than the categorical distractors, while the perceptual distractors were virtually ignored; as well as (e) in both groups distractibility in the four-term analogies was unrelated with distractibility in the simple perceptual conflict task, suggesting that these two distraction types tap into different cognitive mechanisms. Importantly, a significantly stronger distractibility in the schizophrenia group could not be explained by their lower intelligence, because the two groups were matched on the fluid reasoning test. We conclude that during complex cognitive processing schizophrenia patients become captured by irrelevant semantic associations. The patients are also less willing to critically evaluate their responses.