Dyslexia and syllogistic reasoning in adults: Differences in strategy usage.

People with dyslexia have been found to prefer spatial over verbal strategies when performing word-based syllogistic reasoning tasks that require self-generated responses. The current research investigated whether this was also the case for pictorially based syllogisms, when responses were required to either concrete or abstract stimuli, and when multiple-choice answers were presented. Adults with and without dyslexia, matched for non-verbal ability, were presented with sets of isomorphic reasoning problems in which the stimuli were either concrete words, abstract words, concrete shapes or abstract pictograms. As expected, there was no group difference in reasoning accuracy. Unlike previous findings, the adults with dyslexia preferred to use a mixed verbal and spatial strategy and performed better with this strategy, while the individuals without dyslexia preferred a verbal strategy and performed more successfully when employing this strategy. The provision of answer options to facilitate strategic change in individuals with dyslexia is discussed.