prisoners use an inflexible strategy in a continuous performance test: A replication

The k-test is a computerized continuous performance task in which subjects decide if the letter k is present among 10 distractor characters. Distractors can be filled ‘squares’, favoring a global processing approach, or random ‘letters’, favoring sequential processing. In a previous study we found that prisoners (N = 102) were much less able to shift strategy appropriately between the two tasks than all other subjects (N = 322). In this study, three new groups of prisoners (N = 130) were compared to the previous groups of subjects, and to psychology students (N = 33), brain lesion patients (N = 14), criminal (N = 12) and noncriminal schizophrenic patients (N = 34) and dyslexies (N = 23). Again, all prisoner groups were markedly different by not switching strategy appropriately. Unexpectedly, dyslectics were similar to prisoners. The prisoner/nonprisoner difference was large (1.0 SD) and highly significant. Dyslexia is common among prisoners (40–60%) and may represent a link between the findings for prisoners and dyslexics.