Order of card selection from the 1st to the 100thtrial. The black and red lines show the mean number of disadvantageous cards drawn by OCD patients and controls, respectively, in each block of 20 cards. Horizontal bars indicate standard error of the means. Children with OCD chose more cards from the disadvantageous deck towards the end of the task. OCD, obsessive compulsive disorder; * Significantly higher compared to controls (Mann–Whitney test; P < 0.05).