Figure 4.

Flanker task and probabilistic selection task. (a) Flanker task. Top: subjects viewed a string of arrows or letters varying in screen position. The goal was to indicate the direction (left: arrow or S; right: arrow or M) of the central character flanked by either the same (congruent) or different (incongruent) flankers using the left or right button. Bottom: mean response time (RT) for congruent and incongruent conditions for Obsessive compulsive disorder (OCD) and healthy volunteers (HVs). (b) Probabilistic selection task. Top: During training, subjects learned stimulus contingencies from randomly presented stimulus pairs from three probability configurations followed by monetary feedback for correct and incorrect choices. Correct choices were determined probabilistically (ratio of positive/negative monetary feedback is shown in parentheses for each stimulus). In the testing phase novel combinations were presented to assess high and low conflict decisions. This schematic illustration was adapted from Frank et al, (2007). Bottom: mean RT for low conflict (LC), high conflict win–win (HCWW), and high conflict lose–lose (HCLL) conditions in OCD and HV. Error bars represent SEM.