Only spontaneous counterfactual thinking is impaired in patients with prefrontal cortex lesions.

Counterfactual thoughts (CFT) are mental simulations of what might have been if another behavior had been executed. They are pervasive in everyday life, help people learn from experience, modulate their emotional state, and contribute to decision-making and social functioning. To test the hypothesis that the prefrontal cortex (PFC) is involved in the generation, content, and use of CFT, we studied 18 patients with strictly prefrontal cortex lesions. Our results indicated that the PFC is crucial only for self-generated counterfactual reflections. We did not detect CFT generation differences based on lesion location within the PFC. CFT performance correlated positively with measures of attention, creativity, verbal skills, conscientiousness, and self-esteem and negatively with depression and dysexecutive symptoms. An impairment in counterfactual thinking may contribute to the lack of regret and insight often observed in patients with frontal lobe lesions.