A neuropsychological investigation of decisional certainty.

The certainty that one feels following a decision increases decision-making efficiency, but can also result in decreased decision accuracy. In the current study, a neuropsychological approach was used to examine the impact of damage to the ventromedial prefrontal cortex (vmPFC) on core psychological processes promoting decision certainty: selective exposure, overconfidence, and decisiveness. Given previous research demonstrating that vmPFC damage disrupts the generation of negative emotional (somatic) states that have been associated with selective exposure and overconfidence, it was hypothesized that damage to the vmPFC would disrupt engagement in selective exposure, decrease overconfidence, and increase indecision. Individuals with vmPFC damage exhibited increased indecision, but contrary to our hypothesis, engaged in similar levels of selective exposure and overconfidence as the comparison groups. These results indicate that indecision may be an important psychological mechanism involved in decision-making impairments associated with vmPFC injury. The results also suggest that the vmPFC may not be critical for selective exposure or overconfidence, which provides support for a recent "desirability" account of selective exposure.