The somatic marker hypothesis (SMH) represents a rich neuropsychological framework to study emotion-based decision-making. It originates from early brain lesion studies using the Iowa Gambling Task (IGT), which showed that adaptive decision-making relies on intact ventromedial prefrontal cortex for the integration of so-called "hot" affective signals and rational "cold" perceptual cognitive computations. Subsequent studies over the past 20 years have provided converging evidence for the reliability and validity of the IGT in assessing decision-making in both healthy and clinical samples, although some discrepancies remain. In healthy individuals, it has been shown that differences in emotional states prior to taking the IGT result in different outcomes, thus potentially accounting for some of the variation within this group. However, the precise role of such transient modulations of emotional states remains unclear. In this study we sought to examine the role of specific induced moods under carefully controlled conditions. Accordingly, we randomly assigned 44 healthy college undergraduates to a positive, negative, or neutral affect condition in which they simultaneously viewed images and listened to music that previous studies had shown to induce specific moods. Results indicated that mood induction was successful, and the positive affect group showed a clearly different pattern of IGT performance compared to the other two groups, in that they showed a rapidly established and stable bias favoring the positive expected value (EV) card decks. The negative affect group showed significantly lower bias towards the positive EV decks, although this group was not different from the neutral affect group. Bayesian analyses confirmed these findings. While consistent with SMH, these current findings may be best understood in support of a more general effect of normal mood on cognition as outlined in the broaden-and-build theory of positive emotions.
Keywords: Decision-making; Iowa Gambling Task; emotions.