Does Autonomic Arousal Distinguish Good and Bad Decisions?

Abstract

The somatic marker hypothesis (SMH) proposes that physiological feedback to the brain influences cognitive appraisal and human decisions, however, the strength of evidence in support of the SMH is equivocal. We examined the validity of the SMH by measuring physiological arousal in a population of healthy individuals playing the Iowa Gambling Task (IGT), which is a computerized card game designed to assess real-life decisions. We also examined the influence of reinforcer type on IGT performance and physiological reactivity. Skin conductance level (SCL) reactivity was measured in 41 participants performing the IGT using either facsimile or real money. Participants were categorized as normal (i.e., nonimpaired) or impaired on the basis of their IGT performance, and differences in performance and physiological reactivity between groups were examined. No differences in SCL were found between normal and impaired groups. However, greater SCL rises were borderline significant when anticipating choices from bad decks compared with good decks, and a significantly greater SCL rise followed a reward from a bad deck. The effect of reinforcer type also revealed marginally greater performance when using facsimile money. This was corroborated physiologically by Deck × Reinforcer Type interactions, showing a marginally significant tendency for a greater SCL rise when anticipating a choice from a bad deck using facsimile but not real money, and a significantly greater SCL rise following a reward from a bad deck when using facsimile but not real money. Findings constrain the SMH, suggesting that autonomic activity may discriminate between good and bad decks (i.e., good vs. bad decision-making) by reflecting the magnitude of gains and losses, but is independent of long-term consequences and does not discriminate between overall good and bad performance (i.e., normal vs. impaired decision-makers).