Authors:

DUNN, B.D., DALGLEISH, T. & LAWRENCE, A.

Reference:

Year of publication:

2006

CBU number:

6238

Abstract:

The somatic marker hypothesis (SMH; Damasio, 1994) proposes that emotional biasing signals arising from the body are integrated in higher brain regions, in particular the ventromedial prefrontal cortex (VMPFC), to regulate decision-making in situations of uncertainty and complexity. Evidence for this theory is largely based on performance on the Iowa Gambling Task (IGT: Bechara et al., 1996), linking anticipatory skin conductance responses (SCRs) to successful performance on a decision-making paradigm in healthy participants. These 'marker' signals were absent in patients with VMPFC lesions and were associated with poorer performance on the IGT. The current article first presents an empirical review of the IGT findings, arguing their interpretation is undermined by the cognitive penetrability of the reinforcement schedule and competing explanations of how to explain the behavioural and psychophysiological results on the task. Further, there is a shortage of causal evidence linking peripheral feedback to IGT performance. Next, lesion, neuroimaging, and psychopharmacology data evaluating the neural substrate underpinning the SMH are reviewed. Finally, some conceptual reservations about the novelty, parsimony and specification of the SMH are raised. It is concluded that, while presenting an elegant theory of how emotion influences decision-making, the SMH requires some conceptual revision and additional empirical support to remain tenable.