Response to Anticipated Reward in the Nucleus Accumbens Predicts Behavior in an Independent Test of Honesty

Abstract

This study examines the cognitive and neural determinants of honesty and dishonesty. Human subjects undergoing fMRI completed a monetary incentive delay task eliciting responses to anticipated reward in the nucleus accumbens. Subjects next performed an incentivized prediction task, giving them real and repeated opportunities for dishonest gain. Subjects attempted to predict the outcomes of random computerized coin-flips and were financially rewarded for accuracy. In some trials, subjects were rewarded based on selfreported accuracy, allowing them to gain money dishonestly by lying. Dishonest behavior was indexed by improbably high levels of self-reported accuracy. Nucleus accumbens response in the first task, involving only honest rewards, accounted for ϳ25% of the variance in dishonest behavior in the prediction task. Individuals showing relatively strong nucleus accumbens responses to anticipated reward also exhibited increased dorsolateral prefrontal activity (bilateral) in response to opportunities for dishonest gain. These results address two hypotheses concerning (dis)honesty. According to the "Will" hypothesis, honesty results from the active deployment of self-control. According to the "Grace" hypothesis, honesty flows more automatically. The present results suggest a reconciliation between these two hypotheses while explaining (dis)honesty in terms of more basic neural mechanisms: relatively weak responses to anticipated rewards make people morally "Graceful," but individuals who respond more strongly may resist temptation by force of Will.

Cognitivism, Motivation, and Dual-Process Approaches to Normative Judgment

“…recent research has generated a number of suggestive results. it now appears that signals broadcast from (a) circuitry involved in reward learning and action selection (e.g., the basal ganglia, midbrain dopaminergic nuclei) and (b) circuitry involved in emotional arousal and motivation (e.g., the amygdala, hypothalamus, anterior insular cortex) to (c) the vmPFC are key to understanding the intuitive-affective (Abe & Greene 2014;Haruno & Frith 2010;Tusche, Bode, & Haynes 2010). These (a) and (b) structures thus seem to simultaneously (i) regulate affect and guide action selection, and (ii) generate consciously accessible normative thoughts.…”

Suboptimal Dishonesty: Rationality in the Absence of Strategic Behavior in Honesty Experiments

“…Importantly, even taking an agnostic view on the sources of the cost can still elucidate the mechanisms underlying (dis)honesty. Integrating the empirical findings of heterogeneous cost as an a priori assumption, subjects showing a spectrum of accuracies when facing identical financial reward (as seen in in Abe and Greene, 2014) becomes an expected result of rational individuals maximizing their utility. Still, there is much to be gained from attempts to refine the understanding of the basis and magnitude of this cost.…”

“…In contrast, the "will" hypothesis suggests that people actively suppress dishonest behaviors, which arise naturally. A study by Abe and Greene (2014) has reconciled these two seemingly inconsistent theories by showing that the drivers of honesty depend on the desirability of the reward.…”

“…Under the pretense of an experiment on clairvoyance, participants in Abe and Greene (2014) were asked to predict future outcomes of randomized coin flips in an fMRI scanner. Their rewards depended on the accuracy of those predictions and accuracy was self-reported, thus providing both incentive and opportunity for lying.…”

“…Consistent to this, they found significant responses in the DLPFC only for subjects in the ambiguous and dishonest groups when refraining from dishonesty. These combination of results led Abe and Greene (2014) to conclude that honesty flows automatically in presence of weak responses to anticipated rewards, while "will" is needed to refrain from dishonest behaviors in cases of high relative responses.…”