| Previous research has shown that creative insight problem-solving is distinct from systematic analytical problem-solving. Behaviorally, a positive mood has shown to facilitate insights but without knowing the processes that are fundamental to insight, the mechanisms as to how a positive mood facilitates insights have remained unspecified. Here, we investigate the neural basis of how a positive mood facilitates insight-solving. We assessed mood/personality variables in 79 participants before they tackled word problems that can either be solved with insight or analytically. Participants higher in positive mood solved more problems, and specifically more with insight, compared to participants lower in positive mood. Functional magnetic resonance imaging (fMRI) was performed on 27 of the participants while they solved problems. Positive mood correlated with preparatory brain activity within the anterior cingulate cortex (ACC) that preceded each solved problem. Modulation of this preparatory activity in ACC biased people to solve either with insight or analytically. Analyses examined whether (a) positive mood modulated activity in brain areas showing increased preparatory signal; (b) positive mood modulated activity in areas showing stronger activity for insight solutions than analytical solutions and (c) insight effects occurred in areas that showed a positive mood-related preparatory effect. Across three analyses, ACC showed sensitivity to both mood and insight, demonstrating that positive mood alters preparatory activity in ACC, biasing participants to engage in processing conducive to insight solving. We next manipulated positive and neutral mood states within each participant to draw strong causal inferences as to whether a positive mood induction (MI) would specifically facilitate insights. When participants were in the positive MI, they showed increased preparatory activity in ACC, particularly for preparation leading to insights, and solved more problems overall compared to when they were in the neutral MI. These results from the mood induction study replicate the positive mood-insight facilitatory effect observed in our assessed mood study. Specifically, across both studies, we show that a positive mood enhances insight by modulating attention/cognitive control mechanisms within the ACC to either allow more sensitivity to detect competing solution candidates, to enhance switching and/or to enhance selection processes to converge to the correct solution. |
