A Brain Mechanism for Facilitation of Insight by Positive Affect

Previous research has shown that people solve insight or creative problems better when in a positive mood (assessed or induced), although the precise mechanisms and neural substrates of this facilitation remain unclear. We assessed mood and personality variables in 79 participants before they attempted to solve problems that can be solved by either an insight or an analytic strategy. Participants higher in positive mood solved more problems, and specifically more with insight, compared with participants lower in positive mood. fMRI was performed on 27 of the participants while they solved problems. Positive mood (and to a lesser extent and in the opposite direction, anxiety) was associated with changes in brain activity during a preparatory interval preceding each solved problem; modulation of preparatory activity in several areas biased people to solve either with insight or analytically. Analyses examined whether (a) positive mood modulated activity in brain areas showing responsivity during preparation; (b) positive mood modulated activity in areas showing stronger activity for insight than noninsight trials either during preparation or solution; and (c) insight effects occurred in areas that showed mood-related effects during preparation. Across three analyses, the 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. This result suggests that positive mood enhances insight, at least in part, by modulating attention and cognitive control mechanisms via ACC, perhaps enhancing sensitivity to detect non-prepotent solution candidates.

Reaction Time Crossover with an Interfering Task

The present study investigated reaction time with and without tapping as an interfering task. 66 undergraduate students were instructed to press and hold a button when a stimulus disappeared from a computer screen, then release it as quickly as possible when it reappeared at the end of each preparatory interval, using the preferred hand. Lengths of preparatory intervals were either 1, 2, 4, 8, 16, or 25 sec. and occurred sometimes in a regular sequence of preparatory intervals of the same length and sometimes in an irregular randomly ordered sequence. Half of the participants were assigned to tap the tabletop with the forefinger of the nonpreferred hand throughout the task. A 2 × 6 × 2 analysis of variance showed significant effects for regularity, length of preparatory interval, and the interaction between regularity and length of preparatory interval. A significant main effect for tapping indicated that reaction times were slower in the tapping group. There were no significant interactions between tapping and other variables, indicating that the pattern of reaction times did not differ significantly between the two groups. Tapping produces a dual-task interference that increases reaction time similarly across different conditions.