Induction and relief of curiosity elicit parietal and frontal activity

Abstract

Curiosity is a basic biological drive, but little is known about its behavioral and neural mechanisms. We can be curious about several types of information. On the one hand, curiosity is a function of the expected value of information, serving primarily to help us maximize reward. On the other hand, curiosity can be a function of the uncertainty of information, helping us to update what we know. In the current studies, we aimed to disentangle the contribution of information uncertainty and expected value of rewards to curiosity in humans. To this end, we designed a lottery task in which uncertainty and expected value of trial outcomes were manipulated independently and examined how neural activity and behavioral measures of curiosity were modulated by these factors. Curiosity increased linearly with increased outcome uncertainty, both when curiosity was explicitly probed as well as when it was implicitly tested by people's willingness to wait. Increased expected value, however, did not strongly relate to these curiosity measures. Neuroimaging results showed greater BOLD response with increasing outcome uncertainty in parietal cortex at the time of curiosity induction. Outcome updating when curiosity was relieved resulted in an increased signal in the insula, orbitofrontal cortex, and parietal cortex. Furthermore, the insula showed a linear increase corresponding to the size of the information update. These results suggest that curiosity is monotonically related to the uncertainty about one's current world model, the induction and relief of which are associated with activity in parietal and insular cortices, respectively.