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 of either sex. 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. Significance statementHumans are curious by nature. When you hear your phone beep, you probably feel the urge to check the message right away, even though the message itself likely doesn't give you a direct reward. In this study, we demonstrated that curiosity can be driven by outcome uncertainty, irrespective of reward. The induction of curiosity was accompanied by increased activity in the parietal cortex, whereas the information update at the time of curiosity relief was associated with activity in insular cortex. These . CC-BY-NC-ND 4.0 International license peer-reviewed) is the author/funder. It is made available under a The copyright holder for this preprint (which was not . http://dx.doi.org/10.1101/195461 doi: bioRxiv preprint first posted online Sep. 29, 2017; 3 findings advance our understanding of the behavioral and neural underpinnings of curiosity, which lies at the core of human information-seeking and serves to optimize the individual's current world-model.

Choosing to view morbid information involves reward circuitry

“…In the last decade, neuroscientific research has made a major contribution to a better understanding of choice, value and curiosity. Most of this work, however, has focused on extrinsically rewarding information (Bartra et al, 2013;Braver et al, 2014), or on an intrinsically-motivated curiosity for neutral or positive information (e.g., Kang et al, 2009;van Lieshout et al, 2018;Gruber et al, 2014). The present study demonstrates that choosing intensely negative stimuli engages similar brain regions as those that support extrinsic incentives and regular curiosity (Diekhof et al, 2012;Bartra et al, 2013;Kidd & Hayden, 2014;Sakaki et al, 2018).…”

“…This is in line with previous work on curiosity (Gruber, et al, 2014) that found robust neural activation when inducing curiosity (e.g., presentation of trivia questions), but not when relieving curiosity (e.g., presentation of trivia answers). Other work on curiosity, that did find differences in the relief phase, contrasted a condition in which curiosity was relieved, with a condition that withheld information (van Lieshout et al, 2018) or a condition that showed irrelevant information (Jepma et al, 2012). In the present study, however, we contrasted the relief phase in the active-choice condition with viewing the exact same information in the passive-viewing condition.…”

“…The negative choices made by our participants are most likely consistent with the latter intrinsic motive. Participants chose images that were not hedonically pleasing and, in contrast to other recent (neuroscientific) studies targeting curiosity (e.g., Kobayashi et al, 2019;van Lieshout et al, 2018), there was no monetary outcome associated with choosing (negative) images.…”

“…In the present study, we tested the preregistered hypothesis that the striatum and IFG (ROI-analyses) and the anterior insula and ACC (whole-brain analyses) will engage more when people deliberately choose to view negative images, as compared to a passive viewing condition. This hypothesis reflects our assumption that "morbid curiosity", expressed by a choice to view a negative stimulus, engages similar neural regions as regular curiosity (van Lieshout et al, 2018;Gruber et al, 2014;Jepma et al, 2012;Kang et al, 2009). In addition, we tested a second hypothesis that the regions described above will engage more strongly when people choose to view a negative stimulus, as compared to a positive stimulus.…”

“…), in combination with the predicted reduction of this uncertainty when choosing to view images. Curiosity is often seen as a desire to resolve uncertainty (Berlyne, 1966;Loewenstein, 1994;Gottlieb & Oudeyer, 2018) and several recent studies have demonstrated that people experience higher levels of curiosity for uncertain stimuli (Kobayashi et al, 2019;van Lieshout, et al, 2018). People even engage with aversive stimuli to reduce uncertainty, preferring a reduction in uncertainty above a negative outcome (e.g., shock, Hsee & Ruan, 2016).…”