PT  - JOURNAL ARTICLE
AU  - Hause Lin
AU  - Blair Saunders
AU  - Cendri A Hutcherson
AU  - Michael Inzlicht
TI  - Midfrontal theta and pupil dilation parametrically track subjective conflict (but also surprise) during intertemporal choice
AID  - 10.1101/172122
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 172122
4099  - http://biorxiv.org/content/early/2017/08/03/172122.short
4100  - http://biorxiv.org/content/early/2017/08/03/172122.full
AB  - Many everyday choices are based on personal, subjective preferences. When choosing between two options, we often feel conflicted, especially when trading off costs and benefits occurring at different times (e.g., saving for later versus spending now). Although previous work has investigated the neurophysiological basis of conflict during inhibitory control tasks, less is known about subjective conflict caused by competing subjective preferences. In this pre-registered study, we investigated subjective conflict during intertemporal choice, whereby participants chose between smaller immediate versus larger delayed rewards (e.g., $15 today vs. $22 in 30 days). We used economic modeling to parametrically vary eleven different levels of conflict, and recorded EEG data and pupil dilation. Midfrontal theta power, derived from EEG, correlated with pupil responses, and as predicted, these signals tracked even fine gradations of subjective conflict. Unexpectedly, both signals were also maximally enhanced when decisions were surprisingly easy. Therefore, these signals may track events requiring increased attention and adaptive shifts in behavioral responses, with conflict being only one type of such event. Our results suggest that the neural systems underlying midfrontal theta and pupil responses interact when weighing costs and benefits during intertemporal choice. Thus, understanding these interactions might elucidate how individuals resolve self-control conflicts.