Poster Session A, Saturday, March 23, 1:30 pm - 3:30 pm, Pacific Concourse
Decisions to explore are preceded by neural interruption and response conflict
Cameron Hassall1, Craig McDonald2, Olave Krigolson1; 1University of Victoria, 2George Mason University
Economic choices often involve a trade-off between exploiting the known and exploring the unknown. Despite numerous studies on the topic, little is known about the time course of the neural processes underlying decisions to explore or exploit. We addressed this issue by recording EEG while participants played several gambling games. After classifying responses as either explorations or exploitations using a computational model, we examined event-related potentials locked to two events: the appearance of the choice stimuli and the arrival of feedback prior to decisions to explore/exploit. In particular, we examined the feedback-locked P300 component, thought to index a phasic release of norepinephrine (a neural interrupt signal), and the reward positivity, thought to index a phasic release of dopamine (a neural prediction error signal). We observed an exploration-dependent enhancement of the P300 only, suggesting a critical role of norepinephrine (but not dopamine) in triggering decisions to explore. Similarly, we examined the N200/P300 components evoked by the appearance of the choice stimuli. In this case, exploration was characterized by an enhancement of the N200, but not P300, a result we attribute to increased response conflict. Thus, exploratory decisions were preceded by two distinguishing events: a feedback-locked neural interrupt signal (enhanced P300) and a choice-locked increase in response conflict (enhanced N200).
Topic Area: THINKING: Decision making