On 16 May, Dr Ian Krajbich (a neuroeconomist at the Department of Psychology, Ohio State University, USA) visits to give a talk in the SWE Colloquia series.

The neural dynamics of attention and choice

When making decisions, people tend to shift their attention back and forth between stimuli, choosing options that they look at more overall and immediately prior to their responses.  These relationships, and others, are well-described by sequential sampling models that assume that evidence for a given alternative is collected over time in proportion to its subjective value, amplified by attention.  Furthermore, findings from a number of studies support a causal effect of attention on choice.  What is unclear is how this attention-guided decision process unfolds in the brain. Here we designed a task that draws out the decision process, allowing us to control the stream of evidence seen by the decision-makers. Using this approach, we were able to clearly dissociate neural signatures associated with evaluating the on-screen evidence vs. integrating all the evidence needed to decide. We find that these signals are isolated to separate regions of the brain. Importantly, we find that both signals are affected by visual attention, demonstrating that gaze affects the stored representations of past evidence. In another study, we causally manipulate attention-related brain activity using transcranial magnetic stimulation and find that this impacts the effects of gaze on choice in ways predicted by our model.  Together, these studies establish a brain network guiding gaze-weighted evidence accumulation for value-based choice.