The idea that the brain forms decisions by accumulating evidence up to a criterion or “bound” has been the major driver of decades of fruitful theoretical, behavioral, neuroscientific and clinical research into decision making. However, the most prominent competing model variants disagree on whether and how the extent of accumulation is limited through either of two means: 1) growing “urgency” to respond, which effects a collapsing decision bound, and/or 2) “leakage” of past evidence. These model variants are indistinguishable based on the quality of behavioural data fits for most tasks, yet can yield fundamentally discrepant interpretations of the same data. Our recent discovery that sensory evidence encoding, evidence accumulation and motor preparation can be simultaneously traced in neurophysiological recordings from the human brain has opened a new path to gaining definitive, convergent insights into the operation of these mechanisms in any task.
Pioneering a unique approach which exploits these dynamic neural signatures to construct, constrain and validate multi-tiered decision models, we will establish when and why urgency and leakage are invoked and adapted across diverse decision scenarios encompassing expanded judgements, discrete discriminations and continuous monitoring. These fundamental insights will have wide ranging impact on basic and clinical research into cognition.
