The importance of decision onset

Abstract

The neural mechanisms of decision making arethought to require the integration of evidence over time until a response thresholdis reached. Much work suggests that response threshold can be adjusted viatop-down control as a function of speed or accuracy requirements. In contrast, thetime of integration onset has received less attention and is believed to be determinedmostly by afferent or preprocessing delays. However, a number of influentialstudies over the past decade challenge this assumption and begin to paint amultifaceted view of the phenomenology of decision onset. This review highlightsthe challenges involved in initiating the integration of evidence at the optimal timeand the potential benefits of adjusting integration onset to task demands. The reviewoutlines behavioral and electrophysiolgical studies suggesting that the onset of theintegration process may depend on properties of the stimulus, the task, attention,and response strategy. Most importantly, the aggregate findings in the literaturesuggest that integration onset may be amenable to top-down regulation, and may beadjusted much like response threshold to exert cognitive control and strategicallyoptimize the decision process to fit immediate behavioral requirements.