The silent period of decision making

Abstract:

In a typical experiment on decision making, one out of two possible stimuli is presented per trial. Observers decide which one was presented. The underlying decision making process is commonly viewed as a one-stage process in which sensory evidence for both stimulus alternatives is accumulated until evidence for one of the stimuli crosses a threshold ("race-to-threshold process"). Using a two-stimulus presentation paradigm, we found that decision making is a two-stage process in which evidence integration precedes a race-to-threshold process. This evidence integration stage is "invisible" in one-stimulus presentation paradigms which, thus, underestimate the duration of the entire decision making process.