Understanding the causes of adapting, and failing to adapt, to time pressure in a complex multi-stimulus environment

We examined how people respond to time pressure factors in a complex, multi-stimulus environment. In Study 1, we manipulated time pressure by varying information load via stimulus complexity and the number of stimuli. In Study 2, we replaced the complexity manipulation with deadline – that is the time available to classify stimuli presented within a trial. We identified several ways that people can adapt to time pressure: Increasing the rate of information processing via effort or arousal, changing strategy by lowering response caution, and adjusting response bias. We tested these mechanisms using the LBA model of choice and response time (Brown & Heathcote, 2008). Whereas stimulus complexity influenced the quality of choice information, the number of stimuli influenced response caution, and deadline pressures caused a failure of encoding that was only partially compensated for by increased effort or arousal. Our results reveal that, rather than having a common response, people adapt, and fail to adapt, to the different time pressure factors in different ways.