Abstract:

Humans often must respond quickly to events happening in their environment. To support fast perception and action, the brain has evolved a warning system. Warning stimuli are used to elicit a transient state of readiness for perception and action (phasic alertness) that results in faster perceptual processing and faster decision-making for action. Phasic alertenss is assumed to be “unintelligent” in the sense that it is driven by the warning stimuli, irrespective of the cognitive task set and the expectations guiding goal-directed behavior in the current task. Here, we review recent findings that falsify this assumption. We provide evidence that phasic alertness presupposes an expectation that stimuli can serve as a warning within the current task. In addition, we show that within a task, phasic alertness unfolds in action-focused episodes that restrict its effects to only the next action in an action sequence. Together, these findings reveal that phasic alertness is not entirely stimulus-based (bottom-up), but also relies on the cognitive mechanisms for (top-down) control of task-driven and goal-directed action and thus the “intelligent” interaction with the environment.