What is prepared in temporal preparation? A review and a historical appreciation

Temporal preparation refers to systematic changes in performance that arise when the timing of an event becomes predictable. From very early on in experimental psychology, research has shown that temporal predictability robustly shortens response times and modulates attentional states across a wide range of tasks. This review provides a comprehensive historical and contemporary synthesis of theoretical and empirical contributions to temporal preparation research. First, we present a brief overview of basic concepts, paradigms, and findings in temporal preparation research, and review mechanisms that have been suggested to address the question of how preparation emerges and how it may impact human cognitive processing. Second, in the main part of this article, we review findings from behavioral and electrophysiological studies that shed light on which cognitive processes are affected by temporal preparation in humans, aiming to take stock of the most robust empirical phenomena. Here, the main focus will be on the rich tradition of foreperiod effects, complemented by relevant results from temporal cueing and related paradigms. We show that temporal preparation has widespread consequences for cognitive processing, from increasing sensory gain to changes in response dynamics and various motor-related measures. These findings challenge traditional accounts that locate temporal preparation in specific processing stages (e.g., historically, the motor system). Instead, contemporary models must take into account a multi-component view of temporal preparation, in which preparatory processes impact various processes.