No evidence for short-timescale temporal declines in expectations within a controlled cognitive task

People waiting to receive information about a personally relevant future event often become increasingly pessimistic as the event draws near. These temporal declines in expectations have been demonstrated robustly across both naturalistic and laboratory settings. However, the low-level cognitive processes that give rise to temporal declines in expectations remain unclear. Here, we investigated the temporal boundary conditions of this effect. In a controlled cognitive task involving repeated probabilistic gambles, we assessed the dynamics of participants' reward expectations over a 12-second waiting period prior to revelation of the gamble outcome. Across two experiments (total N = 120), we found no evidence for temporal declines in expectations over this short waiting period, no matter whether expectations were measured via direct probability report (Experiment 1) or via an incentive-compatible `cash-out' decision (Experiment 2). These results demonstrate that temporal declines in expectations are not an invariant characteristic of human expectations regarding personally relevant future events