Humans derive task expectancies from sub-second and supra-second interval durations

Is Self-Related Cognition Resistant to Time-Based Expectancy?

Individuals adapt to their environments by scheduling cognitive processing capacities selectively to the points in time where they are most likely required. This effect is known as time-based expectancy (TBE) and has been demonstrated for several cognitive capacities, like perceptual attention, task set activation, or response preparation. However, it has been argued that self-related cognition (i.e., processing of information linked to oneself) is universally prioritized, compared to non-self-related information in the cognitive system. Consequently, self-related cognition should be resistant to temporal scheduling by TBE, because individuals maintain a constantly high expectancy for self-related cognition, irrespective of its temporal likeliness. We tested this hypothesis in a task-switching paradigm where participants randomly switched between a self-related task and a neutral task. The tasks were preceded by a short or a long warning interval in each trial, and the interval duration predicted probabilistically the task type. We found that participants showed TBE for the neutral task but not for the self-related task. We conclude that the individual cannot benefit from time-based task expectancy when the to-be-expected task is constantly activated, due to its self-related nature.

Time-based task expectancy: perceptual task indicator expectancy or expectancy of post-perceptual task components?

The temporal predictability of upcoming events plays a crucial role in the adjustment of anticipatory cognitive control in multitasking. Previous research has demonstrated that task switching performance improved if tasks were validly predictable by a pre-target interval. Hence, far, the underlying cognitive processes of time-based task expectancy in task switching have not been clearly defined. The present study investigated whether the effect of time-based expectancy is due to expectancy of post-perceptual task components or rather due to facilitation of perceptual visual processing of the coloured task indicator. Participants performed two numeric judgment tasks (parity vs. magnitude), which were each indicated by two different colours. Each task was either more or less frequently preceded by one of two intervals (500 ms or 1500 ms). Tasks were indicated either by colours that were each more frequently (or in Exp. 1 also less frequently) paired with the interval or by colours that were equally frequent for each interval. Participants only responded faster when colour and task were predictable by time (expected colour), not when the task alone was predictable (neutral colour). Hence, our results speak in favour of perceptual time-based task indicator expectancy being the underlying cognitive mechanism of time-based expectancy in the task switching paradigm.

Investigating time-based expectancy beyond binary timing scenarios: evidence from a paradigm employing three predictive pre-target intervals

When the duration of a pre-target interval probabilistically predicts the identity of the target, participants typically form time-based expectancies: they respond faster to frequent interval-target combinations than to infrequent ones. Yet, previous research investigating the cognitive time-processing mechanisms underlying time-based expectancy assessed time-based expectancy always in situations with a binary set of intervals (i.e. short vs. long). Here we aim to test whether time-based expectancy transfers to more complex settings with three different predictive time intervals (short, medium, long) in which each predicts one of three different target stimuli with 80% probability. In three experiments we varied how the medium interval was computed (arithmetic mean, geometric mean, or in between both). Our results showed that participants were able to learn the time-event contingencies for the short and the long as well as for the medium interval, and were, thus able to flexibly redirect their target expectancy two times during the course of a trial. The evidence concerning the impact of the manipulation of the medium intervals’ absolute duration on time-based expectancy was, however, mixed, as time-based expectancy for the medium interval could only be observed in one of three reported experiments. In sum, the findings of the present study suggest a previously unknown cognitive flexibility underlying time-based expectancy and offer important theoretical implications, challenging future research on the timing mechanisms involved in time-based expectancy.

Time-Based Transition Expectancy in Task Switching: Do We Need to Know the Task to Switch to?

Recent research has shown that humans are able to implicitly adapt to time-transition contingencies in a task-switching paradigm, indicated by better performance in trials where the task transition (switch vs. repetition) is validly predicted by the pre-target interval compared to trials with invalidly predicted transitions. As participants switched between only two different tasks, not only the transition, but also the specific task was predictable; at least indirectly when taking into account the temporally predicted transition in the current trial together with the task in the previous trial. In order to investigate if the time-based expectancy effect for transition in previous studies was due to a specific task preparation or due to an unspecific transition preparation, three different tasks were used in the present study. One of two possible pre-target intervals (500 and 1500 ms) predicted a task switch in the upcoming trial with 90 % probability, whereas the other interval predicted a task repetition with 90 % probability. Results revealed that participants were able to prepare both upcoming repetition as well as switch requirements based on predictive pre-target intervals. This means that humans seem to be able to prepare a task switch in a rather unspecific manner, most likely by inhibiting the task just performed in the previous trial. By suggesting a two-stage preparation model in which switches as well as repetitions benefit both from time-based transition expectancy, although apparently with different cognitive processes being involved, the present study provides important impulses for future research on the cognitive processes underlying human task-switching behavior.

How does positive mood modulate time-based event expectancy?

In the present study, we investigated how positive mood affects the formation of time-based event expectancies. After positive or neutral mood inductions, participants performed a binary choice response task in which two target stimuli (circle and square) and two pre-target intervals (800 and 1600 ms) appeared equally often. One of the targets was paired with the short interval and the other target with the long interval in 90% of the trials. We found that participants from the positive and neutral groups showed markedly different behavioral patterns of time-based expectancy. The time-based expectancy was restricted to shorter intervals for the positive group and to longer intervals for the neutral group. We propose that positive mood increases attentional prioritization of information that is temporally closer to us.