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.

Interaction of prior category knowledge and novel statistical patterns during visual search for real-world objects

Two aspects of real-world visual search are typically studied in parallel: category knowledge (e.g., searching for food) and visual patterns (e.g., predicting an upcoming street sign from prior street signs). Previous visual search studies have shown that prior category knowledge hinders search when targets and distractors are from the same category. Other studies have shown that task-irrelevant patterns of non-target objects can enhance search when targets appear in locations that previously contained these irrelevant patterns. Combining EEG (N2pc ERP component, a neural marker of target selection) and behavioral measures, the present study investigated how search efficiency is simultaneously affected by prior knowledge of real-world objects (food and toys) and irrelevant visual patterns (sequences of runic symbols) within the same paradigm. We did not observe behavioral differences between locating items in patterned versus random locations. However, the N2pc components emerged sooner when search items appeared in the patterned location, compared to the random location, with a stronger effect when search items were targets, as opposed to non-targets categorically related to the target. A multivariate pattern analysis revealed that neural responses during search trials in the same time window reflected where the visual patterns appeared. Our finding contributes to our understanding of how knowledge acquired prior to the search task (e.g., category knowledge) interacts with new content within the search task.

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.

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.

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

Recent studies in the field of task switching have shown that humans can base expectancies for tasks on temporal cues. When tasks are predictable based on the duration of the preceding pre-target interval, humans implicitly adapt to this predictability, indicated by better performance in trials with validly compared to invalidly predicted tasks. Yet, it is not clear which internal timing mechanisms are involved. Previous research has suggested that intervals from the sub- and supra-second range are processed by distinct cognitive timing systems. As earlier studies on temporally predictable task switching have used predictive intervals stemming from both ranges, it was not yet clear if the time-based expectancy effect was driven by just one of the two internal timing systems. The present study used clearly sub-second intervals (10 ms and 500 ms) in Experiment 1, while clearly supra-second intervals (1500 ms and 3000 ms) were used in Experiment 2. Substantial adaptation effects were observed in both experiments, showing that sub- as well as supra-second timing systems are involved in time-based expectancies for tasks. The present findings offer important implications for our theoretical understanding of the internal timing mechanisms involved in time-based task expectancy.

Children with autism spectrum disorder show increased sensitivity to time-based predictability

Objectives: We studied timed-based expectancy as well as general perceptual-motor speed in children with autism spectrum disorder (ASD). Methods: In Experiment 1, 11 children with ASD and 11 typically developing children (TD) (6-13 years) completed a binary choice response task in which foreperiod duration predicted the response target's location with a probability of 0.8. In Experiment 2, we compared performance between 10 children with ASD (6-11 years) and 10 TD children by using a simple reaction time test. Results: Employing a binary forced choice task where the duration of a pre-target interval (800 or 1400 ms) probabilistically predicted the target, we found that children with ASD were sensitive to the temporal regularity, whereas TD children were not. Children with ASD were faster for expected combinations of interval and target location but they were also less accurate for those combinations. Results from an additional simple reaction time test indicate that the development of general perceptual-motor processes was delayed in children with ASD. However, the ability for children with ASD to form time-based expectancies was not correlated with their performance in the simple reaction time test. Conclusion: Children with ASD show significantly greater sensitivity towards time-based predictability than TD children. However, the development of general perceptual-motor processes was impaired in children with ASD.

Transfer of time-based task expectancy across different timing environments

Recent research on time-based expectancy has shown that humans base their expectancies for responses on representations of temporal relations (e.g., shorter vs. longer duration), rather than on representations of absolute durations (e.g., 500 vs. 1000 ms). In the present study, we investigated whether this holds also true for time-based expectancy of tasks instead of responses. Using a combination of the time-event correlation paradigm and the standard task-switching paradigm, participants learned to associate two different time intervals with two different tasks in a learning phase. In a test phase, the two intervals were either globally prolonged (Experiment 1), or shortened (Experiment 2), and they were no longer predictive for the upcoming task. In both experiments, performance in the test phase was better when expectancy had been defined in relative terms and worse when expectancy had been defined in absolute terms. We conclude that time-based task expectancy employs a relative, rather than an absolute, representation of time. Humans seem to be able to flexibly transfer their time-based task expectancies between different global timing regimes. This finding is of importance not only for our basic understanding of cognitive mechanisms underlying time-based task expectancy. For human-machine applications, these results mean that adaptation to predictive delay structures in interfaces survives globally speeding up or slowing down of delays due to different transmission rates.

Time-based event expectancies in children with Autism spectrum disorder

Here, we studied the time-based event expectancies in children with Autism spectrum disorder. Nine children with Autism spectrum disorders and ten (6-11 years) typically developing children participated. In a choice-response task with two different pre-target intervals, participants had to indicate the left or right direction of a target stimulus. The target was predicted by the duration of the pre-target interval with 80% validity. We found that, in children with Autism spectrum disorder, in contrast to typically developing children, the formation of time-based event expectancies was restricted to the relatively longer pre-target interval. This pattern is rather typical for healthy young adults. These findings indicate that children with Autism spectrum disorder are able to form time-based event expectancies, and that, similar to healthy young adults, longer pre-target intervals enable them to make more optimal temporal predictions.

Time-based expectations entail preparatory motor activity

Human behavior is guided by expectations that facilitate perception of upcoming events or reaction to them. In natural settings expectations are often implicitly based on time, e.g., when making a phone call one would expect to hear either a person answering (earlier) or a voicemail greeting (later). We investigated how time-based expectations can improve performance in the absence of explicit prior information on the pending stimulus or the associated response. Visual stimuli were presented after a characteristic short or long foreperiod, and a forced-choice categorization using either the left or the right hand was required. The electroencephalogram (EEG) revealed a decrease in central 9-12 Hz power over the course of the trial. Moreover, lateralized pre-motor potentials were observed which changed polarity after the short foreperiod. At stimulus onset, amplitudes of pre-motor potentials co-varied with performance, so that higher (more negative) amplitudes were associated with slower responses to unexpected targets. Altogether, the results suggest that implicit time-based expectations entail effector-specific preparatory brain activity, which is inhibited until the expected onset time of the event. Thus, time-based expectations prepare for action.