Effects of Preparation Time and Foreknowledge on Task Switching

In task switching, switch cost is the performance differences in task-switch and task-repetition trials. Recently, some researches have attempted to specify nature and origins of switch cost to uncover the mechanisms underlying task switching performance. Theoretically, there is disagreement as to whether switch cost actually represents the task-set reconfiguration or the task-set inertia. Many studies found that a prolonged preparation time reduces switch costs, which has been attributed to a task set reconfiguration process. However, unlike manipulations of preparation time, other studies varied the predictability of task sequence and found that the preparation benefit was the same for switches and repetitions. The aim of the present study was to investigate the effect of foreknowledge and preparation time on task switching. Two experiments were conducted in the present study. There were 30 participants (12 males and 18 females) volunteered to take part in experiment 1 and another 30 participants (9 males and 21 females) took part in experiment 2. In order to investigated the effect of foreknowledge on task switching, the experiment 1 was conducted with a 3 (foreknowledge type: no foreknowledge, part foreknowledge and full foreknowledge) × 2 (task type: switch task and repetition task) within-subject design. In the experiment 2, a 3 (preparation time: 100ms, 600ms and 1000ms) × 3 (foreknowledge type: no foreknowledge, part foreknowledge and full foreknowledge) × 2 (task type: switch task and repetition task) within-subject design was conducted to examined the mechanisms of effects of foreknowledge on task switching under the conditions of difference preparation time. The correct RT and switch cost were measured as the main index. The results showed that: (1) the amount of switch cost depend on foreknowledge, switch cost was smaller with full foreknowledge than with part and no foreknowledge, but not difference significantly between the later two. (2) The interaction between preparation time and foreknowledge was significant, and with increased preparation time, the effect of foreknowledge was more remarkable. Current findings suggest that the cognitive process that foreknowledge affected was task-set reconfiguration, rather than task-set inertia, and the effect was mediated by preparation time.

Inattention is a symptom of many clinical disorders including attention deficit hyperactivity disorder (ADHD) and is thought to be primarily related to limitations in working memory. In two studies, we investigated the implications of inattention for task switching performance. In study one, we measured task switching performance using predictable and unpredictable conditions in adults who self-rated inattention and other ADHD-related tendencies. Tasks required proactive control and reactive control, respectively, under both high and low working memory loads. Results revealed that inattentive, but not hyperactive/impulsive traits, predicted switch costs when switching was predictable and working memory load was high. None of the ADHD traits were related to unpredictable switch costs. Study two was designed to: (1) de-confound the role of proactive control and the need to keep track of task order in the predictable task switching paradigm; (2) investigate whether goal neglect, an impairment related to working memory, could explain the relationship between inattention and predictable task switching. Results revealed that neither predictability nor the need to keep track of the task order led to the association between switch costs and inattention, but instead it was the tendency for those high in inattention to neglect preparatory proactive control, especially when reactive control options were available.

Event-related potentials (ERPs) and total time-frequency power analyses have shown that performance costs during task switching are related to differential preparation to switch tasks (switch cost) and repeat the same task (mixing cost) during both proactive control (cue-to-target interval; CTI) and reactive control (post-target). The time-frequency EEG signal is comprised of both phase-locked activity (associated with stimulus-specific processes) and nonphase-locked activity (represents processes thought to persist over longer timeframes and do not contribute to the average ERP). In the present study, we used a cued task-switching paradigm to examine whether phase-locked and nonphase-locked power are differentially modulated by switch and mixing effects in intervals associated with the need for proactive control (CTI) and reactive control (post-target interval). Phase-locked activity was observed in the theta and alpha bands, closely resembled that seen for total power, and was consistent with switch and mixing ERP positivities. Nonphase-locked analyses showed theta and alpha power effects for both switch and mixing effects early in the CTI and as well as more sustained alpha and beta activity around cue onset, and extending from mid-CTI into the post-target interval. Nonphase-locked activity in pretarget alpha and posttarget theta power were both correlated with response time mixing cost. These findings provide novel insight into phase-locked and nonphase-locked activity associated with switch and mixing costs that are not evident with ERP or total time-frequency analyses.

Investigations of concurrent task and modality switching effects have to date been studied under conditions of uni-modal stimulus presentation. As such, it is difficult to directly compare resultant task and modality switching effects, as the stimuli afford both tasks on each trial, but only one modality. The current study investigated task and modality switching using bi-modal stimulus presentation under various cue conditions: task and modality (double cue), either task or modality (single cue) or no cue. Participants responded to either the identity or the position of an audio–visual stimulus. Switching effects were defined as staying within a modality/task (repetition) or switching into a modality/task (change) from trial n − 1 to trial n, with analysis performed on trial n data. While task and modality switching costs were sub-additive across all conditions replicating previous data, modality switching effects were dependent on the modality being attended, and task switching effects were dependent on the task being performed. Specifically, visual responding and position responding revealed significant costs associated with modality and task switching, while auditory responding and identity responding revealed significant gains associated with modality and task switching. The effects interacted further, revealing that costs and gains associated with task and modality switching varying with the specific combination of modality and task type. The current study reconciles previous data by suggesting that efficiently processed modality/task information benefits from repetition while less efficiently processed information benefits from change due to less interference of preferred processing across consecutive trials.

Exploring task-set reconfiguration with random task sequences

The capacity to switch between tasks is a central component of executive functioning. Previous studies assessing effects of task-switch training have revealed mixed results, both in terms of processes that may be improved and the extent of beneficial effects on non-trained tasks. These studies primarily used few training sessions, which may have limited training and transfer effects. Here, 31 students were trained for 21 days on a cued switching task. Both the trained group and an active control group (n = 29) performed a number of cognitive tasks before and after training. Training reduced both switch and mixing costs, which mostly reached an asymptote after approximately four to six training sessions, although there were residual costs at the end of training. The switch cost reduction was restricted to trials with a short cue–stimulus onset interval (CSI). Training benefitted performance on another switching task, reflecting near transfer. However, this benefit was limited to the switch cost and to trials with a short CSI. There were no beneficial effects on far-transfer tasks measuring interference control, response inhibition, working memory, and general IQ. The results suggest that the present extensive training protocol, implicating overtraining, specifically enhanced the efficiency of processes involved in preparing for the relevant upcoming task set and/or inhibition of the previous task set. However, the lack of beneficial far-transfer effects is in line with previous cognitive training studies employing fewer training sessions, suggesting that the extent of training is not critical for (not) finding transfer effects.

Disparate bilingual experiences modulate task-switching advantages: A diffusion-model analysis of the effects of interactional context on switch costs

Whether the effect of switch probability on switch and mixing costs is explained by an activation or preparation account is unclear. To investigate the account of the effect of switch probability on switch and mixing costs. We used a cued task-switching paradigm with three switch probabilities (high, 75%; medium, 50%; and low, 25%) with 19 healthy young adults and recorded the cue- and target-locked event-related potentials (ERPs) and behavioral performance. The task included switch and stay trials under high, medium, and low switch conditions, as well as pure trials. There was no significant difference in reaction time (RT) in switch and mixing costs between the high and medium switch conditions. The RT in switch and mixing costs in the high and medium switch conditions was significantly less and more than in the low switch condition, respectively. The cue-locked ERPs revealed significant effects on mixing costs (stay - pure) that were cue early frontal positivity (260-300 ms) in the high and medium switch conditions, and on switch costs (switch - stay) that were cue early central positivity (240-260 ms) in the low switch condition. Moreover, the target-locked ERPs of the mixing costs revealed significant effects on mixing costs that were target P3b (440-540 ms) in all three switch conditions, and on switch costs that were target P3b in the medium and low switch conditions. The effect of switch probability on switch and mixing costs is explained by the activation account.

Recent research on voluntary task switching indicates that people use different strategies to manage multitasking constraints. In this study, we conducted two experiments to investigate individual task selection behavior and provide empirical evidence for two theoretically derived strategies-local and global-aimed at balancing time-related costs in a self-organized task switching paradigm. We implemented a delay for the stimulus required for task repetition (i.e., stimulus-onset asynchrony [SOA]), which increased with each consecutive repetition until a task switch reset the SOA. Thus, repeating a task required waiting, while switching incurred performance costs. We examined individual waiting times at which participants chose to switch tasks (switch SOA) and their task performance (switch costs) across conditions. Results revealed that some participants had switch SOAs similar to their switch costs, consistent with a local strategy. Others showed considerably smaller switch SOAs compared to their switch costs, aligning with the global strategy. These individuals likely accounted for the fact that task switching in this paradigm reduces waiting times in subsequent trials. Importantly, our visual observations of behavioral patterns were confirmed using the expectation-maximization method, a technique sometimes applied in machine learning, providing statistical support for the existence of these two strategies. Overall, the findings suggest that individuals differ in their preferred task selection strategies, with preferences remaining relatively stable across varying experimental conditions. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Switch costs occur whenever participants are asked to switch between two or more task sets. In a typical task switching experiment, participants have to switch between two task sets composed of up to four different stimuli per task set. These 2 (task sets) x 4 (stimuli) contain only 8 different stimulus-response (S-R) mappings, and the question is why participants base their task performance on task sets instead of S-R mappings. The current experiments compared task performance based on task rules with performance based on single stimulus-response mappings. Participants were led to learn eight different S-R mappings with or without fore-knowledge about two underlying task sets. Without task set information no difference between shifts and repetitions occurred, whereas introducing task sets at the beginning led to significant switch costs. Most importantly, introducing task sets in the middle of the experiment also resulted in significant switch costs. Furthermore, introducing task rules at the beginning of the experiment lead to slower RTs when simple stimuli (Experiment 1) had to be processed. This detrimental effect disappeared with more complex stimuli (Experiment 2). Results will be discussed with respect to cognitive control.

Pre-stimulus EEG effects related to response speed, task switching and upcoming response hand

The relationship between language switching and task switching has been well studied in bilingualism literature. This study employs novel experiments involving magnitude-parity switching and transparency-orientation switching and compares the costs associated with these two types of task switching with language switching. Switching costs and the reduction in switching costs (RISC) effect were used as indices of inhibitory control and preparatory control, respectively. The results from Experiment 1 revealed strong positive correlations for all three types of switching, with language switching being less costly than magnitude-parity and transparency-orientation switching. In Experiment 2, we increased the cue-stimulus interval and again found significant or marginally positive relations between the three switching costs. The RISC effect emerged in magnitude-parity and transparency-orientation switching but not in language switching. In Experiment 3, the experimental blocks included both language switching and either magnitude-parity or transparency-orientation switching. Language switching costs were significantly greater than but no longer positively correlated with magnitude-parity switching or transparency-orientation switching costs. Together, these results suggest that more inhibitory control (in Experiments 1 and 3) and less preparatory control (in Experiment 2) in language switching is required compared to magnitude-parity and transparency-orientation switching. Moreover, partially overlapping mechanisms are engaged in the three switching domains.

Response repetitions in auditory task switching: The influence of spatial response distance and of the response-stimulus interval

Meta-control is necessary to regulate the balance between cognitive stability and flexibility. Evidence from (voluntary) task switching studies suggests performance-contingent reward as one modulating factor. Depending on the immediate reward history, reward prospect seems to promote either cognitive stability or flexibility: Increasing reward prospect reduced switch costs and increased the voluntary switch rate, suggesting increased cognitive flexibility. In contrast, remaining high reward prospect increased switch costs and reduced the voluntary switch rate, suggesting increased cognitive stability. Recently we suggested that increasing reward prospect serves as a meta-control signal toward cognitive flexibility by lowering the updating threshold in working memory. However, in task switching paradigms with two tasks only, this could alternatively be explained by facilitated switching to the other of two tasks. To address this issue, a series of task switching experiments with uncued task switching between three univalent tasks was conducted. Results showed a reduction in reaction time (RT) switch costs to a nonsignificant difference and a high voluntary switch rate when reward prospect increased, whereas repetition RTs were faster, switch RTs slower, and voluntary switch rate was reduced when reward prospect remained high. That is, increasing reward prospect put participants in a state of equal readiness to respond to any target stimulus—be it a task repetition or a switch to one of the other two tasks. The study thus provides further evidence for the assumption that increasing reward prospect serves as a meta-control signal to increase cognitive flexibility, presumably by lowering the updating threshold in working memory.

ABSTRACTThe present study investigates the representation of task-sets in a joint dual-task setting. To this end, a task-switching approach is used. Task switching is associated with a switch cost, which can be decomposed in several markers of task-set coordination. These markers can be used to investigate whether participants represent the co-actor's task-set in a joint dual-task setting. A joint task-switching procedure was used in which two participants performed a distinct task and the participants’ turn to respond could switch or repeat on a trial-by-trial basis. The results indicate that joint task switching also elicits a switch cost. However, this switch cost does not seem to be related to the representation of the co-actor's task-set. It is suggested that the switch cost observed in joint task switching is based on processes of task monitoring, which increase the saliency of task-irrelevant stimulus information.