Victor Mittelstädt

Cognitive control-the ability to regulate one's behavior in accordance with internal goals-is fundamental to adaptive behavior. Despite substantial progress in our understanding of different cognitive control functions supporting goal-directed behavior, most studies rely on externally instructed tasks, whereas in real-world contexts, people often have the autonomy to choose which task to perform. Although research suggests that having the opportunity to choose can enhance a variety of psychological processes (e.g., motivation or learning), it remains unclear whether and how cognitive control differs between instructed and voluntarily chosen tasks. The present study addresses this question using a novel paradigm to investigate how one core function of cognitive control-the flexibility to switch between tasks-differs between self-determined (free-choice) and externally determined (forced-choice) tasks. We reasoned that self-determined task choice may enable individuals to optimize control more effectively (e.g., by switching when control demands are relatively low) and/or may motivate individuals to invest more effort in flexibility-related control processes. Consistent with performance optimization and motivational accounts, switch costs in task performance (in particular, reaction times) were reduced under free-choice compared to forced-choice tasks across multiple experiments. This reduction was driven specifically by shorter reaction times on switch trials in free-choice tasks, suggesting that voluntary task choice takes advantage of control processes that promote cognitive flexibility, such as disengaging from a previous task or reconfiguring a new one. Overall, the present study provides new evidence linking self-determined task choice to improvements in higher order cognitive control functions-specifically, cognitive flexibility. (PsycInfo Database Record (c) 2026 APA, all rights reserved).

The visual Simon task is widely used to study action control in the presence of conflicting target and distractor information. However, it is unclear how one of the core parameters of this task, visual target eccentricity, affects conflict processing. Building on a quantitative dual-route model Diffusion Model for Conflict Tasks (DMC), we hypothesized that increased eccentricity alters the relative strength of target- and distractor-based activation at the stage where conflict emerges, through two mechanisms: (a) weakened target processing due to reduced perceptual quality, and/or (b) enhanced distractor processing via continuous spatial coding of location. Using DMC simulations, we demonstrate that relying solely on mean reaction time (RT) to assess eccentricity effects may obscure underlying processing differences: depending on the timing of distractor-based activation, the impact of eccentricity on mean Simon effects may vary – even when the strength of target and/or distractor processing remains unchanged. In the present two experiments, we therefore first conducted distributional (delta plot) analyses to account for the temporal dynamics of distractor processing, revealing generally larger Simon effects for far compared to near targets. Analyses of DMC best-fitting parameters showed that, in both experiments, the increased conflict with greater eccentricity was due to decreased target-based accumulation rates. Moreover, distractor-based activation increased with eccentricity in Experiment 1 but not Experiment 2, suggesting that spatial locations are coded continuously rather than categorically when they can serve as mutual reference points (e.g., within blocks). We discuss implications for the mechanisms underlying the Simon effect by elaborating on how the timing and strength of target and distractor processes jointly shape conflict dynamics.

Conflict tasks often yield smaller mean congruency effects when relevant (target) and irrelevant (distractor) information is mostly incongruent rather than mostly congruent. While this proportion congruency effect may reflect proactive control adaptation, only a few previous studies have provided convincing evidence for proactive control adaptation when ruling out contingency learning and reactive (item-specific) control adaptation. In this study, we present further evidence for proactive control adaptation (as reflected in proportion congruency effects and asymmetrical list-shifting effects in contingency-free transfer items) across three experiments (each N = 100 participants) using manual counting Stroop tasks (Experiment 1: number words as distractors; Experiment 2: Arabic numerals as distractors; Experiment 3: number words and Arabic numerals as inducer and transfer items, or vice versa). To better understand the processes underlying proactive control adaptation, we conducted fine-grained distributional analyses (delta functions) and model-based analyses (diffusion model for conflict tasks). These analyses suggest that proactive control adaptation in manual counting Stroop tasks mainly reflects adjustments in the strength of distractor suppression rather than in the timing of distractor suppression, the strength of target amplification, or response caution. Additional distributional and diffusion model re-analyses of the data by Spinelli and Lupker (2023, Experiments 1–3) revealed a similar pattern in vocal color Stroop tasks. In conclusion, the present study provides new evidence for proactive control adaptation in manual counting Stroop tasks, and indicates that proactive control adaptation mainly reflects adjustments in the strength of distractor suppression in both manual and vocal Stroop tasks.

We investigated how self-determined (free) versus imposed (forced) choices influence task performance. To this end, we examined how changes in perceptual and central decision-processing difficulties affect task performance in an environment where free-choice and forced-choice tasks were intermixed. In Experiments 1 (N = 43) and 2 (N = 42), perceptual processing difficulty was varied by altering colored dot proportions (easy vs. hard color discrimination task). In Experiment 3 (N = 58), decision-processing difficulty was adjusted by changing the rotation degree of letters (easy vs. hard letter rotation task). Across all experiments, both free-choice and forced-choice performance were more impaired with harder stimuli, but this effect was generally less pronounced in freely chosen tasks. Specifically, this was evident from significant interactions between processing mode (free vs. forced) and difficulty (easy vs. hard) in the mean reaction times (RTs) for the tasks with the difficulty manipulation. Thus, processing in free-choice tasks is generally less affected by environmental changes (i.e., variation in information difficulties). We discuss how the benefit of self-determined choices over imposed choices can be explained by motivational and performance-optimization accounts, while also considering the finding that participants adjusted their task choices toward tasks with easier stimuli (i.e., significant main effect of task difficulty on choosing the task with the difficulty manipulation). Specifically, we discuss how having control over task choices might lead to more stable information processing and allow people to choose more difficult tasks when this increased difficulty has a relatively small impact on their performance.

In four experiments, we investigated the impact of outcomes and processing mode (free versus forced) on subsequent voluntary task-switching behavior. Participants freely chose between two tasks or were forced to perform one, and the feedback they received randomly varied after correct performance (reward or no-reward; loss or no-loss). In general, we reasoned that the most recently applied task goal is usually the most valued one, leading people to prefer task repetitions over switches. However, the task values might be additionally biased by previous outcomes and the previous processing mode. Indeed, negatively reinforcing tasks with no-reward or losses generally resulted in more subsequent switches. Additionally, participants demonstrated a stronger attachment to free- compared to forced-tasks, as indicated by more switches when the previous task was forced, suggesting that people generally value free over forced-choice task goals. Moreover, the reward manipulation had a greater influence on switching behavior following free- compared to forced-tasks in Exp. 1 and Exp. 3, suggesting a stronger emphasis on evaluating rewarding outcomes associated with free-task choices. However, this inflationary effect on task choice seemed to be limited to reward and situations where task choice and performance more strongly overlap. Specifically, there was no evidence that switching behavior was differentially influenced after free-and forced-task as a function of losses (Exp. 2) or reward when task choice and task performance were separated (Exp. 4). Overall, the results provide new insights into how the valuation of task goals based on choice freedom and outcome feedback can influence voluntary task choices.

Congruency effects in conflict tasks are typically larger after congruent compared to incongruent trials. This congruency sequence effect (CSE) indicates that top-down adjustments of cognitive control transfer between processing episodes, at least when controlling for bottom-up memory processes by alternating between stimulus-response (S-R) sets in confound-minimised designs. According to the control-retrieval account, cognitive control is bound to task-irrelevant context features (e.g., stimulus position or modality) and retrieved upon subsequent context feature repetitions. A confound-minimised CSE should therefore be larger when context features repeat rather than change between two trials. This study tested this prediction for a more abstract contextual stimulus feature, speaker gender. In two preregistered auditory prime-probe task experiments, participants classified colour words spoken by a female or male voice. Across both experiments, we found confound-minimised CSEs that were not reliably affected by whether the speaker gender repeated or changed. This indicates that speaker transitions have virtually no influence on the transfer of control adjustments in the absence of S-R repetitions. By contrast, when allowing for bottom-up memory processes by repeating the S-R set, CSEs were consistently larger when the speaker gender repeated compared to changed. This suggests that speaker transitions can in principle influence transfer between processing episodes. The discrepancy also held true when considering learning and test episodes separated by an intervening episode. Thus, the present findings call for a refinement of the control-retrieval account to accommodate the role of more abstract contextual stimulus features for the maintenance of memory traces in auditory conflict processing.

This study investigated the temporal dynamics of task performance and voluntary task choice within a multitasking paradigm in which the task-related processing outcomes themselves determined the to-be-performed task. In the novel forced-no-go trials, the stimulus for one task required an overt response, but the stimulus for the other task was associated with a no-go response. Task performance results showed that participants often processed the no-go task’s stimulus before switching to the go-task. Dual-task interference effects and switch costs indicated various forms of multitasking interference, with their underlying causes appearing to overlap, as engagement in parallel processing seemed to be limited by switch-related reconfiguration processes. Intermixing free-choice trials, where both stimuli were associated with overt responses, revealed costs associated with switching between processing modes, providing new evidence that the distinctions between free and forced task goals stem from differences in their internal representations rather than alterations in processing due to different presentations in the environment. Task choice results align with this perspective, demonstrating a preference for repeating a free- over a forced-choice task. Furthermore, these free-choice results illuminate the interplay of cognitive (task-repetition bias) and environmental constraints (first-task bias) in shaping task choices: It appears that task-specific information increases goal activations for both task goals concurrently, with participants favoring central processing of the second- over the first-presented task to optimize their behavior when shorter central processing is required (task repetition). Overall, this study offers new insights into the dynamics of task processing and choice in environments requiring the balance of multiple tasks.

Subjective inferences of probability are critical for decisions involving uncertainty. Recent studies have suggested that extreme outcomes bias beliefs about the value of uncertain options toward the best/worst outcome possible when learning the odds through experience, leading to increased preferences for uncertain options over equivaluable sure bets when there is the prospect of gain and, conversely, aversion to uncertain options when there is the prospect of loss. However, prior studies regarding the influence of extreme outcomes on decisions involving uncertainty have only done so using 50/50 gambles, and it was unclear whether extreme outcomes biased probability perception more broadly. Across three pre‐registered experiments, we found that when people made decisions between equivaluable certain and uncertain options, they particularly preferred uncertain options at low probabilities (20%) when there was the prospect of gain and avoided them when there was the prospect of loss, with these preferences being reduced or even reversed at medium (50%) and high (80%) probabilities. We also found that uncertainty preferences were influenced by outcome extremity and the relative certainty associated with safe reference options. We conclude that extreme outcomes accentuate the overweighting of low probabilities and the underweighting of high probabilities in experience‐based choice.

Deciding which task to perform when multiple tasks are available can be influenced by external influences in the environment. In the present study, we demonstrate that such external biases on task-choice behavior reflect reactive control adjustments instead of a failure in control to internally select a task goal. Specifically, in two experiments we delayed the onset of one of two task stimuli by a short (50 ms), medium (300 ms), or long (1,000 ms) stimulus-onset asynchrony (SOA) within blocks while also varying the relative frequencies of short versus long SOAs across blocks (i.e., short SOA frequent vs. long SOA frequent). Participants’ task choices were increasingly biased towards selecting the task associated with the first stimulus with increasing SOAs. Critically, both experiments also revealed that the short-to-medium SOA bias was larger in blocks with more frequent long SOAs when participants had limited time to prepare for an upcoming trial. When time to select an upcoming task was extended in Experiment 2, this interaction was not significant, suggesting that the extent to which people rely on reactive control adjustments is additionally modulated by proactive control processes. Thus, the present findings also suggest that voluntary task choices are jointly guided by both proactive and reactive processes, which are likely to adjust the relative activation of different task goals in working memory.

In the present study, we examined how the relevance of potentially distracting information modulates the interplay of target and distractor processing in conflict tasks. Specifically, we manipulated the degree to which distracting information is relevant for performing the overall task by varying the proportion of trials in which a response to the distractor(s) (Experiments 1a and 1b: location in a Simon task; Experiment 2: flankers in an Eriksen flanker task) instead of to the target was required. Across all experiments, the congruency effect on mean RT was larger with the increasing relevance of the distractor(s). Critically, the slopes of the delta plot were more strongly increasing when the distractors were potentially relevant (as opposed to completely irrelevant), suggesting that cognitive control affects the timing of suppressing distractor-based activation. In addition, delta plot and diffusion model analyses revealed that the strength of suppressing distractor processing and the efficiency of target processing were enhanced when the distractors were less relevant. Overall, the present study dissociated multiple and time-dependent adjustments of control processes (i.e., target processing enhancement plus timing and strength of distractor suppression) in environments that encourage either a more stable or more flexible processing mode. (PsycInfo Database Record (c) 2023 APA, all rights reserved).