Although habits are widely recognized as playing a key role across psychological science, current laboratory methods may limit our understanding of these behaviors. Within the dual‑system framework, habits are defined as context-triggered, outcome‑insensitive responses that emerge gradually with repeated instrumental training. Many human experimental paradigms have been developed in an attempt to test this characterization of habits. However, in most cases, they have not provided clear evidence of habit formation, suggesting a gap between habit theory and existing methodologies. In the present study, we systematically review evidence on the construct validity of fourteen paradigms in which the amount of training was manipulated. We also reanalyze publicly available datasets from studies using these paradigms to assess the psychometric reliability of their main measures, thereby extending the available validity evidence. Paradigms that most closely mirror classical approaches derived from habit theory have consistently failed to induce habits, whereas more recent approaches have revealed training effects. However, these novel paradigms often rely on broader operationalizations that substantially diverge from traditional definitions of habit. Among the paradigms reviewed, the forced‑response task stands out as capable of inducing habitual behavior while providing a narrowly operationalized measure with acceptable reliability. Finally, we argue that strengthening the credibility of the field will require greater attention to the psychometric properties of habit measures, including precise operationalization, reliability, and systematic validity testing.

Individual differences in the capacity to learn and control habits are central to current models of psychopathology, which assume an overreliance on habit behavior in transdiagnostic compulsivity. However, whether these tendencies reflect stable, trait-like cognitive processes remains unclear. We examined the temporal stability of individual differences in habit learning and expression. Across two preregistered experiments, we assessed stimulus–response habits using the same stimuli after one day or different stimuli after four months. Evidence for stable individual differences in habit commissions was strong and comparable across experiments, indicating trait-like habit learning and expression. Improvements in response time across learning were stable and correlated with habits, suggesting an early trait-like index of habitualization. Stable processes of habit formation were reflected during both habit acquisition and expression.

Habits are stimulus-driven responses that are produced independently of the current outcome value. They enable efficient actions in familiar contexts while freeing up cognitive resources. Habits are expected to influence behavior after substantial experience, whereas limited training leaves behavior under goal-directed control. This transition from goal-directed to habitual control is well-documented in animal research but remains challenging to replicate in humans. Using a free-operant task, recent studies have suggested that human habits can be fully learned even after short training. This would produce a ceiling effect, explaining null results when the amount of training is manipulated. Here, we propose an alternative explanation: the devaluation protocol was ineffective for a subset of participants who appeared ‘habitual’. To test this hypothesis, we conducted a pre-registered conceptual replication of the free-operant task with improved devaluation. As in previous research, we found no difference in habitual responses between short and extended training. In contrast to prior reports, most participants were sensitive to outcome devaluation. Habitual responding was strongly correlated with the effectiveness of the outcome devaluation protocol; habit-like responses were mostly produced by the few participants for whom the devaluation did not work. We further supported our hypothesis by reanalyzing previous datasets, finding that, across all studies, participants who showed more habit-like responses were those for whom the devaluation was less effective. Taken together, our findings suggest that suboptimal outcome-devaluation protocols may have biased previous results, leading to habit-like goal-directed responses regardless of the amount of previous instrumental training.

There is plenty of evidence showing that the history of stimulus-reward pairings can cause such stimuli to capture our attention more easily, even when attending to them actually prevents the delivery of a reward. Once established, these Pavlovian attentional biases are believed to operate automatically and persist even when they no longer predict a reward. This reflects an inflexible form of attentional sign-tracking. In this study, we investigated how reversal learning of Pavlovian attentional biases is affected by explicit knowledge. Across three experiments, we demonstrate that verbal instructions alone can modulate previously learned attentional biases (Experiments 1 and 2a) and that, when not informed of the reversal, participants still exhibit strong associations between Pavlovian attentional biases and individual differences in awareness of the new, reversed contingencies (Experiment 2b). Computational modelling of a previously published dataset reveals that instructions may prompt a rapid model-based revaluation by eliciting the automatic updating of the stimuli's value representation. However, such updating can be counterproductive, as attending to the previously high-value distractor reduces the likelihood of receiving a reward when contingencies are re-evaluated. These findings emphazise the importance of explicit knowledge in the updating process.

Replacing a habitual action with goal-directed control involves a cost whose neural mechanisms in humans are not well established. Our study quantifies this cost and uncovers its neural correlates using fMRI and neurostimulation. Training S-R links in overtrained stimuli (compared to less trained ones, termed standard-trained stimuli) increased RT switch costs, explained by drift diffusion modeling. Training engaged sensorimotor areas and the posterior putamen, whereas standard-trained behaviors recruited the posterior caudate, insula, and prefrontal regions. A cortical network orchestrated habit expression (right S1 with the left anterior insula/prefrontal areas) while also implicating the basal ganglia when overriding habits (left premotor with the putamen). Importantly, stimulation of the left premotor cortex played a causal role in habit control, enhancing performance across both the training and devaluation phases. Our findings reveal an interaction between habitual and goal-directed brain regions, highlighting shared neural dynamics when overriding habitual behaviors.

In experimental psychology and behavioral neuroscience, habits are considered stimulus-response (S-R) associations formed through extended reward training. Accordingly, habits are assessed using one of two tests: 1) Outcome devaluation, in which the value of the outcome (reward) is reduced, making it less desirable, and 2) Contingency degradation, in which the response-outcome association is reversed so that responding prevents the delivery of a reward. If a behavior is controlled by S-R links, then it should remain mostly insensitive by these two manipulations. Animal research using the outcome devaluation test has shown that initially goal-directed actions can become habitual after extended operant training. However, replicating this transition in human research has proven challenging, representing a significant problem for translational research. Notably, the contingency degradation test has rarely been used in human research. In this study, we aimed to demonstrate a shift from goal-directed to habitual control through three pre-registered experiments. Participants were trained in two S-R-O (stimulus-response-outcome) mappings for three days, with one condition (the 'overtrained') occurring four times more frequently than the other ('standard'). Importantly, we assessed the habitualization of both responses by using a degraded contingency test. Overall, we found no evidence of an overtraining effect - that is, the 'overtrained' condition did not lead to increased habitual responding. We discuss the theoretical and applied implications of these findings and explore further directions for studying habitual behavior.

In experimental psychology and behavioral neuroscience, habits are considered stimulus-response (S-R) associations formed through extended reward training. Accordingly, habits are assessed using one of two tests: 1) Outcome devaluation, in which the value of the outcome (reward) is reduced, making it less desirable, and 2) Contingency degradation, in which the response-outcome association is reversed so that responding prevents the delivery of a reward. If a behavior is controlled by S-R links, then it should remain unaffected by these two manipulations. Animal research using the outcome devaluation test has shown that initially goal-directed actions can become habitual after extended operant training. However, replicating this transition in human research has proven challenging, representing a significant problem for translational research. Notably, the contingency degradation test has rarely been used in human research. In this study, we aimed to demonstrate a shift from goal-directed to habitual control through three pre-registered experiments. Participants were trained in two S-R-O (stimulus-response-outcome) mappings for three days, with one condition (the ‘overtrained’) occurring four times more frequently than the other ('standard’). Importantly, we assessed the habitualization of both responses by using a degraded contingency test. Overall, we found no evidence of an overtraining effect — that is, the ‘overtrained’ condition did not lead to increased habitual responding. We discuss the theoretical and applied implications of these findings and explore further directions for studying habitual behavior.

The N2pc is widely employed as an electrophysiological marker of an attention allocation. This interpretation was largely driven by the observation of an N2pc elicited by an isolated relevant target object, which was reported as Experiment 2 in Eimer (1996). All subsequent refined interpretations of the N2pc had to take this crucial finding into account. Despite its central role for neurocognitive attention research, there have been no direct replications and only few conceptual replications of this seminal work. Within the context of #EEGManyLabs, an international community-driven effort to replicate the most influential EEG studies ever published, the present study was selected due to its strong impact on the study of selective attention. We revisit the idea of the N2pc being an indicator of attentional selectivity by delivering a high powered direct replication of Eimer's work through analysis of 779 datasets acquired from 22 labs across 14 countries. Our results robustly replicate the N2pc to form stimuli, but a direct replication of the N2pc to color stimuli technically failed. We believe that this pattern not only sheds further light on the functional significance of the N2pc as an electrophysiological marker of attentional selectivity, but also highlights a methodological problem with selecting analysis windows a priori. By contrast, the consistency of observed ERP patterns across labs and analysis pipelines is stunning, and this consistency is preserved even in datasets that were rejected for (ocular) artifacts, attesting to the robustness of the ERP technique and the feasibility of large-scale EEG replication studies.

Habits are stimulus-driven responses that are produced independently of the current outcome value. They enable efficient actions in familiar contexts while freeing up cognitive resources. Habits are expected to influence behavior after substantial experience, whereas limited training leaves behavior under goal-directed control. This transition from goal-directed to habitual control is well-documented in animal research but remains challenging to replicate in humans. Recent studies have suggested that human protocols are so effective at inducing habitual control that habits can appear even after short training, thereby masking the training effects. These studies typically test habits by reducing outcome value (e.g., food, through satiation) and report persistent habit-like behavior in minimally trained participants. Here, we propose an alternative explanation: we think that the devaluation protocol was ineffective for this subset of ‘habitual’ participants. To test this hypothesis, we conducted a pre-registered experiment using the same task but with monetary rewards instead of food, hypothesizing that money can be more effectively devalued and avoid the social issues associated with eating. We found no difference in habitual responses between short and extended training. In contrast to prior reports, most participants were sensitive to outcome devaluation. We further supported our hypothesis by reanalyzing previous datasets, finding that across all studies (including ours), participants showing more habit-like responses were those for whom the devaluation was less effective. We discuss the theoretical and methodological implications of these findings.

The N2pc is widely employed as an electrophysiological marker of an attention allocation. This interpretation was largely driven by the observation of an N2pc elicited by an isolated relevant target object, which was reported as Experiment 2 in Eimer (1996). All subsequent refined interpretations of the N2pc had to take this crucial finding into account. Despite its central role for neurocognitive attention research, there have been no direct replications and only few conceptual replications of this seminal work. Within the context of #EEGManyLabs, an international community-driven effort to replicate the most influential EEG studies ever published, the present study was selected due to its strong impact on the study of selective attention. We revisit the idea of the N2pc being an indicator of attentional selectivity by delivering a high powered direct replication of Eimer's work through analysis of 779 datasets acquired from 22 labs across 14 countries. Our results robustly replicate the N2pc to form stimuli, but a direct replication of the N2pc to color stimuli technically failed. We believe that this pattern not only sheds further light on the functional significance of the N2pc as an electrophysiological marker of attentional selectivity, but also highlights a methodological problem with selecting analysis windows a priori. By contrast, the consistency of observed ERP patterns across labs and analysis pipelines is stunning, and this consistency is preserved even in datasets that were rejected for (ocular) artifacts, attesting to the robustness of the ERP technique and the feasibility of large-scale multilab EEG (replication) studies.

Animal research has shown that repeatedly performing a rewarded action leads to its transition into a habit—an inflexible response controlled by stimulus-response associations. Efforts to reproduce this principle in human populations have yielded mixed results. Only two laboratory paradigms have successfully demonstrated behavior habitualization following extensive instrumental training compared to minimal training conditions: the forced-response task and the ‘aliens’ outcome-devaluation task. Notably, these paradigms measure behavior habitualization through distinct measures. The forced-response task focuses on the persistence of a trained response when a reversal is required, whereas the outcome-devaluation task measures reaction time switch costs—slowdowns in goal-directed responses that conflict with the trained habit. Although both measures have produced results consistent with those expected from learning theory—showing stronger evidence of habits in overtrained conditions—their construct validity remains insufficiently established. In this study, participants completed four days of training in each paradigm. We then examined the reliability of each measure and evaluated their convergent validity. Habitual responses in the forced-response task and reaction time switch costs in the outcome-devaluation task demonstrated good reliability, allowing us to assess whether individual differences remained stable across measures. However, the two measures were not associated, providing no evidence of convergent validity. This finding suggests that these measures capture distinct aspects of the balance between habitual and goal-directed control. Our results highlight the need for further evaluation of the validity and reliability of current measures used to investigate habit control in humans.

Habitual behavior is thought to emerge with extended training and reduced sensitivity to outcome devaluation. However, little is known about how habit-like oculomotor responses adapt when devaluation is implicit or embedded within a previously learned context. We examined this in a novel oculomotor learning task involving visual shape-reward associations with both standard and overtrained stimuli. Twenty-six participants completed a shape-color learning task while their eye movements were recorded using an eye-tracker system (1000 Hz). The task involved 11 blocks, including training, intra-block reversal (implicit stimulus-reward changes), and classical devaluation phases (explicitly instructed reward changes). Statistical analyses were performed using linear mixed-effects models on accuracy and response time (RT) measures. As expected, higher accuracy and faster responses for overtrained versus standard-trained stimuli were observed during training, confirming stronger learning. In the classical devaluation phase, overtrained stimuli elicited significantly more errors compared to standard-trained stimuli, relative to the performance in the training phase. This indicates stronger resistance to goal-directed updating. The effect was more pronounced during intra-block reversal of associations, where reward contingencies changed without warning. While RTs were not affected by classical devaluation, intra-block reversal significantly increased RTs for overtrained stimuli, relative to RTs in the training phase. This suggests a higher cognitive cost for overriding well-learned habitual responses when changes are unpredictable. These findings provide new evidence for the behavioral rigidity associated with overtraining of oculomotor behavior and suggest that unexpected outcome changes impose an additional switch cost on habitual oculomotor behavior.

Previous research has shown that cues that are good predictors of relevant outcomes receive more attention than nonpredictive cues. This attentional bias is thought to stem from the different predictive value of cues. However, because successful performance requires more attention to predictive cues, the bias may be a lingering effect of previous attention to cues (i.e., a selection history effect) instead. Two experiments assessed the contribution of predictive value and selection history to the bias produced by learned predictiveness. In a first task, participants responded to pairs of cues, only one of which predicted the correct response. A second task was superficially very similar, but the correct response was determined randomly on each trial and participants responded based on some physical characteristic of a target stimulus in each compound. Hence, in this latter task, participants had to pay more attention to the target stimuli, but these stimuli were not consistently associated with a specific response. Results revealed no differences in the attentional bias towards the relevant stimuli in the two tasks, suggesting that the bias induced by learned predictiveness is a consequence of deploying more attention to predictive stimuli during training. Thus, predictiveness may not bias attention by itself, adding nothing over and above the effect expected by selection history. ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ©American Psychological Association, 2024. This paper is not the copy of record and may not exactly replicate the authoritative document published in the APA journal. The final article is available, upon publication, at: 10.1037/xhp0001240

Three experiments explored how the repetition of a visual search display guides search during contextual cuing under conditions in which the search process is interrupted by an instructional (endogenous) cue for attention. In Experiment 1, participants readily learned about repeated configurations of visual search, before being presented with an endogenous cue for attention towards the target on every trial. Participants used this cue to improve search times, but the repeated contexts continued to guide attention. Experiment 2 demonstrated that the presence of the endogenous cue did not impede the acquisition of contextual cuing. Experiment 3 confirmed the hypothesis that the contextual cuing effect relies largely on localized distractor contexts, following the guidance of attention. Together, the experiments point towards an interplay between two drivers of attention: after the initial guidance of attention, memory representations of the context continue to guide attention towards the target. This suggests that the early part of visual search is inconsequential for the development and maintenance of the contextual cuing effect, and that memory representations are flexibly deployed when the search procedure is dramatically interrupted.

Intolerance of Uncertainty (IU) is thought to lead to maladaptive behaviours and dysfunctional decision making, both in the clinical and healthy population. The seminal study reported by Luhmann and collaborators in 2011 showed that IU was negatively associated with choosing a delayed, but more certain and valuable, reward over choosing an immediate, but less certain and valuable, reward. These findings have been widely disseminated across the field of personality and individual differences because of their relevance to understand the role of IU in maladaptive behaviours in anxiety-related disorders. We conducted a study to replicate and extend Luhmann et al.’s results with a sample of 313 participants, which exceeded the size necessary (N = 266) to largely improve the statistical power of the original study by using the small telescopes approach . The results of our well powered study strongly suggest that the relationship between IU and the tendency to prefer an immediate, but less certain and less valuable reward is virtually negligible. Consequently, although this relationship cannot be definitely discarded, we conclude that it cannot be detected with Luhmann et al.’s (2011) decision-making task. ### Competing Interest Statement The authors have declared no competing interest.

Intolerance of Uncertainty (IU) is thought to lead to maladaptive behaviours and dysfunctional decision making, both in the clinical and healthy population. The seminal study reported by Luhmann and collaborators in 2011 [1] showed that IU was negatively associated with choosing a delayed, but more probable and valuable, reward over choosing an immediate, but less probable and valuable, reward. These findings have been widely disseminated across the field of personality and individual differences because of their relevance for the understanding of the role of IU in the development and maintenance of anxiety-related disorders. Given their importance it would be desirable to have replications of this study, but none have been carried out so far. The current study has been designed to replicate and extend Luhmann et al.'s results. Our sample will include 266 healthy participants (more than five times the sample size used by Luhmann et al.) to detect with a power of 95% the effect size that can be detected with a power of 33% in the original study. To increase our chances of getting such a sample size, the experiment will be conducted online, To increase our chances of getting such a sample size, the experiment will be conducted online, adding check trials to the original decision-making task to monitor participants' engagement. Additionally, we will explore the role of impulsivity in the relationship between IU and willingness to wait. This study will add empirical evidence about the role of IU in decision making and, in case of replication of Luhmann et al.'s results, will support the hypothesis that high-IU individuals may engage in inefficient or costly behaviour in exchange for less time enduring an uncertain situation.

In a typical probabilistic cuing experiment, participants are asked to find a visual target among a series of distractors. Although participants are not informed about this, the target appears more frequently in one region of the display, resulting in faster search times for targets located in this region. This bias is thought to depend on a habit-like attentional control mechanism, unconstrained by the availability of working memory (WM) resources. However, the only study that has explored this feature in the past suffers from methodological shortcomings that leave the results open to alternative explanations. In three experiments we aimed to confirm whether probabilistic cuing is unaffected by visual, spatial, and spatiotemporal WM load. For each experiment, one group of participants performed the visual search task during the retention interval of a WM task (high-load group), whereas other group of participants (no-load group) carried out the visual search task after the WM task. We hypothesized that the probabilistic cuing effect would be larger for the no-load group compared to the high-load group. This hypothesis was confirmed in one experiment, but exploratory analyses suggest that the results can be highly dependent on the analytic approach, casting doubts on its robustness. Overall, our results provide partial support for the hypothesis that probabilistic cuing is not affected by a secondary task. However, given that some analyses reveal an effect of WM load, we conclude that it might be premature to rule out the possibility that the expression of this attentional bias requires WM resources.

Self-generated overt actions are preceded by a slow negativity as measured by electroencephalogram, which has been associated with motor preparation. Recent studies have shown that this neural activity is modulated by the predictability of action outcomes. It is unclear whether inner speech is also preceded by a motor-related negativity and influenced by the same factor. In three experiments, we compared the contingent negative variation elicited in a cue paradigm in an active vs. passive condition. In Experiment 1, participants produced an inner phoneme, at which an audible phoneme whose identity was unpredictable was concurrently presented. We found that while passive listening elicited a late contingent negative variation, inner speech production generated a more negative late contingent negative variation. In Experiment 2, the same pattern of results was found when participants were instead asked to overtly vocalize the phoneme. In Experiment 3, the identity of the audible phoneme was made predictable by establishing probabilistic expectations. We observed a smaller late contingent negative variation in the inner speech condition when the identity of the audible phoneme was predictable, but not in the passive condition. These findings suggest that inner speech is associated with motor preparatory activity that may also represent the predicted action-effects of covert actions.