Libet Clock Task Research Articles

Attention and expectation likely underlie temporal binding measured using the Libet Clock.

An interesting finding that has emerged in studies of the sense of agency is that of a perceived compression of the temporal interval between actions and the outcomes they produce. This is generally referred to as temporal binding. Although temporal binding has been studied using various paradigms, possibly the most popular of these is the Libet Clock task. The Libet task is also interesting because it suggests that temporal binding can be decomposed into two components, one purportedly relating to actions and the other relating to outcomes. These are termed action binding and outcome binding, respectively. In this article, I focus specifically on temporal binding revealed using the Libet Clock task and propose the idea that attention underpins the action binding effect, while outcome binding, on the other hand, is driven by the effects of expectation.

Depressive traits are associated with a reduced effect of choice on intentional binding

A sense of agency (SoA) over wilful actions is thought to be dependent on the level of choice and the nature of the outcome. In a preregistered study, we manipulated choice and valence of outcome to assess the relationship between SoA across the depression and psychosis continuum. Participants (N = 151) completed a Libet Clock task, in which they had either a free or forced choice to press one of two buttons and received either a rewarding or punishing outcome. Participants also completed questionnaires on depressive and psychosis-like traits. Rewarding outcomes increased intentional binding. The evidence favoured no effect of choice on average, but this was influenced by inter-individual differences. Individuals reporting more depressive traits had less of a difference in intentional binding between free and forced choice conditions. We show that implicit SoA is sensitive to outcome valence and the effect of choice differs across the depression continuum.

A reduction in the implicit sense of agency during adolescence compared to childhood and adulthood.

Sense of agency(SoA), the fundamental feeling of control over our actions and their consequences, may show key developmental changes during adolescence. We examined SoA in childhood (9-10), mid-adolescence (13-14), late-adolescence (18-20) and adulthood (25-28) using two tasks (Libet Clock and Stream of Letters). SoA was implicitly indexed by intentional binding that reflects the agency effect on action-outcome temporal association. We found age effects on the sub-processes in both tasks. In the Libet Clock task, where performance was more reliable, we observed a U-shaped developmental trajectory of intentional binding suggesting an adolescent-specific reduction in the experience of control. This study provides evidence for the developmental effects on the implicit agency experience and suggests adolescence as a critical period. We discuss the possible implications of these findings.

The Role of Intentional Strength in Shaping the Sense of Agency.

Awareness of action is a pervasive personal experience that is crucial in understanding self-generated and other-generated actions as well as their effects. A large body of research suggests that action awareness, as measured by the magnitude of temporal binding between an action and its effect in an operant action task (i.e., intentional binding), is rooted in the human capacity to experience self-agency and establish action intentions. Whereas previous research mainly addressed the role of intentionality itself in these socially well-shared experiences, in the present study we focused specifically on one important aspect of it: the quality or strength of action intentions. We expected and established that stronger intentions increase intentional binding. Specifically, the magnitude of the binding effect, as assessed by the Libet clock task in which two actions were followed by the same neutral tone, was elevated for the action that was enacted with stronger intentions. We briefly discuss the implications of the observed role of intentional strength in temporal binding between action and effect, for promoting a better understanding and examination of how the concept of intentionality is associated with action awareness in general, and the experience of being the agent of one’s own actions in particular.

The involuntary nature of binge drinking: goal directedness and awareness of intention.

Binge drinking represents a public health issue and is a known risk factor in the development of alcohol use disorders. Previous studies have shown behavioural as well as neuroanatomical alterations associated with binge drinking. Here, we address the question of the automaticity or involuntary nature of the behaviour by assessing goal‐directed behaviour and intentionality. In this study, we used a computational two‐step task, designed to discern between model‐based/goal‐directed and model‐free/habitual behaviours, and the classic Libet clock task, to study intention awareness, in a sample of 31 severe binge drinkers (BD) and 35 matched healthy volunteers. We observed that BD had impaired goal‐directed behaviour in the two‐step task compared with healthy volunteers. In the Libet clock task, BD showed delayed intention awareness. Further, we demonstrated that alcohol use severity, as reflected by the alcohol use disorders identification test, correlated with decreased conscious awareness of volitional intention in BD, although it was unrelated to performance on the two‐step task. However, the time elapsed since the last drinking binge influenced the model‐free scores, with BD showing less habitual behaviour after longer abstinence. Our findings suggest that the implementation of goal‐directed strategies and the awareness of volitional intention are affected in current heavy alcohol users. However, the modulation of these impairments by alcohol use severity and abstinence suggests a state effect of alcohol use in these measures and that top‐down volitional control might be ameliorated with alcohol use cessation.

Schizotypy and awareness of intention: Variability of W judgments predicts schizotypy scores.

Abstract Patients with schizophrenia often have unusual experiences of action. For example, patients suffering from delusions of control feel that their voluntary actions are under the control of an external force. It has been argued that deficits in self-monitoring are responsible for these symptoms. However, to-date the self-monitoring of intention has been overlooked in studies on schizophrenia. Here we aim to address this oversight. We carried out a preliminary investigation of possible intention monitoring issues in schizophrenia by examining the relation between the awareness of intention and schizotypy in a healthy population. Using the Libet clock task we found that the variability of intention (or W) judgments was uniquely predictive of schizotypy: the more variable these judgments the higher the schizotypy score. We discuss the relevance of the findings for schizophrenic illness. We also discuss the utility of this intention variability measure for examining volitional disturbances more generally.