Libet-style Experiments Research Articles

Freeing the Will from Neurophilosophy: Voluntary Action in Thomas Aquinas and Libet-Style Experiments

This essay presents a substantive Thomist response to neurophilosophy’s main experimental challenge to free will: the Libet-style experiments on the neural antecedents of conscious voluntary actions. My response to this challenge will disclose that Thomists are rationally justified in rejecting both the conclusions of neurophilosophy skeptics of free will, and more fundamentally, the rival philosophical conceptions of voluntary action and free will that were chosen to be operationalized in these neuroscientific experiments. I show how the Thomists’ alternative conception of human action justifies a significantly different interpretation of Libet-style experiments, one which reveals the psychological phenomenon targeted by these experiments is miscategorized as a voluntary action.

The place of Free Will: the freedom of the prisoner.

Debates about the concept of Free Will date back to ancient times. About 40years ago, Benjamin Libet designed an experiment showing that the conscious intention to move is preceded by a specific pattern of brain activation. His finding suggested that unconscious processes determine our decisions. Libet-style experiments have continued to dominate the debate about Free Will, pushing some authors to argue that the existence of Free Will is a mere illusion. We believe that this dispute is because we often measure Free Will using arbitrary human decisions rather than deliberate actions. After reviewing the definition of Free Will and the related literature, we conclude that the scientific evidence does not disprove the existence of Free Will. However, our will encounters several constraints and limitations that should be considered when evaluating our deeds' personal responsibility.

The relationship between free will and consciousness

Reflection on the relationship between free will and consciousness has mainly revolved around Libet-style experiments, for example by criticizing the claim that conscious intentions never cause what we do. Less attention has been paid to whether this response captures the sense in which consciousness is relevant for free will, however. In this paper I argue that scholars seem to accept two assumptions they should reject: (1) that the relationship between free will and consciousness is best characterized in terms of conscious states and/or processes being part of the causal chain leading up to the action, and (2) that the third-person perspective is a suitable means to capturing the relationship between free will and consciousness. I provide an alternative proposal of how free will and consciousness may be related, in which an agent’s self-understanding of what she is doing and why, while acting, takes center stage. In order to capture the relationship between the two, I argue, the first-person perspective should be investigated instead of explained away.

The Libet paradigm and a dilemma for epiphenomenalism

ABSTRACT Epiphenomenalism is the thesis that though physical events may cause mental events, those mental events never cause physical events. In this paper, I will be concerned with the claim that our thoughts, intentions, and awareness play no causal role in producing actions. Though epiphenomenalism has been defended with a priori philosophical arguments, the majority of the support that it has gained in recent years has come from advances in neuroscience. At the center of these experiments is the Libet paradigm that aims to show that our actions are initiated by unconscious brain processes prior to our awareness of the intention or decision to perform the corresponding actions. It has been widely suggested that these studies support the view that consciousness is epiphenomenal, and if Libet-style experiments support this conclusion, the results have direct implications for free will. I argue by way of a dilemma that any study that relies on reports of subjects’ awareness in its methodology cannot be used to support epiphenomenalism because the experimenters would have to rule out the possibility that consciousness plays a causal role in order to do so.

Brain as agent and conscious mind as action guide: from Libet-style experiments to necessary conditions for free will

Many neuroscientific experiments, based on monitoring brain activity, suggest that it is possible to predict the conscious intention/choice/decision of an agent before he himself knows that. Some neuroscientists and philosophers interpret the results of these experiments as showing that free will is an illusion, since it is the brain and not the conscious mind that intends/chooses/decides. Assuming that the methods and results of these experiments are reliable the question is if they really show that free will is an illusion. To address this problem, I argue that first it is needed to answer three questions related to the relationship between conscious mind and brain: 1. Do brain events cause conscious events? 2. Do conscious events cause brain events? 3. Who is the agent, that is, who consciously intends/chooses/ decides, the conscious mind, the brain, or both? I answer these questions by arguing that the conscious mind is a property of the brain due to which the brain has the causal capacity to interact adaptively with its body, and trough the body, with the physical and sociocultural environment. In other words, the brain is the agent and the conscious mind, in its various forms - cognitive, volitional and emotional - and contents, is its guide of action. Based on this general view I argue that the experiments aforementioned do not show that free will is an illusion, and as a starting point for examining this problem I point out, from some exemplary situations, what I believe to be some of the necessary conditions for free will.Key-words: Agent brain, conscious mind, free will, Libet-style experiments.

Libet's experiment: A complex replication.

Libet's experiment is an influential classical study, which does not stop provoking heated debates. However, a full-scale replication has not been carried out to this day. Libet-style studies have usually focused on isolated ideas and concepts and never on the whole experiment in all its complexity. This paper presents detailed methodological description and results of a complex replication study. The methodology follows Libet's directions closely in most cases; when it does not, the differences are described and elaborated. The results replicate Libet's key findings, but substantial differences were found in some of the results' categories, such as the introspective reports or the number of readiness-potentials found. The discussion also addresses some current problems pertaining the methodology of the Libet-style experiments and provides some recommendations based on a detailed process evaluation.

Libet's experiment: Questioning the validity of measuring the urge to move.

The time of subjectively registered urge to move (W) constituted the central point of most Libet-style experiments. It is therefore crucial to verify the W validity. Our experiment was based on the assumption that the W time is inferred, rather than introspectively perceived. We used the rotating spot method to gather the W reports together with the reports of the subjective timing of actual movement (M). The subjects were assigned the tasks in two different orders. When measured as first in the respective session, no significant difference between W and M values was found, which suggests that uninformed subjects tend to confuse W for M reports. Moreover, we found that W values measured after the M task were significantly earlier than W values measured before M. This phenomenon suggests that the apparent difference between W and M values is in fact caused by the subjects' previous experience with M measurements.

Libet-style experiments, neuroscience, and libertarian free will

People have disagreed on the significance of Libet-style experiments for discussions about free will. In what specifically concerns free will in a libertarian sense, some argue that Libet-style experiments pose a threat to its existence by providing support to the claim that decisions are determined by unconscious brain events. Others disagree by claiming that determinism, in a sense that conflicts with libertarian free will, cannot be established by sciences other than fundamental physics. This paper rejects both positions. First, it is argued that neuroscience and psychology could in principle provide support for milder deterministic claims that would also conflict with libertarian free will. Second, it is argued that Libet-style experiments—due to some of their peculiar features, ones that need not be shared by neuroscience as a whole—currently do not (but possibly could) support such less demanding deterministic claims. The general result is that neuroscience and psychology could in principle undermine libertarian free will, but that Libet-style experiments have not done that so far.

A Reason To Be Free

Recent Libet-style experiments are of limited relevance to the debate about free action and free will, and should be understood as investigations of arbitrary actions or guesses. In Libet-style experiments, the concept of 'free action' is commonly taken to refer to a 'self-initiated voluntary act', where the self prompts an action without being prompted. However, this idea is based on the problematic assumption that the conscious self needs to be free from every constraint in order to be actually free. We maintain that a fundamental condition for free action is the presence of reasons to act responsibly. By analyzing a recent neuroscientific experiment, we indicate how its results could be interpreted as indicating how free action operationalization is inappropriately focusing on arbitrary actions. Hence, the way free action has been experimentally studied may have had a misleading influence on the debate about free will.

Lost in time...

In 1983 Libet et al. found that the Readiness Potential (RP) precedes the intention to act by 350ms and the actual movement by 500ms on average. Using our own replication study, we illustrate how seemingly innocuous technical details are actually crucially relevant to the debate surrounding the interpretation of Libet-style experiments. For instance, using one specific method for determining the RP onset actually led to a reversal of Libet's results (i.e., the intention preceded the RP onset) for one of the participants. Claims regarding the causal relation between RP and intention cannot be based on averages, but require individual, case by case analyses, which show no exceptions in the temporal relation between RP and intention. We conclude that, properly speaking, Libet-style results in themselves cannot yet be taken as proof for the type of conclusions that are often formulated regarding the non-existence of free will.

Comparing incommensurable theories

While the question whether free will exists or not has concerned philosophers for centuries, empirical research on this question is relatively young. About 35 years ago Benjamin Libet designed an experiment that challenged the common intuition of free will, namely that conscious intentions are causally efficacious. Libet demonstrated that conscious intentions are preceded by a specific pattern of brain activation, suggesting that unconscious processes determine our decisions and we are only retrospectively informed about these decisions. Libet-style experiments have ever since dominated the discourse about the existence of free will and have found their way into the public media. Here we review the most important challenges to the common interpretation of Libet-style tasks and argue that the common interpretation is questionable. Brain activity preceding conscious decisions reflects the decision process rather than its outcome. Furthermore, the decision process is configured by conditional intentions that participants form at the beginning of the experiment. We conclude that Libet-style tasks do not provide a serious challenge to our intuition of free will.