Gathering evidence across disciplines is a strength of interdisciplinary fields like neuroethics. However, conclusions can only be made if the evidence applies to the issue at hand. Libet and colleagues' Citation1983 experiment is an interesting case study in this problem. Despite ongoing critiques about the methods used and the replicability of its findings, many people consider Libet and colleagues' methodology a valid strategy to investigate free will and related topics. We reviewed studies using methods similar to those of Libet and (...) colleagues (N = 48) to identify its use and the evidence produced. Overall, we found substantial variation between studies. While the Libet paradigm may be useful for examining how stimuli affect temporal judgments, the link between this and free will or moral responsibility is not clear. Being aware and critical of the methods used to gather results is important when applying scientific experiments to complex, abstract phenomena. (shrink)

Neuroscientific studies have shown that brain activity correlated with a decision to move can be observed before a person reports being consciously aware of having made that decision . Given that a later event cannot cause an earlier one , such results have been interpreted as evidence that decisions are made unconsciously . We argue that this interpretation depends upon an all-or-none view of consciousness, and we offer an alternative interpretation of the early decision-related brain activity based on models in (...) which conscious awareness of the decision to move develops gradually up to the level of a reporting criterion. Under this interpretation, the early brain activity reflects sub-criterion levels of awareness rather than complete absence of awareness and thus does not suggest that decisions are made unconsciously. (shrink)

The concept of free will has been heavily debated in philosophy and the social sciences. Its alleged importance lies in its association with phenomena fundamental to our understandings of self, such as autonomy, freedom, self-control, agency, and moral responsibility. Consequently, when neuroscience research is interpreted as challenging or even invalidating this concept, a number of heated social and ethical debates surface. We undertook a content analysis of media coverage of Libet’s et al.’s :623–642, 1983) landmark study, which is frequently interpreted (...) as posing a serious challenge to the existence of free will. Media descriptions of Libet et al.’s experiment provided limited details about the original study. Overall, many media articles reported that Libet et al.’s experiments undermined the existence of free will, despite acknowledging that several methodological limitations had been identified in the literature. A propensity to attribute greater credibility than warranted to neurobiological explanations could be at stake. (shrink)

The belief in free will has been frequently challenged since Benjamin Libet published his famous experiment in 1983. Although Libet’s experiment is highly dependent upon subjective reports, no study has been conducted that focused on a first-person or introspective perspective of the task. We took a neurophenomenological approach in an N = 1 study providing reliable and valid measures of the first-person perspective in conjunction with brain dynamics. We found that a larger readiness potential is attributable to more frequent occurrences (...) of self-initiated movements during negative deflections of the slow cortical potentials . These negative deflections occur in parallel with an inner impulse reported by an expert meditator which may in turn lead to a voluntary act. We demonstrate in this proof-of-principle approach that the first-person perspective obtained by an expert meditator in conjunction with neural signal analysis can contribute to our understanding of the neural underpinnings of voluntary acts. (shrink)

Four experiments examined how accurately participants can report the times of their own decisions. Within an auditory reaction time task, participants reported the time at which the tone was presented, they decided on the response, or the response key was pressed. Decision time reports were checked for plausibility against the actual RTs, and we compared the effects of experimental manipulations on these two measures to see whether the reported decision times showed appropriate effects. In addition, we estimated the amount of (...) error associated with individual decision time reports by checking how often participants’ decision time reports were implausibly early or late , and by using several quantitative models. Overall, the results suggest that decision time reports are not very accurate but they may be usable for some purposes. (shrink)

We report two experiments in which participants had to judge the time of occurrence of a stimulus relative to a clock. The experiments were based on the control condition used by Libet, Gleason, Wright, and Pearl [Libet, B., Gleason, C. A., Wright, E. W., & Pearl, D. K. . Time of conscious intention to act in relation to onset of cerebral activities : The unconscious initiation of a freely voluntary act. Brain 106, 623–642] to correct for any bias in the (...) estimation of the time at which an endogenous event, the conscious intention to perform a movement, occurred. Participants’ responses were affected systematically by the sensory modality of the stimulus and by the speed of the clock. Such findings demonstrate the variability in judging the time at which an exogenous event occurs and, by extension, suggest that such variability may also apply to the judging the time of occurrence of endogenous events. The reliability of participants’ estimations of when they formed the conscious intention to perform a movement in Libet et al.’s study is therefore questionable. (shrink)

Awareness of intention je fenomenální zkušenost prožitku motorické intence, charakterizovaná jako vědomé uchopení akce, kterou se agent chystá provést. Typicky bývá ztotožňována s okamžikem, kdy si participant vzpomíná, že se rozhodl provést svou akci, reportovaným prostřednictvím pozice ručičky na ciferníku Libetových hodin. Intenzivní výzkum prožitku jednání (sense of agency) v posledních letech přinesl velké množství poznatků, ale také kritiku metodologických slabin, mezi které patří závislost výsledků na metodě reportování a závislost na arbitrárních vlastnostech reportovacích nástrojů. Filozofové si zase všímají intervenujících (...) klamů vědomí či chyby Karteziánského divadla. Význačnou otázkou je také značná heterogenita experimentálních výsledků. Východiskem textu je argument, že mnohé z problémů tohoto výzkumného program souvisí se sadou implicitně zastávaných postojů, které vnímají awareness of intention jako integrovaný, unitární proces charakterizovaný graduálním nárůstem premotorické mozkové aktivity a náhlým nástupem uvědomění. Tato konceptuální východiska jsou převážně nereflektovaná, kontingentní a představují významné omezení pro explanaci současných empirických pozorování. Těžištěm článku je nástin nového teoretického rámce, který jde za implicitní předporozumění integrované perspektivy a umožňuje integrovat rozporné behaviorální výsledky. Tato rekonceptualice staví na Schoolerově teorii meta-uvědomění a teorii access a phenomenal consciousness Neda Blocka a nachází také oporu v neurovědných studiích. Představená rekonceptualizace přichází s dichotomií fenomenálního awareness of intention, souvisejícího s přípravou motorické intence v prefrontální oblasti a reflexivního meta-awareness of intention, které patrně souvisí s procesy v parietálním kortexu. (shrink)