ArticlePDF Available

Unconscious determinants of free decisions in the human brain

Authors:

Abstract

There has been a long controversy as to whether subjectively 'free' decisions are determined by brain activity ahead of time. We found that the outcome of a decision can be encoded in brain activity of prefrontal and parietal cortex up to 10 s before it enters awareness. This delay presumably reflects the operation of a network of high-level control areas that begin to prepare an upcoming decision long before it enters awareness.
... There are several fundamental causes to every decision, sometimes it's more affected by either emotion (Angie et al., 2011), the level of intelligence (Leslau, 2010), the experience (Brockmann and Simmonds, 1997), or most important our evolution (Wilke and Todd, 2010). Most of the decisions one takes are usually unconsciously taken, even though one thinks of taking them with precise calculation and critical thinking (Soon et al., 2008). Within a human-machine interaction framework, the pendant to decision making in critical settings is human error and performance degradation in general. ...
Article
Full-text available
Manned-Unmanned Teaming (MUM-T) can be defined as the teaming of aerial robots (artificial agents) along with a human pilot (natural agent), in which the human agent is not an authoritative controller but rather a cooperative team player. To our knowledge, no study has yet evaluated the impact of MUM-T scenarios on operators' mental workload (MW) using a neuroergonomic approach (i.e., using physiological measures), nor provided a MW estimation through classification applied on those measures. Moreover, the impact of the non-stationarity of the physiological signal is seldom taken into account in classification pipelines, particularly regarding the validation design. Therefore this study was designed with two goals: (i) to characterize and estimate MW in a MUM-T setting based on physiological signals; (ii) to assess the impact of the validation procedure on classification accuracy. In this context, a search and rescue (S&R) scenario was developed in which 14 participants played the role of a pilot cooperating with three UAVs (Unmanned Aerial Vehicles). Missions were designed to induce high and low MW levels, which were evaluated using self-reported, behavioral and physiological measures (i.e., cerebral, cardiac, and oculomotor features). Supervised classification pipelines based on various combinations of these physiological features were benchmarked, and two validation procedures were compared (i.e., a traditional one that does not take time into account vs. an ecological one that does). The main results are: (i) a significant impact of MW on all measures, (ii) a higher intra-subject classification accuracy (75%) reached using ECG features alone or in combination with EEG and ET ones with the Adaboost, Linear Discriminant Analysis or the Support Vector Machine classifiers. However this was only true with the traditional validation. There was a significant drop in classification accuracy using the ecological one. Interestingly, inter-subject classification with ecological validation (59.8%) surpassed both intra-subject with ecological and inter-subject with traditional validation. These results highlight the need for further developments to perform MW monitoring in such operational contexts.
... With contemporary brain scanning technology, Soon et al. (2008) were able to predict with 60% accuracy whether subjects would press a button with their left or right hand up to 10 seconds before the subject became aware of having made that choice. This doesn't of itself negate conscious willing because these prefrontal and parietal patterns of activation merely indicate a process is in play, which may become consciously invoked at the time of the decision, and clearly many subjects (40% of trials) were in fact making a contrary decision. ...
Article
Full-text available
This paper presents a potential mechanism for the conscious brain to anticipate impending opportunities and threats to survival through massively parallel weak quantum measurement (MPWQM) induced by the combined effects of edge of chaos sensitivity and phase coherence sampling of brain states. It concludes that the underpinnings of this process emerged in single-celled eucaryotes in association with (a) excitability-induced sensitivity to electro-chemical perturbations in the milieu as an anticipatory sense organ and (b) cell-to-cell signalling necessary for critical phases in the life cycle. This gives rise to watershed implications for the capacity of conscious experience to anticipate impending events in direct ways which complement computation based on past experiences and implies that conscious intentionality or 'free-will' may have physical influences beyond the raw application of the brain to an organism's immediate behaviour. Contents:
... This anticipatory process is crucial for decision-making. Prior to making a conscious decision, specific brain areas are activated to provide information predicting the outcome of a motor decision 39 . We showed for the first time that individuals with schizophrenia were able to anticipate a reduction in tool-associated effort in a similar way to healthy controls. ...
Article
Full-text available
Abstract: Humans frequently use tools to reduce action-related efforts. Interestingly, several studies have demonstrated that individuals had tool-related biases in terms of perceived effort reduction during motor imagery tasks, despite the lack of evidence of real benefits. Reduced effort allocation has been repeatedly found in schizophrenia, but it remains unknown how schizophrenia patients perceive tool-related benefits regarding effort. Twenty-four schizophrenia patients and twenty-four nonclinical participants were instructed to move the same quantities of objects with their hands or with a tool in both real and imagined situations. Imagined and real movement durations were recorded. Similarly to nonclinical participants, patients overestimated tool-related benefits and underestimated tool-related effort in terms of time when they mentally simulated a task requiring the use of a tool. No association between movement durations and psychotic symptoms was found. Our results open new perspectives on the issue of effort in schizophrenia. Keywords: Schizophrenia, Motivation, Effort, Tool use, Motor imagery
... Comme on ne peut pas connaître l'ensemble des facteurs influençant un individu (génétiques, épigénétiques, mécanismes inconscients, diététiques, parcours de vie, état émotionnel, motivations, normes personnelles et sociales, capacité à se projeter dans le futur, etc. …), il est difficile de prédire son comportement, bien que des données statistiques existent sur la corrélation entre ces facteurs et le comportement individuel. On peut donc défendre l'idée que le libre arbitre, souvent associé exclusivement à la conscience humaine, est une illusion qui cache un comportement déterministe dont les facteurs d'influence et les mécanismes inconscients nous échappent (Bignetti, 2014;Soon et al., 2008). Être libre de prendre des décisions impose qu'elles soient prises par soi-même et adaptées à une situation dynamique. ...
... To demonstrate a possible illusion of our perceived free will, diverse experiments have been conducted in the past. One such experiment was realized by Soon et al. (2008) with the integration of the latest neuro-imaging technologies. Through the interpretation of fMRI scans, the researchers were able to accurately predict (i.e. at 10% above chance) what button the participants would choose to press 4-7 seconds before the participants' own awareness. ...
Thesis
Full-text available
This research examines the possibility of free will in the sense of voluntary human decision-making by regarding the two variables, ego strength and sense of agency. Ego strength is the result of a healthy psychosocial development, which acquired profound life experiences are believed to influence people’s individuality and evaluative ability by allowing people to choose their responses from a larger repertoire of memories. Sense of agency, on the other hand, is a person’s consciousness of being agent of one’s thoughts and actions, which is acquired through extensive internal evaluations and understanding. However, since human agency is difficult to assess as a single construct, the dimensions self-reflection and insight were chosen in this study as a representative measure. For the assessment, the Psychosocial Inventory of Ego Strength together with the Self Reflection and Insight Scale were implemented. For the analysis, a Pearson product-moment correlation was performed. The results showed a statistically significant, moderate, positive correlation between the two variables, indicating a relationship between a positive psychosocial development and increased situational consciousness. These findings therefore suggest further research into the concept of ego strength as a possible measure for intentionality and voluntariness of human behavior, indicating the extent to which a person acts “freely”. This, in fact, could be of great interest for future research in the assessment of human accountability and responsibility in a legal and moral manner.
Chapter
Full-text available
Von einem (bedingten) freien Willen kann aus einer philosophisch aufgeklärten neuropsychologischen Perspektive (nur) – unter sehr eingeschränkten Bedingungen – bei bestimmten bewussten und überlegten Abwägungsentscheidungen im Sinne eines (schwachen) probabilistischen (Quasi-)Determinismus gesprochen werden. Die Diskussion ist darum sehr umstritten, wobei zu berücksichtigen ist, dass ein sehr hoher Anteil von alltäglichen Entscheidungen in hohem Maße unbewusst und automatisiert abläuft. Das Libet-Experiment und seine Varianten stellen jedoch im Sinne dieses schwachen (Quasi-)Determinismus auf Grund der Vielzahl von (methodischen) Einwänden kein Argument für die Widerlegung der menschlichen Willensfreiheit dar.
Chapter
We, humans, live under the impression that agents’ conscious intentions to act are at the origin of our actions. However, experimental evidence challenged this common intuition of free will, suggesting that such subjective experience is something of a perceptual illusion. The awareness of the intention to act would be generated as a side effect of unconscious processes that determine our decisions. If proven true, such a conclusion would shake the cornerstones of western ethics and law as it would require a profound revision of the concept of moral responsibility. A possible way outcomes from our ability to inhibit “pending” actions, i.e., to exert a veto power. In fact, although awareness of intention appears after the start of an action-related brain process, it still precedes the physical execution of a movement, allowing a person enough time to withhold the upcoming action if the expected outcome might be inappropriate. Thus, we would be in control of our actions by exerting free will not. Although it is appropriate to be very cautious when interpreting the results of the empirical approach of neuroscience to such complex mental phenomena, as it bears some intrinsic limitations, empirical evidence gathered so far suggests that, except specific medical conditions, we are free of choosing what and how to do, and thus, we are responsible for our actions.
Article
Is consciousness—the subjective awareness of the sensations, perceptions, beliefs, desires, and intentions of mental life—a genuine cause of human action or a mere impotent epiphenomenon accompanying the brain’s physical activity but utterly incapable of making anything actually happen? This article will review the history and current status of experiments and commentary related to Libet’s influential paper (Brain 106:623–664, 1983) whose conclusion “that cerebral initiation even of a spontaneous voluntary act …can and usually does begin unconsciously” has had a huge effect on debate about the efficacy of conscious intentions. Early (up to 2008) and more recent (2008 on) experiments replicating and criticizing Libet’s conclusions and especially his methods will be discussed, focusing especially on recent observations that the readiness potential (RP) may only be an “artifact of averaging” and that, when intention is measured using “tone probes,” the onset of intention is found much earlier and often before the onset of the RP. Based on these findings, Libet’s methodology was flawed and his results are no longer valid reasons for rejecting Fodor’s “good old commonsense belief/desire psychology” that “my wanting is causally responsible for my reaching.”.
Chapter
Se presenta la relación entre factores emocionales y racionales en el proceso de toma de decisiones morales. Sin embargo, se basa principalmente en el análisis y generalización de los principales estudios empíricos sobre el tema, cada uno de los cuales, a su vez, utiliza los métodos de las ciencias, especialmente de las neurociencias. Se preconiza el hecho de que el proceso de toma de decisiones morales no puede describirse mediante un modelo simple que se base en un factor emocional o racional, y se sostiene que la toma de decisiones morales se caracteriza por diferentes tipos de interacción entre las emociones y el razonamiento racional. La influencia de los factores emocionales y racionales en una decisión moral no es lineal: la decisión no es proporcional a las emociones o consideraciones que la preceden o están determinadas únicamente por ellas.
Chapter
El capítulo analiza el dualismo razón-emoción a través de dos autores teóricamente enfrentados, Lawrence Kohlberg y Jonathan Haidt, quienes infieren la existencia de dos esferas para la valoración ética: la racional de pensamiento lógico, con el que se toman decisiones morales ponderadas y por otro lado, una vía no racional, emotiva, que responde de manera automática a los estímulos y a las impresiones humeanas.
Article
Full-text available
Intention is central to the concept of voluntary action. Using functional magnetic resonance imaging, we compared conditions in which participants made self-paced actions and attended either to their intention to move or to the actual movement. When they attended to their intention rather than their movement, there was an enhancement of activity in the pre-supplementary motor area (pre-SMA). We also found activations in the right dorsal prefrontal cortexand left intraparietal cortex. Prefrontal activity, but not parietal activity, was more strongly coupled with activity in the pre-SMA. We conclude that activity in the pre-SMA reflects the representation of intention.
Article
Full-text available
Complex problem-solving and planning involve the most anterior part of the frontal lobes including the fronto-polar prefrontal cortex (FPPC), which is especially well developed in humans compared with other primates. The specific role of this region in human cognition, however, is poorly understood. Here we show, using functional magnetic resonance imaging, that bilateral regions in the FPPC alone are selectively activated when subjects have to keep in mind a main goal while performing concurrent (sub)goals. Neither keeping in mind a goal over time (working memory) nor successively allocating attentional resources between alternative goals (dual-task performance) could by themselves activate these regions. Our results indicate that the FPPC selectively mediates the human ability to hold in mind goals while exploring and processing secondary goals, a process generally required in planning and reasoning.
Article
Roger Penrose has suggested that when we consider consciousness the usual physical rules for time may not apply. But that notion is based on a false interpretation of physiological observations.
Article
Voluntary acts are preceded by electrophysiological “readiness potentials” (RPs). With spontaneous acts involving no preplanning, the main negative RP shift begins at about—550 ms. Such RPs were used to indicate the minimum onset times for the cerebral activity that precedes a fully endogenous voluntary act. The time of conscious intention to act was obtained from the subject's recall of the spatial clock position of a revolving spot at the time of his initial awareness of intending or wanting to move (W). W occurred at about—200 ms. Control experiments, in which a skin stimulus was timed (S), helped evaluate each subject's error in reporting the clock times for awareness of any perceived event. For spontaneous voluntary acts, RP onset preceded the uncorrected Ws by about 350 ms and the Ws corrected for S by about 400 ms. The direction of this difference was consistent and significant throughout, regardless of which of several measures of RP onset or W were used. It was concluded that cerebral initiation of a spontaneous voluntary act begins unconsciously. However, it was found that the final decision to act could still be consciously controlled during the 150 ms or so remaining after the specific conscious intention appears. Subjects can in fact “veto” motor performance during a 100–200-ms period before a prearranged time to act. The role of conscious will would be not to initiate a specific voluntary act but rather to select and control volitional outcome. It is proposed that conscious will can function in a permissive fashion, either to permit or to prevent the motor implementation of the intention to act that arises unconsciously. Alternatively, there may be the need for a conscious activation or triggering, without which the final motor output would not follow the unconscious cerebral initiating and preparatory processes.
Article
We investigated the relation between neural events and the perceived time of voluntary actions or the perceived time of initiating those actions using the method of Libet. No differences were found in either movement-related potentials or perceived time of motor events between a fixed movement condition, where subjects made voluntary movements of a single finger in each block, and a free movement condition, in which subjects chose whether to respond with the left or the right index finger on each trial. We next calculated both the readiness potential (RP) and lateralised readiness potential (LRP) for trials with early and late times of awareness. The RP tended to occur later on trials with early awareness of movement initiation than on trials with late awareness, ruling out the RP as a cause of our awareness of movement intiation. However, the LRP occurred significantly earlier on trials with early awareness than on trials with late awareness, suggesting that the processes underlying the LRP may cause our awareness of movement initiation.
The hypothesis is formulated that in all voluntary movements the initial neuronal event is in the supplementary motor areas (SMA) of both cerebral hemispheres. Experimental support is provided by three lines of evidence. 1. In voluntary movements many neurones of the SMA are activated probably up to 200 ms before the pyramidal tract discharge. 2. Investigations of regional cerebral blood flow by the radioactive Xenon technique reveal that there is neuronal activity in the SMA of both sides during a continual series of voluntary movements, and that this even occurs when the movement is thought of, but not excuted. 3. With voluntary movement there is initiation of a slow negative potential (the readiness potential, RP) at up to 0.8 s before the movement. The RP is maximum over the vertex, i.e. above the SMA, and is large there even in bilateral Parkinsonism when it is negligible over the motor cortex. An account is given of the SMA, particularly its connectivities to the basal ganglia and the cerebellum that are active in the preprogramming of a movement. The concept of motor programs is described and related to the action of the SMA. It is proposed that each mental intention acts on the SMA in a specific manner and that the SMA has an ‘inventory’ and the ‘addresses’ of stored subroutines of all learnt motor programs. Thus by its neuronal connectivities the SMA is able to bring about the desired movement. There is a discussion of the manner in which the mental act of intention calls forth neural actions in the SMA that eventually lead to the intended movement. Explanation is given on the basis of the dualist-interactionist hypothesis of mind-brain liaison. The challenge is to the physicalists to account for the observed phenomena in voluntary movement.
Article
Deciding advantageously in a complex situation is thought to require overt reasoning on declarative knowledge, namely, on facts pertaining to premises, options for action, and outcomes of actions that embody the pertinent previous experience. An alternative possibility was investigated: that overt reasoning is preceded by a nonconscious biasing step that uses neural systems other than those that support declarative knowledge. Normal participants and patients with prefrontal damage and decision-making defects performed a gambling task in which behavioral, psychophysiological, and self-account measures were obtained in parallel. Normals began to choose advantageously before they realized which strategy worked best, whereas prefrontal patients continued to choose disadvantageously even after they knew the correct strategy. Moreover, normals began to generate anticipatory skin conductance responses (SCRs) whenever they pondered a choice that turned out to be risky, before they knew explicitly that it was a risky choice, whereas patients never developed anticipatory SCRs, although some eventually realized which choices were risky. The results suggest that, in normal individuals, nonconscious biases guide behavior before conscious knowledge does. Without the help of such biases, overt knowledge may be insufficient to ensure advantageous behavior.
Article
Prospective memory (PM) refers to the functions that enables a person to carry out an intended act after a delay. Despite the ubiquity of this behaviour, little is known about the supporting brain structures and the roles that they play. In this study, eight healthy participants performed four different PM tasks, each under three conditions: a baseline, and two conditions involving an intention. In the first of the intention conditions, subjects were asked to make a novel response to a certain class of stimuli whilst performing an attention-demanding task. However, the expected stimuli never actually occurred. In the second intention condition subjects were expecting to see these stimuli as before, and they did occur on approximately 20% of trials. Relative to the baseline condition, increases in regional cerebral blood flow (rCBF) as estimated by oxygen-15 positron emission tomography technique across all four tasks were seen in the frontal pole (Brodmann's area 10) bilaterally, right lateral prefrontal and inferior parietal regions plus the precuneus when subjects were expecting a PM stimulus regardless of whether it actually occurred. Further activation was seen in the thalamus when the PM stimuli occurred and was acted upon, with a corresponding rCBF decrease in right lateral prefrontal cortex. It is argued that the first set of region play a role in the maintenance of an intention, with the second set involved additionally in its realisation.
Article
The conclusions drawn by Benjamin Libet from his work with colleagues on the timing of somatosensorial conscious experiences has met with a lot of praise and criticism. In this issue we find three examples of the latter. Here I attempt to place the divide between the two opponent camps in a broader perspective by analyzing the question of the relation between physical timing, neural timing, and experiential (mental) timing. The nervous system does a sophisticated job of recombining and recoding messages from the sensorial surfaces and if these processes are slighted in a theory, it might become necessary to postulate weird operations, including subjective back-referral. Neuroscientifically inspired theories are of necessity still based on guesses, extrapolations, and philosophically dubious manners of speech. They often assume some neural correlate of consciousness (NCC) as a part of the nervous system that transforms neural activity in reportable experiences. The majority of neuroscientists appear to assume that the NCC can compare and bind activity patterns only if they arrive simultaneously at the NCC. This leads to a search for synchrony or to theories in terms of the compensation of differences in neural delays (latencies). This is the main dimension of the Libet discussion. Examples from vision research, such as "temporal-binding-by-synchrony" and the "flash-lag" effect, are then used to illustrate these reasoning patterns in more detail. Alternatively one could assume symbolic representations of time and space (symbolic "tags") that are not coded in their own dimension (not time in time and space in space). Unless such tags are multiplexed with the quality message (tickle, color, or motion), one gets a binding problem for tags. One of the hidden aspects of the discussion between Libet and opponents appears to be the following. Is the NCC smarter than the rest of the nervous system, so that it can solve the problems of local sign (e.g., "where is the event"?) and timing (e.g., "when did it occur?" and "how long did it last?") on its own, or are these pieces of information coded symbolically early on in the system? A supersmart NCC appears to be the assumption of Libet's camp (which includes Descartes, but also mystics). The wish to distribute the smartness evenly across all stages of processing in the nervous system (smart recodings) appears to motivate the opponents. I argue that there are reasons to side with the latter group.
Article
Trevena and Miller (2002, this issue) provide further evidence that readiness potentials occur in the brain prior to the time that participants claim to have initiated a voluntary movement, a contention originally forwarded by Libet, Gleason, Wright, and Pearl (1983). In their examination of this issue, though, aspects of their data lead them to question whether their measurement of the initiation of a voluntary movement was accurate. The current article addresses this concern by providing a direct analysis of biases in this task. This was done by asking participants to make subjective timing decisions regarding a stimulus that could be measured objectively. Our findings suggest that their timing task was indeed biased such that participants' tend to report events as happening approximately 70 ms later than they actually happened. Implications for the original Libet et al. claims are discussed.