University of Essex
Department of psychology
PS901: fundamentals of neuroscience and neuropsychology
“Neuroscientific evidence suggests that conscious free will is an illusion”
Word count: 1966
Conscious free will (also referred to as agency) refers to our ability to control our behaviour, conscious free will states that we have a sense of being able to select between different courses of action. Controlled actions are viewed as intentional as opposed to accidental or reflexive behaviours (for example ducking to avoid low branches while walking). Control and responsibility are often viewed as interchangeable, this, however, is not the case and the two exist very separately. This is evident in the case of an individual suffering from paranoid schizophrenia, who attempts to kill someone for “listening to their thoughts”; in this instance the individual has control over their actions but has diminished responsibility. On the other hand, a drunk driver who kills someone would have diminished control over their own actions however they are still seen as responsible for the death of the individual as the possible consequences of their actions could have been foreseen.
Controlled behaviour is most commonly explained by reference to its anti-thesis automatic behaviour, (Schneider &Shiffrin, 1977). Controlled behaviour is seen as slow, conscious, and based on reason, automatic behaviours are fast, often unconscious and based on intuition. In the past these two methods of decision making (controlled and automatic) have been viewed as in opposition to one another, however, it has been seen that controlled behaviour has advantages as it is able to override automatic behaviours (Norman & Shallice, 1986). This behaviour is referred to as the executive functions of the brain and has been most prominently associated with the prefrontal cortex (Goldberg, 2001). Controlled behaviour can result from two separate means, primarily the prefrontal cortex may provide a biasing signal that either activates or inhibits the functioning of the other regions of the brain (Miller & Cohen, 2001). Alternatively, the prefrontal cortex may hold in mind the current and future goals of the individual as well as keeping in mind elements of the current problem, this is related to the notion of working memory (Baddeley & Della Sala, 1996).
The distinction between automatic and controlled behaviour is not clear, behaviour is rarely one or the other. It has been argued that much of our behaviour occurs unconsciously (Suhler & Churchland, 2009). The occurrence of unconscious behaviour leads us to the debate as to whether we really are in control of and responsible for our own actions. Social studies have shown that participants who are primed using words relating to rudeness as opposed to politeness are more likely to interrupt a staged conversation than those who were primed with politeness or not primed at all (Bargh, et al, 1996). Furthermore, participants who have been primed in an irrelevant task with words related to old age will walk more slowly to get to an elevator than those who have been primed with youthful words (Bargh et al, 1996). Finally, it has been found that individuals are more likely to litter in areas where there is already graffiti (Keizer et al, 2008). These studies raise an important issue of the notion of control; some argue that we can be believed to be in control of our actions (and responsible for them) even if we are not consciously aware of the amount of information required for that decision (Suhler & Churchland, 2009). This approach aims to define control and responsibility, relative to a normative model of brain function.
Free will as a concept is hard to define, however, it is crucial to both individual life and social life (Kane, 2005). The issue of free will and physical determinism has only been addressed in the last 50 years by neuroscience. The pioneering research in this field focussed on the supposed unconscious intentions taking place in decisions previously conceived to be free and voluntary. Research suggests a form of deflation of freedom due to the readiness potential (Libet, 1983). More recent studies indicate a different interpretation of readiness potential, suggesting that the apparent build-up of brain activity prior to subjectively spontaneous and voluntary movements may, in fact, reflect the ebb and flow of the background neuronal noise which can be a result of a range of different factors (Schurger et al, 2016). This more recent interpretation seems to link the neuroscientific perspective of free will with the more common-sense view of free will (Roskies, 2010).
To establish the legitimacy of the concept of free will a great deal of research has been conducted to establish if there is, in fact, a direct link between measurements of brain functioning and the theoretical constructs already in existence. The most famous piece of research in this field, focusing on brain activity was conducted by Libet et al. (1983) this research focused on the supposed unconscious intention which impact decisions frequently regarded as free and voluntary. Libet’s work was based on an initial study by Kornhuber and Deecke’s (1965) in which they discovered the “Bereitschaftpotential” (the reaction potential) which is a slow build up of scalp electrical potential, measured through electroencephalography. This was described as a sign of the planning, preparation and initiation of volitional acts (Kornhuber & Deeke, 1965). Libet’s experiment required participants to move their right wrist and report the exact moment they believed they had made the decision to do so, from this it was possible to estimate the time of awareness relating to the beginning of the movement using an electromyogram (reporting muscle contraction). During the study participants’ brain activity was also monitored through an electroencephalograph, researchers were focusing particularly on a the reaction potential; it is believed that this activity originated from the supplementary motor area (an are involved in motor preparation). Libet’s study found that reaction potential begins in the prefrontal motor areas sometime before the individual has made a decision to take action, it was found that participants became aware of their intention to act around 350ms after the onset of reaction potential, with the volitional process being detected to start unconsciously at 550ms before the action is made (in the case of actions that are not pre-planned) and 1000ms (in the case of pre-planned actions). These findings demonstrate that our simple manoeuvres are triggered by unconscious neural activity, furthermore, the awareness of those actions occurs later, when we are willing to act (Libet, 1983).
Later studies have used similar methods to the aforementioned study, however, have asked participants to perform a different task. One study, for example, asked participants to move either their right or left index finger in a series of repeated trials, the reaction potential and the lateralized readiness potential in these studies were measured. Within this study, it was found that the reaction potential occurred later in the trials, with early awareness of movement initiation. However, it was found that lateralized readiness potential occurred significantly earlier in the trial suggesting that the process behind the lateralized readiness potential is the origin of the awareness of our behaviour. (Haggard & Eimer, 1999). From this study, it is possible to argue that the awareness of our intention to move originates from a decision made by the brain.
Recent research has focused on the impact of parietal lesions on one’s awareness of deciding to move. Studies have found that when participants with parietal lesions are asked to carry out the same task as outlined in Libet’s study, these individuals only become aware of their decision to act when the action itself is being carried out. In these individuals the awareness of the decision to act does not even start before the beginning of the movement, instead, it coincides with the motor action itself (Siguru et al, 2004). It would appear from this research that the alteration in the brain has reduced, or cancelled the interval of consciousness prior the execution of action (Desmurget et al, 2009)
A further study into the neurological basis of free will investigated neural activity. 1019 neurons activity was recorded while participants carried out a self-initiated finger task. The study demonstrated progressive neuronal recruitment, especially in the supplementary motor area, over 1500ms prior to the participant reporting a decision to move. Researchers suggested that a population of 256 supplementary motor neurons was sufficient to predict in single trials the impending decision to move; neural activity was found 700ms prior to the participant becoming aware of the decision to move (Fried et al, 2011).
Many studies have found supporting evidence for the theory that free will is merely an illusion, for example, one study has produced results which do support this hypothesis. In a study requiring participants to complete Libet’s task during transcranial magnetic stimulation (TMS) of the pre-supplementary motor area. During this experiment, the stimulation of the pre-supplementary motor area through TMS occurred at different time intervals in relation to simple voluntary movements. It was found that when stimulation was applied 200ms after the movement judgement was not moved back in time, suggesting that the perception of the intention was influenced by the neural activity of the pre-supplementary motor area after the action was made (Lau & Passinham, 2007).
A later experiment required participants to push a button whenever they wished, and later had to indicate the precise moment at which they had intended to do so, when the button was pressed the participant received auditory feedback with a time delay of 5 to 60ms; giving the impression that the response occurred after they had pushed the button. This study found that despite participants not being aware of the time delay between the action and the auditory feedback, the intention to press the button was reported as occurring later in time (Banks & Isham, 2009)
A further experiment conducted to test the illusion of free will combined the paradigm of the stop signal (Logan et al, 1984) with an intentional action paradigm (Chapman, 1984). In this study participants were required to react as quickly as possible by pushing a button as soon a stimulus was presented on the computer screen. Two conditions existed in this study one in which a stop signal was shown, requiring participants to stop responding or a decision signal after which participants were participants had to decide whether or not to press the button. Participants in the decision trials, were then asked if their actions were a result of a decision or if they had merely not been able to stop before the decision signal was processed. The results demonstrated that in some cases the participants judged responses that were (based on reaction times) failed inhibitions as intentional responses. (Kühn & Brass, (2009).
Most recent research has focused on the activity of the frontal and parietal cortex in the study of free will. Researchers have found the rise of a choice or a decision a few seconds prior to the participant being aware of it, suggesting that the unconscious brain processes have already decided to act (Soon et al, 2008). One study by Soon et al (2008) required participants to carry out a freely paced motor decision task while their brain activity was monitored using fMRI. Participants then had to report the moment of decision by selecting a letter that was being presented in a sequence it was found that activation occurred primarily in the premotor cortex and the supplementary motor are, however, activation was also found in the frontopolar cortex, used to establish decision of action prior to action occurring. (Soon et al, 2008)
From this substantial amount of evidence, it is possible to suggest that our actions are not, in fact, occurring as a result of conscious free will. The evidence here suggests that our actions originate from a number of complex processes occurring within the brain. With evidence demonstrating activity within the brain prior to our decisions to move, it is possible to argue that we are in fact controlled by these neurological processes, as opposed to being our own agents.
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