Je ne regrette rien (2): Consciuous decisions in the lab

Credit: Abir Sultan / ELSC
Credit: Abir Sultan / ELSC

Psychologists and neurologists have been interested in the problem of free will since the beginning of their specialities, though the first clearly devised and relevant experiments on the topic were those of Libet and colleagues1, in the early eighties. In this famous experiment, subjects who were before a clock, and whose brain electrical waves were being observed, were asked to flex a finger, and to notice as accurately as possible the moment in which, according to the clock, they had consciously decided to perform the movement. Though obviously the conscious decision was experienced before the finger’s movement, an electrical potential known to be correlated with voluntary actions since the sixties was observed by Libet’s equipment about 0,2 seconds before the reported making of the conscious decision, and about 0,5 seconds before the movement itself. By the way, the motivation of Libet’s experiment was that of testing a prediction made in the seventies by the Nobel prize winner, the Christian dualist neurobiologist John Eccles, who had conjectured that the electrical potential should be observed after the reported conscious decision of the subjects. Of course, Libet’s experiments created a deep disturbance amongst defenders of free will. Libet himself declared that, though his discovery seemed to preclude the existence of free “will”, it did allow the existence of something like free “won’t”, i.e., the capacity of conscious free choice for ‘vetoing’ a decision that has already been unconsciously triggered by our brain.

Nevertheless, further experiments have not only largely confirmed Libet’s former discovery, but have helped to discard the “free won’t” interpretation. For example, Filevich et al. (2013)2 have studied in a Libetian way the neural precursors of decisions to inhibit actions, finding that also in this case there is a considerable time lag (around 0,1 sec) between the electrical signal that the action has been vetoed, and the perceived vetoing decision of the subject.

A similar experiment, but without the need of a clock, was carried out by Matsuhashi and Hallet (2006)3. They asked the subjects to freely decide to move a finger at random intervals, while listening tones that sounded also at random times. The subjects had to report whether the tone had sounded after their conscious thought to move the finger, but after the movement itself, and had to try to stop the movement in that case. Consistently with Libet’s result, these experiments also showed that the conscious perception of the decision to move occurred systematically too late to be the physical cause of the movement.

Other experiments have shown that we can be easily mislead into attributing to ourselves voluntary actions that are not really ours. For example, in one study by Daniel Wegner4 the participants were invited to use a computer mouse in concert with someone who is a secret confederate of the experimenter. They are told to choose freely where on the screen to move the cursor, although in fact the confederate is the one making the selection. When, just before the mouse is moved, subjects hear in their headphones a word corresponding to the confederate’s chosen target, they have an increased tendency to report that they acted intentionally in making the selection. There are more studies showing how external events (e.g., the testimony of others) can lead subjects to falsely attributing to themselves actions they did not performed.

Based on this type of results, the psychologist Wegner has been one of the main defenders that conscious free will is really an illusion. However, it can be argued that one thing is to establish that our conscious experience of free deciding is not causally responsible of our physical actions (something that experiments like the ones referred to above certainly seem to establish beyond any doubt), and a different thing is to deny the voluntariness of our actions or the causal relevance of consciousness tout court. Regarding the former, my own interpretation is that conscious will must not be identified with voluntary action: there are voluntary (e.g., deciding what to prepare for meal) and involuntary actions (e.g., sneezing), that are not only different from a phenomenological point of view, but also with respect to the neuronal and brain structures involved in each of them, and to the interactions between those structures in each case. Not all involuntary actions are unconscious, nor are all voluntary actions conscious, but complex voluntary actions usually demand the exercising of our conscious attention and deliberation. The fact that our conscious perception of our voluntary decision happens some milliseconds after some neural events have started to trig our action, does not entail that these neural events cannot be classified as voluntary; i.e., one thing is the voluntariness of our action, and another thing is our perception of that voluntariness. Usually, dualist thinkers in the Cartesian tradition have tended to identify voluntariness with conscious voluntariness, but our knowledge of the brain functioning seems to entail that this is a mistake: consciousness is an essential part of a process of which it is simply not the ‘uncaused first cause’.

Regarding the second point, consciousness might play a causal role in our behaviour even if its role is not that of initiating our decisions. It can be as important to consciously notice whether something that has happened has been a voluntary decision of mine, as to consciously notice that there are three different trains I may take this afternoon. The neural event consisting in our consciously perceiving that we have made a voluntary decision may just be a way our brain has of classifying certain types of other events (i.e., the event of having made a voluntary decision), in order to produce relevant regularities that can be stored in our long term memory, so as to modify our future behaviour in a more adaptive way. For, after all, how can one learn, if not in this way, that one can do something like voluntarily act in the world?

References

  1. Libet, B. (1985) “Unconscious cerebral initiative and the role of conscious will in voluntary action”. The Behavioral and Brain Sciences 8, 529–566.
  2. Filevich E., Kühn S., Haggard P. & Pourtois G. (2013). There Is No Free Won’t: Antecedent Brain Activity Predicts Decisions to Inhibit, PLoS ONE, 8 (2) e53053. DOI:
  3. Matsuhashi, M., Hallett, M. (2006): The timing of conscious thought into action. Clinical Neurophysiology 117(suppl. 1), S96.
  4. Wegner, D. (2002) The illusion of conscious will. MIT Press, Cambridge (Mass.).

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