Consciousness as an epiphenomenon?

A very famous and interesting experiment is that of Benjamin Libet during the early 1980’s which started a long debate about the free will on humans [1].

Description:

The actual experiment consisted of human subjects that were asked to move their finger whenever they liked. Libet then, measured the time when the subject became consciously aware of the decision to move their finger. This was done by asking the subjects to look at a clock and note at which exact time they were aware of the conscious decision to move their finger. During this experiment their brain activity was monitored by an Electronencephalongram (EEG). The surprising results of the EEG showed that before the actual conscious decision of the subject to move their finger, an electrical potential in the brain was already measured to prepare for the movement of the finger. Specifically, Libet found that the conscious decision to move the finger preceded the muscles by 200ms but also that an unconscious activity had already started to prepare for the action 350ms before the conscious decision.

Insights:

The motivation for this experiment and the final key insights are related to some other previous studies. Specifically, Kornhuber and Deecke [2] (1964) discovered that an electrical potential could be measured in the brain long (500ms) before a subject flexed a finger which they called readiness potential. John Eccles speculated that this is because the subject must become conscious of the intention of the action before the actual action. Thus Libet tried to test Eccle’s speculation. By achieving to show that brain activity could be measured for the readiness potential before the conscious decision to move the muscle he indicated that the timing of our actions is predetermined. Unfortunately, a lot of deniers of free will quickly jumped in the conclusion that this experiment proved that humans do not have free will and we are always predetermined to act a specific way. Psychologist D. Wegner argues that consciousness is the cause of brain activity and not the other way around [4]. Libet did not support that claim and counter-argued this idea by another experiment where he tried to show that subjects could “consciously veto” an action before it happened, meaning that even though the brain had already started the readiness potential, subjects could consciously stop the action before the RP reached the threshold to complete the action. He mentions this counter-argument as an example of Free Won’t (similar to Free Will)

Limitations / Assumptions:

This experiment was done in a very controlled environment where subjects were specifically told to move their muscles whenever they pleased. This preparation for the action and the certainty of that this action will be completed could play a considerable role to how the brain prepares and acts on this situation. This could be seen as the result of the Hawthorne effect (observer effect) where the subjects, even unconsciously, change their actions or behaviour in response to the fact that they know they are being studied thus undermining the results of the experiment.

As Alfred Mele, points out [3], the appearance of a readiness potential activity in the brain does not mean that this is what causes the action. The RP could just be the result of the intention to act but not the act by itself.

Another limitation of Libet’s Free Won’t experiment is that the EEG devices are triggered to show brain activity when an action happens and thus no activity could be shown if no action would be performed.

References:

1. Libet, B., Gleason, C.A., Wright, E.W. & Pearl, D.K. ‘Time of conscious intention to act in relation to onset of cerebral activity (readiness-potential). The unconscious initiation of a freely voluntary act’, Brain (1983) 106: 623- 642.

2. H. Kornhuber, Hans & Deecke, Lüder. (2016). Brain potential changes in voluntary and passive movements in humans: readiness potential and reafferent potentials. Pflügers Archiv - European Journal of Physiology. 468. 10.1007/s00424-016-1852-3.

3. Alfred R. Mele, Effective Intentions: The Power of Conscious Will, Oxford UP, 2009,, ISBN 9780195384260.

4. Wegner, Daniel M. (2002). The Illusion of Conscious Will. MIT Press. Page 317:

“Does the compass steer the ship? In some sense, you could say that it does, because the pilot makes reference to the compass in determining whether adjustments should be made to the ship’s course. If it looks as though the ship is headed west into the rocky shore, a calamity can be avoided with a turn north into the harbor. But, of course, the compass does not steer the ship in any physical sense. The needle is just gliding around in the compass housing, doing no actual steering at all. It is thus tempting to relegate the little magnetic pointer to the class of epiphenomena — things that don’t really matter in determining where the ship will go.

Conscious will is the mind’s compass. As we have seen, the experience of consciously willing action occurs as the result of an interpretive system, a course-sensing mechanism that examines the relations between our thoughts and actions and responds with “I willed this” when the two correspond appropriately. This experience thus serves as a kind of compass, alerting the conscious mind when actions occur that are likely to be the result of one’s own agency. The experience of will is therefore an indicator, one of those gauges on the control panel to which we refer as we steer. Like a compass reading, the feeling of doing tells us something about the operation of the ship. But also like a compass reading, this information must be understood as a conscious experience, a candidate for the dreaded “epiphenomenon” label.”