Free The Illusion of Conscious Will by Daniel M. Wegner Page B

motor area of patients during brain surgery. The surgery was con-ducted under local anesthetic while the patient was conscious ( fig. 2.5 ), and this allowed Penfield to ask what happened when, for example, the stimulation caused a person’s hand to move. In one such case, the patient said, “I didn’t do that. You did.” (Penfield 1975, 76). When further stimulation caused the patient to vocalize, he said: “I didn’t make that sound. You pulled it out of me.” Penfield (1975, 77) observed of the patient that “If the electrode moves his right hand, he does not say ‘I wanted to move it.’ He may, however, reach over with the left hand [of his own accord] and oppose the action.”
    Now, the movements the patient was making here were not the spasms one might associate with electrical stimulation of a muscle itself. These were not, for example, like the involuntary ear jerks that Bair (1901) prompted in his subjects when he electrified a muscle to get them to wiggle an ear. Instead, the movements Penfield stimulated in the brain were smooth movements involving coordinated sequences of the operation of multiple muscles, which looked to have the character of voluntary actions, at least from the outside (Penfield and Welch 1951; Porter and Lemon 1993). They just didn’t feel consciously willed to the patient who did them. In this case, then, the stimulation appears not to have yielded any experience of conscious will and instead merely prompted the occurrence of voluntary-appearing actions.

    Figure 2.5
    Penfield’s (1975) photo of the exposed conscious brain of patient M. The numbers were added by Penfield to indicate points of stimulation, and do not indicate the discovery of the math area of the brain. Courtesy Princeton University Press.
    Penfield’s remarkable set of observations are strikingly in counterpoint, though, with those of another brain stimulation researcher, José Delgado (1969). Delgado’s techniques also stimulated the brain to produce movement, but in this case movement that was accompanied by a feeling of doing. Delgado (1969) reported,
    In one of our patients, electrical stimulation of the rostral part of the internal capsule produced head turning and slow displacement of the body to either side with a well-oriented and apparently normal sequence, as if the patient were looking for something. This stimulation was repeated six times on two different days with comparable results. The interesting fact was that the patient considered the evoked activity spontaneous and always offered a reasonable explanation for it. When asked “What are you doing?” the answers were, “I am looking for my slippers,” “I heard a noise,” “I am restless,” and “I was looking under the bed.” (115-116)
    This observation suggests, at first glance, that there is indeed a part of the brain that yields consciously willed action when it is electrically stimulated. However, the patient’s quick inventions of purposes sound suspiciously like confabulations, convenient stories made up to fit the moment. The development of an experience of will may even have arisen in this case from the stimulation of a whole action-producing scenario in the person’s experience. In Delgado’s words, “In this case it was difficult to ascertain whether the stimulation had evoked a movement which the patient tried to justify, or if an hallucination had been elicited which subsequently induced the patient to move and to explore the surroundings” (1969, 116). These complications make it impossible to point to the “feeling of doing” area of the brain, at least for now. And given the rare conditions that allow neurosurgeons ethically to tinker with brain stimulation at all, it is not clear that this particular approach is going to un-cover the precise architecture of the brain areas that allow the experience of conscious will.
    No matter where such an area might be, though, the comparison of Delgado’s patient with the one