Who Is Moving Your Hand?

Neuroscientists have never stopped using words like “voluntary” and “involuntary” to describe some obvious phenomena. Reflexes are obvious examples of involuntary actions; so are autonomic functions like peristalsis, heart rate, sweat-gland activity, and the like, as opposed to the control of skeletal muscles, which is voluntary in the usual sense.

We now know that autonomic functions can come under voluntary control, at least temporarily, when people are given conscious feedback signals activated by those functions. Biofeedback training seems to bring autonomic responses under the control of the conscious-voluntary system. All these cases present obvious contrasts between voluntary and involuntary control of the same physical functions.

Another remarkable example of a neurophysiological contrast between voluntary and involuntary control was described by Penfield and Roberts in 1959. These neurosurgeons used a low-voltage electrode to explore the exposed cerebral cortex of conscious patients in order to identify and avoid critical areas where surgery might cause serious damage.

In one case, as the surgeon probed the motor cortex, the patient’s hand moved, and the patient was asked, “Are you moving your hand?” She replied, with perfect accuracy, “No, doctor, you are moving my hand.”

How could the patient possibly tell the difference between the brain mechanisms that were under “her own” control and those under the surgeon’s control? The physical movement of the hand may appear much the same, yet the conscious experience of agency is entirely different.

Is volition really a psychologically significant issue? The evidence indicates that, for outwardly similar events, voluntary control can make a fundamental difference: between reflexes, slips, and unwanted habits compared with the same actions when they are deliberately imitated; between “social” and spontaneous facial expressions; and, finally, between actions triggered by direct brain stimulation and those that are initiated in the normal way by the actor.

Volition is therefore at the crux of many basic psychological issues. Common sense may be well justified in giving voluntary control a fundamental psychological role.