The evidence is overwhelming for an observing self in the brain

Response to Thomas Clark, “Is there an observing Self?” SCR, 2004

The evidence is overwhelming for an observing self in the brain

By Bernard J. Baars

Dr. Clark tells us there is no observing self, but he offers no evidence. Like consciousness, the observing Like consciousness, the observing self is an empirical questionself is an empirical question. Clark’s denial of a self goes back to Gilbert Ryle, who argued that there could be no observing “homunculus” in the brain, because that would lead to an infinite regress. But even Ryle’s famous student Daniel Dennett has given up that argument, and now maintains there is no philosophical objection to an observing self if it can be decomposed into subsystems that are not just other homunculi.

In science, no serious proposal for an observing self has been vulnerable to Ryle’s infinite regress argument. Self was always viewed as an executive system related to goals, and in ego psychology, it was specifically a system that balanced competing goals. Forty years of excellent research on split brain patients shows that the Left Hemisphere contains a language-based narrative self system (which you, the reader, are probably hearing right now in inner speech). But very likely the Right Hemisphere has a non-linguistic executive system that has at least receptive language, and which has long been known to accept verbal requests, carry out voluntary control over skeletal muscles (especially the most distal limbs like the hands and feet), and can do intelligent tasks like selecting matching pictures upon instruction.

These are executive systems in a very straightforward sense. They are involved in decision-making over the voluntarily-controlled elements of the nervous system. That implies they can control the voluntary muscles (but not the smooth muscles of the digestive tract), as well as inner speech (just try saying your own name to yourself right now!) The ego psychology claim that the self is involved in reconciling competing goal systems is also plausible; we even know where those goal systems are located. They involve subcortical appetitive and emotional systems, like the hypothalamus, PAG, amygdala, and other limbic regions. It is well established that the prefrontal cortex exercises inhibitory control over these “impulsive” mammalian motivational systems. Overall executive control surely involves regions of the prefrontal cortex, but there are times when subcortical systems take over, as when we are tempted to take one more bite of that delicious chocolate cake, even while warning ourselves (in our Left Hemisphere, which tends to control speech production) not to do so.

In what sense are these executive regions “observing” things? Gazzaniga’s “Left Hemisphere interpreter” (his phrase) can observe conscious input from the right side of the visual field. It does not observe the left side (except via eye movements), but it does control the contralateral hand and foot in a voluntary fashion. Since it takes in conscious perceptual information, and interprets it to make voluntary decisions, it seems perfectly accurate to call it an “observing” self.

A great deal of reliable evidence falls into place with this viewpoint. For example, there is a vast literature in psychiatry on “self-alien syndromes.” What makes anxiety A great deal of reliable evidence falls into place with this viewpointdisorders pathological is the loss of control by executive functions over normal anxiety. What makes obsessive-compulsive disorders so disturbing is the loss of executive control over ordinary actions like checking a door lock. All the Axis I disorders of the Diagnostic and Statistical Manual of the American Psychiatric Association (DSM-IV) involve self-alien disorders. That classification could not work if we lacked a conception of an observing executive.

In brain damage we find a range of similar disorders. Neglect patients may suffer from “alien limb” syndrome, in which they literally feel that their own left arms and legs are not their own, and may try to throw them out of bed. Even physical trauma, like breaking a leg, may leads to a sense of alienation from self, as Oliver Sacks has pointed out in “A Leg to Stand On.”

There is much more to be said for an observing self, but this gives a sense of the evidence. (See Baars, 1997, 1988 for further information; www.nsi.edu/users/baars). It is noteworthy that common sense psychology never dropped the idea of a self, even through a century of philosophical and psychological attacks on the idea. That is because it is so useful and explanatory. And after a century of denial, all the rejected terms are back. Psychologists were told by John B. Watson that consciousness was just “another word for the soul of religion.” Today, we see more than 5000 citations in the biomedical literature each year to the term consciousness. For fifty years we were told that mental imagery was a myth. Today there is a flourishing scientific literature on imagery. The same goes for all the taboo terms of behaviorism — memory, goals, inner speech, emotional feelings — about two-thirds of the entire vocabulary of English and related languages.

Today we still hear about two taboos, against “volition” and “self.” But the evidence for those taboos is no better than it was in the case of consciousness. A search in PubMed online on “voluntary control” and “executive functions” reveals hundreds of recent references, especially based on brain imaging studies. We know where to find these functions in the brain, and we are learning more and more about their details.

Baars et al (2003) suggest that unconscious states may involve not just a loss of conscious contents, but also a loss of functioning of the observing self. The evidence for that comes from brain imaging studies of four deeply unconscious states: deep sleep, comatose states, epileptic loss of consciousness, and general anesthesia. All these states show a steep drop in metabolic activity in cortical regions involved with observing self functions, particularly parietal and prefrontal areas. This cannot be explained by a local loss of conscious sensory functions, because sensory cortex is not involved. This suggests that “self-functions” may be interrupted during these states. That is an empirical hypothesis and prediction. It may be true or false. But it is testable. Whether it is right or not we may find out, as brain imaging gives us better and better understanding over the coming years.

© 2004 BJ Baars
Bernard J. Baars
Affiliate Research Fellow
The Neurosciences Institute
San Diego