The Mind's Past

Upon reflection, I have decided that I am perhaps not the best person to review this book, for I have spent my entire professional career in and around psychology and neuroscience. As a result, I fear that my intuitions about what is old hat in mind/brain studies and what is new, inventive, and exciting are quite warped. This is probably not a good thing if I am to report back about a book written for the lay public, for I am completely lacking a sense of what the lay public already believes and what it might find surprising.

This caveat notwithstanding, let me tell you about Michael Gazzaniga's latest book, The Mind's Past. I found lots of it to be old hat, but maybe you wouldn't. It certainly is written in a clear, easy-to-follow style. (No small achievement for most academics, but Gazzaniga has always been an exception here.) In The Mind's Past, Gazzaniga makes three large claims. First, he notes that we are biological organisms, evolved from creatures past. We need to keep this fact firmly in mind as we attempt to study ourselves, reminding ourselves over and over that our mental faculties, such as they are, evolved to promote the four F's of survival: feeding, fleeing, fighting, and reproducing (Gazzaniga focuses mainly on the fourth). Second, most of what occurs in the mind happens outside of conscious awareness. Indeed, consciousness has little role to play in anything we do of interest. Third -- and here is where the title of the book comes in -- our minds devote much energy to spinning wild stories about what we have done and are doing that only occasionally bear any resemblance to the actual facts of the matter. Our memories aren't veridical; neither are present perceptions. But we interpret as best we can and we do so all the time.

I completely agree with all three claims. I find them to be old news, but then this book wasn't written for me. It was written for those well outside the study of cognition. And even those of us steeped in these ideas need to be reminded of them often. Gazzaniga does a good job of explaining and reminding and for this reason alone I recommend his book.

Nevertheless, I do admit to a few worries concerning his presentation. Gazzaniga starts off the book by proclaiming that psychology is dead (p. xi). It failed largely because it is completely divorced from our biological heritage. This is a lament he repeats often: psychologists (and others with whom he does not agree) study humans by making us do silly things under highly artificial conditions. Making us do these silly things won't tell us one whit about what we are really like, in the wild, or so he claims.

Gazzaniga could very well be right. I will leave that debate to others. My concern is that he himself fails to heed to his own warning. Most of the empirical work he discusses comes from traditional cognitive psychology, carried out in a traditional laboratory, using traditional experimental protocols. Indeed, Gazzaniga himself is one of the worst "offenders" of his own maxim. He made his professional reputation (and a deservedly good one at that) by examining what happens we tell some fact to only one hemisphere of a brain that has been surgically split in two. How do these people compensate (if they do) for such odd inputs? His studies are quite interesting, but they certainly don't mimic the wild. Often it seemed to me that Gazzaniga chides his opponents for not looking at how our minds and brains work under normal biological conditions when he disagrees with them, but then overlooks this criticism when describing data he believes.

At this early stage in understanding the mind/brain, I would think that the best position to take would be to keep Gazzaniga's admonition in mind -- we are biological creatures evolved to procreate, among other things -- but to use whatever data we can get. Sure, most laboratory experiments are highly artificial, but that does not mean that they are ipso facto useless. Cloud chambers are artificial too, but they still tell us a lot about electrons.

Gazzaniga is more successful in how he wields his second point, that consciousness isn't at the center of our mind. I would imagine that many would find this claim to be fairly extraordinary, especially in the extreme way that Gazzaniga makes it. But I think he is right nonetheless. My concern here is how closely he wants to tie this claim to the notion that Mother Nature selected for most, if not all, of our specialized brain modules that handle most of our day-to-day activities. Of course, we do have specialized brain areas that we should expect to be directly tied to our genetic heritage -- thermoregulatory devices, for example. However, it becomes less clear how to think about such things the more cognitive the process becomes.

Here is one way to think about my worry. Humans have about 35, 000 genes (give or take). Maybe as many as half are concerned with building the brain, with all its 10¹⁴ connections. Much of what are brain genes are concerned with is building the periphery, getting our sensory systems put together just right. So, obviously, we are not talking a one gene-one neuron connection for the higher cortical areas. There simply aren't enough genes to do it.

One of the ways Mother Nature has learned to compensate for this deficiency is by making us creatures who can learn. The things she doesn't program in, we get through experience. In addition, insofar as we live in diverse environments with diverse challenges (and we do live just about everywhere on this globe) we need to be as possible flexible in the skills we acquire. Hence, our capacity to learn is innate, but once we get to the peculiarly human skills, it is no longer clear whether we should talk about specialized brain areas selected over evolutionary time or areas that develop similarly in similar animals via learning. Probably the correct story will be a complex one in which genes and environment engage in iterated feedback loops, in which our specialized areas are flexible in what they can do, but not completely free to do everything.

It is entirely possible that many of our unconscious processors are not innate, but develop through environmental interactions. This fact shouldn't detract from Gazzaniga's central claim that these unconscious processors are rampant and largely out of our control, though I think that sometimes he confuses these issues.

One of these unconscious processors is what Gazzaniga calls our interpreter. He believes that the interpreter lives in our left hemisphere (ignoring the interesting brain differences we find in left-handed and ambidextrous folk as well as differences in lateralization across the sexes) and is devoted to trying to make sense of the data it gets from the environment as well as what the brain reconstructs as "memory." In many ways this is Gazzaniga's most interesting claim and it is the one he is best known for in professional circles. I wish he had made articulating this point more central to his discussion. Nevertheless, he does present compelling evidence for the existence of almost blind interpreters in our brains, though his argument for why we might have evolved such a thing is less than compelling (starting with the claim that this is an evolved mechanism at all, as opposed to an evolutionary free-rider, like our chins, or something we learn to do as being socialized creatures). Gazzaniga believes that we need such a mechanism to be able to predict our environment. Certainly, it behooves us to be able to predict. But this need doesn't explain why we can't say "I don't know" when we don't in fact know instead of fabricating some outlandish tale.

The ways our interpreters work overtime and with poor-to-nonexistent data are fascinating, puzzling, and astonishing. I hope it will be the focus of Gazzaniga's next book, for I am sure he has much to say about the topic that he has not yet written. In the meantime, The Mind's Past will give you a delicious preview of some of the more amazing facets of our biological minds.

Valerie Gray Hardcastle, Department of Philosophy / Science and Technology Studies,Virginia Tech