Big brains and Boskops: Phrenology lives!

As early as the 4th century BC, evidence linking the brain to intelligence was sufficient to support explicit theories to that effect. Famous among those for his anatomical work and for such a theory was Herophilus (335–280 BC), doctor, scientist, and teacher (von Staden, 1989). Born in Cos, he established his practice in Alexandria where it was permissible to perform dissections on human cadavers. Although his works are long lost, he is noteworthy for being cited appreciatively by Galen (Acar, Naderi, Guvencer, Türe, & Arda, 2005). He ranks among the pioneers in the neurosciences (Wills, 1999). He was the first to distinguish the functions of cerebellum and cerebrum and, against the Aristotelians, to locate intellectual functions in the brain rather than the heart.

Hippocrates earlier and Galen later reached similar conclusions and helped to establish in the process a scientific interest in the relationship between neuroanatomy and cognition, but Hereophilus was a true pioneer. He may well have discovered and recognized the respective functions of sensory and motor nerves and he may also have argued that all forms of mental competence were inextricably bound to functions of the brain. So the main part of the story of what is now called “neurophilosophy” dates to the third century BC and even much earlier if the Hippocratics are included; not to mention an Egyptian priest or two many centuries before that.

By 1800 Franz Gall would conclude, without significant challenge from the scientific community, that the brain was the organ of mind in all of its manifestations, here echoing the earlier controversial summary La Mettrie offered; viz. that, “the soul is surely an enlightened machine” (La Mettrie, 1748/1943, p. 22). Gall focused on the early signs of both genius and mental enfeeblement and concluded that the various mental faculties are innate, their development depending on the mass of the brain “organs” devoted to them. Although scientists no longer consult the Phrenology charts of Gall and Spurzheim, the core precepts of Phrenology are now more or less official. Consider, for example, an editorial essay in Neurology playfully titled, “Hat Size, Brain Size, Intelligence, and Dementia: What Morphometry Can Tell Us About Brain Function and Disease” (Drachman, 2002). For many the controversy is settled, needing only further confirmatory evidence of the sort presented in a recent path-breaking book by Lynch and Granger titled Big Brain: The Origins and Future of Human Intelligence (2008). The authors are both accomplished scientists. Gary Lynch is Professor of Neurobiology at the University of California, Irvine, and a specialist in the biochemistry of synaptic mechanisms. Richard Granger is Director of the Brain Engineering Laboratory at Dartmouth. They are not latter day phrenologists in any strict understanding of the term. The phrenologists produced a table of some 35 distinct faculties, each tied to a specific brain “organ.” In the matter of intelligence, Lynch and Granger regard the unit of consequence to be not a specific region or organ of the brain but the overall mass of the brain (2008, p. 157). The seemingly unique mental powers of Homo sapiens arise, they say, from “no shockingly new circuit types—just more of the same in outlandish excess” (2008, p. 157). Redundancies in the basic circuitry permit human beings to parlay their limited experiences into various and complex possibilities envisaged by “that unseen observer ‘me,’ floating behind our continuous memories” (2008, p. 159). As all this is attributable to big brains, even greater and more prodigious mental achievements would arise from even bigger brains. Enter the Boskops, featured in Chapter 12 of Big Brain (Lynch & Granger, 2008).

Who were the Boskops? Lynch and Granger recount the discovery in 1913, in Boskop, South Africa, of a very large skull, later assessed as having some 1,800 cc of volumetric capacity. This is about 25% greater than the average human skull. A few comparably large skulls were then found in the same area and revealed yet another characteristic: Pedomorphosis, the lingering of child-like features in the adult sample. Lynch and Granger note the attention given to these discoveries in the immediately following years, including Loren Eiseley’s book, The Immense Journey (1957), which reproached those who would seek to depict the “man of the future, that being (who) has already come, and lived, and passed away” (1957, p. 164).

Presumably the Boskops, seen as precursors of Homo sapiens, had a native superiority owing to cognitive powers arising from a significantly larger brain. Their big brains permitted them to think faster and more efficiently than we do. As Lynch and Granger say, these outsized brains are nothing less than chastening: “The Boskop skulls represented an important affront; a direct challenge to the presumed ‘upward’ trajectory and ultimate supremacy of present-day humans” (2008, p. 10). Given such brains and, “even if brain size accounts for just 10–20 percent of an IQ test score,” the Boskops in today’s classroom would have an average IQ of 149 and 15–20% would exceed 180! (2008, p. 177).

That there ever were such brains should come as no surprise on the thesis advanced by Lynch and Granger, for the overall morphology of any creature arises from a genetic lottery. The authors contend that, “It is not just possible but highly likely that very small random genetic changes could have produced other hominid species” (2008, p. 49). The random genetic change of interest to Lynch and Granger is the one that resulted in the absolute enlargement of the brains of Homo sapiens: “Human brains…are qualitatively the same as those of other primates; the primary difference is that they are enormous” (2008, p. 154).

The central thesis defended in Big Brain is disclosed by the title itself: Human beings are superior to the balance of the animal economy in virtue of having big brains; not big relative to their height or weight, but big absolutely. There is empirical support for the thesis. Deaner, Isler, Burkart, and van Schaik (2007) have shown that the absolute size of the brain is the best predictor of primate cognitive ability. Deaner et al. also found that there is no indication that neocortex-based measures are superior to measures based on the brain as a whole. Their statistical analyses suggest that the same relationships obtain in human populations. As they say,

Again, research on humans has yielded similar outcomes: IQ is generally predicted equally well by whole brain volume, subcortical volume, and neocortical volume…These results suggest that the functional integration of different brain regions is so strong that the brain as a whole is a relevant unit for cognitive performance. (p. 121)

Lynch and Granger (2008) offer still other supportive findings. If the data are reliable, the best predictor of adult brain size is birth size. This would seem to be a good omen, for birth weight seems to increase year by year.

Still, both the thesis and the data assumed to be supportive beg the foundational question: How is “cognitive ability” to be understood and assessed in different species? If the measure is that of survival itself, then the Boskops failed utterly though Rhesus monkeys have not. Why did the Boskops fail? Lynch and Granger have no settled position on why Homo sapiens lived and they didn’t. One hypothesis advanced by the authors is that the Boskops were more peaceable than we “and we likely exterminated them” (2008, p. 213). Another suggestion is that, “Perhaps they didn’t want to…Perhaps the Boskops were trapped in their ability to see clearly where things would head” (2008, p. 203). Here, then, was a truly advanced species, now cursed by brains so large as to confer a demoralizing prescience as to how the world would fare in the hands of lesser beings—human beings! Rather than bearing witness to the spectacle, they simply willed themselves out of existence. This is a striking thesis but one at odds with the presumption of great intelligence. It would not be too much to expect of so intellectually and morally advanced species that it might place a higher premium on life as such and would not choose oblivion over attempts to bring about a very different world in which all could live with greater peace and security. All such conjectures would be no more than the stuff of science fiction were there no evidence of the disappearance of such a superior species; a species so highly evolved as to see a future not worth confronting and thereupon standing aside so that a lesser version of one’s kind might impose its less-developed will on the balance of creation. It is surely something of a challenge to evolutionary theory itself just in case a creature of superior cognitive prowess failed in the struggle for survival, only to be replaced by a relatively stupid variety within the same species. So the question arises again: Just what happened to the Boskops? Where did they go?

As it happens, there is no credible evidence that the Boskops ever existed. There is no scientific relevance to the question of why they disappeared if they never appeared in the first place. The possibility calls for a reassessment of the discovery of 1913 and its fate under the light of further and more refined study. By 1930 questions arose as to the basis on which “Boskopoids” had been discovered. The skull unearthed in 1913 was not complete and its thickness was an obstacle to precise calculation of cranial volume. In the early 1950s, Ronald Singer of the University of Cape Town had thoroughly explored the area, retrieving thousands of artifacts. Singer is perhaps best known for the two-volume Encyclopedia of Paleontology (1999). Turning his attention to the Boskopoids, he concluded in 1958 that, “what was justifiable speculation (because of paucity of data) in 1923, and was apparent as speculation in 1947, is inexcusable to maintain in 1958” (Singer, 1958, p. 177). Based on large and carefully measured samples of skulls, Singer placed the “Boskopoids” comfortably within the established metrics for the Hottentot and the Negro. On this very point, and in response to Big Brain (Lynch & Granger, 2008), the paleontologist, John Hawks, cites Singer and puts the case this way:

What happened is that a small set of large crania were taken from a much larger sample of varied crania, and given the name, “Boskopoid.” This selection was initially done almost without any regard for archaeological or cultural associations—any old, large skull was a “Boskop.” Later, when a more systematic inventory of archaeological associations was entered into evidence, it became clear that the “Boskop race” was entirely a figment of anthropologists’ imaginations. (Hawks, 2008, para. 11).

One might consider this dismissal of the very foundation of Big Brain to be devastating. It is instructive, however, to regard it as factually jejune but otherwise interesting and suggestive. After all, the Boskopoids are imaginable whether they existed or not. Suppose, as Lynch and Granger (2008) assumed, possession of such large brains was finally an unsuccessful genetic bequest, inclining the Boskops to judgments and analyses too excruciating to permit decisive action. Would it still make sense to regard their powers as “superior”? Would it still be consistent to speak of such powers as cognitively superior? Would one be able to enter into joint action with such a “race” and, if not, what would the proper disposition toward them be? More sharply, one might ask whether brain mass as such really explains anything worth knowing about the human condition and its possibilities. Even more fundamentally, one might ask whether the resources afforded by evolutionary theory are really up to the task of assessing human nature in its most defining manifestations.

At the center of evolutionary theory, including versions bolstered by modern genetics, stands the blind pragmatism of conflict and survival. It is unclear that evolutionary theory can accommodate the concept of intelligence in terms that are indifferent to measured success within a given species. Wisely Lynch and Granger (2008) eschew the temptation to legislate on the matter of intelligence and valid modes of assessment. Still, they mark off the Boskop brain as exceptional on the conjecture that it would be generative of high IQ scores. At least implicitly they take such measures as somehow accounting for the class of achievements that identify a distinctly human nature. On this view, they are not to be faulted for believing that brain mass explains much that is worth knowing about the appearance and nature of human nature and that, even without risky eugenic initiatives, a refined and even new human species is within the reach of neuropharmacologists. Of such newly fashioned Boskops, Lynch and Granger look rather poignantly at the prospects: “Perhaps they’ll come and this time survive. Perhaps they’ll have things to teach us. Perhaps we’ll learn.” (2008, p. 214). In point of fact a large number of the usual kind have come and did have things to teach: Enough to allow human beings to walk on the moon, replace defective hearts, democratize knowledge, and establish constitutional modes of governance unmatched in all of earlier human history. That the brains of Aristotle, Newton, Shakespeare, and Einstein may or may not have been big is a question safely reserved to the histology laboratory. What history teaches at the level of fact is that such persons were of truly unusual ability, fortified by cultures either nurturing or at least not hostile to the contributions for which they are now revered. There is a moral to this tale. It would be absurd to suggest that, between Herophilus and today’s MRIs not much new has been learned about the functional anatomy of the nervous system. It would be similarly absurd to suggest that comparable developments will not take place in the decades and centuries to come. Is it not of interest, then—is it not suggestive—that, in the face of such extraordinary progress, reductionistic explanations still suffer from ontological “gaps”? Clearly, the size of the gap has remained constant amidst extraordinary progress at the level of basic science. It has not been narrowed by data. It is not likely to be narrowed by data, for the gap itself arises not from ignorance but from knowledge. As it happens, the unity and phenomenology of conscious life require no confirming findings, stand in need of no tests of validity, and even present themselves as the necessary preconditions if any sort of “finding” is to be incorporated within the framework of human cognition. Again, the “gap” is not epistemic, nor does it disappear once we learn about “category mistakes.” Needless to say, there is all the difference between Bernice arriving in a sedan chair and arriving in a veil of tears, but this is not at all the species of difference that obtains between Bernice arriving in a given brain state and her arriving with the right to a fair trial.

The size of brains in the Age of Pericles was probably not much different from those in the heads of the succeeding generations that surrendered Athenian democracy to Alexander the Great. The Germany and Japan of 1940 are utterly unlike what we find today in those same nations now occupied by men and women whose heads are not at all unusual. It is perhaps past time to recognize that defining human achievements are not revealed by SAT scores or IQ tests, even less by hat size. The achievements are found in the cultural, moral, and aesthetic dimensions of lived life. At this level there is just cause for concerns not likely to be relieved either by megalocephaly or megalomania.