“Where in the brain is intelligence?” This is the first sentence of Jung & Haier's (J&H's) target article. The article does a very fine job of solving a problem – but, unfortunately, not the problem it sets out to solve with this question.
What problem does it solve? The problem it solves is: “Where in the brain are there functions that, when measured in particular ways, show correlations with scores on conventional IQ-related tests?” This is a problem very different from, and much more limited than, the problem posed in the first sentence of the article. It is not a bad problem to solve, but it is more restricted in scope than the problem of “where in the brain is intelligence?”
Why does the target article not solve the problem of where in the brain intelligence is? There are four reasons.
First, the article assumes that intelligence is “in the brain.” Where else, you might ask, could it be? It is, rather, in the interaction between organisms and their environments. Hence, intelligence cannot be localized “in the brain.” Intelligence has traditionally been defined as the ability to adapt to the environment (Sternberg & Detterman Reference Sternberg and Detterman1986), so both organisms and the environments to which they must adapt matter for localizing intelligence.
The adaptive demands of different organisms and kinds of organisms are different, and they differ across time and place. Consider, first, the demands of changing times, then of changing places.
As an example with respect to time, mathematical-computation skills were important when I was growing up in the 1950s, and they were a notable part of aptitude and achievement tests, as well as of school success. Today, with the advent of electronic computational devices, these skills are much less important than they once were. This lesser importance is reflected in tests and in school. Conversely, the abilities to deal with computational devices were once unimportant, because the devices did not exist, but today are quite important. Someone who successfully can navigate today's Internet environment is in a much better position to adapt than someone who cannot. Is intelligence today the same as in the 1950s? No. What was once “intelligence” has changed. Attempts to locate intelligence “in the brain” cannot succeed if one assumes that the same areas of the brain will always be relevant to intelligence.
As an example with respect to place, consider that in cultures other than our own, different skills may be relevant to the concept of intelligence (see review in Sternberg Reference Sternberg2004). For example, we found, in a study in rural Kenya, IQ actually may be negatively correlated with the skills needed for adaptive success (Sternberg et al. Reference Sternberg, Nokes, Geissler, Prince, Okatcha, Bundy and Grigorenko2001). The reason is that, in this environment, the people identified as “intelligent” in terms of adaptive demands learn practical skills not measured by the tests, such as knowledge of natural herbal medicines used to combat parasitic illnesses. In Alaska, Yup'ik Eskimo children who are viewed as successfully adaptive are those who have developed the hunting and gathering skills necessary to adaptation, not those who excel in academics (Grigorenko et al. Reference Grigorenko, Meier, Lipka, Mohatt, Yanez and Sternberg2004). What matters in rural Alaska may change in the future, but that is my point. Attempts to localize intelligence in the brain need to take into account that different areas of the brain may be differentially important in different places as well as times. The static approach taken by J&H will not work.
Second, from an evolutionary point of view, intelligence as adaptation to an ecological niche does not even require a brain. Hence, we cannot localize intelligence in certain parts of the brain. We humans battle, and, in a sense, have been outsmarted by, organisms that do not even have brains. Consider, for example, a virus such as HIV. It has no brain; so, in terms of the J&H article, it presumably has no intelligence. But it has managed to outwit the many millions of people it has killed and will kill. It also has outwitted some of the world's most brilliant scientists, who have been trying to eradicate it but have, as yet, been much less than fully successful. Ditto for the malaria parasite and any of numerous other organisms with which humans are in competition. In terms of the adaptive niches in which they live, HIV, Plasmodium falciparum, and many other species have shown themselves to be quite intelligent, despite the fact that they have no brain.
Are these organisms showing intelligence in outwitting humans? Certainly there are objections that might be posed. One might say that any individual virus or parasite is no match for any one intelligent human. But at the level of a gene pool, they do not seem to be doing badly at all, comparatively speaking. If their gene pool eradicates the human one, what humans counted as “intelligence” may have been a serious misdefinition in terms of biological adaptation that benefited them only so long as they survived as a gene pool.
The same principle applies within, as well as across, species. The Romans probably thought themselves much more intelligent than the “Barbarians” who were knocking at their gates, until their Empire came crashing down in the face of the barbarian onslaught. Once the Romans were almost wiped out, those who were left could repent at leisure their underestimation of the people they considered to be barbarians. Contemporary civilization may find itself with similar challenges. We may someday conclude that we were defeated by the greater viciousness, or birthrate, or brutality of an enemy; but in the end, it will not matter what story glorifying our intelligence we wish to tell, because we will not be around to tell it.
One could argue that a hurricane would pass the above test for intelligence. It would not, because it spreads its destruction equally. It does not target. And it is inanimate. Its genes are not “clever,” because it has no genes.
Third, the article assumes that IQ tests measure intelligence. This is a convenient assumption for those who have been brought up on a steady of diet of IQ-like tests (SATs, GREs, LSATs, etc.), and who have done well on them, thereby helping to promote, in their society, their own economic well-being. To a large (although not full) extent, scores on these tests are proxies for socioeconomic and educational status (Ceci Reference Ceci1996; Gardner Reference Gardner1983). Even in our own society, IQ-related indices are far from a complete predictor of either school success (Hedlund et al. Reference Hedlund, Wilt, Nebel, Ashford and Sternberg2006; Sternberg & the Rainbow Project Collaborators Reference Sternberg2006) or real-life success. Other forms of intelligence – creative, emotional, practical, social – may be needed to supplement the analytical intelligence measured by IQ in order to more accurately predict adaptation to the environment (Kihlstrom & Cantor Reference Kihlstrom, Cantor and Sternberg2000; Mayer et al. Reference Mayer, Salovey, Caruso and Sternberg2000; Sternberg et al. Reference Sternberg, Forsythe, Hedlund, Horvath, Snook, Williams, Wagner and Grigorenko2000; Wagner Reference Wagner and Sternberg2000).
Fourth, the article assumes some kind of causality whereby brain determines IQ. But research shows that learning affects the brain, which in turn affects IQ-related scores and various kinds of performances (e.g., Greenough & Black Reference Greenough, Black and Kazdin2000). What the studies cited in the article show is a correlational, not causal, relationship.
In sum, IQ helps people solve problems, such as that of identifying correlates of brain and IQ-test functioning. Where it is not so helpful is in making sure that the problem being solved is the optimal one to solve. Scientists therefore need especially to ensure that they are solving the optimal problem, because their training may better prepare them for problem-solving than for problem-finding. And if they find the wrong problem, they may indeed come up with the right solution, but not to the problem they were seeking to solve, and not necessarily to a problem of great importance.
