A series of articles today in the New York Times nicely captures several of the themes of Neuroanthropology—(1) the importance of evolution, with an emphasis on comparative work, variation, and mechanism in addition to adaptive function; (2) examining the interaction between the environment and behavioral biology, where the environment can significantly shape and even alter basic behavioral biology; (3) that brains are there not just to process information or create accurate representations, but are designed for doing things; and (4) social context matters, shaping what people do and what they experience (again, brain-environment interaction), so a focus on the brain alone will not explain significant social patterns or problems.
Evolution and social context are both necessary to successful neuronanthropology, which in turn focuses on what people do and feel through the lens of person-environment interaction. Our approach avoids placing analysis into any one academic category (saying something is an anthropological or a neurological problem alone) and eschews the essentialism that most academic fields incorporate into their causal explanations (culture or biology or psychology made them do it). So here are the articles.
Nicholas Wade reports on new research that shows that the evolution of brain complexity is related to synaptic structure, and not just to the number of neurons (the older “bigger brain” theory). The following graphic shows the sequence well.
Synapses had been viewed as a standard feature across animal brains. “In fact the synapses get considerably more complex going up the evolutionary scale, Dr. Grant and colleagues reported online Sunday in Nature Neuroscience. In worms and flies, the synapses mediate simple forms of learning, but in higher animals they are built from a much richer array of protein components and conduct complex learning and pattern recognition, Dr. Grant said… ‘From the evolutionary perspective, the big brains of vertebrates not only have more synapses and neurons, but each of these synapses is more powerful — vertebrates have big Internets with big computers and invertebrates have small Internets with small computers’.”
How about evolutionary origins? “[Yeast] contain many proteins equivalent to those in human synapses, even though yeast is a single-celled microbe with no nervous system. The yeast proteins, used for sensing changes in the environment, suggest that the origin of the nervous system, or at least of synapses, began in this way.”
And further adaptive specialization? “Vertebrate synapses have about 1,000 different proteins, assembled into 13 molecular machines, one of which is built from 183 different proteins. These synapses are not standard throughout the brain, Dr. Grant’s group has found; each region uses different combinations of the 1,000 proteins to fashion its own custom-made synapses.”
Henry Fountain writes of some remarkable research in male barn swallows competing for female affection. In barn swallows, a bright red chest is a big sex sexy signal, and the normal (i.e., old school biological determinism) thinking has been that the amount of testosterone determines how red the chest.
But Rebecca Safran, a biologist at the University of Colorado, decided to pull out her permanent red marker. Some male barn swallows suddenly looked positively crimson. What happened over the breeding season? The poor, disenfranchised regular males (read, controls) lost testosterone, the normal pattern. The artificially enhanced males saw their testosterone levels go up!
Dr. Safran’s thoughts on why? “It was likely because of the social context the birds found themselves in: the redder males got more amorous attention from females, and more jealous attention from males. The findings show that in this case at least, it’s not just that physiology affects signaling — signaling can also alter physiology. And it didn’t take much. ‘What’s really surprising,” Dr. Safran said, “is that all we did was give the male a new outfit’.”
Benedict Carey takes on optical illusions, where recent research indicates illusions are due not just to the brain filling in things that are expected to be there but actively anticipating what is going to come next.
“It takes time for the brain to process visual information, so it has to anticipate the future to perceive the present,” said Mark Changizi, the lead author of the paper, who is now at Rensselaer Polytechnic Institute. “One common functional mechanism can explain many of these seemingly unrelated illusions”… Because it takes the brain at least a tenth of a second to model visual information, it is working with old information. By modeling the future during movement, it is “seeing” the present.
Why see the present? Activity! “Timothy Hubbard, a psychologist at Texas Christian University, said the principle of perceiving the present was sound, adding, ‘If a person’s response to an object, to catch, hit, block, whatever, is to be optimal, that response should be calibrated to where the object would be’— not a split second earlier, when the perception occurred.”
Nickolas Bakalar writes on recently released data on violent deaths from the Center for Disease Control. The big killer? Suicide. More than half of violent deaths are self inflicted in the United States. One quarter are homicides. The other twenty percent were largely “undetermined” due to difficulties in tracking this sort of data.
What’s behind violent death? “Debra L. Karch, a behavioral scientist at the C.D.C. and the lead author of the report, said three major factors were common in violence of all kinds: intimate partner relationships, substance abuse and mental disturbances. ‘These are things we could focus on in an attempt to prevent violent deaths,’ she said.”
Relationships are obvious as “context,” but substance abuse and mental disturbances? Well, at least substance abuse, which requires exactly the sort of evolution, social context, activity (experience, behavior, and more), and person-environment interaction approach to understand better. For more on that, see our series of articles on both addiction and obesity.