Monday, October 02, 2006


In his conclusion to Chapter 7, “Adaptations to Predators and Prey” in Handbook of Evolutionary Psychology, pp. 219-220, H. Clark Basset discusses how small, incremental changes in the brain, based on adaptations during our evolution from animal to man, still affect the modern human animal. Enjoy! Everything that follows is a long quotation from the chapter.

“Given the importance of predators and prey in human evolution, it is likely that we have only begun to uncover the full array of predator-prey adaptations that the mind contains. Until very recently, attack by formidable alien beasts was a real and constant possibility in everyday life. The word alien means creatures whose bodies and minds were not human, but who were exquisitely adept at finding, stalking, and killing primates who were weak, slow, and perceptually deficient in comparison to many other species. Selection to be aware of these creatures, of their thoughts, plans, and intentions, as well as a strategic intelligence to take advantage of this awareness, would have been strong. Here, we need to think in science fiction terms. Imagine the human mind as an exquisitely designed computer, armed with state-of-the-art sensors, trackers, detectors, and inference engines all engineered for the purpose of predator defense and evasion. What would these look like? Without doubt, the best equipment designed by military science does not even come close. Yet, relatively little attention has been paid to predator detection and evasion as adaptive problems that could shed light on the design of our minds.

(Photo: Shot from a moving car on Route 2, east of the Cascades.
I love this kind of barren landscape, and I don't know why.
Perhaps there's a bit of Gila Monster DNA in my bones.)

“On the other side of the coin, humans are predators by nature. We have been hunters of other animals for millions of years. Far from diminishing with time, selection for the skills necessary to stalk and kill animals has accelerated over the course of human evolution, as hunting has played an ever-increasing role in human subsistence. For those who have never hunted, the difficulty of the task is easy to underestimate. Dawkins (1976) coined the term the life/dinner principle to refer to the asymmetry in fitness payoffs to predators and prey for the two possible outcomes of a predation event: If the predation event is a success, the predator wins dinner, but the prey loses his life; vice versa, if it fails. There is another asymmetry, which might be called the anywhere but here principle: For a predator to succeed, the predator must manage to be in exactly the same place as the prey at exactly the same time; for the prey to succeed, it need only be anywhere else. Obviously, it is much easier to satisfy the latter condition than the former. This means that whereas prey can use all kinds of ‘dumb’ tactics to avoid predation, including hiding, crypsis, and living in holes or trees, predators must be designed to bring about a very unlikely and nonrandom physical state of the world, which prey are expressly designed to avoid. For tool-using predators, there is an added complication: We must either cause our own position to converge with that of the prey or cause the position of a projectile or trap to do so. This poses other adaptive problems such as the perceptual and motor problems involved in successfully aiming a projectile. Our minds are likely to be full of many detection, tracking, and behavior anticipation mechanisms of which we might not be fully aware.

“For psychology, there likely remains much to discover about human predator-prey adaptations. There might be as yet undiscovered mechanisms for detecting predators using motion and other perceptual cues, including perceptual templates for common predators such as big cats; mechanisms for assessing formidability of animals (predators, prey, and even other humans) using cues such as size, muscularity, and so on; early-developing responses to dangerous animals that require little or no learning; aspects of the fear system that have not been discovered using only snakes and spiders as stimuli; undiscovered mood or emotion states specific to stalking or being stalked; and more. The notion of intentional schemas that I have proposed here—specific, prepared, content domains within the domain of intentional reasoning, of which predator-prey would be only one—has scarcely been investigated, but it would be surprising if intentional reasoning were not rich with evolved, content-specific procedures. In addition, we might find predator-prey adaptations operating in unusual contexts, co-opted to deal with problems outside their proper domains, from detecting oncoming objects in traffic to strategic reasoning in games or business. Finally, it is possible that investigating evolutionarily relevant problem domains such as predation, which are rarely considered by most contemporary cognitive and developmental psychologists, could lead to drastic reconsideration of how the domains of thought are organized: Rather than thinking of broad domains such as social cognition and theory of mind, we might realize that the mind is not organized around a few large problems but around many small ones such as agency detection, tracking objects, and inferring intention from motion, which do not map neatly onto the categories of contemporary psychology.”

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