Read The Folly of Fools Online

Authors: Robert Trivers

The Folly of Fools (8 page)

BOOK: The Folly of Fools
6.26Mb size Format: txt, pdf, ePub
ads

INTELLIGENCE AND DECEPTION

 

Deception spawns the mental ability to detect it. In the above case, this includes the ability to discriminate very similar objects, the ability to count, the ability to adjust discriminatory powers to contextual factors, and the ability to act as if making multiple inferences: eggshells on ground, egg destroyed, nest parasitized, investment best curtailed, and so on.

These improved intellectual abilities select for more subtle means of deception, which, in turn, select for greater abilities to detect the deception. In short, deception continually selects for mental ability in the deceived. Since the target of apprehension is a moving target—that is, evolves away from your ability to detect it—ever-new discriminations proliferate. The ability to see through a deception requires special talents unnecessary for discriminating a target that has no ability or interest in hiding. Thus, deception has probably been a major factor favoring intelligence, certainly in highly social species.

Intelligence also helps deceivers. In behavioral deception, intelligence presumably increases the range and quality of the deception displayed. In humans, at one extreme, the behaviorally retarded will largely be limited to nonverbal forms of deception—a lunge in one direction when the opposite is intended—but rarely sophisticated patterns of verbal deception. By contrast, the very bright can lie in multiple dimensions. Thus, deception selects for intelligence on both sides, though more reliably on the perceptual side. For example, a moth’s back comes to more and more exactly represent tree bark. This requires no new mental abilities on the part of the moth but implies growing powers of discrimination in its visual predators, such as birds and lizards. Not so for behavioral deception.

The best evidence for a robust role of intelligence in deception comes from a study of monkey and ape brains. The size of the neocortex (so-called social brain)—or better still, its relative portion of total brain—is positively associated with the use in nature of tactical deception, which includes any kind of deception that can be seen to give an advantage. The relative size of the neocortex is, in turn, a good measure of relative intelligence, especially social intelligence. Scientists used published studies of monkey and ape behavior in nature to assemble a large set of examples of deception, then solicited a still larger sample of unpublished studies. They next made sure the evidence was not biased by group size, or degree to which a species had been studied, or applied only to some monkeys and apes but not others. The strong conclusion was that among monkeys and apes, the smarter the species, the more often deception occurs. So perhaps does self-deception. We shall see later that the brighter children are, for a given age, the more often they lie. The importance of this can’t be overemphasized. We often think that greater intelligence will be associated with less self-deception—or at least intellectuals imagine this to be true. What if the reverse is true, as I believe it is—smarter people on average lie and self-deceive more often than do the less gifted?

FEMALE MIMICS

 

You would think that telling the sexes apart would evolve easily and reliably, but in an extraordinary number of cases, one sex imitates the other (or the same sex of another species). In each case, females are being mimicked, as in the following three examples. In many groups of fireflies, particular species have evolved to prey on others by sexual mimicry. A predatory female of one species responds to the courtship flash of a male of another species by giving not her own flash of interest but that of a female of
his
species. He turns toward her, expecting to enjoy sex, and is seized and eaten instead. Sex is a very powerful force and especially in males often selects for “indiscriminate eagerness,” which provides fertile ground for deception to parasitize.

In another example, that of orchids, fully one-third of all species are pollinated through deception—that is, the plant offers no actual reward to its pollinators, only the illusion of one. Most species mimic the smell of their pollinators’ food without supplying any. A smaller number (about four hundred species) mimics an adult female of the pollinator species in both appearance and smell, so as to induce pseudo-copulation by the aroused male. The plant takes care not to give the male a full copulation with ejaculation, presumably to keep him in a perpetually aroused state, driven to seek out new “female” after new “female,” pollinating the flowers all the way. Males who find pseudo-females do not linger and test nearby flowers as do males in plant species that have just given a nectar reward. Instead they fly immediately to a new patch of flowers, presumably in search of actual rewards. Thus, sexual mimics tend to be more outbred than closely related species that offer a real reward—a side effect of being deceived that may actually benefit the species itself.

Selection has also repeatedly favored males who mimic females within their species to fool territorial males into thinking they are females so they can get close enough to steal paternity of some or all of the eggs about to be laid by real females. These eggs will be cared for by the territorial male as his own. Sometimes selection for deception has been strong enough to mold morphs that are permanently committed to deception, that is, morphological forms whose strategy depends entirely on a life spent deceiving others. A classic example occurs in the bluegill sunfish, where a specialized male form has evolved that mimics a female in appearance and behavior, being one-sixth the size of a territorial male and roughly the size of an actual female. This female-mimic seeks out a territorial male, permits himself to be courted, and responds enough to keep the other male interested, so that when a true female spawns, the pseudo-female is ready nearby to help fertilize the eggs. It is as if the territorial male imagines he is in bed with two females when in fact he is in bed with one female and one male. The female almost certainly knows the truth.

The two kinds of males appear to be distinct forms that never turn into each other. To have persisted for so long, their long-term reproductive success must be identical—that is, over evolutionary time, the deceiver is doing exactly as well as the deceived—and this equality must, in turn, be enforced by frequency-dependent selection. When the female-mimic is relatively rare, he will do relatively well; when common, less so. Whether the female expresses any kind of preference for either male is unknown, but in general, females prefer rare males, that is, the less frequent of two choices. Perhaps one of the most spectacular cases of sexual mimicry is performed by a tiny blister beetle, itself a parasite on a solitary bee. To achieve dispersal, one hundred to two thousand individuals aggregate in groups that mimic in size, color, and perching location a single female of the host bee species, even moving as a unit up and down a tree. So here a kaleidoscopic falsehood is produced, its individual parts one-hundredth or less the size of the picture they are creating. In turn, a male bee copulating with the picture will serve to disperse the beetles to future bee nests since the beetles attach to him.

FALSE ALARM CALLS

 

Alarm calls occur in a variety of species, especially birds, and serve to warn other individuals (often relatives) that a predator is nearby. An alarm call is obviously a key moment—with little room for error on the receiving end. Thus, it is not surprising that true alarm calls have served as a template for the repeated evolution of false alarm calls. In mixed-species flocks of birds found in the tropics, an individual will give a false warning call when another bird has caught and is about to eat a large, tasty insect. Half the time, this causes the bird to drop the insect and dive for cover. In the other half of the cases, the bird is not fooled—while it always responds to a true alarm call with immediate flight. Thus, the birds have evolved to tell false from real alarm calls half the time.

In skuas, false warning calls by parents are used to frighten warring offspring into separating and fleeing for cover, at which point the parents intervene to prevent further strife. In swallows, males apparently use false alarm calls to guard their paternity. They will give an alarm call when they spot their mate near another male, often causing both birds to dive for cover. Males breeding in colonies almost always give such calls when returning to an empty nest during egg laying (when female copulations outside the pair are frequent and threaten his paternity of the offspring) but not at other times (even swallows do not wish to cry “wolf”). Antelopes have been discovered playing the same trick. After a male has spent a day or two in sexual consort with an adult female, he will give a warning bark if the female seeks to move on, as if signaling that a predator lurks nearby and she should remain with him.

CAMOUFLAGE

 

Camouflage is so common in nature as almost to escape notice. Most creatures are selected at the very least to blend in to their backgrounds, with stick and leaf insects merely extreme examples. But at the behavioral level, octopuses and squid are so advanced as to be worth special note.

Octopuses and squid are fat, tasty creatures without a protective shell, so they are naturally sought after by a wide range of predators, mostly fish but also mammals and diving birds. Their only defense (beyond ink clouds and biting) is camouflage, and here they have evolved a remarkable system in which each skin-color cell is innervated by a single neuron, thus cutting out all synaptic delays and permitting a near-perfect adjustment to the background in about two seconds. While feeding, the animal can move very slowly across a great range of backgrounds, continuously remaining nearly invisible to others by adjusting its color to each new surface—sand, mud flats, coral reefs, rocks, sea-grass beds, and so on. Octopuses look as if they are slowly rolling while continuously adjusting to what is below. When they want to swim fast, they mimic flounders, in shape, color, swimming movements, and speed, darting swiftly along the sea bottom.

At intermediate speeds (when foraging), they adopt a most unusual strategy of randomly displaying variant phenotypes at about the rate of three per minute, for hours at a time, as if they are shuffling through a deck of cards featuring different camouflaged versions of themselves. This helps prevent the predator from forming a specific search image for any particular version. Just as the predator recognizes potential prey, the prey has morphed into a novel camouflaged form. One species of squid has also evolved a female mimic, one so good that he sometimes fools even fellow female mimics, who approach in search of copulation. This is yet another case of deception being too convincing for its own good.

DEATH AND NEAR-DEATH ACTS

 

It has long been known in predator/prey relations that deception can work anywhere from first detection until final consumption. Consider two examples near the time of death itself. The feigning of death typically occurs after the prey is caught, and is thought to inhibit the final death-dealing strike. The bird acts dead, lifeless, but remains conscious and alert so that often the only sign of life is its open eyes. Chickens run at the first opportunity, typically when the predator lets go, but a duck threatened by a fox often remains immobile for some time after release, especially if other foxes appear to be present. The fox’s counteradaptations are to kill some prey immediately upon capture and to disable the remaining ones by severing a wing on each.

In the broken-wing display, a bird near its nest tries to distract a potential predator by acting like an injured bird, with one broken and extended wing. The bird moves awkwardly near the predator with wing extended but flies away quickly when attacked. This display is much more dramatic the closer the predator is to the nest. Birds have a variety of other acts they conduct when their nest is threatened. Crakes, ground-nesting birds, will mimic rats scurrying away from their nest, their backs slightly hunched, with both wings partly open and drooping to mimic a fat rat scurrying away in the wide open—an easy prey that looks tasty to various mammals and birds, but one that can suddenly take to the air when attacked. At other times, among reeds, the crake will drop like a stone into the water, creating a big splash, and then move loudly through the reeds, much like a frog staying at the surface. What is noteworthy is that the crake calls attention to itself while acting as if it is not. It must not be such a good rat or frog that it remains undetected, yet it must act like a target trying to avoid detection. Thus, movements are outwardly furtive but louder than usual.

RANDOMNESS AS A STRATEGY

 

We use patterns to detect deception, and randomness is the absence of pattern. It is often not appreciated how valuable randomness is as part of a deceptive strategy designed to avoid detection. Consider a couple of examples. Fake butterfly eggs are actually plant structures evolved to prevent butterflies from laying their eggs—since butterflies avoid laying eggs where they see some have already been laid. The fake eggs appear at random on the surface of the plant’s leaves. Yet in closely related species, where the plant structures serve their original function, they are symmetrically located on each side of the leaf. Thus, natural selection created the randomness, presumably since butterflies had evolved to treat symmetrical patterns of eggs as if they were not really eggs (as indeed they are not). An ongoing struggle for randomness occurs in a pronghorn antelope. The pronghorn mother leaving her offspring hidden between nursings while she eats initially orients herself away from her offspring, then for much of the time she faces in random directions. Finally, only just before returning to nurse does the mother reveal the offspring’s position by facing it.

Now consider a human example. In the old days, when customs officers routinely searched most bags in the owner’s presence, a tried-and-true method to detect smuggling was to poke around randomly while watching the owner out of the corner of their eye. Whenever the owner became agitated or showed undue attention, the customs officer eliminated the rest of the bag and concentrated on the suspicious section. Again, by poking around (and paying close attention), the officer allowed the owner to guide him or her to the problem, presumably something illegal. Note that lack of preparation for this eventuality—being caught—only heightens one’s anxiety and inadvertent information leakage.

BOOK: The Folly of Fools
6.26Mb size Format: txt, pdf, ePub
ads

Other books

The Sevarian Way by Justine Elyot
After Hello by Mangum, Lisa
Antes bruja que muerta by Kim Harrison
The Loner by J.A. Johnstone
The Traherns #1 by Radke, Nancy
The Intruder by Hakan Ostlundh
Chemistry by Jodi Lamm
Driven by W. G. Griffiths
Undeniable Love by Piaget, Emeline
Tumultus by Ulsterman, D. W.