Editor’s note: The following is an excerpt from the newly released book, Animal Algorithms: Evolution and the Mysterious Origin of Ingenious Instincts, from Discovery Institute Press.
Zoologists have engaged in such extreme denial of motivation and goal-directed behavior, not to mention animal consciousness and complex intellectual abilities, that until very recently mechanisms for them are not widely sought or even hypothesized. At present, this is perhaps the greatest conceptual void in evolutionary ethology.Mary Jane West-Eberhard
There is genius in Lilliput. I don’t mean Jonathan Swift’s Lilliput, a fictional island peopled with petty humans six inches tall. I mean the Lilliputian world of birds and bees, termites, ants, and butterflies. There is genius here, and that genius poses a mystery, particularly in the case of clever insects. Their brains can be as small or smaller than a sesame seed, and yet these insects perform extraordinary mental feats.
Honey bees live in complex social communities where there is a division of labor based on a caste system. Each bee knows its assigned function and carries out its responsibilities accordingly. Honey bees are also expert navigators and communicators, helping them forage for food and locate new sites for their hives. This despite the fact that a bee brain has only one thousandth of one percent of the neurons found in the human brain.
Monarch butterflies migrate annually two thousand to three thousand miles between Canada and Mexico. It takes up to three generations of butterflies to complete the journey, suggesting the knowledge of the migration route is innate rather than learned. Each generation of monarchs has a clear goal for its segment of the annual migration. The accuracy of their navigation is such that they often spend the winter in Mexico in the same tree as their predecessors.
Spiderwebs are constructed of silk, which has several unique properties that human scientists struggle to replicate, including strength and elasticity. But equally remarkable is the behavior of the spiders in their spinning of the webs. The shape of the webs they engineer is elegant and exquisitely functional. And when part of a web is damaged, the spider promptly begins repairs to restore the original design. In addition to trapping prey, the webs enhance the spider’s ability to locate prey once trapped. Even in the dark spiders can determine the exact location of trapped prey based on the vibrations in the web sensed through their legs.
Some species of termites construct nests that have impressed architects, engineers, and artists alike. The nests can reach more than twenty feet high and typically include a royal chamber, nurseries, gardens, waste dumps, a well, and a ventilation system that reduces heat and removes carbon dioxide.
Adult wasps feed on nectar, but they hunt for other insects to provide food for their larvae. The insects they hunt vary according to wasp species, and include honey bees, beetles, tarantulas, and cicadas. But the most amazing aspect of this is the wasp’s ability to paralyze the captured prey. The location of the neural ganglion that must be injected with a neurotoxic venom to paralyze the prey differs from one prey species to another. For example, a wasp that specializes in honey bees “inserts her sting accurately between two distinct plates on the underside of the bee’s neck, immobilizing but not killing it.”
A Motor Program in Control
Research has confirmed that the recognition of prey is innate, and that the stinging behavior, which must be done with precise accuracy to work, is controlled by a motor program — that is, a series of sub-routines ordered in a particular sequence to perform a given movement or task. And no simple one. To grasp this, imagine the software program that would be required to enable an advanced micro-drone to deliver a neurotoxin to the precise location in the honey bee to immobilize it. In assessing the complexity and evolution of this wasp behavior, Jerry Fodor and Massimo Piatelli-Palmarini conclude that “such complex, sequential, rigidly pre-programmed behaviour could have gone wrong in many ways, at any one of the steps… Such cases of elaborate innate behavioural programs cannot be accounted for by means of optimizing physio-chemical or geometric factors.”
The above examples of innate or programmed behaviors are just a handful of numerous such instances in the animal kingdom. Surprisingly, in many instances the behaviors of what we normally think of as primitive animals can be just as complex as those of more advanced animals, including mammals. Indeed, there is little correlation between the cognitive capacity of animals and their ability to produce sophisticated, apparently innate behaviors. The reason may be that such behaviors really are programmed and therefore innate, so the animals do not require significant cognitive capacity to perform them. What they do require is the specific neural “circuitry” that controls the behavior — circuitry that is quite sophisticated but apparently does not require large brains.
Effusive descriptions of these behaviors can be found in everything from National Geographic television programs to science books and articles. Jennifer Ackerman’s The Genius of Birds and Martin Giurfa’s “The Amazing Mini-Brain: Lessons from a Honey Bee” are two examples among many. The world of science is astounded by some of the complex innate behaviors found in the animal kingdom.
Enigmatic, Mysterious Behaviors
Many of these behaviors are routinely described as enigmatic or mysterious, because their origin is not understood. Thus do we encounter book titles such as The Mystery of Migration and Nature’s Compass: The Mystery of Animal Navigation.
In On the Origin of Species the 19th-century naturalist Charles Darwin laid out his revolutionary case for common descent by gradual evolution. Darwin could not be faulted for timidity. He pressed his case at nearly every turn. But even he conceded at one point in the book that many instincts are “so wonderful” that their development “will probably have occurred to many readers, as a difficulty sufficient to overthrow my whole theory.”
Undaunted, however, he went on to insist that instincts were essential elements of his theory, and like the great variety of biological forms, they too developed through gradual evolution. “I can see no difficulty in natural selection preserving and continually accumulating variations of instinct to any extent that may be profitable,” he wrote. “It is thus, as I believe, that all the most complex and wonderful instincts have originated. No complex instinct can possibly be produced through natural selection, except by the slow and gradual accumulation of numerous, slight, yet profitable, variations… The canon of ‘Natura non facit saltum’ applies with almost equal force to instincts as to bodily organs.”
A Deleted Sentence
Curiously, Darwin deleted the last sentence from later editions of The Origin, although he continued to adhere to its principle. A primary aim of the present book is to explore whether Darwin’s assertion about the origin of complex instincts stands up to current evidence. Does the accumulated evidence from the intervening 160-plus years support the idea, in broad outline at least? If not, is there a better explanation—one drawn either from what is known as the “extended evolutionary synthesis” or from an explanation that reaches beyond that paradigm? This is the central question of the present book.
Complex programmed behaviors are evident throughout the animal kingdom, but in these pages the focus will primarily be on less advanced animals. The reason is that more advanced animals, such as primates, have significant cognitive ability, so they exhibit much more of a combination of programmed and learned behaviors, and in such cases the two are not always easily disentangled. It is easier to discriminate between programmed and learned behaviors in less advanced animals, such as bees and butterflies.
Explaining the origin of these programmed animal behaviors in evolutionary terms is challenging because the behaviors themselves are, in many cases, quite complex and likely undergirded by an extraordinarily sophisticated neurological substrate. Animal behaviors are also strikingly diverse, arguably just as diverse as the breathtaking diversity of physical characteristics we find in the animal kingdom. Those factors alone do not mean the explanatory task is impossible. But it does mean that something more than breezy just-so stories are required to provide a causally adequate explanation for their evolution.