Caveman Logic: The Persistence of Primitive Thinking in a Modern World (2 page)

Yes, it’s true that we can fit more songs than ever on an iPod and we regularly expand the boundaries of medical knowledge. But we also show the sophistication of a Neanderthal in evaluating fragmentary evidence and are still prone to reaching conclusions about ghosts, “signs,” and magical powers in the world around us. We can design and repair rocket engines, but most humans are unable to confine that primitive part of their minds to the back burner. Caveman Logic continues to inform the most personal side of our belief systems.

In this book, we have chosen the caveman as a symbol of our less-rational, more-superstitious self. I hate to pick on cavemen and stigmatize them any further. Cavemen have been turned into caricatures in popular culture by everything from cartoons like
The Flintstones
,
B.C.
,
Alley Oop
, and
The Far Side
to a series of highly successful commercials by GEICO Insurance (“So simple, even a caveman can do it”).
²
These depictions all convey misinformation for comic effect. But there is one trait we can be pretty sure of: cavemen were not very bright. Few of us would consult a caveman for financial or romantic advice; nor would we want to worship with one. Yet, in a sense, we do all three. That’s how much power our Stone Age minds have in everyday affairs.

While we can parody those who worship fried food or bargain with deities to intervene in their everyday affairs, these kinds of activities remain alarmingly widespread. Why are we so illogical and why do we reach similar superstitious conclusions the world over? This book examines both of these questions and finds answers rooted in evolutionary psychology.

Evolutionary psychology is a relatively new field that offers a scientific, indeed a biological approach, to understanding human behavior. Unlike other fields of psychology, an evolutionary approach attempts to understand humans as part of the biological world in which they evolved. Many of those puzzling, irrational behaviors may stem from adaptations made by our ancestors. If so, we are stuck with mental modules that weigh us down in both laughable and dangerous ways. That mental equipment we carry in our modern skulls is over a hundred thousand years out of date. But instead of challenging our limitations and trying to remedy their effects, we create cultural institutions that normalize them. At this rate, we’ll remain stuck in the Pleistocene for years to come.

I don’t blame our prehistoric ancestors for being who they were. They did their jobs by surviving and reproducing and contributing to the chain of events that led to us. Their world was very different from ours and they understood a lot less about their place in it. Most of what we inherited from them, mentally speaking, is pretty impressive. From an evolutionary point of view, we are the descendants of a long line of successful competitors. But times have changed. The Pleistocene Age, when the bulk of human evolution took place, is over, although it left some deep marks on our minds. Fortunately, they weren’t written in indelible ink.

Is this book taking potshots at a few primitive and superstitious individuals? Has magical thinking gone the way of the Middle Ages, if not the Stone Age? Sadly, the answer to both questions is no. Caveman Logic is alive and well in our everyday lives. Our ancestors who made it through the Pleistocene Age did so with brute force and a brain full of “primitive instincts.” Most of that brute force is long gone or illegal, but some very primitive forms of mental life are still with us today. Worse yet, those cognitive and perceptual flaws often function unchallenged in our daily lives. Their roots may lie in the Pleistocene Age, but their costs in the modern world are very real. Those winners in the relentless competition that preceded us passed along everything they had. We got the full package, warts and all. At best, we are saddled with too many mistaken beliefs. At worst, we may end up annihilating each other.

We need to see our defective Stone Age minds for what they are if we ever hope to drag ourselves, kicking and screaming, into the twenty-first century. This book advocates a difficult transition from the Pleistocene to the modern age. Our bodies seem to be standing up rather well; it’s our minds that are slipping into obsolescence.

Is such a transition possible? Will it require a brain transplant to fix the problems we identify here? I believe we can do it without surgery. The good news is that we actually have something to say about how we use our minds. We may be predisposed to Caveman Logic but we are not bound by it. Biology is not destiny.

Our Stone Age brains will continue to send us hair-triggered perceptions and conclusions that are just plain wrong. What we need more than anything is the will to question those messages as quickly as they occur. It won’t be easy. Those autopilot reactions not only feel “right”—they often feel “good.” They have been second nature to us for so long that we can’t imagine not accepting them at face value.

Caveman logic persists for another reason as well: it receives social support. That’s no small incentive when it comes to human behavior. We are arguably the most social species on the planet and consensual validity counts for a lot with us. But we can level the playing field a bit by developing support systems for those courageous people who do question their Stone Age reactions. At present, there is very little of that support available.

If we fail to do any of this, we are relinquishing control to our ancestors. Whether or not we take those first few halting steps out of the Pleistocene night is the agenda of this book. It’s time to unlock the manual override portion of our brains, put those primitive autopilot settings into storage, and explore the real mental potential of our species.

H
uman beings evolved in a world unlike the one we inhabit today. Our sense of history, as it is taught in high school and portrayed in films, doesn’t begin to do justice to what our species has been through.

Going back two hundred years for an entertaining “historical drama” leaves us squarely in modern times, evolutionarily speaking. Other than different hair and clothing styles, that brief journey hasn’t begun to move us out of the modern world. Even if we go back to the time of Jesus or, further yet, to Greek civilization, we’re still in modern times. Gone are the trains, planes, automobiles, and iPods, but if we could magically visit these times and places, we’d still see recognizable humans acting in recognizable ways. That is why stories set in so-called ancient times still resonate with us today. Their settings are very recent.

Human beings may be a very new species in terms of life on Earth, but we still go back a long time. The hominids that would eventually become humans split away from a common ancestor, leaving the apes behind about 6 million years ago. Those early proto-humans went through a hell of a lot so you could download music and buy airline tickets online. The selection pressure on them to survive and reproduce was tremendous, and living conditions were harsh beyond our imaginations. The physical appearance of these early hominids was also different from what we take for granted today. Physical changes were evolving and accumulating slowly in both the minds and the bodies of our early ancestors.

Natural selection was in no hurry. On one hand, it is a ruthless efficiency expert, heartlessly excluding those features that do not maximize reproductive success. On the other hand, it can only select among existing alternatives. That slows things down. Natural selection can’t cause giraffes to grow long necks just because the food supply happens to be located above their heads. But if a relatively long-necked individual does show up, he or she is more likely to experience reproductive success. Because that longer neck is coded in the individual’s genetic material, and because that individual may be more successful than its short-necked competitors, long-necked giraffes may gradually become more numerous in the population.

Plainly, evolution through natural selection only works on traits that have a genetic basis. Heredity is the cornerstone of Darwinian theory. Without it, the effects of natural selection would be confined to a single generation. Every generation would be starting from scratch. If some trait (e.g., a snazzy new hairstyle) were acquired during an individual’s lifetime, then natural selection could do nothing with it other than conferring some transient rewards (perhaps a few more sexual partners). Here on Earth, almost every important behavioral and physical feature of plant and animal life is transmitted genetically and is directly vulnerable to selection pressure. Thus, traits that lead to greater reproductive success eventually spread and often become standard equipment for a species.

Traits that meet environmental challenges and enhance reproductive success are known as
adaptations
. When the person carrying the genes for these traits reproduces, there is a chance the traits will be carried into the next generation. The final results also depend on the genome of the sexual partner. For all the pleasure it produces, sexual reproduction also carries some disadvantages. The most obvious is that each partner contributes only half of the new genome.

It makes sense that individuals do not mate indiscriminately. No one, whether a Nobel laureate or a tree frog, wants a substandard partner. All forms of animal life have evolved methods for “screening” potential mates in order to select those with the best genomes. Such screening need not be conscious; indeed, it rarely is, even among our own species. Human mating rituals, whether practiced at high school dances or in so-called primitive societies in the Amazon basin, are only one example of this. A zoologist could dazzle us with stories of how other animal species choose or attract partners. One of my favorites involves the gladiator frog (
Hyla rosenbergi
). As in most species, the female is very particular when it comes to choosing the father of her offspring. Since “toughness” is a desirable trait in this pugnacious species, the female practices a very simple screening technique. She approaches her potential mate and literally does her best to knock him off his feet. If she succeeds, that’s one Mr. Froggie that won’t get lucky with her.

Natural selection is not really a very contentious process despite the uninformed political debate that swirls around it. At its most basic level, natural selection simply means that heritable differences within a species lead to different levels of reproductive success. The most successful adaptations tend to spread in the population. That hardly seems like a difficult or dangerous idea. Dog breeders routinely take advantage of it, substituting their own preferences for the traits that nature might select.

According to most surveys, the majority of Americans do not “believe in” Darwinian evolution. This seems an unfathomable state of affairs in the twenty-first century. Obviously, someone has to understand a viewpoint before deciding whether to accept or reject it. I’ve talked to enough high school students and teachers to conclude that Darwinian evolution is neither well taught nor well understood. It is entirely possible that the view of Darwin many Americans reject would also be rejected by most scientists. It is simply wrong. The misunderstanding is so pervasive. Most people can’t even tell you the name of Darwin’s famous book. Ask someone and, if they know the book at all, they are likely to report
Origin of the Species
rather than
On the Origin of Species
. It is a subtle difference, but quite telling. Even Spencer Tracy, appearing as Clarence Darrow in the award-winning 1960 film
Inherit the Wind
, got it wrong.

At a time when debates over the teaching of evolution are turning neighbor against neighbor and throwing local school districts into chaos, it would seem criminal not to bring combatants to a common understanding.
Then
let them debate. This has plainly not happened and is a glaring fault of the American educational system. When students tell me (as they occasionally do in Introductory Psychology classes) that they do not accept Darwin, I usually ask them what they mean. I cannot recall a single occasion when such a forcefully opinionated student has gotten it right. The most frequent response is, “It means we come from monkeys.” Who wouldn’t reject that? Whether by incompetence or willful misrepresentation, natural selection is just not getting a good hearing.

Perhaps if people
understood
natural selection, they’d be more likely to
accept
it. The principle does not seem very threatening (although the wrongheaded version can be quite upsetting to many). Moreover, as Richard Dawkins argues, natural selection is inevitable once you accept a few basic premises. Susan Blackmore concludes in her book
The Meme Machine
, “If there is a replicator that makes imperfect copies of itself, only some of which survive, then evolution simply
must
occur. . . . The inevitabilty of evolution is part of what makes Darwin’s insight so clever. All you need is the right starting conditions and evolution just has to happen.”
¹

So what conditions must be in place for this inevitable process to occur? For one thing, we are all replicators. Human beings replicate sexually. Some anti-Darwinians may be uncomfortable acknowledging that process, but it is nonetheless true. I have never heard an anti-Darwinian debate heredity. Most, if not all, accept that we pass along our genetic information, which is then combined with our partner’s contribution to form a new organism. That is not contentious. The fact that our offspring are composed of a mixture of maternal and paternal DNA is also not contentious. Every gene you carry came from either your mother or your father. No one debates that.

So far, so good. We’ve got the “replicator” part into the acceptance column. What about that “makes imperfect copies” part? This simply means that copying errors occur. They don’t occur very frequently (maybe about one in a million), but they do occur. These errors are called
alternative alleles
or, more commonly,
mutations
. They result in some change in the phenotype. Most of the time they are inconsequential. When they do matter, they are usually negative. In other words, the ancestral allele was a better deal than the mutated one. And so the mutation does not spread in the population. But the important point here—and it is indeed a central point to natural selection—is that mutations, those inevitable copying errors, provide variation in the human genome. Variation is
good
. You wouldn’t want uniformity or perfection. Those errors are essential to the survival of the species. If there were no errors (i.e., if copying were perfect), there would be no variation among phenotypes and nothing for natural selection to work on.