An Introduction to Evolutionary Ethics (5 page)

Conflating explanation and justification One might reasonably suspect that some of the popular resistance to contemporary evolutionary psychological accounts stems from a confusion over what these accounts are aiming at. Some critics of evolutionary psychology mistakenly suppose that such accounts amount to an endorsement or justification of the relevant behavior. So when, for example, they hear that the male tendency to prefer multiple sexual partners (assuming such a tendency exists) is accounted for by the forces of sex selection, it is all too tempting to think that such an account is meant to excuse males (“How can you blame him? It's in his genes!”). But this temptation must be resolutely fought. As the old saying goes, “To understand is not to forgive.”

Simply put, evolutionary psychologists seek to
explain
, not to
excuse
. They are attempting to describe the causal processes that lead to observed human behavior; they are
not
attaching value either to the processes or to the behavior. They are
not
claiming, for example, that male promiscuity is good or bad, virtuous or vicious. Such claims are – or, at least should be – left up to those who seek to understand the nature of goodness and badness, virtue and vice. So while you may hear evolutionary psychologists describe a psychological mechanism as “fitness-enhancing” or “effective” or “reliable” or “detrimental,” none of these adjectives should be thought of as ascribing value (or disvalue) to the mechanism
beyond the merely biological context.
If we seek to know whether a mechanism is good
all things considered
, presumably we must look beyond biology. As this discussion makes clear, the distinction between explanation and justification carries particular significance in the moral realm. As such, we will be revisiting this subject in part II.

Misunderstanding the scope of evolutionary explanations If you want to understand why you do the things that you do, it would be a mistake to turn to evolutionary psychology for anything but the most indirect and abstract explanation. To see why, consider an analogy. If I want to figure out what kind of music you like (without your assistance, that is), I might choose to conduct a poll to find out what
most
people in your demographic like in the way of music. Suppose I find out that, based on a representative sample, 73 percent of those in your demographic prefer hip-hop. How confident should I be that
you
like hip-hop? Well, sort of confident; it's better than flipping a coin, I guess. But a better approach would be to investigate the kinds of music you were exposed to growing up, especially through your teenage years – what your parents listened to, what your siblings listened to. Most of all, I would want to know what your friends listen to. These lines of detail are going to be essential in forming predictions about the kinds of music
you
like. Polls might help narrow down the field, but only crudely.

Similarly, evolutionary psychological accounts of human behavior are like polls in this sense: they measure large-scale trends. They predict what
most
humans will be like. Actually, such accounts are more general than even this. Evolutionary psychological accounts predict what most humans will be like
under specified circumstances
. Even the most ardent defender of evolutionary psychology will recognize the tremendous adaptability of the human mind. We are fabulous learners (even if we are notorious forgetters). What this means is that psychological adaptations rely critically on environmental input, a point that can't be over-emphasized. That's why knowing why you do the things you do will require knowing a lot about your environment. At best, the psychological adaptations posited by evolutionary psychologists might provide the framework for some probability claims about you: you will
probably
prefer this over that or think this rather than that,
in the presence (or absence) of these specific environmental inputs.
But this is a very “low-resolution” picture. This is like a charcoal outline of who you are. For a “photo-realism” picture, you need to supply all the rich details of your environment. Thus, the
scope
of evolutionary explanations about human psychology is notably limited. They explain, at best, patterns at the level of populations; they won't tell you much about what makes you, in all your rich detail, you.

Succumbing to the temptation of genetic determinism I warned against this temptation in the Introduction, but it bears repeating. Although the structure of your mind is partly the result of your genes (at least according to evolutionary psychology), and although you have the genes you do in part because of your evolutionary history, none of this
determines
how you will behave, in the sense that there is only one course of action open to you. (So you're not likely to get much mileage out of the excuse: “Darwin made me do it!”) The reason is, there is simply no causal chain linking gene sequence ABC to behavior XYZ. Gene sequence ABC will tend toward a
range
of behaviors depending on, among other things, other genetic structures, learned behaviors, and ongoing environmental input. You are not, as the biologist Paul Ehrlich emphasizes, “captives of tiny self-replicating … genes” (2002: preface). Genes do not, he says, shout commands at you; “at the very most, they whisper suggestions.” Remember: your genes represent but the barest outline of the kind of person you are. Your environment (your parents, your friends, your culture) plays a critical role in shaping how you will respond to various situations.

Indeed, when we note the tremendous impact your upbringing has on your behavior, one has to wonder whether genetic determinism should worry us less than
environmental
determinism, according to which your behavior is determined by (or, let's say, strongly influenced by) the environment in which you were brought up. Just think of the variety of excuses that have made their way into courtrooms: “the abuse excuse, the Twinkie defense, black rage, pornography poisoning, societal sickness, media violence, rock lyrics, and different cultural mores” (Pinker 2002: 178). The truth is, the worry over genetic (or biological) determinism is actually a symptom of a deeper philosophical mystery, one that philosophers are still actively wrestling with: the problem of moral responsibility. It is not that behavior-caused-by-genes is any more (or less) morally problematic than behavior-caused-by-environment; the morally problematic notion, in the eyes of philosophers at least, is the mere notion of behavior-that-is-caused. After all, can we not
ultimately
link the causes of one's behavior to some force(s) outside one's skull? “If we
ever
hold people responsible for their behavior,” Pinker maintains, “it will have to be in spite of any causal explanation we feel is warranted, whether it involves genes, brains, evolution, media images, self-doubt, bringing up-ke, or being raised by bickering women” (2002: 180). In conclusion, whatever the prospects of evolutionary psychology, they do not rise or fall with the set of philosophical problems raised by the specter of determinism. Even if your genes shouted commands at you (which they do not), this wouldn't show that evolutionary psychology was a defective scientific hypothesis. Unsettling, yes. Untrue, no.

So, let's review the missteps to avoid. First, the search for psychological adaptations is
not
the search for adaptive behavior, but rather the search for those psychological traits that were adaptive during the long period of our species' evolution. Second, to explain a piece of human behavior in terms of evolution is
not
to justify (or endorse or recommend or applaud) that same piece of behavior. Third, to explain on evolutionary grounds why humans, as a group, tend to behave in the ways they do does
not
explain – in any interesting detail, that is – why you or I performed
that
action at
that
moment. Finally, you are not condemned to act in the ways that are (at most) “outlined” in your genes; at most, your genes, mediated by your brain,
suggest
lines of action.

So how do these missteps bear on our main inquiry, the evolution of the human moral sense? First, it would be a mistake to conclude that our moral sense is
not
a psychological adaptation on the grounds that it does not produce biologically adaptive behavior in
this
environment. Second, if our moral sense is indeed an adaptation and if a given piece of behavior (call it
B
) is indeed produced in part by that sense, we cannot automatically conclude that
B
is good or virtuous or whatever. (Conversely, if
B
is not produced by that sense, we cannot conclude that
B
is bad or vicious or whatever.) And finally, in case it was not already obvious, having a moral sense does not guarantee moral behavior. More importantly, it would be a mistake to conclude that our moral sense is not a psychological adaptation on the grounds that
not everyone
behaves morally or makes correct moral judgments. After all, we don't conclude that our visual system is not an adaptation on the grounds that our eyes sometimes fool us. The existence of an evolved moral sense is compatible not only with different moral judgments (concerning the same event, say), but also with wide-ranging differences in moral behavior. This is an under-appreciated point. Psychological adaptations, if there are any, do not entail universal – or even near-universal – similarities in thought or behavior. This might be the case if the environment did not have a role in shaping our psychology. But we know that just the opposite is true.

1.7 Conclusion In this chapter I've tried to present the building blocks for understanding evolutionary adaptations – in particular, psychological adaptations. All adaptations have this in common: they started out as genetic mutations; because those mutations tended to give their possessors a reproductive advantage, however slight, they eventually spread to the entire population. The central tenet of evolutionary psychology is that, like the body, the mind contains an array of adaptations, each designed to assist an individual in managing a particular kind of recurrent adaptive problem. Narrowing our focus even further, we can see how proponents of an evolved moral sense are going to go about making their case: such a sense tended to give our ancestors a reproductive advantage (however slight) over other members of the species. The moral sense is presumably specialized, in the sense that its function is distinct from other functions of the mind, and this is so even if it draws on the operations of other subsystems.

There are, however, other building blocks that need to be laid in place before approaching our main subject. For, as it turns out, natural selection has apparently “primed the pump” for moral thought.

Biologists going back to Darwin have observed in non-human animals behavior that might be described, loosely at least, as
moral
behavior: sharing, self-sacrifice, cooperation, and the like. But such observations seem plainly at odds with natural selection's competitive nature. Indeed, the sight of worker bees sacrificing themselves to protect their hive deeply unsettled Darwin, for his theory had no way to explain this “special difficulty.” Such behavior, feared Darwin, was not just “insuperable,” but “actually fatal to the whole theory” of natural selection (2003/1859: 236). But through a series of recent breakthroughs, modern biology has erased the unease. Natural selection can actually explain these behaviors. What this means for our purposes is that when early humans came onto the scene they already possessed, by way of inheritance, the mental mechanisms responsible for moral-like behavior, however distant these behaviors are from
genuine
moral behavior. In the next chapter we will explore these recent breakthroughs and consider what natural selection may have added to those early minds to give us the moral minds so special to our species.

Further Reading Barkow, Jerome, Leda Cosmides, and John Tooby (1995)
The Adapted Mind: Evolutionary Psychology and Generation of Culture
(Oxford University Press).

Buller, David (2006)
Adapting Minds: Evolutionary Psychology and the Persistent Quest for Human Nature
(Bradford Books, MIT).

Carruthers, Peter, Stephen Laurence, and Stephen Stich (eds.) (2005/6)
The Innate Mind
, vols. 1 and 2 (Oxford University Press).

Darwin, Charles (2003/1859)
On the Origin of Species
(Signet Classics).

Darwin, Charles (2009/1871)
The Descent of Man
(Dover Publications).

Dawkins, Richard (1995)
The Selfish Gene
(Oxford University Press).

Dennett, Daniel C. (1995)
Darwin's Dangerous Idea: Evolution and the Meanings of Life
(Simon & Schuster).

Ehrlich, Paul R. (2002)
Human Natures: Genes, Cultures, and the Human Prospect
(Penguin).

Lorenz, Konrad, and Robert D. Martin (1997)
The Natural Science of the Human Species: An Introduction to Comparative Behavioral Research
(MIT Press).

Mayr, Ernst (2002)
What Evolution Is
(Basic Books).

Pinker, Steven (1997)
How the Mind Works
(Norton).

Pinker, Steven (2002)
The Blank Slate: The Modern Denial of Human Nature
(Viking).

The (Earliest) Roots of Right

Call it a clan, call it a network, call it a tribe, call it a family:

Whatever you call it, whoever you are, you need one.

(Jane Howard, Families)

Commitment is healthiest when it is not without doubt but in spite of doubt.

(Rollo May, The Courage to Create)

Defenders of Darwin have some explaining to do. The theory described in the previous chapter asserted that genetic mutations that tended to increase an individual's ability to survive and reproduce would, all things being equal, eventually spread to the entire population. This seems to imply that genetic mutations that tended to
decrease
an individual's ability to survive and reproduce would eventually be eliminated from the population. So when we look out into the world, we should not observe individuals regularly sacrificing their own reproductive advantages for the reproductive advantages of others. For how on earth could such individuals ever get a foothold in the population, let alone come to dominate it? After all, didn't Darwin himself insist that “any variation in the least degree injurious would be rigidly destroyed”? What we should observe, then, is a world of
pure egoists
. Clear enough. But there's only one problem. That's not the world we observe!

Set aside human behavior – which contains too many acts of cooperation, sharing, and self-sacrifice to name – and focus simply on non-human animals. Every school-age child knows that puppies and ducklings, kittens and cubs, foals and piglets, all have mommies and daddies, and mommies and daddies care for their babies. But school-age children will also tell you that birds (and baboons and bears and even beetles) care for their brothers and sisters. And those children would be right. But where's the self-interest in all this? Doesn't Darwin's theory imply that individuals should only behave in ways that benefit
themselves
?

It gets worse. Vampire bats regularly donate foodstuff (i.e. blood) to other bats (some related, some not) who have failed to feed on a given night (Wilkinson 1984). Ground squirrels and vervet monkeys regularly risk their own lives by alerting others to terrestrial predators (Seyfarth and Cheney 1984). When a ground squirrel sees a coyote, it will often emit a high-pitched call that allows other squirrels to escape to safety; the danger of course is drawing the coyote's attention to the alarm-caller (Dunford 1977). The famed primatologist Frans de Waal has documented thousands of cases of compassion, nurturing, and sympathy among primates (e.g., de Waal 1989, 1996, 2006).
¹
Among birds, white-fronted African bee-eaters, like bluebirds and scrub jays, will delay and sometimes forgo reproduction in order to help raise a neighbor's clutch of baby birds (Emlem and Wrege 1988). Social insect colonies (ants, bees, termites, and wasps) represent perhaps the most pronounced obstacle to Darwinian theory: instead of reproducing, these individuals devote their lives to sustaining the hive and the queen.

Evidently, the world contains not just occasional altruists, but
pure
altruists as well! So should we conclude (as one website promoting creationism does) that Darwin's theory is “badly flawed”? If so, should we abandon evolution as a source of explanation for our moral impulses? The answer to both of these questions is
No
. In this chapter, we will consider how some breakthroughs in evolutionary biology (namely, inclusive fitness and reciprocal altruism) account for the sorts of helping behavior noted above. More importantly, we will explore how these breakthroughs can account for at least some of the human behavior we think of as
moral behavior
. In chapter 3, I will try to point out what these breakthroughs do not explain as far as our moral lives are concerned. For although most theorists agree that inclusive fitness and reciprocal altruism can go some way toward explaining our moral lives, disputes remain as to whether these forces can go all the way.

2.1 Together We Stand?

Perhaps there's an easy way out of the puzzle for Darwinians. They might argue that helping behavior in the natural world evolved to benefit
groups
– not individuals. Surely a group of individuals working toward the greater good will have a reproductive advantage over a group of egoists. A group of ground squirrels, say, containing individuals disposed to alarm-calling will, over time, survive more coyote encounters than another group of squirrels, none of whom tends to alert others of nearby coyotes. (When it's “every man for himself,” every man tends to suffer.) The natural result, then, would be selection for groups of (moderately) self-sacrificing individuals. The logic was good enough for Darwin: “a tribe including many members who … were always ready to give aid to each other and sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection” (2003/1859: 537).

Unfortunately, modern evolutionary biology has all but shut down this escape route. In the mid-1960s the idea of group selection suffered a pretty serious setback: several prominent biologists – most notably, G.C. Williams (1966) and J. Maynard Smith (1974) – showed (to the satisfaction of most) that group selection is, at best, an extremely weak evolutionary force. True, under unusual experimental conditions, where parameters are carefully calibrated, group selection might yield some significant evolutionary results; however, those conditions only very rarely could be expected to obtain in the natural world. (That's why they're “unusual.”) Without getting too bogged down in the details, the problem of group selection as an explanation for helping behavior is this: a group of helpers is almost always vulnerable from
mutant egoists
within. Dawkins called it “subversion from within.” Egoists, by definition, act in ways that ultimately promote their own good, so when an egoist pops up in a population of helpers (presumably by mutation), he will exploit the generosity of his neighbors for his own good. Assuming that “his own good” translates into
reproductive advantage
, it will only be a matter of time before the egoism mutation drives helpers into extinction. On this model, nice guys do not finish first; they become extinct.

Reports of the “total demise” of group selection are, however, premature. Some biologists and philosophers continue to maintain that group selection plays a more notable role in evolutionary explanations than the canonical view allows (e.g., Sober and Wilson 1998). Some argue, for example, that inclusive fitness and reciprocal altruism are in fact special cases of group selection. This is not – thankfully for us – a debate we need to take up, for whether or not such forces count as instances of group selection, there can be little doubt that they are potent biological forces. It's time now to reveal how these forces work.

2.2 Inclusive Fitness and the “Gene's-Eye” Point of View

Richard Dawkins famously described genes as “selfish.” Taken literally, this is of course nonsense: genes are no more selfish than toenails. To be selfish requires self-interested
motives
, and genes, as sophisticated they may be, have no motives – selfish or otherwise. But Dawkins was making a different point. Viewing genes as selfish – as “interested” in their own good – serves to locate the
level
at which natural selection works. And this in turn locates where most of the (biological) explanatory work is done. When you want to understand the workings of a big scandal, journalists will tell you: follow the money. In this case, when you want to understand the workings of evolution, biologists will tell you: follow the genes. Here's why.

The theory of natural selection, as it was presented in the previous chapter, encouraged the idea that (as Dennett puts it) “what's good for the body was good for the genes and vice versa … The fate of the body and the fate of the genes are tightly linked” (1995: 325). After all, a genetic mutation that allows a gazelle to run faster will eventually lead to more gazelles with copies of those genes. But what happens when what's good for the genes is not good for the individual, or vice versa? What happens when an individual gazelle forgoes feeding in order to protect her brothers from a predator? Because her brothers share 50 percent of her genes, such an act promotes the survival of her genes, but it surely threatens her own survival. Good for her genes, not good for her. You might think that such an individual, with her particular genome, is headed for extinction. Not so.

In 1966 William Hamilton demonstrated that when the interests of an individual conflict with the interests of its genes, natural selection will tend to reward the genes. Since the gazelle's brothers share 50 percent of her genes and since the gene(s) responsible for helping kin is likely to be
among
those genes, promoting her brothers' survival is another way of replicating (copies of) her own genes, including the gene(s) responsible for helping kin. Thus, what may not be good for the body may still be good for the genes – and that's what drives the evolutionary engine. Dawkins offered a vivid way of appreciating the point: our genes are not here to make more bodies like these; instead, our bodies are here to make more genes like these. A body is simply a gene's way of making more genes.

The most immediate consequence of adopting this “gene's-eye” point of view is that it illuminates the
biological value of relatives
. To repeat, our relatives share – to differing degrees – our genes. And since natural selection, strictly speaking, is driven by the replication of genes and not the replication of individuals, it does not matter if copies of a gene are replicated through me or through a relative –
so long as they're replicated
. For this reason, biologists speak of
inclusive fitness
, a concept Dawkins describes this way:

The inclusive fitness of an organism is not a property of himself, but a property of its actions or effects. Inclusive fitness is calculated from an individual's own reproductive success plus his effects on the reproductive success of his relatives, each one weighted by the appropriate coefficient of relatedness. (Dawkins 1982: 186)

To get a grip on this concept, let's consider again alarm-calling in ground squirrels.

If an individual squirrel was disposed, by some slight genetic mutation, to emit an alarm call to
anyone
in the vicinity of a predator, that genetic mutation faces a bleak future. The reason? If we can assume that the majority of the individuals who benefit from that alarm call do
not
have that mutation, then the costs of making alarm calls are not offset by the benefits to individuals with that mutation. Ground squirrels without the mutation – and, hence without the disposition to alert others – enjoy the benefits of being alerted, but without running the risks that come with doing the alerting. Hence,
indiscriminate alarm-callers
will quickly be driven to extinction. But change the scenario slightly. Imagine a genetic mutation that disposes an individual ground squirrel to emit alarm calls in the presence of predators
but only when it senses the presence of kin
. Although that individual now runs a greater risk of attack, if that individual can manage to survive and pass on that mutation to offspring, over time, the costs of alarm-calling to any individual squirrel will be offset by the benefits to the gene for that mutation – which happen to be located in genetic relatives. While non-alarm-callers may reap the occasional benefit of an alarm (by being in the right place at the right time), they will eventually be driven, if not to extinction, at least to a minority position in a population. The genes for discriminate alarm-callers have an inclusive fitness advantage over both
indiscriminate
alarm-callers and
non
-alarm-callers.
²

This is just one example of a phenomenon that, according to Hamilton, should cut across the biological realm. According to inclusive fitness theory, natural selection will favor helping behavior in almost every instance in which (what we now think of as) Hamilton's Rule is met:

The rule states, roughly, that for any act of assistance, the benefits (
b
) to a given relative, multiplied by the genetic relatedness (
r
) of actor and recipient (.5 for parents, children, and siblings; .25 for grandparents, grandchildren, half-siblings, uncles, aunts, and so on), are
greater than
the cost (
c
) of performing that act. (Benefits and costs are measured in terms of reproductive successes.) In concrete terms, this means that if a kind of behavior typically produces a benefit to one's full sibling that is more than twice the cost of producing it, we can expect natural selection to favor that kind of behavior. This rule makes it clear why indiscriminate alarm-callers, for example, will eventually be driven to extinction: the cost of the behavior is greater than the benefit to recipients, since the coefficient of relatedness among the recipients is quite small.

On the other hand, the rule should smoothly explain the instances of helping behavior with which we began the chapter. For example, white-fronted African bee-eaters, bluebirds, and scrub jays, it turns out,
selectively
assist others in rearing their young: the recipients almost always bear a genetic relation to the donors (Emlem and Wrege 1988). Among Japanese macaques, defending others from attack and food-sharing occur almost exclusively among kin (Chapais
et al.
2001). The inclusive fitness theory also dissolves the mystery of sterility among social insect colonies: in a unusual twist of the genetic lottery, females within the
hymenoptera
order (ants, bees, wasps, sawflies) can share up to 75 percent of their genetic material with sisters, but only 50 percent with offspring. According to Hamilton's rule, with a coefficient of relatedness this high, natural selection will strongly favor behavior that benefits sisters, even at the cost of not reproducing themselves. Adopting the gene's-eye point of view, then, should bring into focus the root of many kinds of helping behavior among non-human animals.