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Science! Sorta!

Your Humble Blogger caught a few minutes of an On Point episode the other day, and heard a Scientist! in the context of an evolutionary sense of disgust say, and this is a direct quote, [A]ll of our emotions are there to protect us and keep us alive. I reacted strongly against this, and it occurs to me that I don’t have any actual background or knowledge to base that reaction. So I’m going to put this up to my Gentle Readers to explain this shit too me.

Here’s the thing: as I understand natural selection, it absolutely depends on the fundamental idea that people, and all animals, are different one to another. That is, because of sexual reproduction (yay! Good Idea, Divine Creator!) every generation is slightly different from the previous generation, and every individual is different from every other individual, even when those individuals have the same genetic parents, because the genes combine differently in different offspring. Almost all those differences are tiny and insignificant—an eyebrow a touch bushier, a tail a trifle straighter, a slightly different arrangement of phosphorescence. Sometimes the difference is a touch significant, because the offspring is taller or shorter, slower or faster, paler or darker, has better eyesight or sense of smell, differentiates colors better or has worse directional hearing. In fact, again because of sexual reproduction and gene mixing, and because mammals (f’r’ex) are really, really complicated animals, offspring are going to be different from their generation in a myriad of ways, although most of those differences will be tiny, subtle or even undetectable. Over time, though, those changes (mutations, really, although we usually use that word to talk about Big Changes) can make a difference. So (again, as I understand it), those incremental mutations that are helpful for keeping that individual alive to reproduce will be more likely to be passed on, and those incremental mutations that hinder are less likely. Am I right so far?

Thus, in a zillion generations, giraffes develop long necks and mottled camouflage; because the millions and millions of giraffes that had slightly shorter necks and slightly less effective camouflage had slightly fewer offspring than their longer-necked invisible buddies, and those offspring were likely to make with their surviving cousins rather than with lion’s lunch, so further mixing etcetera etcetera. Right? But it does not mean, as I understand it, that two twenty-foot giraffes can’t pass along their genetic whatnot to a giraffe that’s only a sixteen-footer, or that the sixteen-footer won’t reproduce as well (particularly if it’s a strong sixteen feet, or has some other positive trait, such as keen hearing, above-average eyesight, razor-sharp teeth, or laser farts). It does mean that the sixteen-footer with two twenty-foot parents is likelier to have an eighteen-foot offspring than a fourteen-foot offspring, thus in some sense righting the heritage, but another sixteen-footer isn’t out of the question, either. Probably the laser thing will be a recessive, too.

I guess I have two points, at this stage. First is that every individual will have differences and mutations, and that some of those mutations will be positive and some negative, and that one individual negative mutation isn’t necessarily enough to kick an individual out of the genetic ladder, even if it isn’t likely to breed true. The second is that the two giraffes are not going to generate a cow. An albino giraffe, sure. But not a cow. There’s a range of viable possibilities, and we can put some limits around them, but those limits will be fuzzy and every individual that reproduces will by virtue of its differences from every other individual that has ever reproduced change those limits a tiny bit.

I guess that’s my first tell-me-is-this-wrong question: those limits are expanded by individual differentiation through sexual reproduction, but contracted by gene-mixing back to cousins as much as by really terrible mutations being unable to reproduce (possibly because of that whole lion’s lunch thing). Right? Or not right?

Because if I’ve got that much right, and I’ll proceed as if I do, the question for evolutionary psychology (and I’m also proceeding as if evolutionary psychology has some rational, emprical, scientific basis) is whether emotional differentiation, person to person, is in that contracting bit or the expanding bit. Hm, I’ve gone off my metaphor, I suppose—the question is to what extent humans, as a species, are circumscribed in their emotional differentiation by the gene-mixing with our multi-cousins. I haven’t seen persuasive data that, over the last five hundred generations or so, the preponderance of people with substantial emotional differences from their parents have been unable to reproduce. I would say instead that emotional range is orthogonal to reproduction of the genes , so that gene-mixing would be the thing tending to narrow that range in the nth generation offspring.

So the description that our emotions are there to protect us and keep us alive seems to me to be utterly wrong—at most you could say that our emotions tend to be compatible with keeping us alive, and that the dead hand of genetics is restricting our emotions from gross experimentation. Even that I’m somewhat skeptical of. But then, as I say, I have never studied any of this stuff properly, and the little I think I know I probably amalgamated from popularizations and fiction. So I know I have a lot of stuff wrong, I just don’t know what…

Tolerabimus quod tolerare debemus,


I think what we're going for is that the emotions of our ancestors were insufficient to get them killed before they bred.

A much more negative claim about the same thing: Modern science is weakening us as a species, by allowing inferior members to survive and reproduce, when they would've been either unable to find mates, or simply died (or been killed) in previous generations. Bad eyesight, for example, as a mild disadvantage; but also a wide array of formerly-*fatal* physical disadvantages -- and even less popularly, problematic neurophysiological conditions -- are now treatable and survivable, in a way that they weren't for, say, 99.6% of the lifetime of the species (all but a thousand years out of 250,000).

That's surely a good thing on balance, as long as we can keep the science going. (And I personally think we can, so hey.)

I'm probably not knowledgeable enough to answer you even after I understand what you're asking, but give me one clarification anyway, just in case: In your "first tell-me-is-this-wrong question" you're putting the consequences of sexual reproduction on one side, and gene-mixing on the other. But aren't those just different terms for the same thing?

Hm. That is unclear. What I mean (I think) is that while every individual is guaranteed to differ from each of their parents, both of those parents are from the same species, and thus distant cousins (or closer), so there's a great deal of overlap. This is like the thing about how everybody in the world is descended from Charlemagne, or whatever the ridiculous factoid is, but the truth is that we are all multi-cousins many times over, so we are mixing each new generations mutations back into the soup of common humanity. Yes?


If I'm understanding right, then my main objection to the person's statement is about the word “all.”

Let's break down the original statement into multiple aspects:

1. did emotions evolve?

2. have (at least some) emotions kept some of our ancestors alive?

3. is keeping us alive the purpose of emotions?

4. are we talking about all emotions or only some?

Looking at each of those in turn:

1. To me, it seems likely that (at least some) emotions evolved—that is, that they derive from a physiological basis (as opposed to entirely psychological)—hormones and such—that ultimately is influenced/controlled by our genes.

2. It also seems very likely that certain emotions kept some of our ancestors alive—for example, those of our ancestors with a healthy fear of big nasty predators probably survived to breed more often than those of our ancestors who stood there saying “nope, not afraid of you” until they were eaten. (Yes, yes, too much fear is also bad, and bravery improves your chances of killing or taming the critters. But in the early days of interacting with big nasty predators, I bet fear of them was a survival trait.)

Similarly, I bet that disgust about (for example) rotten food was a survival trait.

3. So is keeping us alive the purpose of our emotions, per se? I don't think of evolution as having purposes. But if some emotions kept us alive (long enough to breed) better than others (or better than not having them), and if those emotions have a physiological basis that's influenced by genetics, then that seems close enough to a purpose for me.

4. Were all emotions survival traits? Who knows? Some of them may well have been byproducts (or byproducts of byproducts) of other survival traits (such as intelligence and social interaction).

So I suspect that all the person meant to say was that at least some emotions have been survival traits.

So I think, if I'm understanding your argument, that you may be reading more into the statement than was intended. But I don't know much of the context, so I may well just be misunderstanding.

PS: I'm guessing that your phrase “Good Idea, Divine Creator!” was intended as at least half-joking (I read it in more or less the same tone as my father used to use in saying “Good going, God!” when he saw a particularly pretty sunset); but in the context of a post where you're arguing with a scientist about evolution, I suspect it might come across to someone who doesn't know you as indicating a belief in Intelligent Design.

PPS: In my earlier comment, I certainly didn't intend to suggest that (as you put it) “evolutionary psychology has some rational, emprical, scientific basis.” Most evolutionary psychology just annoys me. If the scientist on the show had said “all men find carrots disgusting, and that's because on the savannah, our distant ancestors learned that if men ate carrots, women would find their breath disgusting and wouldn't mate with them,” then I would mock them. That's the kind of thing I usually hear evolutionary psychologists say—first, everyone has exactly the same abstract beliefs and feelings that I do, and second, therefore those beliefs and feelings must have been an advantage in mate selection among early humans, that's the only possible explanation.

But the general idea that at least some emotions may have conferred evolutionary advantages seems unexceptionable to me.

I wouldn't say that you have a lot of stuff wrong, but I think you do not yet have the right context. Much of what I would view as the significant and well grounded work in evolutionary psychology right now has to do with animal emotions, including their relationship to human (biological animals that we are) emotions, and their role in the lives (and hence, the survival and evolutionary development) of animals. What this study of animal emotions has discovered--contrary to the premises of the behaviorist view of animals as stimulus-response machines that dominated study of animal behavior through the 1970s--is that animals, including even reptiles and fish, have a considerable range of emotions. More significantly, the emotions of mammals, including humans, have a similar range and scope, derived from a strong similarity in the physiological systems related to the generation and awareness of emotion. Thus, the emotional makeup of mammals has a deep evolutionary history, and the scope and social complexity of mammalian emotions appears to a) play a highly significant role in mammal behavior and b) contribute significantly to behaviors that are advantageous to survival. Again, in general, emotions provide two major adaptive advantages. On the one hand, they provide a fast and strongly motivated response system that assists survival--the emotion of fear, for example, prompts a creature to energetically pursue survival strategies when faced with a threat: for humans, it is our emotions, not our reason, that is our first line of response to danger. On the other hand, they enable nuanced and rapid communication that enables and reinforces complex, cooperative social behavior, which also tends to assist survival. Mammals are generally very sophisticated at displaying, perceiving, and interpreting emotional signals--humans included and especially.

Thus, in the long evolutionary view, human emotions come from our mammalian heritage and that set of emotions can be demonstrated, through the study of animal behavior in an evolutionary framework, to be adaptively advantageous. That is, I infer, what this scientist was likely referring to when ta stated: "All of our emotions are there to protect us and keep us alive." In a broader evolutionary context, I would accept that statement as reasonably accurate. It means that our emotions, at base, are generally good for us and useful to us: they are part of the set of resources that our species and our larger families of mammals and animals more generally have developed to assist us in the project of living. In stating it that way, I am deliberately trying to steer away from the negative claim that one might hear implicitly in "All of our emotions are there to protect us and keep us alive," which might be something like "the only thing that our emotions are there for is to protect us and keep us alive." That claim is by no means implied by the fact that emotions are evolutionarily adaptive. It is not, indeed, a scientific claim.

My knowledge of this subject, such as it is, comes from studying the applications of cognitive science, which is increasingly concerned with the role of emotion in cognition, to literary studies, and from there to studying writing that explores human relationships with animals. If you want to get a deeper but accessible view of this topic, I'd recommend Marc Bekoff's The Emotional Lives of Animals. Here's his introductory comment on evolution and emotion:

"Charles Darwin's well-accepted ideas about evolutionary continuity, that differences among species are differences in degree rather than kind, argue strongly for the presence of animal emotions, empathy, and moral behavior. In practice, continuity allows us to 'connect the evolutionary dots' among different species to highlight similarities in evolved traits, including individual feelings and passions. What we have since learned about animal emotions and empathy fits well with what we know about the lifestyle of different species--how complex their social interactions and social networks are. Emotions, empathy, and knowing right from wrong are keys to survival, without which animals--both human and nonhuman--would perish. That's how important they are."

Note that this is a general statement about the observable role of emotions in behavior, not a claim that every emotion that every individual creature feels or acts upon is conduces to protect or sustain the life of that creature. Humans have an adaptive advantage because our reasoning faculty and our consciousness enable us to modify or override our emotional impulses to a great degree. But the general apparatus of our emotions and the each type of emotion produced by that apparatus (like disgust--the type of feeling that we describe as disgust and study through the identification of consistent expressive or neurological phenomena) has developed in keeping with evolutionary processes of natural selection for adaptive advantage. That's the claim.

Hmm, thanks for your clarification, though I'm not really sure how to think about these "limits" of potential variation, at least not in any way that lets me think of the creation of any individual's roll-of-the-dice genome as changing those limits. I suppose in the sense that I might roll unusually many sixes, and hence increase the chances that my own offspring will roll even more sixes [note: I think my metaphor is not only strained but silly] it can act to expand limits. And I guess the "contactive" part of your argument is just another way of describing regression to the mean, so I suppose I'd agree with you. But I recognize I'm not very genetics savvy.

I also wanted to point out that it's not true that all human genes get around -- that's been happening more and more over the past twenty generations as travel becomes easier, but for a far longer time we've been relatively isolated, and subpopulations can of course evolve in separate ways.

In general I find the statement "humans have X, therefore X is evolutionarily superior" to be facile. There are other reasons, from random chance to X being linked to some other actually-reproductively-superior trait, that should be considered. For instance, I'm not convinced that having 5 toes offers enough of an advantage over 6 or 4 to explain our pentatoenicity entirely by reproductive fitness...

Re iriyth's example above is not framed accurately in terms of evolution. Modern science isn't "weakening" us as a species. Rather, it is changing the conditions of the environment whose pressures produce natural selection. Since the environment provides external fixes for problems like nearsightedness and neurological disorders (even, perhaps, as that environment makes such problems more common), there is no longer negative selection associated with those problems, any more than deep-sea fish species experience negative selection for being unable to breathe air. When the environment changes, the environmental pressures that produce natural selection will also change. The number of physically weaker individuals in the human population may be increasing but that is irrelevant to the fitness of the species as a whole to its environment. If high-technology civilization were to collapse, our environment would change dramatically, and the fitness of each individual person to the environment would be tested in new ways.

I am persuaded by Chris that the Scientist! had in mind something like human emotions come from our mammalian heritage and … [is] adaptively advantageous. Which I am willing to accept, I guess. I did in fact interpret it as closer to there cannot exist any human emotion that doesn't serve a protective function, and that protective function is the true reason for that emotion, and while I didn't really think that the Scientist! believed that, it did seem to be what was going in on the conversation.

Also: Jed, I see your point about my reference to the Divine. So, in case anybody wanders by here, my belief in a Divine Creator should not be taken to interfere with natural selection in any way, nor do I consider even my favorite bits of the Divine Creation to be in any way a proof of the existence of a Divine Creator. In other words, Intelligent Design is pretty much horseshit.

I think that Jim's toes are getting at one of my concerns, but… I'm trying to come up with an analogy to being born with 4 or 6 toes (on one foot), which is evolutionarily possible and not obviously detrimental, but doesn't seem to breed true. Similarly, it seems as if the variation in emotion may somehow not breed true, so that humans tend to regress, as you put it, to the mean. People are physically different one to another, but most of us continue to have ten fingers and ten toes; people are emotionally different one to another, but most of us continue to have an emotional palette of fear, disgust, empathy, delight, lust, sadness, curiosity, gratitude, hate, affection, bliss, guilt, pride, glee, and so on.


Chris: Good point. The idea that having bad eyesight makes us "weaker" assumes some sort of objective context that we can be judged by; it actually makes more sense to judge us by the context (environment) we're in.

To put the fish example the other way, it didn't make us any weaker as a species when we lost the ability to breathe water -- unless you think that being able to survive underwater was somehow more important than being able to survive on land.

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