Evolutionary Psychology Panel at CONvergence 2013

I have not seen this, so I have not had a chance to become enraged yet. I will get back to you.

Without referring to evolutionary processes, evolved preferences, and ancestral environments, can someone please explain why, historically and cross-culturally, humans have a taste preference for food high in sugar and fat? Despite the fact that this taste preference has negative health consequences today (e.g., diabetes, cardiovascular disease, obesity), we retain this preference. We can consciously modify our behavior to avoid
food rich in sugar and fat (e.g., dieting), but we cannot modify their taste preference for sugar and fat. So again, please explain why this happens without referring to evolution.

Here's another: Without referring to evolutionary processes and ancestral environments, can someone please explain why, historically and cross-culturally, women in their first trimester of pregnancy typically experience aversions and nausea to foods that are high in teratogens? That is, many women find the sight, smell, and taste of meat and eggs perfectly fine before and after their pregnancy, but during their first trimester, their perceptions change; these things become disgusting. That perceptual shift is psychological. So again, please explain why this happens without referring to evolution.

And let me point out the obvious: Why aren't there any evolutionary psychologists on an Evolutionary Psychology panel? A first-year graduate student in evolutionary psychology could respond to all of these "criticisms."

Agoetz. Those are two great examples of evolved behaviors. The dietary drives are probably shared widely among mammals but I'd be interested to find evidence of aversions being modified in humans and derived in relation to other primates. So far I don't know of anything indicating that

Dr. Laden (or Greg?),

Thanks for your prompt reply.

Technically, those aren't evolved behaviors. No typo. They're evolved preferences. Humans do have some evolved behaviors (e.g., infants reflexes), but most of what's more likely to evolve than mechanisms to produce specific behavior are mechanisms associated with motivation, perception, and emotion. In other words, most behavioral phenomena in the world today is not necessarily generated by specific behavioral mechanisms but by motivational, perceptual, and emotional systems. (Think of a system here as a network of evolved mechanisms.) For example, Daly and Wilson (1982) documented that mothers and maternal kin attribute an infant's resemblance to the father much more often than fathers and paternal kin attribute resemblance to the father. In delivery rooms, for example, they heard new mothers (and the mother's family) tell the men "he looks just like you" or "he has your [insert trait]." This reliably documented bias to attribute resemblance to the father is not generated by a specific "attribute infant resemblance to father mechanism" as some on the panel would probably wrongly suggest. Instead, this effect is likely just an expression of women's (and maternal kin's) motivation to decrease paternity uncertainty. The neuroarchitecture is the motivational system to decrease paternity uncertainty (not any specific "recognize-infant-as-social-father" mechanism). Another manifestation of this motivational system would be women's interest in communicating to potential long-term partners that they are nothing like a hypothetical woman who cheats on guys (Dosmukhabetova & Manstead, 2011).

And needless to say, as with all science, there is good EP.and bad EP.

We behavioral biologists use the term behavior for everything..

Meanwhile, I'm the trying to remember if Margo and Martin were in the room for the birth. I think they were visiting scholars at that time so they may have been.

But I have noticed that very new babies often DO look more like their fathers. Later on, the resemblance is not so strong, and it is not always there in the first place, of course, but it happened often enough that it surprised me, because I did not expect it. I recall often thinking, "too bad, she's going to look just like her dad…".
The forager Kua with whom I did fieldwork would pass a newborn around the extended family and point out all the resemblances to various other people - they focussed on ears and eye shapes, as well as facial structure.

More seriously, what I found unfortunate about the original formulation by Tooby and Cosmides was the sort of geographic "environment" that was identified as the EEA. In fact, I consider it more fruitful to see "culture" as the real EEA, the one that exerted the most draconian selection pressure on human cognitive systems. By the emergence of Homo erectus, the rest of the body structure was already pretty functional - but the major changes appears to be happening inside heads. It appears, too, that there was some feedback toward developing a more energy efficient skeletal structure, and this really becomes apparent once this neurological adaptation to a forager culture was, well, let's not say completed, let's just say, optimized… ?

agoetz, in terms of what was discussed on the panel, do you consider your example more in line with the study Greg ran in his class or the work he talked about being done currently at UCLA and why?

Interesting panel. I admit I didn't get enraged, but then my training and interest (such as it is) is in behavioral ecology/biology. Anyway, it's true, I think, that a lot of science starts out as "male answer syndrome", and maybe EP hasn't got past that point yet. Maybe it's stuck. A lot of people (sometimes even in science) find science (or what is called "science" in the popular mind) difficult or vaguely threatening. Personally, I'm inclined to explain it by saying that we humans are hard-wired for the quick answer - we go for fast processing; for snap judgements. Prejudice; stereotypes, "thinking is hard", all that sort of thing - saves time and effort. Familiar is good; unfamiliar is bad, because we understand familiar but not unfamiliar. Easier to think up a plausible-sounding explanation and assume it's correct. Just so. Of course, when some spiders show learning and "rational" response to novel situations, and "simple" arthropods show behaviors like significant maternal care, it's hard to make a case that big brains are needed for complicated behaviors, but maybe that's just because I don't know or understand enough. The trouble with not being graded on things any more is that I generally don't bother to think about stuff I don't find engaging. Luckily, there are a few weblogs that hit me with stuff that makes me think a little in spite of my innate laziness.

Stephanie Zvan, I'm sorry, I don't know to which example of mine you're referring. My two previous posts included four specific examples. To which one are you referring?

Also, I listened to the audio of the panel over a week ago, so I don't remember what study Greg ran in his class. Please tell me at what point in the video this is mentioned. Also, I'm not sure which work you're referring to being conducted at UCLA. All work related to human behavior and evolution? All evolutionary psychology? All evolutionary anthropology? Specific studies?

Finally, before I answer your questions, I would appreciate it if you answered my original questions: Without referring to evolution, how do you explain our taste preferences for sugar and fat and how do you explain women's pregnancy sickness.

We can't have a productive discussion if we pick and choose which questions we respond to.

Thanks.

how do you explain our taste preferences for sugar and fat

I recall a very simple behavioural explanation from Colin Tudge in The Food Connection (I no longer have it so I can't check if my memory is incomplete or wrong in some other way).

The argument was that in pre-agricultural societies, very calorie dense / high nutritional value foods like fat and sugar were pretty hard to get. You either had to kill a largish animal and break open bones and skull to get at marrow and brain or you had to climb and / or fight off bees to collect honey.

The people who had the strongest drive to do such things were the ones who got the best nutrition by acquiring those foods. My feeling is that this presumes that food is only consumed by immediate family rather than more extended groups. Even then, I suppose you could argue that groups with a higher proportion of people willing to take those risks were more likely to succeed.

I suspect that the real story is more sophisticated. Maybe a social one - those who elbow their way to the fore or otherwise grab such foods before others will also succeed in some way. Or maybe rationing and distributing such foods is a strong social driver and people who supply the foods are held in high esteem / get first pick / whatever.

The real story is probably some narrative that links high nutritional value with more social value of some kind. Different groups would work this out in different ways. But all of those ways lead to a strong preference for calorie dense foods.

Given that primate diets are low in fat (but fat is good) and that plants have also evolved behaviors ... providing just enough sugar to get the primate to bite (part of seed dispersal syndromes) I would expect that these preferences evolved long before humans or any recent hominids. However, once *Homo* started with the large brain thing, preferences would possibly have been fine tuned.

Regarding the scramble for food, it is important to contrast what most primates, including chimps, do vs. what humans do, when it comes to acquiring and distributing food. We have been doing something very different for a long(ish) time. (check out an upcoming Skeptically Speaking for my comments related to that, just recorded last night.)

agoetz, that audio was impossible. I suggest you read the transcript at least to figure out what the positions of people on the panel actually are. I make that suggestion because all of your examples (I was referring to your paternity example) are answered by the panel.

agoetz: regarding your question "Without referring to evolution, how do you explain our taste preferences for sugar and fat and how do you explain women’s pregnancy sickness." I'm pretty sure that was answered. These are good examples where research has linked these things so evolutionary models. The alternative explanations might be: Evolution isn't for real, the traits don't really exist, or they are random outcomes of no consequences.

Also, people certainly can pick and chose what answers that are raised can be responded to or ignored. Otherwise, individuals can determine the validity of the conversation based on whether or not their particular questions are addressed, and since there is no a priori reason to assume that any one individuals's questions are interesting or relevant, that would be bad!

Dr. Laden, I noticed that you were careful to distinguish evolutionary psychology and behavioral biology. Both those disciplines attempt to answer questions about behavior and evolution and I guess they can be considered two different research programs with different premises, methods and so on.

According to David J. Buller's chapter in the Cambridge Companion to the Philosophy of Biology (2007), the phrase evolutionary psychology has been used to denote two different things:

- as a specific research program (i.e. the one that you are criticizing)
- as an entire field of "evolution of behavior" (including many different research programs, such as behavioral ecology, sociobiology, evolutionary psychology etc.).

How much of the criticisms against the "Laden / Zvan / PZM arguments against evo psych program" do you think stems from not understanding the difference between evolutionary psychology as a specific research program and "evolutionary psychology" as the research field regarding evolution of behavior?

i.e. could it be the case that a lot of your critics falsely assume that you are criticizing behavioral biology when you are actually criticizing the evolutionary psychology program?

Emil, good question, and you are basically correct. First, let's be clear: Evolutionary Psychology is not the correct term for the overarching study of behavior from an evolutionary perspective. That is a mistake people make a lot. Having said that, some of the negative reaction to anything I may have said about evol. psych may be a misunderstanding of that distinction. Yes, some of my "critics" seem to think I'm saying that evolutionary biology (or even evolution) is invalid, but Ive never once said anything to give that impression to anyone willing to listen to entire paragraphs!

Someone above asks "why is there not a real evolutionary psychologist on the panel." At the time of the birth of Evol Psych, I had essentially the same training and background as anyone else in the field, and for several years I regularly attended conferences, read the journals, participated in research (though it was not my main area). Today there are actually people trained as evolutionary psychology at a couple of institutions that focus heavily on this, but in the end they get their PhD in Anthropology (or something else general) just like everybody else does. There are no "board certified" evolutionary psychologists.

Stephanie Zvan, even if I were to invest another hour reading the transcript and another few hours generating a detailed response to every comment made by the panel, it would all be in vain. If my arguments were backed with rich data, I still would not convince you that most EP published in peer-reviewed journals is good science. Ed Clint did just that with Rebecca Watson (generated an excellent, detailed reply to her), and has that changed her mind about EP? No. Months ago, Rob Kurzban responded to Amanda Marcotte, but there she is, on that panel with the same complaints and misconceptions.

And to be clear, I'm not accusing just you of being entrenched. I'm accusing most of us, even myself. People committed to a particular perspective rarely change their minds. Max Planck famously said, "A scientific truth does not triumph by convincing its opponents and making them see the light, but rather because it’s opponents simply die off. Science progresses one funeral at a time."

I hope you'll understand why I'm bowing out from this discussion.

agoetz, Is there data to indicate that foods avoided during early pregnancy because of nausea have higher levels of teratogens?

There is data that indicates that high levels of nausea in early pregnancy is associated with better fetal outcomes, but that could have nothing to do with exposure to teratogens as affected by food choice. The association could be a spandrel.

http://en.wikipedia.org/wiki/Spandrel_%28biology%29

I suspect that the nausea of early pregnancy is a side effect of a high NO level (my current field of research), and that nausea is also triggered by high NO as part of what regulates sickness behaviors. During an acute infection, the NO level is made very high by iNOS and that triggers things like nausea so as to reduce digestion metabolic load on the liver.

NO has to be very high during the first trimester so as to facilitate hemoglobin production (via HIF and Epo), angiogeness for placental vascularization, and mitochondria biogenesis in the liver (to later support gluconeogenesis for lactation). I suspect that the metabolic demands during later pregnancy have increased quite fast (in evolutionary terms) so as to support a large infant brain made out of fat. The metabolic demands during the first trimester are actually quite low.

What would make the idea of first trimester nausea not a “just so” story would be actual data on teratogen content of foods eaten and avoided during pregnancy. Non-human animals should also avoid foods containing teratogens. Do they? If animals are compelled to eat foods they would otherwise reject during pregnancy do they have increased birth defects?

Many teratogens are nitric oxide synthase inhibitors (for example thalidomide).

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3447183/

As a nitric oxide synthase inhibitor, thalidomide would likely work pretty well as an anti-nausea medication. If eating something that reduces nausea actually increases birth defects, that kind of falsifies the hypothesis of nausea being something that protects against teratogens by altering food choice.

agoetz, it doesn't take an hour to read the transcript of an hour-long session. In fact, it probably takes less time to read the transcript than it took to write those four comments were missing the point of the criticisms that you could have saved yourself from making by reading the transcript.

No, Ed Clint did not give a good response to Rebecca. He produced a bunch of information orthogonal to her point and called her a science denialist. Other people gave her relevant information, and she incorporated it into subsequent deliveries of her talk.

I don't know what Rob Kurzban said to Marcotte, but given my experience reading him and your wording in presenting the information--along with the fact that you refuse to read the transcript to find out what criticisms she did make on this panel--I doubt that he said much worth reading.