The keynote address will be given by Paul Bloom (Yale), author of How Pleasure Works: The New Science of Why We Like What We Like.

On the joint day between the Animal Behavior Society and the Human Behavior and Evolution Society, there will be two featured speakers:

• William Rice, University of California, Santa Barbara

• Mary Jane West-Eberhard, Smithsonian Tropical Research Institute, Universidad de Costa Rica

The Plenary Speakers have also been announced.

• Clark Barrett, Department of Anthropology, University of California at Los Angeles

Barrett does research on cognitive development both in U.S populations and among the Shuar of Ecuador. He currently coordinates the AHRC Culture and the Mind Project.

• Laura Glynn, Department of Psychiatry and Human Behavior, University of California at Irvine

Glynn describes her interests as focusing on “biological and psychosocial effects during pregnancy and subsequent outcomes.”

• Brian Hare, Department of Evolutionary Anthropology, Duke University

Brian Hare is among the growing list of scholars who study animals whose names are also animals. He heads the Hominoid Psychology Research Group, investigating problem-solving abilities, including in dogs, one of which is pictured here.

• Karen Kramer, Department of Human Evolutionary Biology, Harvard University

Karen Kramer describes the key question that animates her research as “how did there get to be so many of us?” She studies human population growth, drawing on data from extant traditional populations.

• Karen Wynn, Department of Psychology, Yale University

Karen Wynn is the directly of the Infant Cognition Center. She studies, among other topics, the development of numerical competence in infants.

Robert Kurzban was upset by my critique of science journalism and evolutionary psychology [Evolutionary Psychology Crap in New Scientist]. You might recall that my criticism is based on many common features of evolutionary psychology but the most important are the unwarranted assumptions that: (1) a particular specific behavior has a strong genetic component. (2) that the behavior is adaptive, and (3) that we know how our ancestors behaved.

Remarks in the comments were salty. From his reading of my web site, for instance, he draws the inference that I am not a genuine scientist, but he helpfully tells me how I could become one, which it turns out has to do with picking the right collaborators, writing:

… evolutionary psychologists seem to avoid doing real science. They prefer to just assume that their model is correct and look for good stories to “confirm ” it.

Robert Kurzban’s website is a good example of that. A scientist would write ….

We are interested in testing whether certain human behaviors have a strong genetic component and, if so, whether the behavior is adaptive. If the answers to those question are “yes” then we’d like to do some work to find out when such traits might have evolved. 

We are collaborating with geneticists to identify potential adaptive behavior alleles and to see if there’s any evidence of a selective sweep of the corresponding region of the genome.

With that as background, my interest is that at the time I read Moran’s post, I recall being struck by his claims about the three assumptions that characterize the field. Not only were they wrong, but they were wrong in such a basic way that it seemed  to me that he probably hadn’t read anything at all about the field.

This semester I am teaching Psychology 272, Evolutionary Psychology, to about 100 University of Pennsylvania undergraduates. Their first exam was last week, so I thought I would put my guess to the test, presenting Moran’s assumptions as the topic of an essay question.

I had to edit slightly, but I preserved his actual words as well as I could. Here is the essay question as my students saw it on the exam:

Recently, someone writing about evolutionary psychology wrote that the field makes a set of assumptions. In particular, the writer claimed that evolutionary psychologists who are studying a particular behavior assume that (1) the behavior “has a strong genetic component,” (2) the behavior “is adaptive,” and (3) we know how our ancestors behaved.

For TWO of the three assumptions above (5 points for each), based on your readings and the material presented in lecture, indicate whether or not each of the three assumptions is indeed made by evolutionary psychologists. If the assumption is correct, provide a justification for the assumption. If it is not, explain why it is wrong and how you would change the assumption to make it correct.

My interest was in measuring how much instruction someone would need to be able to identify (and therefore not make) the errors in Moran’s post. At the time of the exam, my students had had 8 lectures of 1 hour and 20 minutes, or about 11 hours total. (I put the readings that were assigned at the end of this post.) This is an undergraduate class, with Sophomores, Juniors, and Seniors. The only prerequisite is introductory psychology.

Before I give the results, I want to be clear that my argument here isn’t about whether the assumptions are themselves correct; my interest is in what evolutionary psychology as a field assumes. How much time and effort would it take to learn enough about the field to avoid making the mistakes that Moran makes, even if it turns out that the assumptions themselves are problematic?

Here are the data. The results were that 53 of 76, or 70% answers to assumption (1) indicated that the assumption was false. For the second and third assumptions these numbers were 30 of 40 (74%) and 33 of 41 (82%). To summarize, a clear majority of my students, with four weeks of instruction in my undergraduate course, were able to recognize that Moran’s claims about what evolutionary psychology assumes were wrong.

These values actually underestimate a little bit. In the case of the first assumption, many students who said that the assumption was right reinterpreted the statement to make it more reasonable, emphasizing that all traits are jointly caused by genes interacting with the environment. (This is not to say that some students did not get it wrong, just that 70% doesn’t properly capture the fraction that got it right.) Also, I want to sound a note of thanks to Jennifer DeSantis, my superlative TA, who, I should say, actually did all the heavy lifting on the grading of the essays.

To give a sense of what they said, here are some excerpts from their essays. (I received permission to post from the authors of the answers.)

On the first assumption, Kathryn Raynor writes: “When studying a particular behavior, evolutionary psychologists do not make the assumption that the behavior has a strong genetic component. This would be an example of the gene vs. environment [dichotomy] that evolutionary psychologists try to avoid. The notion of genes vs. environment is a bad dichotomy because each heavily influences the other. An organism’s behavior results from the complex interplay between genes and environment…”

On the second assumption, that behavior is “adaptive,” Kathryn Raynor, again, writes: “Evolutionary psychologists also do not [her underline] automatically make the assumption that a particular behavior is adaptive. This  is a very strong claim; in order to assert that some behavior is adaptive, there must be evidence that the behavior serves a function, that is, it solves an adaptive problem, AND that it is specialized or well-designed to perform that function….” Laura Micu similarly penned: “Evolutionary psychologists don’t assume that a behavior is an adaptation, they study it to find out whether it is an adaptation, a by-product or a ‘cheap’ left-over…”

Finally, on the third assumption, Laura Micu, again, writes “…we don’t know, or are able to say for sure, what our ancestors’ behavior might have been. We can only speculate given historical and present-day social observations, as well as observations of animals that are closely related to us…” Similarly, Geoffrey Bass writes: “The above assumption is incorrect. It would be absurd to assume that we could determine with a great deal of accuracy how our prehistorical ancestors actually behaved, and evolutionary psychologists make no such claim. They are interested,  to some extent, in the origin and development of adaptive behaviors… it requires that we can identify or speculate about specific challenges our ancestors might have faced…”

Again, I want to be clear that the issue for this purpose is not whether the assumptions are good ones. Perhaps there is a logical flaw in the adaptationist analysis that I asked my students to entertain. Perhaps we can know for sure what our ancestors did. What I’m saying is that my students, by and large, correctly identified the assumptions of the discipline, a feat that Moran was unable to accomplish.

The broader point is that Moran is only one instance of a larger phenomenon, and critics of evolutionary psychology frequently demonstrate innocence of the field’s basic assumptions and theoretical commitments. As I’ve said in the past, an interesting question is why critics feel comfortable voicing such strong objections to the field, given their lack of background, even to the point, as in this case, of accusations of the discipline not being a science. I don’t pretend to understand the motives, but it’s an area that merits closer study. I’m afraid that we can be confident that there will be plenty of additional data along the same lines from our voluble critics of evolutionary psychology.

Required Reading for Psychology 272, through Week 4

Cartwright (2008), pp. 1-91, 145-170, 191-228, Dawkins (2006), pp. 1-165; Miller (2007); Kurzban, 2010, Chapter 2; Tooby & Cosmides (2005)

Cartwright, J. (2008). Evolution and Human Behavior: Darwinian perspectives on human nature (2^nd ed.).Cambridge,MA: MIT Press.

Dawkins, R. (2006). The Selfish Gene: 30th Anniversary Edition. Oxford: Oxford University Press.

Kurzban, R. (2010). Why everyone (else) is a hypocrite: Evolution and the modular mind. Princeton, NJ: Princeton University Press.

Miller, G. F. (2007). Sexual selection for moral virtues. Quarterly Review of Biology, 82(2), 97-125.

Tooby, J. & Cosmides, L. (2005). Conceptual foundations of evolutionary psychology. In D. M. Buss (Ed.), The Handbook of Evolutionary Psychology (pp. 5-67). Hoboken, NJ: Wiley.

Abstracts for the HBES conference are due March 16th, and will be submitted through the web site.

There are two awards for which nominations can now be submitted, the Early Career Award and the Lifetime Achievement Award. Here are the announcements for each:

The HBES Early Career Award for Distinguished Scientific Contribution recognizes excellent young scientists who have made distinguished theoretical and/or empirical contributions to the study of evolution and human behavior. The nomination letter should include the following information:

•   What are the general themes of the nominee’s major lines of research?
•   What are the important research findings discovered by the nominee?
•   To what extent have the nominee’s contributions generated research in the field?

Nominations for the HBES Early Career Award should include a statement about the worthiness of the nominee, curriculum vitae of the nominee, a recent complete bibliography, and no more than five reprints representative of the nominee’s contributions. The awards are subject to the following limitation: The nominee must be no more than 10 years post-Ph.D. Deadline for nomination: March 31, 2012. Please send nominations directly to: catherine_salmon@redlands.edu

The Committee for the HBES Lifetime Career Award for Distinguished Scientific Contribution is now collecting nominations. The HBES Lifetime Career Award for Distinguished Scientific Contribution is presented to candidates who have made distinguished theoretical or empirical contributions to basic research in evolution and human behavior. For these awards, nominators should include in the letter of nomination a statement addressing the following questions:
• What are the general themes of the nominee’s major lines of research?
• What are the important research findings usually attributed to the nominee?
• To what extent have the nominee’s contributions generated research in the field?
• What has been the significant and enduring influence of the nominee’s research?
• What historical contribution has the nominee’s research made to the field?
• Compare the nominee with others in her/his field.
• What influence has the nominee had on students and others in the same field of study?
• Where possible, please identify the nominee’s students by name.

Nominations for these awards should include a letter of nomination, a curriculum vitae, a recent complete bibliography, up to five representative reprints and the names and addresses of several scientists familiar with the nominee’s work. Deadline for nomination: March 31,2012. Send nominations directly to:  sarahhrdy@citrona.com

Discussion

Never mind.

Anyway, there has been tremendous discussion recently of the resource model of self-control, which I’ve discussed (here, here, and here) in the past, including a book (Willpower) by Roy Baumeister and John Tierney – not to mention a recent (Feb 1) piece (subscription) in New Scientist – as well as a tremendously large scientific literature drawing on these ideas. I won’t go through the model in detail; the gist is that there is a mysterious resource that you need to exert self-control, and that this mysterious resource isn’t mysterious at all, but it’s actually glucose. You need glucose in your blood to feed your brain to be able to exert self-control and, when you do exert self-control, you burn glucose, which in turn makes it harder to exert self-control in the future. This explains why you can’t solve word puzzles after you don’t eat cookies, or something like that.

I have an interest in this model, having published on it both in the pages of the online journal that hosts this blog as well as in my book, voicing, in both places, a somewhat, let us say, skeptical view of the idea. The basic problems are these: 1) it’s metabolically implausible, 2) the data in the key paper purporting to support the idea don’t, actually, support the idea, and 3) it isn’t even the right sort of explanation for how the mind works, akin to thinking that the reason that a web page is loading slowly is because your laptop battery is only at 80%.

Having said all that, there is a related phenomenon that seems to be genuine: people behave differently when they’ve ingested calories recently as opposed to when they haven’t. Less hungry organisms might be more patient, less punitive, and better able to concentrate on a task before them, for instance. This should seem intuitive to all of us who get really grouchy when we haven’t eaten in a while (as in the hungry people in commercials from the clever series of Snickers ads) and makes a lot of sense from the standpoint of thinking about how to design an organism that has many possible priorities. Hungry organisms should be expect to behave differently from full ones, generally shifting their attention and energy toward getting food, to the exclusion of other priorities.

Anyway, a new paper by Molden et al. to appear in Psychological Science, “The Motivational versus Metabolic Effects of Carbohydrates on Self-Control,” reports four experiments that put these ideas to the test.

In the first study, the authors wanted to address a shortcoming of prior work by using very accurate tools to measure glucose. Subjects fasted for 4 hours, had their blood glucose measured, performed a self-control task frequently used in this literature, and then had their blood glucose measured again. For the glucose model of self-control to be correct, the readings must be lower after the task than before. Not only did glucose not go down, but it went up (from 81.27 mg/dL to 82.39 mg/dL), though not statistically significantly.

To connect this back to the key paper in this literature (cited 287 times, as of this writing), in that paper (Gailliot et al., 2007), across four studies reported (for subjects who did not fast), glucose also went up about 1 mg/dL. So that’s consistent with the prior results. It contrasts, however, with the report from that same paper of a drop of 5.88 mg/dL, results from subjects who had fasted. This implies that there was indeed a problem with the measurement in that study, or there was some other problem with the data.

In a second experiment, the authors drew on some studies from the exercise literature that I pointed out in the paper in Evolutionary Psychology. In this work, it was found that merely rinsing with sugar solutions increases performance on physical activity (e.g., bicycling), suggesting that increased performance on cognitive tasks might be due to the sensation of reward when one drinks a beverage with carbohydrates in it, rather than willpower fuel.

Molden et al used a similar procedure, having people complete a self-control task and then swish – but not swallow – solution with sugar or a non-sugar sweetener. Briefly, they found that swishing the glucose solution – but not the sweetener – yielded effects frequently seen in this literature, suggesting that, just as in the exercise case, it’s the reward, not the glucose itself, that’s affecting behavior. A third study replicated the second; the last study showed that swishing with the sugary solution doesn’t give rise to more glucose in the blood.

In sum, these data, as well as other sets of results, clearly show that exerting self-control does not, in fact, reduce glucose, a finding which is not surprising, given that it is consistent with what is known about brain metabolism. The results that apparently contradict this result, those reported by Gailliot et al (Study 1), might very well, it seems, be due to error in the measurement device, or some other factor.

The findings that exerting self-control doesn’t reduce blood glucose critically undermines the larger model, which turns on the idea that whatever the resource is, performing self-control task uses it up. If self-control tasks do not reduce blood glucose, then the reason for subsequent drops in self-control tasks can’t possibly be due to a drop in glucose.

As for other results showing that drinking a sugary beverage changes behavior – making one more patient or less punitive – these can be understood as a phenomenon similar to what one observes in the exercise literature. Quoting myself quoting others:

[Chambers et al., 2009] conclude that “improvement in exercise performance that is observed when carbohydrate is present in the mouth may be due to the activation of brain regions believed to be involved in reward…” (p. 1779). Carter, Jeukendrup, and Jones (2004) showed a similar result, concluding that “the mechanism responsible for the improvement in high-intensity exercise performance with exogenous carbohydrate appears to involve an increase in central drive or motivation rather than having any metabolic cause” (p. 2107).

So, anyway, to return to the running joke I mentioned at the top of this entry… about that whole, “glucose is willpower fuel” thing… never mind…

References

Carter J. M., Jeukendrup A. E., and Jones D. A. (2004). The effect of carbohydrate mouth rinse on 1-h cycle time trial performance. Medicine and Science in Sports and Exercise, 36, 2107–2111.

Chambers, E. S., Bridge, M. W., and Jones, D. A. (2009). Carbohydrate sensing in the human mouth: Effects on exercise performance and brain activity. Journal of Physiology, 587, 1779-1794.

Gailliot, M. T., Baumeister, R. F., DeWall, C. N., Maner, J. K., Plant, E. A., Tice, D. M., Brewer, L. E., and Schmeichel, B. J. (2007). Self-control relies on glucose as a limited energy source: Willpower is more than a metaphor. Journal of Personality and Social Psychology, 92, 325-336.

Molden, D. C., Hui, C. M., Scholer, A. A., Meier, B. P., Noreen, E. E., D’Agostino, P. R., & Martin, V. (in press).  The Motivational versus Metabolic Effects of Carbohydrates on Self-Control. Psychological Science.

I’m not going to dwell on these points, and I don’t pretend to know what price Elsevier ought to be charging for its products or what units they should be selling them in. However, given the controversy emerging surrounding the boycott of Elsevier journals, I thought it appropriate to make some remarks and explain my position.

As a co-Editor-in-Chief of E&HB, I might be expected to be biased, and so probably I am. Having said that, I don’t consider myself to be an apologist for Elsevier, and while I am hoping that members of the evolutionary psychology community do not join the boycott, this is not due to any love for Elsevier or concern for their bottom line. (Disclosure: I do get a modest stipend for my editorial duties. By my last calculation, it comes out to less than about $9/hr.)

A tiny bit of history. Michael McGuire founded the journal in 1980, then titled Ethology & Sociobiology. The title was changed with the ascent of Martin Daly and Margo Wilson as co-editors. As with most new journals, impact was initially modest and submissions few. In 1996, the journal was receiving about 70 manuscripts per year. That number more than quadrupled to about 300 in 2011, and the impact factor currently stands at 3.6, up from 2.6 in 2008, helped, I believe, by the general improvement of scholarship in the area in general, but also by the hard work of Ruth Mace, Dan Fessler, Martie Haselton, and Steve Gaulin, who have served the journal as editors over the last decade as editors.

Like many other people, I do find it odd that we find ourselves in a situation in which authors are giving away content and reviewers are giving away time, both of which are then sold at a profit by the publisher, whether it is Elsevier or one of its competitors. This model made a certain amount of sense when publishers produced a service for which they had a comparative advantage, organizing the publication process, printing and distributing journals, and so on. Certainly, in the present technological environment, it makes sense to think about the logic of the model.

These points have been discussed in a number of forums, in other discussions about this topic, including on the AEPS group on facebook, and in this discussion and elsewhere the conversations have frequently given rise to two questions. First, why do people publish in Elsevier journals, and, second, why doesn’t someone generate alternatives?

The second question is easy to answer: they have. This blog is associated with an open-access journal that publishes in the same area as E&HB, and is run frugally by the editors, indeed frugally enough that authors aren’t charged to publish here. There is also Frontiers in Evolution Psychology, which I currently head, though we get almost no submissions, possibly because, unlike Evolutionary Psychology, there are fees to publish. And of course there are other journals as well, such as Human Nature, and so on.

This then makes the first question all the more puzzling;  why publish in E&HB, particularly given the open source alternatives? My guess is that the answer is that publishing work in E&HB is valued because it is the official journal of the Human Behavior and Evolution Society, and is widely read by people both inside and outside the field. For scholars who wish to promote their ideas, E&HB is an excellent option. In addition, and perhaps the more important reason for many, the fact of the matter is that Chairs, Deans, and personnel committees look at the impact factor of journals in which faculty place articles. For better or worse, scholars’ livelihood depends in no small part on placing their work in high impact journals. Newer journals tend to have less cachet and lower impact, which discourages some from submitting as a matter of professional strategy, which in turn makes starting new outlets difficult. None of this, I think, is likely to change significantly any time soon, though of course some newer journals do indeed bend upward with some speed.

So, with that as background, here is my view on the boycott. For me, the central issue should be about how we can produce the best scientific papers that reach the broadest audience. Whatever we do should, in my opinion, be in the service of this goal. I say this in part because it seems to me that the goal should not have to do with indulging jealousy. I would rather reach more people with Elsevier making more money than reach fewer people while reducing Elsevier’s profit margins. My business is in communicating scholarship; their business is, well, business. Yes, to the extent that their pursuing their goals interferes with mine, then, sure, we have conflicts to resolve. But my goals have to do with the communication of ideas, not the eroding of margins of our friends in the Netherlands.

Next, I do think it’s important to keep things in perspective. As of this writing, the drop-down menu on the petition web site indicates 80 people in the “Psychology” category as having joined. This is a tiny fraction of scholars in the field. If more scholars sign up, what will the impact be? Holding aside the symbolic value, I take it that the intended impact of the boycott will be that Elsevier journals such as E&HB will get fewer submissions, and the ones that we do get will get inferior vetting by the scholarly community, eventually leading to a decline in the quality of the journal. Will this ultimately harm Elsevier’s bottom line by forcing them to charge less because the quality of their product has gone down? Will they lose market share? Maybe. Certainly while this process is ongoing, the quality of papers could indeed be compromised. For obvious reasons, I would resist this outcome, and so I oppose the boycott as a means to achieve the particular end I have in mind.

Are there other routes to reform? In my view, HBES should work over the next year to consider alternatives to the existing contract. To this end, I will propose to the Executive Council at the HBES annual meeting this year that the Society appoint a committee to investigate alternatives to the present arrangement, and produce one or more concrete proposals. It seems to me that one possibility is going with another academic publisher, such as Wiley or SAGE, though of course many will view this as no better than the current state. Another option would be to try to develop a means of doing without a publisher entirely. I myself don’t know what this sort of option looks like, particularly if we want to continue to have a hard copy of the journal published, but these are the sorts of issues that a committee might look into. (Views differ on the value of having a paper journal. Are there places that we hope to reach that don’t have access to electronic resources that we take for granted? I don’t know the answer to that question.)

In short, I don’t care very much about Elsevier’s profit margins per se. I do care about making papers in our discipline – and other disciplines, for that matter – as good as they can be, and spreading ideas as broadly as possible. Elsevier does do something to advance this goal, including structuring the process of manuscript evaluation and disseminating the journal in print and on the web. Still, the US$31.50 price tag on a single article, or US$477 for a subscription does seem steep, though it’s worth noting that anyone joining HBES gets the journal and pays only a small fraction of that amount. (By the way, my understanding from Elsevier’s statement of policy on preprints, which I grant might be mistaken, is that Elsevier allows authors to post a version of their paper to their own web site, with the caveat that it can’t be the .pdf of the final, published paper itself. So if the issue is getting ideas out, for free, I think, but am not sure, that we as authors can do this. Someone feel free to correct me if I’m wrong about this.)

Can we do better than the present arrangement? It seems like a possibility. Still, having said that, my view, for what it’s worth, is that refusing to submit to the journal and referee for the journal is not a constructive way to proceed. Evolution and Human Behavior is the official journal of HBES, and its current status is due to efforts of people like Margo Wilson, Martin Daly, and the dedicated authors and reviewers who have contributed over the years. It is not perfect, and of course authors, reviewers, and editors have made mistakes along the way. No doubt they will continue to do so, regardless of the means by which articles are published. My view is that we should be working to make our journal, the Society’s journal, as good as it can be, scientifically, while simultaneously working to increase its impact. If there are viable ways to preserve the journal while at the same time reducing the price, then we should work as a community to find those ways. I, for one, welcome any ideas, and any help, in the service of reaching this goal.

I, unfortunately, was unable to go, which is really too bad, since there is no zoo I like better than San Diego’s. So, I can’t give you a first hand report, though I welcome any comments from those who could attend.

Still, I’m very interested in what people who present at SPSP are discussing. I think of SPSP – perhaps unfairly – as the community of researchers who study human social behavior typically, but not always, without any emphasis on evolution. (Note that there as been an evolutionary pre-conference every year since 2003, however.) I think that SPSP gives a window on what you look at if you’re not guided by the sorts of theories that evolutionary psychologists are guided by.

To have a look at this, I took the text from the SPSP program and fed it into a word frequency count program. It’s not a perfect assay for a number of reasons, but I thought this might help to give a sense of what this community is focusing on.

The first bunch of words in the list consists of the predictable articles and conjunctions, and I’ll just ignore stuff like that. Other than “university” (3,497), the first content word to come up is, again unsurprisingly, “social” (1,656), which maybe doesn’t count because it’s a social psychology conference, after all (though “personality” is only 674). The first real content word that comes up is… “self,” with 1,363 occurrences. The word appears in places such as Symposia titles, as in “Threat’s Effect On The Self And How The Self Fights Back,” in theories, such as “self-regulation,” and in the methodological context, as in “self-report.” “Psychology” and “relationship” come in 575 and 561, the latter because it’s used not just in the sense of “romantic relationship” but also as in “the relationship between the variables.” The plural, “relationships,” comes in at 309.

“Negative” (461) edges out “positive” (440), but “over” (189) comes in over “under” (104).

“Moral” (292) is arguably the highest frequency content word that doesn’t have the sort of problems that “relationship” and “control” have, and I confess the popularity of moral, morality, immoral and immorality make me feel a bit like I’m on the bandwagon, given this is one area I’ve been looking at. Just below “moral” comes prejudice (288), with the word “implicit” (282) shortly thereafter. “Emotion” and “emotional” (277, 280) follow close behind, with “affect” (256) in the mix, though of course the term has multiple common meanings.

Between 300 and 200, here is another set of words that I thought were interesting.

269      identity
266      perceptions
255      threat
249      power
236      emotions
235      goals
233      health
232      partner
230      sexual
227      sails
212      esteem
206      bias

The word “Sails” confused me, until I saw that it was the name of one of the rooms in which presentations took place. Between 200 and 100, again using the technique of Words That Seem Interesting To Me In This Context:

199      cultural
197      romantic
194      cognitive
193      status
189      motivation
183      intergroup
179      sex
179      racial
161      attachment
160      stereotype
150      judgments
146      race
146      interpersonal
128      regulation
127      risk
121      political
120      strategies
119      jennifer
119      discrimination
119      david
118      stress
117      identification
117      anxiety
115      ingroup
113      couples
113      aggression
109      attitude
105      trust
103      science
103      love
102      neural

And then below there you have the also-rans. “Facebook” made a surprisingly strong appearance, with 51 occurrences. “Happiness” and “friends” had a satisfying tie at 76 each. Michigan had the honor of being the most frequent state (Go Blue), excepting the host, befitting the state’s role in social psychology.

Oh, and evolution-related terms (evolutionary, evolved, evolution, evolutionary) came in at 30, 15, 11, and 4, respectively the same amounts as Purdue, embodiment, blue, and… seldom.

A recent paper by Hansen et al. in Proceedings of the Royal Society – B investigates one putative function of the pattern of white triangles visible on the petals of Lapeirousia oreogena (see image), a member of the genus iris. One proposal is that these markings function in much the same way as landing lights on a runway – or signposts, to use the authors’ favored analogy. Below the petals of this flower is a long tube, with nectar in a little pool at the bottom. Insects have specialized structures – a long proboscis – designed to reach the nectar, extracting it from the flower. When the insect is positioned properly to do this, it simultaneously – and not coincidentally – is positioned such that it rubs up against the anther and stigma, picking up and/or depositing pollen. In this way, the flower uses the insect for fertilization, providing nectar as the incentive.

The insect must be positioned just so. Hansen et al proposed that the white markings in the iris they chose were “nectar guides,” aiding the pollinating insect so that it could insert its appendage properly into the iris’ long tube.

To explore this possibility, Hansen et al. conducted an experiment in a natural environment — literally a field study –  in a wildlife preserve in South Africa.

Their manipulation was clever but simple. They used a black marker to cover none, some, or all of the white triangles on the flowers. To control to ensure that it was the lack of markings – rather than being written on with a marker – they also applied ink to the control flowers, but over the already-black portions rather than the white triangles.

Lapeirousia oreogena (Photo: Tim Waters)

One dependent variable was the behavior of the flies. They monitored their test subjects for two and a half hours during the day, counting how many fly approaches there were, also counting decisions insects made when faced with flowers with different numbers of intact markings. In addition, the authors applied fluorescent powder to the flowers’ anthers, and then surveyed the area after dark with an ultraviolet lamp, which allowed them to check for the dispersal of the powder. Finally, they looked at the fruiting behavior of plants with and without the modifications made to the white triangles, counting the number of viable seeds.

Changing the markings did not seem to influence fly approaches; there was no difference in the number of approaches for flowers whose triangles had been blotted out compared to those that weren’t. However, whether or not the insect inserted its proboscis in the tube successfully did depend on the manipulation. While nearly all of the insects on the unmodified flowers probed successfully, fewer than 10% of the insects alighting on the flowers without markings did so. Similar results obtained for the other measures. The authors write: “Only one out of 20 flowers without arrow-markings exported dye grains, to only one neighbouring flower, whereas 11 out of 21 flowers with arrow-markings exported dye grains.” From these and other results, the authors conclude:

Our results clearly demonstrate the importance of the white arrow-markings on L. oreogena flowers for proboscis insertion by their pollinator. These arrow-markings could thus be considered to be functional nectar guides ‘sensu stricto’—i.e. visual markings on tepals of nectariferous flowers that guide flower visitors towards a concealed nectar reward… our results provide clear evidence of a strong causal link between presence of nectar guides and both male and female components of plant fitness in a natural system.

Roughly, insects seem to use the white triangles as local guides for their proboscis, rather than as a global cue to the flower, more like runway lights – which is used by pilots on final approach – rather than as a beacon getting the pilot to the airport itself.

This paper is not obviously about evolutionary psychology. I’m writing about it for a couple reasons. First, it’s cool. I think it’s pretty neat that patterns on flowers serve a nose-guiding function for insects with long proboscises. Second, I think it’s important to continually examine the standards of evidence used to evaluate functional claims by those who study species other than our own. From this study, it’s clear that the researchers think that behavioral experiments (well, the behavior of another organism, really) are relevant to evaluating a candidate functional explanation. Generally, I think it’s worth monitoring in the primary literature how claims about function – in this case about increasing pollen uptake through proboscis-guiding – are tested by researchers in the biological community. In this case, it’s through behavioral experiments, using dependent measures that are plausible proxies for fitness. That seems perfectly reasonable…

Citation

Hansen, D. M., Van der Niet, T., & Johnson, S. D. (2012). Floral signposts: testing the significance of visual ‘nectar guides’ for pollinator behaviour and plant fitness. Proc Roy Soc B, 279, 634-639.

In the studies reported, subjects faced one of four tasks. For instance, in the “foraging task,” subjects had to forage for apples, picking one of two possible sites about which they had information; their task (presented by computer) was to pick the one that had the larger expected value of apples in it. Information about the right answer could come from one of two sources, either in the form of 1) a number of presentations of draws from each site’s distribution, or from 2) information about which of the two sites other people had chosen, with the former constituting the “social learning” choice. (You can think of this as choosing to go fishing in a pond based on how often you catch fish there, or basing your choice on which ponds other people choose to fish at.) Other tasks were a mental rotation task, a length-estimation task, and an auditory pitch discrimination task.

Their particular interest was in the factors that influenced when people used social information, such as how many other people chose a particular option, the degree of consensus in others’ observed choices, how hard the task was, and so on. So, for example, in, say, the foraging task, subjects might be provided information that five other subjects had chosen patch A over patch B, whereas three subjects had made the reverse choice. How does the information about others choices influence individuals’ choices?

Summarizing, the pattern of data suggest (roughly) the following: in these tasks, people are more likely to use social information when making a choice as the number of social models increases, as the consensus of the models they observe goes up, when individual learning is costly, when the models observed are doing particularly well, and when the subject’s own confidence in their answer goes down. These sorts of effects are predicted by various models that are likely to be familiar to readers of this blog.

(As a side note, to return to the Dennett quote from last time, my guess is that this work won’t be attacked as unscientific, post-hoc or storytelling because the ideas at stake here, having to do with social learning, don’t have the same political heat as issues other research programs have. “The evolutionary basis of human social learning” is a title that won’t raise hackles. But if one were to change the last two words – “conflict,” “aggression,” “sex differences” – well, that might change things…)

(A second side note, this time on terminology. A couple of posts ago, a commenter quoted Laland and Brown regarding their favored use of the terms “adaptation” and “adaptive,” with this passage:

“An adaptation is a character favored by natural selection for its effectiveness in a particular role. It is something that has evolved to fulfill that function, and it may or may not be adaptive in the current environment. Adaptive behavior is functional behaviour that increments reproductive success, and it may or may not be an adaptation.”

I mention this because this article — which includes Laland as an author –  uses the term “adaptively” and its variants in several places, including the abstract:

The number of demonstrators, consensus among demonstrators, confidence of subjects, task difficulty, number of sessions, cost of asocial learning, subject performance and demonstrator performance all influenced subjects’ use of social information, and did so adaptively.

My sense is that what they mean here is that people used social information in a way that made them more likely to choose the correct answer, and they render this as “adaptive” behavior.)

The second recent paper appeared in Evolution and Human Behavior, entitled “Prestige-biased cultural learning: Bystander’s differential attention to potential models influences children’s learning,” and investigated the possibility that young children use cues to prestige when making decisions about which model to imitate.

I thought the manipulation of prestige was particularly interesting. In the first study, 4-year-olds were shown a little clip in which two people looked either at a model to the right of them or to the left of them, the attention serving as the cue to which of the two models was the more prestigious. The two models then engaged in various behaviors – playing with different toys, for instance – and the young subjects were later asked to choose which of they toys they wanted to play with. The prediction was that children would choose to play with the one the “high prestige” model played with, which indeed turned out to be the case. This implies that four year olds monitor who others are attending to, using that information to shape their own subsequent choices.

The second study in this paper was slightly more complex. I won’t describe it in detail, but only mention that the most interesting result, to me, is the “cross domain” finding. If a child observes a model being attended to while exhibiting a food preference, the child follows the model’s food choice. However, the child is not more likely to show a preference for the toy that this individual played with. In other words, young children seem to infer that these models are domain-specific experts, which is pretty cool.

And completely unrelated… a recent paper in the Journal of Evolutionary Biology entitled, “Sick ants become unsociable” shows that ants infected with a fungus change their behavior, including spending most of their time outside the nest, possibly the result of an adaptation designed to reduce the communication of the pathogen to others. The authors conclude: “Our results provide evidence for the evolution of unsociability following pathogen infection in a social animal and suggest an important role of inclusive fitness in driving such evolution.” I just thought it was interesting, in part because anti-parasite adaptations are just really cool, and also I like these examples in biology journals in which data from behavioral experiments are considered (ho-hum, no big deal) relevant to an evolutionary claim.

References

Bos N., Lefèvre T., Jensen A. & D’Ettorre P. (2012) Sick ants become unsociable. Journal of Evolutionary Biology, 25, 342-351.

Morgan, T. J. H., Rendell, L. E., Ehn, M., Hoppitt, W., & Laland, K. N. (2012). The evolutionary basis of human social learning. Proceedings of the Royal Society – B, 279, 653-662.

Chudek, M., Heller, S., Birch, S. & Henrich, J. (2012) Prestige-Biased Cultural Learning: Bystander’s Differential Attention to Potential Models Influences Children’s Learning. Evolution and Human Behavior, 33, 46-56.

Answers range from the predictable – evolution, Turing, the double helix – to esoteric – “Denumerable Infinities Are The Same Size,” “The Precession of the Simulacre” — to the poetic “The Beauty In A Sunrise,” and “A Sphere.” Replies to the Edge question, as usual, make for some good, if variable, grazing.

Evolution made a good showing, accounting, in various ways, for a good proportion of answers. A number of ideas in physics also appeared with a certain frequency.

One passage that caught my eye was Dan Dennett’s contribution, who wrote about sea turtles, but closed with this paragraph, which links to some remarks that I’ve made recently, and it’s a theme I’ve hit in prior posts. After talking about the explanation for why sea turtles travel so far to lay their eggs, Dennett adds this:

I have noticed that there is a pattern in the use of the “just-so story” charge: with almost no exceptions it is applied to hypotheses about human evolution. Nobody seems to object that we can’t know enough about the selective environment leading to whales or flowers for us to hold forth so confidently about how and why whales and flowers evolved as they did.  So my rule of thumb is: if you see the “just-so story” epithet hurled, look for a political motive. You’ll almost always find one. While it is no doubt true that some evolutionary psychologists have advanced hypotheses about human evolution for which there is still only slender supporting evidence, and while it is also no doubt true that some evolutionary psychologists have been less than diligent in seeking further evidence to confirm or disconfirm their favorite hypotheses, this is at most a criticism of the thoroughness of some researchers in the field, not a condemnation of their method or their hypotheses. The same could be said about many other topics in evolutionary biology.

It’s not possible to cover all the replies here, but a few patterns caught my attention. I thought it was interesting that PZ Myers – whose attempt to do some evolutionary psychology I discussed in my last post – chose precisely the same beautiful idea chosen by developmental psychologist Paul Bloom, both of them settling on D’Arcy Thomson’s remark that “Everything Is The Way It Is Because It Got That Way.”

Interestingly, another idea that got double billing (Kleinberg, Seife) was the “pigeonhole principle.” The notion is that if you’re putting pigeons in trees, and there are fewer trees than pigeons, then you can know for sure that at least one tree has at least two pigeons. Apparently this idea tells us that 1) there are limits to how much you can compress files and 2) your parents’ most recent common ancestor is more recent than you might have guessed.

John Tooby put on a dazzling display of prose in his contribution, entitled, “Falling Into Place: Entropy, Galileo’s Frames of Reference, and the Desperate Ingenuity Of Life.” Here is a sample, setting up the argument that natural selection pulls organisms out of the vast pit of entropy:

The world given to us by physics is unrelievedly bleak. It blasts us when it is not burning us or invisibly grinding our cells and macromolecules until we are dead. It wipes out planets, habitats, labors, those we love, ourselves. Gamma ray bursts wipe out entire galactic regions; supernovae, asteroid impacts, supervolcanos, and ice ages devastate ecosystems and end species. Epidemics, strokes, blunt force trauma, oxidative damage, protein cross-linking, thermal noise-scrambled DNA—all are random movements away from the narrowly organized set of states that we value, into increasing disorder or greater entropy. The second law of thermodynamics is the recognition that physical systems tend to move toward more probable states, and in so doing, they tend to move away from less probable states (organization) on their blind toboggan ride toward maximum disorder.

Both Dan Sperber and Hugo Mercier raised metarepresentations as their beautiful idea, Mercier more or less directly, Sperber with a bank shot, starting with the interesting story about how Eratosthenes measured the circumference of the planet. (It’s interesting to note that Sperber was not just a contributor, but an object of contribution: one of the beautiful ideas discussed was “Dan Sperber’s Explanation of Culture” (Shirky))

There are a number of contributions from other people whose names will be familiar to readers of this blog, including Randy Nesse, Simon Baron-Cohen, and many others. Read a few at a time for little intellectual snacks.

Postscript: I did some traveling during the break between the Fall and Spring semesters, which is why there was a bit of a hiatus between my last post and this one. During that time, there was a post at PLoS blogs that spent some time talking about evolutionary psychology in general (and some remarks that I’ve made in particular). I haven’t decided yet if I will write a reply, but thanks to those of you who called my attention to it.

Postscript the second: As you can tell, there was an update to the web site. One feature that we now have is the ability to subscribe to posts, so that you are notified when someone comments on an entry, which I had been asked about. If you have comments or questions about the new layout, please feel free to drop me a line.

A commenter (bromion, #23) on Myers’ site had the same question, writing:

I’m wondering why you support this kind of evolutionary explanation of a phenomenon that is difficult to prove directly (we can’t observe an evolutionary fossil record here), but dismiss the entire field of evolutionary psychology as “just so” stories.

Myers (#32) answered as follows:

This hypothesis has the advantage of being based on actual comparative data and the physiology of decidualization. It has an explanation based on the cell and molecular mechanism, not just derived from a phenotype. And it makes a specific, testable prediction about how the shift could have been made.

It isn’t about looking up the fossil record (fossils suck for evaluating most evolutionary hypotheses), but about using the molecular evidence to evaluate the answer. We have molecular evidence. We can also get more much more readily than we can dig up a fossil uterus.

This is really useful because Myers has made explicit his criteria for distinguishing a legitimate scientific hypothesis from a “Just So Story.” (The “Just So Story” label, for the uninitiated, is meant to imply that the hypothesis in question cannot be shown to be false, and therefore is not a legitimate scientific hypothesis.) Myers seems to have committed to what appear to be three reasons having to do with 1) comparative data (which I think is the same as “actual comparative data”), 2) cell & molecular mechanism, 3) predictions about “the shift,” which in context I believe refers to the evolutionary pathway from the ancestral condition to the present condition.

I thought I would apply these three criteria to some hypotheses to see how they fare on the Myers Story Scale (MSS). Let’s take a hypothesis Jerry Coyne proposed in a blog entry some time ago, about why sloths come down to the ground to defecate instead of doing so in the tree. His favored hypothesis seems to be that this is to attract mates; the dung pile is a signal to potential mates that a sloth is present in the dung-adjacent tree. Does it satisfy the three criteria Myers points to?

1. Comparative data. Nope. The post was just about sloths.
2. Based on the cell and molecular mechanism. Fails. Just poop.
3. Makes a prediction about evolutionary course. Fails. No discussion of this.

This hypothesis, then, is 0 for 3 on the MSS, and so is an untestable Just So Story, according to the Myers criteria. Coyne, however, thinks this is a perfectly fine hypothesis, writing that “in principle these theories are testable.  We could see, for example, how sloths manage to find each other at mating time.  We could also do mock-defecation studies from branches, using model sloths, to see if the noise attracts predators.” From this conflict, we can see either that the criteria are wrong, or Coyne is wrong. I don’t see another option.

To take a second example, in Myers’ post, he entertains and rejects one explanation for female menstruation, writing  that one possibility is that “humans have rather aggressive embryos that implant deeply and intimately with the mother’s tissues, and menstruation “preconditions” the uterine lining to cope with the stress. There is, unfortunately, no evidence that menstruation provides any boost to the ‘toughness’ of the uterus at all.”

He rejects this hypothesis, clearly, but he doesn’t reject it because it’s an untestable Just So Story. He accepts it as a legitimate hypothesis because he (implicitly) reasons as follows. If the function of the trait is coping with future embryos, then the trait should have properties (toughness) that contribute to this function. From the observations of toughness (however that is measured), he rejects the hypothesis. The key idea to note is that the claim about the function is, in itself, enough to render the hypothesis testable. The hypothesis did not seem to need comparative data, etc.

Finally, at the end of the post, in a postscript, PZ Myers tried to become an evolutionary psychologist, trying his hand at understanding one aspect of human social behavior, why some people are pro-choice and others pro-life. Here is his explanation:

 The maternal-fetal conflict is also a conflict between males and females: it is in the man’s reproductive interests to have his genes propagated in any one pregnancy, while it is in the woman’s reproductive interests to bail out and try again if conditions aren’t optimal for any one pregnancy. This conflict is also played out in culture, as well as genetics — pro-choice is a pro-woman strategy, anti-abortion is a pro-man position. Sometimes, politics is a reflection of an evolutionary struggle, too.

First of all, it’s obviously very interesting that Myers seems to be trying to explain a psychological phenomenon – here, moral variation – by thinking about the relevant fitness interests. It’s a bit surprising that the people commenting on his blog, many of whom roundly condemn evolutionary psychology, seem not to have had a concern about his proposal here.

It’s not precisely clear, but this remark seems to me to be proposing that the reason for variation in views on abortion has to do with reproductive interests and, in turn, the key variable that underlies these differences is one’s sex, with women gaining an advantage by adopting the pro-choice position. Now, the proposal does poorly according to the MSS — no comparative data, no cellular mechanisms, and no word about the evolutionary trajectory of the trait – but the proposal does seem to make a prediction, that a person’s sex will be the key predictor variable for views on abortion. As it happens, there are a large number of datasets that Myers could have consulted in making this proposal, nearly all of which would have shown that there is no sex difference, and, when there is one, it accounts for a tiny amount of the variation in abortion views.

Now, the part that Myers might be right about is the idea people’s views on sexual issues can be systematically predicted by considering their strategic reproductive interests. But the crucial variable isn’t sex, it’s reproductive strategy. In my opinion, the best work on this is by Jason Weeden, who has gathered and analyzed a tremendous amount of data to interrogate his explanation for variation on abortion views. (Weeden’s dissertation is, with respect, one of the only dissertations I’ve even come across that’s actually worth reading. Note that in the spirit of disclosure, I should mention that I’ve collaborated with Weeden and we have made a similar proposal regarding views on recreational drugs.)

In terms of the broader theme here, my guess is that Myers doesn’t really believe that those three criteria distinguish a testable hypothesis from a Just So Story. As I’ve shown here, he himself produces hypotheses which fare poorly according to his own criteria. It is easy to find other hypotheses from the animal and human literature, measure them against the MSS, and show that hypotheses that fail on this measure are treated as perfectly legitimate hypotheses. The reason is that functional claims entail predictions about the structure of traits, whether physiological or behavioral, as illustrated by the three cases above. The criteria Myers enumerates are not required for making a hypothesis falsifiable, and from his own writing, it seems that he implicitly believes this.

In short, Myers’ proposal shows that he thinks that evolutionary reasoning can form the basis for hypotheses about the human mind and human social behavior. Yes, I wish that he would police himself a bit more, and dip his toe in the pools of data available to evaluate the claims he makes before writing about them, but I’m very happy to look past that because I think it’s encouraging that he’s starting to write about how evolutionary ideas can inform hypotheses about human behavior. He didn’t do all that well this time, but I’m confident that, with helpful policing from others, he can do better.

Reference

Weeden, J. (2003).  Genetic interests, life histories, and attitudes towards abortion. Dissertations available from ProQuest. Paper AAI3087480.

http://repository.upenn.edu/dissertations/AAI3087480