Evolution for Everyone

If you’re an economist, you know about Jan Tinbergen, who shared the first Nobel Prize in Economics with Ragnar Frisch in 1969 for his work on dynamic models of economic processes. If you’re an evolutionist, you know about the other Tinbergen, Jan’s younger brother Niko, who shared the Nobel Prize in Medicine with Konrad Lorenz and Karl von Frisch in 1973 for his foundational work on ethology, the study of animal behavior.

Niko wrote an elegant paper in 1963 titled “On the Aims and Methods of Ethology” that summarizes, in the form of four questions, why evolutionary theory is so good at integrating across disciplines. Tinbergen’s four questions go a long way toward answering the question “What’s evolution got to do with it?”

1) What is the function of the trait, or why does it otherwise exist compared to the many traits that could exist in the lineage? The process of variation and selection winnows a small subset of traits that adapt organisms to their environments from a much larger set of traits that could equally exist but do not because they were not selected. Evolutionists call this ultimate causation. It provides a powerful (but not infallible) way of inferring the properties of organisms knowing only a little bit about the environmental context. For example, we can confidently predict that desert creatures are likely to be sandy colored to avoid being detected by their predators and prey. We can make this prediction for all desert-dwelling creatures, without knowing anything about their genes or physical makeup.

Although this example is simple, adaptationist thinking is full of complexities and pitfalls. Not all traits are adaptive; they can be a product of drift, a byproduct of other traits, or adaptive in the past but not the present. When they are adaptive, they might benefit genes, individuals or groups. They might be a product of sexual rather than natural selection. What counts as adaptive in the evolutionary sense of the word can be perversely maladaptive in the everyday sense of the word. Species can even evolve themselves to extinction. Thus, although the answer to Tinbergen’s first question can be a no-brainer, it can also require a sophisticated understanding of evolutionary theory.

2) What is the phylogeny, or evolutionary history of the trait? Answering this question provides information that was not required to answer the first question. A marsupial’s pouch and placental mammal’s womb have the same function (to develop offspring) but are very different from each other, based on the fact that marsupials and mammals evolved on different continents. Evolution is a historical process and seldom takes exactly the same path twice. A trait will not be fully understood until its particular evolutionary trajectory is known.

3) What is the mechanism of the trait? Regardless its function or history, it also has a physical basis that must be understood in mechanistic terms. Evolutionists call this proximate causation. The functional answer to why flowers bloom in spring is because that’s the best time to bloom for the survival and reproduction of the plant. The mechanistic answer can be completely different, such as a physiological response to day length.

4) How did the trait develop? Organisms have histories in addition to lineages and the development of traits usually reflects a complex interaction between the organism and the environment, even when the outcome is highly invariant, such as the development of the eye.

Each question can be answered independently to a degree but they are best answered in combination. This is the kind of integration that is far more advanced for the biological sciences than for human-related subjects. Even the biological sciences are still a work in progress. It is common for evolutionists to reason on the basis of ultimate causation without paying much attention to proximate causation. It is even more common for biologists who concentrate on proximate causation, such as molecular biologists, to ignore ultimate causation. Phylogenies are often constructed without reference to the selection pressures that partially brought them about. And the so-called modern synthesis that formed in the 1940’s largely ignored development, which is why “evo-devo” became a new field of inquiry in the 1980’s. Research programs that provide answers to all four questions are awesome in their scope and explanatory power, such as Richard Lenski’s research on experimental evolution in microbes. Most biologists would agree that this is the ideal to strive for, even when it is difficult to achieve for particular study systems.

For decades, we have been fancied as set apart from the rest of life by our capacity for cultural change, as if this lifts us outside the orbit of evolution. Once we realize that this capacity is a product of genetic evolution and itself an evolutionary process, the need for Tinbergen’s four questions becomes doubly needed–to explain both the capacity and the specific products of cultural evolution.

The ideal of answering all four questions in an integrated fashion forces the evolutionist to integrate knowledge across disciplines. It is impossible to study human psychology, for example, without consulting anthropology and paleo-anthropology. In the recent EI/NESCent workshop on integrating economics and evolution, the participants represented the fields of anthropology, economics, history, political science, psychology, neurobiology, and theoretical biology. The conversation easily shifted from one discipline to another, because we were all accustomed to thinking about Tinbergen’s four questions in an integrated fashion. Contrast this with the encapsulated nature of economics as a discipline, which isolates it from other human-related disciplines, not to speak of the biological sciences. The workshop participants were trying to formulate an answer to the question “What’s evolution got to do with it?”, but the fact that we were in the same room and capable of talking with each other provided part of the answer.

Who would have thought that the other Tinbergen would have even more to say about economics than his older brother?


  1. #1 Roy Niles
    May 29, 2011

    “But then when will you, D.S.W., come out of hiding and recognize that, as someone has said earlier, all traits in the end evolve from strategically successful behaviors.
    Posted by: Roy Niles | May 17, 2011 9:27 PM”

    And posted again now, because while you wouldn’t respond earlier, you have given part of the answer here, but limited it to some traits, as in: “Not all traits are adaptive; they can be a product of drift, a byproduct of other traits, or adaptive in the past but not the present.”
    But that’s the point, at some time in the evolutionary past, all traits were strategically successful behaviors somewhere. The question being, did these organisms then generate their strategies from experience, or if you are to continue arguing that they didn’t, what was it that so magically produced them? Or did these first forms somehow cause their functions (as you seem to suggest) and functions somehow caused their strategies in turn?
    (Just askin’ for the record of course.)

  2. #2 dmabs
    May 29, 2011

    Sunday Sacrilege pz’s blaspheming head


  3. #3 hazel-rah
    June 1, 2011

    To Roy Niles: I’m afraid that I may be partially to blame for Dr. Wilson’s silence here, since I so insistently monopolized his time and patience on this blog. This said, I imagine another reason for his lack of response so far has to do with the ambiguity of what, exactly, you are asking him to concede. I am having trouble figuring that out myself. For one in Dr. Wilson’s profession, agreeing or disagreeing to the points of an ambiguous argument can have some pretty serious consequences.

    Novel varieties appear in nature through genetic mutations and recombinations. Selection, drift, and gene flow do not create anything ‘new.’ They blindlessly and mindlessly act on what varieties already exist.

    The ‘fitness’ of any variety is relative to the other varieties that are co-present and subject to similar selection pressures. In this sense, ‘fitness’ is a heuristic, not an inherent characteristic of the organism itself. Those varieties that survive and reproduce are ‘more fit’ than those who experienced similar selection pressures and did not live as long or have as many offspring. The ‘more fit’ varieties likely survived and reproduced because of some set of traits that fortuitously surmounted these selection pressures (again, relative to other varieties), and those traits are likely to be inherited by their offspring.

    These traits are adaptations. They result from chance mutations and generations of inheritance. They only look ‘purposeful’ when they seem to ‘match’ ongoing selection pressures within a particular context. For example, an insect’s colorings might hide it from predators upon a particular kind of tree, but those same qualities are a liability if it falls onto a sidewalk.

    Now, considering the possible argument you’re making here. By-and-large organisms are extremely unlikely to ‘cause’ any kind of adaptation. This would require motives, consciousness, and abstract planning that few animals possess. This would be especially unlikely in the ‘first forms’ of organic life. These earliest organisms appeared (probably many times over) by a chance combination of elements and conditions. An infinite number of possible beginnings and subsequent events were possible. But there is nothing ‘magical’ about it – some of the varieties that emerged then are still extant, while others are not. None of them are perfectly adapted to even their own environments.

    You are obviously not ‘just askin’ for the record’ about organisms’ volition or the ‘magical’ production of first forms. In the former case, as I suggest above, no animal other than Homo sapiens has such a set of adaptations that it can consistently represent abstract possibilities to others of its kind. That is, few other animals could ‘teach’ various survival and reproduction possibilities to their young or others. This capacity to create and employ symbolic realities is our species’ most impressive adaptation. We should not confuse it with other animals’ (non-symbolic) behaviors, however tempting or amusing it might be to engage such a Disney-fied version of non-human forms. You might as well ascribe consciousness to a car.

    As for that ‘magical’ production of first forms, I can only interpret here that you mean a divine creator, or some variation on that theme. Don’t you think you’re barking up the wrong tree? Dr. Wilson is not going ‘come out of hiding’ and concede that symbolic reasoning was operating within or above the primordial sludge. Nor is he likely to argue that such an intelligence was present at any time since. The world, as evolutionary scientists tend to understand it, does not work that way.

    I could have your argument all wrong, of course, but that is your problem as much as it is mine. Evolutionary reasoning tells us that nothing is ever perfectly ‘matched’ to the context where we find it. You have offered an uncommonly fine example of this in whatever it is that you’re arguing here.

  4. #4 David Sloan Wilson
    June 1, 2011

    Dear Roy (and Hazel-rah),

    Thanks to Hazel-rah for his informative post. I too have difficulty understanding what you are driving at. If we restrict ourselves to adaptations that evolve by natural selection, it’s true that they are strategically successful by definition, but this begs the question of how they evolved in the total population (e.g., by within-group vs. between-group selection, natural vs. sexual selection). If we consider the non-adaptive side of the evolutionary coin, then your statement “all traits in the end evolve from strategically successful behaviors” appears to be just plain wrong. Can you clarify what you are driving at, including what you think I am trying to hide from?


  5. #5 Roy Niles
    June 1, 2011

    hazel-rah, you seem to be unaware of the new work being done under the headings of adaptive mutation, or self-engineering, or facilitated variation, or anticipatory systems, etc.
    Dr. Wilson is quite aware, but like many who have become committed to one explanation of a process, it seems he’d rather think in private about the new directions being taken in the evolutionary sciences than publicly discuss his thoughts with strangers.
    He does drop a hint or two that he’s not nearly as far behind the curve here as you seem to be. Life is a strategic process. Get used to it.

  6. #6 Roy Niles
    June 1, 2011

    Dr. Wilson, I didn’t see that recent post of yours before responding to hazel-rah. I’ll try to respond later on today in more detail, even though I’ve had these exchanges with you before on more or less the same subject, and the concept of strategies driving the evolution of their forms is not new.

  7. #7 Roy Niles
    June 1, 2011

    OK, I’ll summarize some of what is being discovered as succinctly as I can without making it an argument:
    The cells that retain the memory of an experience then pass on that memory to those they have been divided into. Inheritance of acquired memories of experience, no? And many generations appear to be affected – and the effects of this experience can’t be completely erased from the genome if the experience itself is replicated or repeated in a particular environment. And this seems one of the ways that cells evolve to anticipate and deal strategically with a multitude of problems.
    Because it seems to be the present case with most social species that their form of culture is a preserver of learned strategies, some of which by reason of their effectiveness will become instinctive, and our earliest life forms may have started that instinctive process by passing the memories of learning directly through cell division. While later on when sexual selection and the like evolved, the mechanism for passing on what would be needed as socially instructive was a “culture” that required its lessons taught at least by example – and thus evolved our methods of communication for sharing memories that was more efficient then cell memory copying, especially as that original method of procreation did not apply all that well to multi cellular organisms.
    Which leads one, or at least me, to opine that all evolution from the getgo was and had to have been a social/cultural phenomenon. Learning creates strategies which create forms to fit, which gain experience that strategies adapt to, and through cultural sharing by example or advances in communication, spread the impetus for readaptation throughout the groups accordingly.
    Cultures assist in the heritability of acquired characteristics: Cultures provide the platform for their strategic development and purpose, and in addition help “spread the word” that accelerates the acquisition of these strategies “instinctively.”
    Strategy is the function of intelligence. The form alone has no intelligence. It can’t choose, even though it’s a cause of choice. The function chooses form and/or chooses how it will be caused to adapt.
    There’s more of course, but cutting to the chase, I don’t think there is a non-adaptive side of the evolutionary coin and that indeed it’s more than possible that “all traits in the end evolve from strategically successful behaviors.”

  8. #8 David Sloan Wilson
    June 1, 2011

    This is cool stuff and Jablonka and Lamb’s Evolution in Four Dimensions provides a good review. They frame it in terms of four inheritance systems–genetic, epigenetics, learning, and symbolic thought. The latter three evolved by genetic evolution, so “blind variation and selective retention” is at the root of everything, but some of the resulting processes can legitimately be called anticipatory or Lamarkian, a conclusion that Jablonka and Lamb do not shy away from.

    I think it is too extreme to say that all aspects of evolution are anticipatory. Good old fashioned Mendelian genetics still accounts for a lot.

    In Darwin’s Cathedral, I argue that conscious intentional planning, unconscious anticipatory processes, and blind variation and selective retention all play a role in cultural evolution, including historical periods such as the Protestant Reformation.

  9. #9 Roy Niles
    June 2, 2011

    Dr. Wilson, thanks for the response. But having an anticipatory function doesn’t negate the utility or purpose of these other processes. We, in short, anticipate the accidents of nature – without the one we wouldn’t need or have the other.

  10. #10 hazel-rah
    June 2, 2011

    Ah, I’m sorry Roy, I see now that there was in fact a THIRD possible argument to your postings. I will be sure to “get used” to this revolutionary, pan-physics argument, even as it continues to smack of Lamarkism, intelligent design, and anthropomorphic vitalism. Please let us know when you and your colleagues return to planet earth. We will have your lunch ready.

  11. #11 Roy Niles
    June 2, 2011

    I suspect we’ve already eaten your lunch, but thanks for the offer.

  12. #12 joe
    June 3, 2011

    “We, in short, anticipate the accidents of nature…”


    Tiny human individuals anticipate a lot. But it does not feed upwards to create a historic teleology beyond indivdual destinies. We are not clairvoyant – you see.

    Otherwise, why would entrepreneurs and inventors more often founder than be econimically successful?

    As you cannot get Lamarckism or supra-individual teleology out of the highest cognitive functions, why try getting them out of mutations?

  13. #13 joe
    June 3, 2011

    What I was wanting to say is that I see Niko Tinbergen’s four questions as an argument against unification.

    A standard argument against adaptive explanations of behaviour seems to have been that one should not propose adaptive explanations without knowing anything about the physiology or other details of the trait.

    Ernst Mayr arguet the same with his distinction between proximate and ultimate causes (later on why-questions and how-questions).

    The integration part is that physiological explanations must not blunder against physics or evolutionary biology and vice verse.

    Apart from that I see Tinbergen’s four questions piece as giving freedom to researchers to go ahead before everything else is known. Otherwise, research would be paralysed by ignorance.

  14. #14 David Sloan Wilson
    June 3, 2011

    With respect to Joe’s first comment, I agree that a high degree of intentionality at the individual level can lead to blind variation at the social level. This struck me while learning and writing about the Protestant Reformation in Darwin’s Cathedral. A lot of conscious planning led to a bunch of inadvertent social experiments, a few of which hung together. Another example is the cultural expansion of the Nuer at the expense of the Dinka, two pastoralist African tribes, during the 19th century (see Raymond Kelly’s The Nuer Conquest and my account with Elliott Sober in Unto Others). Members of their own tribe were all consciously attending to their affairs be clueless about the larger scale and longer term consequences of their activities. There’s no evidence of any Dinka saying “Gosh, our culture is being replaced! What should we do about it?” There are sobering lessons for our own culture in this regard.

    I also like what Joe says about the freedom that Tinbergen’s four questions provide to pursue different lines of inquiry in parallel. In defense of adaptationism, however, the easiest first step is often to ask “what would the organism be like if it is well adapted to its environment?” The idea of trying to learn a lot about its physical makeup before asking this question doesn’t make a lot of sense to me. To the extent that the physical makeup leads to heritable variation, that’s the extent to which ultimate causation is a powerful form of explanation from the beginning.

  15. #15 Dorice
    June 3, 2011

    Dr. Wilson,
    My apologies for interrupting the flow of this blog’s stream, but after following the conversation for some time, I find myself pondering the following…
    In your talks, you mention the concept of an “organism”, in reference to humanity as a whole. This makes a lot of sense to me. To extend the metaphor, I have constructed a story in my mind, wherein a spaceship comes from outer space, carrying scientists from another planet. Their job is to examine the Earth, analyse and assess its health and function as a whole, and bring back only ONE report to their home planet. But the report must be written in such a way that ANYONE who reads it can understand it. The first question that comes to mind for me is how the scientists on board can understand each other when they have to work together to gain an understanding of the task ahead? Whose language/jargon is being used? It seems obvious that a common language would have to be developed. I can imagine that happening. But this is where I find the problem with my own story. I, myself, am viewing the problem from formal, or inherited patterns of thinking. If I let go of my previous ideas (as the observer of this story, not as the teller of the story), if, in essence, I let go of my previous idea, I find myself able to view the problem from a more “edified” perspective. I see the story as a story. Doesn’t this require me to edify my “story” from the context of other ways of thinking about my problem?
    So how can any of the discussions being conducted in this thread be resolved without reference to any other sciences? For instance, what would a mathematician have to say about this prolem? How would he formulate it? Would he have any interest in it at all? If not, why not? And then, the final question….what do I, as an individual, do with this problem, after thinking about it?

  16. #16 Roy Niles
    June 3, 2011

    We anticipate that accidents will happen. As a result we try to predict their nature and consistency from our experience of past accidents. Accident of course is our term, not nature’s. But all organisms use predictive algorithms that evolved precisely to deal with the uncertainties presented by their very nature – that they found themselves with the need to make proactive choices. This stuff should be obvious to anyone who takes the time to think before they jerk their neo-Darwinist knee.
    The tragedy of Fukushima was due in part to the fact that we HAVE learned to predict the recurrence of some accidental events with more consistency and accuracy than others. And that in this case failed to take preventive measures, not from a failure to anticipate the event, but failure to anticipate the full weight of the consequences.
    Any more dumb posings of examples like that one and I anticipate I’ll pass.

  17. #17 Roy Niles
    June 3, 2011

    “To the extent that the physical makeup leads to heritable variation, that’s the extent to which ultimate causation is a powerful form of explanation from the beginning.”
    Unless the function that the physical makeup serves is the ultimate cause of the variety of forms in nature and thus a more powerful “form of explanation” for the necessity to adapt the physical to fit the dictates of it’s function’s needs.

  18. #18 John Jacob Lyons
    June 4, 2011

    It seems to me that one of the primary themes of this discussion is the impact that the behavior of organisms has on the evolutionary trajectory of their species. Assuming that this is the case, I would like to introduce the hypothesis that I call ‘Genetic priming’. In essence, this hypothesis suggests that consistent adaptive behavior is never assimilated into the genome as proposed by, what is known as, the ‘Baldwin Effect’. Instead, it suggests that such behavior primes the genome toward gene-variants that support/ encourage the behavior.

    Learned adaptive behaviour is invariably positively correlated with particular genetically-mediated propensities/predispositions. The preferential selection of the adaptive behaviour of organisms will cause the gene variants of these associated propensities/ predispositions to become more frequent in the following generation. This will result in greater numbers of organisms being genetically primed to express the adaptive behaviour in that generation and actually manifesting it. In turn, this will mean that the associated gene variants will again increase in frequency in the next generation. Thus a positive inter-generational feedback loop is created. Over evolutionary time all organisms in the species will be genetically primed to express the adaptive behaviour; needing just a simple environmental trigger for the behaviour to be manifested. There may well be more than one adaptive behaviour ‘trying’ to prime the same or an overlapping set of gene variants concurrently. This would result in the genetic priming, for any particular adaptive behaviour, being rather less than optimal.

    If you consider this relevant to your discussion, please see http://www.scilogs.eu/en/blog/biology-of-religion/2011-03-24/the-genetic-priming-of-religiosity-guest-post-by-john-jacob-lyons?sms_ss=twitter&at_xt=4d8bc83ede65d24d,1

  19. #19 Roy Niles
    June 4, 2011

    These gene-variants are the product of supernatural forces, right? I’ll have to pass on that one.

  20. #20 Dorice
    June 4, 2011

    Wow JJL, thank you sincerely for your open-minded response to my question! I love the hypothesis, and will definitely check out the site you recommended. I happen to think a similar process is at play, but how I have arrived at those conclusions is actually what fascinates me… given that I have never read Darwin’s books, nor participated in any of these online discussions. (The thought I posted was actually my fist visit to this blog, and my first time ever posting anything on a blog site). I’m now glad I did and will check out the sites you recommended for further reading.

  21. #21 John Jacob Lyons
    June 5, 2011

    Thank you for your interest to date.

    The Genetic Priming hypothesis is very general and far-reaching. It can be stated as follows:-

    ‘All living organisms, both plants and animals, are genetically primed for the adaptive behaviour of their species needing just a simple environmental ‘trigger’ for that behaviour to be manifested.’

    Before it can be considered for presentation in a peer-reviewed journal, the hypothesis needs to be empirically tested. As an independent theorist, I will need the collaboration of an appropriate university faculty. I would therefore welcome suggestions/ comments from fellow blogers.

  22. #22 John Jacob Lyons
    June 8, 2011

    At the beginning of Post 18 above I suggest that I would like to address ” — the impact that the behavior of organisms has on the evolutionary trajectory of their species”. I then go on to introduce the Genetic Priming (GP) hypothesis. I want to clarify that I am not suggesting that this is the only interaction between behavior and the genome.

    If I am correct about GP, it would come into play as soon as a consistent adaptive behavior got started and would continue until all organisms in the population were primed for the behavior. However, once such a behavior was widespread in a population it would, effectively, become part of the environment and any mutations that suited that environment would be favorably selected in the usual Darwinian way. GP and Natural Selection would both be at work on the evolutionary trajectory to encourage/support the adaptive behavior.

  23. #23 Father Clifford Stevens
    August 22, 2011

    I would like to post the comment that if, biology is the etiology of religion and behavior, how can be certain of that statement. If biology goes in, biology comes out, The your conclusion is simply a biological package, with no intellectual content to it. The very premise is a contradiction in terms. I claim that religion is a cosmological question and not the result of an invasion of biological forces on the human psyche.

    It is an act of reason that looks to causes and is the recognition of a Primary Cause behind the multitude of other causes that make up the Cosmos. How can you demonstrate that biology is the etiology of religion if biology is incapable of an answer with intellectual content.
    And – if religion has another explanation, far more valid from a scientific point of view, the premise that biology is the cause of religion in the human psyche falls flat.

    Father Clifford Stevens
    Boys Town, Nebraska

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