Why we still wear pants

Peter Turchin recently published a series of blogs (part 1 and part 2) addressing the question of why westerners wear pants.  It's a story I'd heard before years ago in a comparative Indo-European studies course, but not from an expressly evolutionary perspective and not with Peter's flare.  It's a good story, particularly for introducing cultural evolution, and I don't want to spoil it for those who haven't heard it before.  Nevertheless, not much about this post will make sense if I don't at least mention that wearing pants came about whenever riding horses became an important part of warfare.

As much as I like the story, I made what I thought was a somewhat innocuous comment saying that I would like to see a follow up series of blogs that explored why we still wear pants.  After all, very few people ride horses and, aside from some special exceptions, horse cavalry became obsolete in World War 1.  However, not only has the wearing of pants continued, it has spread, both to societies we've come into contact with and to women within our own society.  This spread has happened without any obvious adaptive advantage.  Moreover, this persistence and spread has occurred despite available alternatives and social movements, such as the androgynous movement of the 1980s, that attempted, and failed, to change these established practices.

Peter's response to this question, while not exactly surprising, was surprisingly dismissive.  His position is that there is no need to explain when cultural traits fail to change.  For him, the lack of change is the null hypothesis.  In his own words:

The null model is dp/dt = 0, where p is the frequency of the trait, and dp/dt it’s (sic) rate of change. If there is change, then dp/dt = c, or dp/dt = cp, depending on the details of how the trait changes. In any case, the greater the rate parameter, c, the faster the trait will change. So if c is high enough you will have yearly changes of fashion, if c is small enough, then it will take decades or even centuries.

The failure of something to change, in Peter's view as I understand it, can simply be dismissed as normal inheritance.  In the absence of variation and/or in the absence of selection pressure to change, we simply go on as we've always done.

I object to this position on a number of fronts.  To begin, it appears to be an assumption, not an empirically established fact.  Moreover, all these equations really establish is that some traits change faster than others, hardly a startling revelation.  What they fail utterly to do is account for why some traits change faster than others.  The salient question, for me, is why dp/dt should ever be zero, or even near zero. 

It is, of course, entirely plausible that Peter is right, that the failure of this particular trait to change might be due to simple inertial processes.  However, this is far from the only possibility.  We need only look to biological systems to see why this is so.  Robustness, the propensity of a system to continue functioning in the face of perturbation, is a general property of complex, evolved systems.  The structure of DNA and the genetic code are robust to mutations.  Proteins similarly tend to perform their functions even with amino acid substitutions.  This robustness is evident all the way up the hierarchy of biological complexity.  Even developmental systems are robust to changes in metabolic pathways. 

I see no logical reason to assume this general property of biological systems, a property that is an adaptation in its own right, should somehow no longer hold true once the level of complexity moves outside the skin of the individual organism.  Moreover, if evolutionary approaches to understanding human culture are to meet their full potential, they must grapple with practical problems in the current world, many of which represent historical patterns from which groups seem almost incapable of escaping.  For instance, Nisbett andCohen have traced modern rates of male violence in the southern United States to Celtic herding cultures, an ancestral pattern that has persisted long after herding faded out as a way of life.  Similarly, Robert Putnam has traced failures of democratic institutions in southern Italy to patterns of social capital building that go back 500 years.

Treating the persistence of these problems as nothing more than null hypotheses drastically reduces the chances of finding real solutions.  Aside from blinding ourselves to the root causes of recalcitrance, robustness paradoxically makes evolvability possible.  A handful of textbook examples notwithstanding, it is rare for a single mutation in biological systems to be adaptive.  Most often, adaptations arise from a series of mutations.  Fragile systems, however, are relatively incapable of building pools of useful variation since any slight change is likely to lead to suboptimal performance.  Robust systems, by contrast, tend to build up pools of variation, some combination of which may prove adaptive when new niches present themselves or existing environmental conditions change.

As for the question that ultimately motivated this post, I have no idea why we are still wearing pants.  If I were to hazard a guess, I would say that once pants became associated with warrior castes they acquired protection by virtue of prestige bias.  This in itself, though, might not have been enough to ensure the practice persisted.  More likely, the wearing of pants started to get tied to concepts in addition to warrior attire.  For instance, pants became associated with markers of gender identity, group heritage, etc.  In other words, it became connected to many other cultural constructs in intricate webs not unlike the way genes often have pleiotropic effects in gene networks.  If so, then wearing pants could become difficult to change even if there were compelling reasons to do so.

Sure, this is all purely conjecture at this point.  However, it hopefully goes some ways toward demonstrating that lack of change is a worthy subject for evolutionary study.

Those who help themselves

There was another strand to the conversation I had with Michael Dowd and Connie Barlow the other day that bears consideration.  Namely, the subject of what services churches offered came up.  Connie mentioned that many liberal churches she's visited or been a part of over the years focused extensively on "doing good in the world" and this was translated into multitudes of community services such as soup kitchens or after school programs for troubled  youth.

While this is admirable work and many of these churches really do make a positive difference in people's lives, it does have some rather unfortunate consequences that, while not inevitable, are nevertheless common.  In particular, members are asked to volunteer considerable time and resources to supporting these causes, something regarded by many as a serious strain on their already busy lives.  More importantly, though, they are being asked to expend these resources largely helping people who are not part of their religious community.

Now, this is where things get really interesting.  Before I started studying religious groups I had a very cynical view of the charity work done by churches.  I felt that it was all done primarily as a means of recruiting new believers.  I thought that food, shelter and clothing was being denied to people unless they were willing to subject themselves at the very least to prayer and a sermon.  What I've come to appreciate in my field work, though, is that most churches don't seem to operate this way.  They usually open their doors to everyone and many assiduously avoid even the appearance that their community support is contingent upon acceptance of their world view.

This acknowledgment has softened my cynicism considerably, but it has also given it a new focus.  Namely, interviews with informants over the years have made it clear that while many in these liberal churches are happy to throw bread to the huddled masses outside their doors, they're rather uncomfortable inviting these people into the sanctuary for worship.  What appears on the surface to be an admirable statement of altruism is in effect a line drawn in the sand and those who try to transgress this boundary create a troubling sense of cognitive dissonance for members of the community.  They know all too well that the sign in front of the church says that all are welcome.  But in reality they aren't well prepared for the all that might come through their doors and they don't really want to be face to face with that all on a pleasant Sunday morning when they would rather catch up with friends and family over coffee and donuts.

But now we're back to the central problem, and it's really a problem of sustainability.  If we were to look at this through the lens of Elinor Ostrom's design principles, then these congregations are doing a good job of clearly delineating their boundaries, which, however hypocritical it may seem to be is nevertheless necessary to sustainably manage resources.  Yet they are using these resources not to help themselves but to help others.  The in group is bleeding itself for the sake of the out group.  It doesn't take evolutionary thinking or exposure to Lin Ostrom's scholarship to realize that this state of affairs is not sustainable in the long term except perhaps for those few congregations blessed with an excess of members who are existentially secure with lots of time to spare.

Contrast all of this with more conservative churches, particularly those of the Pentecostal persuasion.  Many of these churches also support soup kitchens and after school programs and the like.  However, they are far less squeamish about using these events to proselytize.  As such, they aren't drawing as distinct a boundary between "them" and "us" since their hope is that the "they" will become part of the "we."  Perhaps even more importantly, though, these churches typically offer a huge number of services to help their members as well as non members in the broader community.  On the one hand, it seems as though a Pentecostal congregation places extra burdens on its members with an expectation that they come to church three or four times a week.  However, congregants are typically getting valuable services for their trouble.  Rather than having to find a baby sitter to watch the kids while they go to teach remedial reading skills in an after school program, parents at an Assemblies of God will more likely drop their kids off at the church daycare while they attend seminars on financial planning, good parenting, or marriage counseling.  Is it any wonder, then, that they are often able to muster more resources and engage higher levels of commitment than many mainstream Protestant churches?  By seeing to the down to earth, practical needs of their members in ways that can help to relieve some of the stresses of modern life they concomitantly increase the ability of those same members to reach out and help those in the wider community, efforts that are unabashedly couched in terms of church growth.

It strikes me that this would be a relatively easy process to study and one we should add to our never diminishing project lists since it leads to a rather simple prediction.  Namely, the higher the proportion of in group vs. out group services a church offers, the better it should do in terms of growth and retention of members as well as its ability to engage volunteerism.  Conversely, the higher the proportion of out group vs. in group services a church offers, the worse it should do in all those same dimensions.

Architecture as a means of cultural canalization?

Part of being a student of David Sloan Wilson means meeting some very interesting characters.  Among some of the more interesting I've come across are Connie Barlow and Michael Dowd.  Connie is a science writer and an atheist who has been heavily involved with the Unitarian Universalist movement over the years.  Michael is a former Evangelical minister and author of Thank God for Evolution.  Together they serve as modern day itinerant preachers for an evolutionary, yet nevertheless highly spiritual, world view.  Or perhaps to put it in George Levine's terms, they advocate for a strongly enchanted evolutionary world view.  I met them once a few years ago when they gave a presentation at a local church, but didn't get the chance to talk with them in any depth.   Luckily, I had the opportunity yesterday when Connie and Michael stopped by the office for a visit to remedy that missed opportunity.

As part of the conversation yesterday, David and I explained our working conception of tight vs. loose groups and how these categories related to tolerance for within group variation.  This came on the heels of a discussion about David's desire to create an historical database of Binghamton area churches.  Connie put these two streams of conversation together to make a very interesting observation.  Namely, she said that congregations associated with old, beautiful church buildings tend to have members running the gamut from religious conservatives to agnostics.  As such, we might be inclined to think of them as generally "loose" congregations.  However, it is often the case that this variation remains largely buried beneath the surface, protected by a series of often unspoken taboos surrounding subjects that members tend to avoid talking about.

I find this observation fascinating on a number of different levels.  At the most basic, it represents a looseness in beliefs accompanied by a tightness in behaviors that we haven't accounted for or even thought about in any of our models.  More importantly, though, it brings together many different strands of my recent thinking that I feared were in danger of unraveling.  I have been so caught up in recent months with practical issues surrounding empirical work that I have had a growing anxiety that I have been losing sight of my broader theoretical questions about cultural robustness and evolvability.  It is important to have moments where you can step back, if even for a moment of clarity, to see how those endeavors are supporting one another.

I'm still mulling all of this over, but a starting point for synthesis comes from Roy Rappaport's Ritual and Religion in the Making of Humanity:

The simple fact of the continued existence of the 1,000-year-old cathedral, for instance, does more than speak of the endurance of a liturgical order and its relationship to a place and a group.  It demonstrates it.  Even a new cathedral build to a traditional plan demonstrates the endurance of the plan, and thus the order specifying it, and so does the manipulation of sacra which are either themselves ancient or which conform to ancient patterns. (location 2251)

Rappaport here is not discussing cultural robustness directly.  Rather, he is discussing the roles of material objects in ritual.  Nevertheless, I think he is hitting on something important to my own interests, something that accounts in part for Connie's observation.

Traditionally, churches have been built along certain plans that evoke the sense of endurance and timelessness that Rappaport illuminates here.  This becomes an important part of the church liturgy, a concrete (and very expensive) statement that the social order represented by the church is unchanging, that its correctness and morality are something outside of time.  This is fine as far as it goes.  However, the fact is that society does change over time and the "facts" deeply embedded within the architectural bones of the church at some point begin to become counterfactuals in the minds of those who have attached themselves in one form or another to that structure.

Yet, as Rappaport so convincingly argues, rituals, and the physical structures that support them, are so powerful in part because they remove ambiguity.  Either someone participates in a ritual or does not.  Either they become a man or woman by virtue of completing a rite of passage or they do not.  Either they have agreed to support a family in their war efforts through dancing around the fire or they have not.  But Connie's observation points to a flaw in Rappaport's argument.  Yes, an ostentatious cathedral enforces the idea that a church's rituals and, hence, ideals are eternal.  However, it does not necessarily communicate exactly what those ideals are.  If these are not made explicit in other ways then individuals are likely to define these idiosyncratically and a high degree of variation in beliefs is likely to accumulate.  That these differences in belief do not necessarily lead to changes in liturgical practices suggests that beautiful, old churches can act as components of cultural canalization.  They become physical means by which underlying variation is, if not suppressed, then at least subsumed in a way that allows the outward appearance of the church, its phenotype if you will, to remain unchanged.

Substrate Neutral Inheritance Systems

My preoccupation with cultural robustness and evolvability has naturally caused me to think frequently about the problem of cultural inheritance.  If we take a broad definition of culture to be non-genetic, non-epigenetic information that is socially transmitted, then culture becomes a Darwin machine like any other. For those unfamiliar with the term, a Darwin machine is any iterative process in which heritable variation is generated and subsequently undergoes some sort of selection.  The components necessary for creating a Darwin machine, then, are variation, selection and inheritance.

Note that this formulation is substrate neutral.  In other words, it does not depend on what the media of variation, selection and inheritance are.  Although the specific details will change, the same general logic applies whether we are talking about genetic systems, certain kinds of evolutionarily inspired computer algorithms or, presumably, culture.  This makes the notion of a Darwin machine potentially quite powerful in its ability to describe and understand many different kinds of systems from within a common framework.  Unfortunately, though, there remains much work to do in order to realize this potential.  In particular, to become more broadly applicable the individual components that make up Darwin machines must also be framed in substrate neutral terms.

To take but one of the necessary ingredients into consideration, how could inheritance systems be framed in substrate neutral terms?  To begin to imagine this I think it makes sense to start by considering the necessary components that make up the system we understand best, the genetic inheritance system.  So thoroughly studied has this system been that a central dogma has arisen around it that describes the flow of information within cells.  This flow begins with information storage in the form of DNA.  Almost every cell within a body contains a complete copy of all the genes necessary to build and maintain the organism.     However, not every gene is expressed at every moment.  Indeed, timing is critical for many cellular processes and so cells have evolved mechanisms to determine which genes should be turned on and off at specific times in response to environmental signals.  Once a gene is turned on, it is transcribed into an RNA intermediate which is, most often, translated into a protein product that performs some important function for the cell, be it structural, regulatory or metabolic.

At some level, carving this system up into essential components is a bit arbitrary.  Nevertheless, I think some general themes do emerge.  For instance, it seems an important component is some kind of information storage system.  Obviously, for inheritance to occur there must be some way of transmitting this information to new entities.  At the same time, there needs to be an information retrieval system and a crucial part of this information retrieval system would seem to be way of "reading" the environment to "know" what information is required and when it is needed.

Are these the minimal necessary components?  Would they be sufficient to establish an inheritance system?  Are all of them needed?  Are there other components missing from this list?  I would very much like to see more discussion along these lines and I welcome any insights others might have.

I recently had someone tell me that there was no need for new, substrate neutral terms.  He felt that genetic inheritance provided a sufficiently broad framework and that it could easily be expanded to accommodate other kinds of systems.  I think this is a mistake for at least two reasons.  First, I worry that using genetic terminology predisposes researchers to only look for the familiar.  While there are undoubtedly similarities in cultural and genetic inheritance systems, there are just as assuredly significant differences as well.  Foregrounding future work with genetically laden conceptual frameworks makes it likely that at least some of these differences could be completely overlooked.

Second, I believe that taking a step back to look at inheritance from a substrate neutral perspective produces new questions and opens space in which to explore them.  For instance, if it is true that an inheritance system needs some form of information storage then an obvious difference between genetic and cultural evolution is that the former contains information in a relatively concentrated from while the latter uses a distributed system.  This observation leads naturally to the question of how concentrated vs. distributed systems might respond differently to natural selection.  It similarly leads to questions about how information retrieval is achieved in a distributed system in a way that allows entities to respond adaptively to their environment.  I don't feel these same kinds of questions emerge as naturally when using analogical reasoning to expand a genetic framework.

Ultimate Sacred Postulates

I was finishing up Malley's How the Bible Works last night and came across this interesting idea, one that is congruent with some thoughts I had a few years back but never really followed up on:

In Rappaport's model, the most fundamental premises of a society are its "ultimate sacred postulates" (USPs).  USPs are distinguished from the other understandings present in a society in that USPs are nonempirical, beyond the reach of logical refutation, and regarded as unquestionable.  Examples of USPs given by Rappaport are the Shema of Judaism and the Shahada of Islam.  Such postulates have an important social function in that they define a community and thus serve as a kind of core around which the community can transform and adapt to circumstances while preserving its essential identity.  It is important for this function that they be neither empirically nor logically falsifiable, because this shelters them from every having to change.  Their nonempirical, often nearly tautologous nature makes them ideal foundations for community identity.  (pp. 137-138)

This passage brings together a number of strands of scholarship without referring to any of them.  For instance, it is resonant with my own interests in cultural robustness and evolvability.  Note in particular how an instance of robustness, the unchanging nature of USPs, is said here to form a core around which a community can adapt.  In other words, the presence of USPs allow a degree of evolvability by virtue of the fact that they can remain constant markers of group identity.  Presumably, if group identity were not so robust, then the social boundaries of that community might have to be renegotiated with every adaptive change, thus risking group cohesion at every twist and turn of a community's evolutionary trajectory.  The proximate mechanisms by which this robust trait is brought about is by placing USPs outside the realm of refutation, a very clever trick when you stop to think about it.

And, of course, this passage evokes, though likely unintentionally, Lin Ostrom's work.  Clear social boundaries are part of the very first design principle.  This naturally leads me to wonder if USPs might also accompany other design principles as well.  My work on religion and natural resource management doesn't currently touch on this question, but it wouldn't take much effort to launch a study of USPs and design principles from this project.  That isn't to say it wouldn't take a lot more work.  We'd basically have to code each instance we've found of religion playing a role in a design principle for whether a USP is evoked or not.  This might require more research into the specific beliefs involved than what we currently have in the database.  However, it might not if we could get by ignoring the requirement that USPs be "regarded as unquestionable" and instead focus exclusively on whether they are "beyond the reach of logical refutation."  For instance, I would be inclined to code the belief that ancestors are watching over a sacred grove as something beyond the reach of logical refutation.  This point could be argued, but it wouldn't be a bad first approximation, and one we could use our existing coding of case studies to address.

Needless to say, Rappaport has moved to the top of my reading list...

I was going to start a new blog entry for this last quotation from Malley, but it seems closely related to these ideas so I'll just continue here.  Malley makes the point that an important aspect of Evangelical Biblicism is the fact that the canonical texts are closed and well defined, making them clearly demarcated from other kinds of texts.  He then goes on to say:

This conventional boundary affords a different kind of flexibility.  By demarcating the boundary of scriptures very clearly, the content of the texts can be left unspecified.  So long as evangelicals can know what counts as a biblical text, they do not need to have a very elaborate knowledge of what is in those texts.  Their practice turns on establishing links between their ideas and some biblical text or other, and this can be done in ad hoc ways so long as one has some way of knowing what counts as a biblical text.  The closure of the canon affords openness in interpretation.  (pp. 150-151)

So once again we see an example in which robustness, in this case the rigidness of canonical boundaries, can lead to greater evolvability in the form of openness of interpretation.  Good stuff!

Caught Between Scylla and Charybdis

It's been many years since I've seen the names Scylla and Charybdis.  In fact, the last time I read those names was probably in middle school when I had something of an obsession for Greek mythology.  With so many years elapsed, I had to refer to Wikipedia just to be sure I remembered them correctly and, though the details had largely vanished from my mind, I did still retain the basic idea.  Scylla and Charybdis were two sea monsters situated on opposite sides of a narrow straight.  Sailors making a wide berth to avoid Scylla, a six headed beast, ran the risk of coming too close to Charybdis, a formerly beautiful daughter of Poseidon who became a hideous bladder that sucked in and spit out water in the ocean to form whirlpools.  Being caught between Scylla and Charybdis, then, is to be caught between a rock and a hard place, but with ghoulish monsters to make things more interesting.

So what brought these images back to my mind?  They were used as a metaphor in Brian Malley's How the Bible Works to describe the tension Evangelicals face when transmitting their interpretive tradition:

The interpretive tradition is perennially caught between the Scylla of interpretive freedom and the Charybdis of irrelevance:  to much hermeneutic freedom and the tradition disintegrates, loosing its epistemological appeal; too little interpretive freedom and the Bible becomes merely an irrelevant historical artifact, rather than the ever living word of God. (p. 124)

This is relevant not only to our collective work on tight vs. loose congregations but also to my own work on cultural robustness and evolvability.  On the latter point, I find Malley's observations particularly illuminating and worthy of further research at some point down the road.  According to him, the interpretive tradition received by lay people is relatively devoid of interpretive freedom.  People aren't really reading the Bible to search for new meaning.  Rather, they read the Bible in the search for relevance.  They do become skilled in finding Biblical passages that confirm beliefs they hold, but in terms of their personal reading of the Bible, they mostly seek to find ways in which what they are reading can speak to their lives at the moment.  When they find this kind of relevance, they perceive it to be God speaking to them through the intervening text.  Note that this is a very different relationship with a sacred text than what is common in, say, Jewish tradition in which each generation is encouraged to wrestle with the Torah and Talmud in order to create new meaning that speaks to an evolving world.

So where, then, is the source for new interpretations in Evangelical traditions?  How do they avoid the Charybdis of irrelevance?  Malley locates at least a partial answer to this question in Evangelical seminaries.  Ministers often undergo extensive training at institutions of higher education in which a true hermeneutic tradition is taught.  New generations of pastors, then, have the opportunity to read the sacred text anew and engage in a Biblical scholarship that can open up new possibilities.  Obviously, this is a relatively conservative process, constrained as it is by notions of what the previous generation of scholars, who are the current professors, deem acceptable deviance from the norms.  Nevertheless, it is a fertile ground for at least some innovation and this, then, after undergoing its own kinds of selection processes, can leak its way into the more general population of believers, who will generally accept it without much critical thought.  This dynamic strikes me as an excellent example of robustness and evolvability at work.

Mind = blown

I don't remember what specifically prompted me to order Brian Malley's How the Bible Works:  An Anthropological Study of Evangelical Biblicism, but it arrived late last week and I've spent most of today devouring it. However the book captured my attention, it has so far been well worth the read and I have no doubt but that I'll be quoting it in our Bible as Cultural Genotype manuscript.

Of all the insights it's given me though, the one that stands out most strongly in my mind after a solid day of reading came in the introduction. I'm still trying to wrap my mind around it and its implications so for now I'll simply quote a thought provoking paragraph (p. 8):

The presumption of textual meaning, it seems to me, is a specific case of the general principle proposed by Dan Sperber and Deirdre Wilson (1995), that although humans generally transmit only partial and ambiguous representations of the messages they intend to communicate, listeners' presumption of an intended message's relevance enables them to select, from among the possible interpretations, the one intended by the speaker.  On Sperber and Wilson's view, all communicative signals are partial and ambiguous representations of their intended messages.  The recipients of signals are therefore confronted with the task of sorting out which of the possible interpretations is intended by the speaker.  They are aided in this task by the speaker's implicit promise that the signal is as appropriate as possible for the intended message (Grice 1989).  Sperber and Wilson give a cognitive explication of this promise:  the speaker, in attracting the listener's attention and offering an utterance, implicitly guarantees that the informational value of the intended message is greater than the energetic cost of cognitively processing it.  The listener recognizes this implicit guarantee, and selects the first interpretation that meets this standard of relevance.  It may be that further interpretations could be explored with more cognitive effort, but once the promise of relevance is satisfied, interpretation stops.  (Of course, the guarantee of relevance may not be given in good faith, or a speaker may misjudge the conditions of relevance for the listener, or a number of other things might go wrong but in general, the principle of relevance guides the listener to the speaker's intended meaning.)  In ordinary conversations, then, interpretation is both initiated and guided by the expectation of relevant meaning.

In other words, "In a sense, the meaning arises only because it is presumed."  (p. 8)

Food for thought, presuming of course that all this really means something.