Differentiating Between Effects And Functions

A few days ago, I had the misfortune of forgetting my iPod when I got to the gym. As it turns out, I hadn’t actually forgotten it; it had merely fallen out of my bag in the car and I hadn’t noticed, but the point is that I didn’t have it on me. Without the music that normally accompanies my workout I found the experience to be far less enjoyable than it normally is; I would even go so far as to say that it was more difficult to lift what I normally do without much problem. When I mentioned the incident to a friend of mine she expressed surprise that I actually managed to stick around to finish my workout without it; in fact, on the rare occasions I end up arriving at the gym without any source of music, I typically don’t end up even working out at all, demonstrating the point nicely.

“If you didn’t want that bar to be crushing your windpipe, you probably shouldn’t have forgotten your headphones…”

In my experience, listening to music most certainly has the effect of allowing me to enjoy my workout more and push myself harder. The question remains, however, as to whether such effects are part of the function of music; that is to ask do we have some cognitive adaptation(s) designed to generate that outcome from certain given inputs? On a somewhat related note, I recently got around to reading George C Williams book, Adaptation and Natural Selection (1966). While I had already been familiar with most of what he talked about, it never hurts to actually go back and read the classics. In the book, Williams makes a lot of the above distinction between effects and functions throughout the book; what we might also label as byproducts and adaptations respectively. A simple example would demonstrate the point: while a pile of dung might serve as a valuable resource for certain species of insects, the animals which produce such dung are not doing so because it benefits the insects; the effect in this case (benefiting insects) is not the function of the behavior (excreting wastes).

This is an important theoretical point; one which Williams repeatedly brings to bear against the group selection arguments that people were putting forth at the time he was writing. Just because populations of organisms tend to have relatively stable population sizes – largely by virtue or available resources and predation – that effect does not imply there is a functional group-size-regulation adaptation activity generating that outcome. While effects might be suggestive of functions, or at least preliminary requirements for demonstrating function, they are not alone sufficient evidence for them. Adapted functionality itself is often a difficult thing to demonstrate conclusively, which is why Williams offered his now famous quote about adaptation being an onerous concept.

This finally brings us to a recent paper by Dunbar et al (2012) in which the authors find an effect of performing music on pain tolerance; specifically, it’s the performance of music per se, not the act of passively listening to it, that results in an increased pain tolerance. While it’s certainly a neat effect, effects are a dime a dozen; the question of relevance would seem to be whether this effect bears on a possible function for music. While Dunbar et al (2012) seem to think it does, or at least that it might, I find myself disagreeing with that suggestion rather strongly; what they found strikes me more as an effect without any major theoretical implications.

If that criticism stings too much, might I recommend some vigorous singing?

First, a quick overview of the paper: subjects were tested twice for their pain tolerance (as measured by the time people could stand the application of increasing pressure or holding cold objects), both before and after a situation in which they either performed music (singing, drumming, dancing, or practicing) or listened to it (varying the tempo of the music). In most cases it was the active performance of music which led to a subsequent increase in pain tolerance, rather than listening. The exception to that set of findings was that the groups that were simply practicing in a band setting did not show this increase, a finding which Dunbar et al (2012) suggest has to do with the vigor, likely the physical kind, with which the musicians were engaged in their task, not the performance of music per se.

Admittedly, that last point is rather strange from the point of view of trying to build a functional account for music. If it’s the physical activity that causes an increase in pain tolerance, that would not make the performance of music special with respect to any other kind of physical activity. In other words, one might be able to make a functional account for pain sensitivity, but it would be orthogonal to music. For example, in their discussion, the authors also note that laughter can also lead to an increase in pain tolerance as well. So really there isn’t much in this study that can speak to a function of music specifically. Taking this point further, Dunbar et al (2012) also fail to provide a good theoretical account as to how one goes from an increased pain tolerance following music production to increases in reproductive success. From my point of view, I’m still unclear as to why they bothered to examine the link between music production and pain the first place (or, for that matter, why they included dancing, since while dancing can accompany music, it is not itself a form of music, just like my exercise can accompany music, but it not music-related itself).

Dunbar et al (2012) also mention in passing at the end of their paper that music might provide some help to the ability to entrain synchronized behavior, which in turn could lead to increases in group cooperation which, presumably, they feel would be a good thing, adaptively speaking, for the individuals involved in said group. Why this is in the paper is also a bit confusing to me, since it appears to have nothing to do with anything they were talking about or researching up to that point. While it would appear to be, at least on the face of it, a possible theoretical account for a function of music (or at least a more plausible one than their non-existent reason for examining pain tolerance) nothing in the paper seems to directly or indirectly speak to it.

And believe you me, I know a thing or two about not being spoken to…

While this paper serves as an excellent example of some of the difficulties in going from effect to function, another point worth bearing in mind is how little gets added to this account by sketching out the underlying physical substrates through which this effect is generated. Large sections of the Dunbar et al paper is dedicated to these physiological outlines of the effect without many apparent payoff. Don’t get me wrong: I’m not saying that exploring the physiological pathways through which adaptations act is a useless endeavor, it’s just that such sketches do not add anything to an account that’s already deficient in the first place. They’re the icing on top of the cake; not it’s substance. Physiological accounts, while they can be neat if they’re your thing, are not sufficient for demonstrating functionality for exactly the same reasons that effects aren’t; all physiological accounts are, essentially, simply detailed accounts of effects, and byproducts and adaptations alike both have effects.

While this review of the paper itself might have been cursory, there are some valuable lessons to learn from it: (1) always try and start your research with some clearly stated theoretical basis, (2) finding effects does not mean you’ve found a function, (3) sketching effects in greater detail at a physiological level does not always help for developing a functional account, and (4) try and make sure the research you’re doing maps onto your theoretical basis, as tacking on an unrelated functional account at the end of your paper is not good policy; that account should come first, not as an afterthought.

References: Dunbar RI, Kaskatis K, Macdonald I, & Barra V (2012). Performance of music elevates pain threshold and positive affect: Implications for the evolutionary function of music. Evolutionary psychology : an international journal of evolutionary approaches to psychology and behavior, 10 (4), 688-702 PMID: 23089077

Williams, G.C. (1966). Adaptation and natural selection: A critique of some current evolutionary thought. Princeton University Press: NJ

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