If you have ever taken a course in life history theory or evolutionary ecology, you may have gotten the impression that all organisms are capitalist optimizers who spend their lives subconsciously trading vital assets in the fitness maximizing pursuit of adaptive returns. In this no-cost primer on life history, we are introduced to the evolutionary market:
Life history theory seeks to explain how natural selection and other evolutionary forces shape organisms to optimize their survival and reproduction in the face of ecological challenges posed by the environment. The theory does so by analyzing the evolution of fitness components, so-called life history traits, and how they interact: size at birth; growth pattern; age and size at maturity; number, size, and sex of offspring; age-, stage- or size-specific reproductive effort; age-, stage- or size-specific rates of survival; and lifespan.
The classical theory treats life history evolution as an optimization problem: given particular ecological factors (e.g., predators, nutrition) that affect an organism’s probability of survival and reproduction, and given limiting constraints and trade-offs intrinsic to the organism, what are the optimal values and combinations of life history traits that maximize reproductive success? To find the solution to this problem we need to understand its boundary conditions: (1) how extrinsic, environmental factors affect survival and reproduction; and (2) how intrinsic connections among life history traits (trade-offs) and other constraints limit whether and how life history traits can evolve.
Once these conditions have been understood and defined, life history models can be used to answer questions such as: How small or large should an organism grow? At what age and size should it mature? How many times should it reproduce? How many offspring should it produce and what size should they be? For how long should it reproduce and how long should it live?
These are profitable questions, no doubt, and they can be answered with fancy Panglossian mathematical models which assume that animals are fully invested in fitness. Animals exist, in other words, to increase their offspring portfolio. This strategy leaves little time for leisure or play which might be seen as a short-term hedge, but which really amounts to a negative return on investment. Play can be accounted for as the precursor to the compounding, or mating strategy, that will bear interest babies. Play, seen this way, is just prudent evolutionary investing.
Profit and prudence aside, there are some questions not asked by life history theory. I was reminded of this while reading David Graeber’s Baffler essay, in which he wonders:
Why do animals play? Well, why shouldn’t they? The real question is: Why does the existence of action carried out for the sheer pleasure of acting, the exertion of powers for the sheer pleasure of exerting them, strike us as mysterious? What does it tell us about ourselves that we instinctively assume that it is?
Graeber’s musings on these questions bring to mind Henri Bergson’s élan vital and Friedrich Nietzsche’s will to power. There is some talk in the essay about lobsters. I like lobsters and often think about lobsters. But I don’t know how anyone can write about lobsters, as Graeber does, without reference to David Foster Wallace’s “Consider the Lobster.” It’s a masterpiece.
Lobsters aside, Graeber’s essay also connects with Robert Bellah’s Religion in Human Evolution: From the Paleolithic to the Axial Age. Bellah contends that mammalian play, as it uniquely developed over the course of hominin evolution, created the cognitive space required for “religious” concepts. While I would like to superfluously spend more writing-energy on this idea, I can’t do so now because this Homo ludens is out of time for non-paying play.