Artifacts as patches: The marginal value theorem and stone tool lifeh histories

North American researchers interested in explaining technological variation and change as a consequence of adaptive problem solving have gravitated toward two conceptual approaches: what is broadly termed, following Nelson ’s (1991) terminology, the study of “Technological Organization” (TO); and Human Behavioral Ecology (HBE). Although they have somewhat dif erent intellectual foundations, the study of technological organization and human behavioral ecology actually share many fundamental goals and presuppositions. Both seek to understand human behavior in terms of economic constraints and payoffs, costs and benefits. Both assume that behavioral alternatives that are closer to optimal will tend to become more common over time, holding conditions constant (all other things being equal). Both focus on energy or time as key currencies in understanding technological behavior. Both assume that variation in technological behavior is not directly subject to natural selection but reflects flexibility in the human behavioral phenotype. HBE goes a step further, assuming that the cognitive apparatus that governs decision making and variation in the behavioral phenotype is under selection, and that selection favors cognitive mechanisms that more effectively arrive at optimal solutions (see Shennan 2008), a proposition also known as the phenotypic gambit (Grafen 1984; Smith and Winterhalder 1992:33). TO is silent on this matter: it assumes economic rationality but does not inquire as to its origins. Both have addressed questions of artifact design and technological investment.