Life History and Evolutionary Psychology 2
Life History Theory and Evolutionary PsychologyThe evolution of life is the result of a process in which variant forms compete to harvest energy from the environment and convert it into replicates of those forms. Individuals "capture" energy from the environment (through foraging, hunting, or cultivating) and "allocate" it to reproduction and survival-enhancing activities. Selection favors individuals who efficiently capture energy and effectively allocate it to enhance fitness within their ecological niche.Energy does not come for free. Were individuals able to expend unlimited energy at no cost, in principle they could evolve to grow and develop so rapidly they could begin reproducing immediately after birth, massively produce offspring, and preserve themselves such that they never age. In biological reality, however, individuals must live within finite energy "budgets" (themselves earned through energy and time expenditures), never spending more than they have available. Allocation of a finite budget entails trade-offs and hence forces decisions about the relative value of possible ways to spend. Acquiring one expensive item means giving up others; consumption today may entails less tomorrow.In the face of trade-offs, how should a budget be spent? People managing their personal expenses presumably spend it based on what they value (even if sometimes only fleetingly and later regrettably). Moreover, their decisions are often based on individual circumstances that, over time, change: Wealthy individuals can afford to spend more on luxury items than can the middle-class or poor; college students often see little value to saving for retirement until, through education, they gain better employment; people with steady, good incomes can afford to keep less as a buffer against bad times than those whose future incomes are uncertain.Selection favors organisms' strategies for allocating energy budgets on the basis of one criterion: The strategy that leads to the allocation of energy that, on average, results in the greatest fitness is the one that wins out over others. In this sense, selection is expected to result in "fitness-maximizing" or "optimal" strategies. (Of course, those strategies are "optimal" only in a restricted sense: They are optimal under the constraints imposed by trade-offs between Life History and Evolutionary Psychology 3 allocations of energy; see Parker & Maynard Smith, 1991 1 ). Just as strategies of how to spend money depend on individual circumstances, so too do optimal energy allocations: Newborns optimally allocate energy differently from adults; healthy individuals optimally allocate differently from those with infectious disease; the best allocation strategy for individuals in stable circumstances differs from that of individuals whose future circumstances are unpredictable.Fundamentally, Life History Theory (LHT) provides a framework that addresses how, in the face of trade-offs, organisms should allocate time and energy to tasks and traits in a w...