Modeling reproductive decisions with simple heuristics

Abstract

AbstractBACKGROUNDMany of the reproductive decisions that humans make happen without much planning or forethought, arising instead through the use of simple choice rules or heuristics that involve relatively little information and processing. Nonetheless, these heuristic-guided decisions are typically beneficial, owing to humans' ecological rationality - the evolved fit between our constrained decision mechanisms and the adaptive problems we face.OBJECTIVEThis paper reviews research on the ecological rationality of human decision making in the domain of reproduction, showing how fertility-related decisions are commonly made using various simple heuristics matched to the structure of the environment in which they are applied, rather than being made with information-hungry mechanisms based on optimization or rational economic choice.METHODSFirst, heuristics for sequential mate search are covered; these heuristics determine when to stop the process of mate search by deciding that a good-enough mate who is also mutually interested has been found, using a process of aspiration-level setting and assessing. These models are tested via computer simulation and comparison to demographic age-at-first-marriage data. Next, a heuristic process of feature-based mate comparison and choice is discussed, in which mate choices are determined by a simple process of feature-matching with relaxing standards over time. Parental investment heuristics used to divide resources among offspring are summarized. Finally, methods for testing the use of such mate choice heuristics in a specific population over time are then described.1. IntroductionHumans make a variety of reproductive decisions throughout their lives, with the most important including who to choose as a mate, when to have offspring with that mate, and how to raise the children that result. Some of these decisions are consciously planned with great deliberation; others (probably the majority) may come about without deep thought, guided instead by simple strategies or rules of thumb and shaped by external environmental factors. And yet these common, less planned, more intuitive decisions often work out well in terms of reproductive success, leading to healthy members of the next generation. This happens despite the great uncertainty that may surround determining who will be a good mate or what is an appropriate way to provision one's children, and without needing to gather a lot of information about the possible courses of action before choosing a mate. In this paper, we outline some of the ways that simple heuristics can be used in making reproductive decisions, and how they can be studied. We begin with an overview of the perspective of ecological rationality within which this research is situated, before proceeding to cover investigations of heuristic rules for mate search and choice, parental provisioning of individual offspring, and decisions related to fertility.This research program on simple heuristics and their effectiveness in appropriate settings represents a new approach to questions in demographics. First, it builds a theoretically motivated, psychologically grounded framework for predicting and understanding population-level patterns of fertility-related behavior, based on the individual-level decision mechanisms that people actually use. Rather than the economists' vision of human decision making employing all of the available information, fully known preferences, and fully processed implications of both, simple heuristics are built on realistic assumptions of the limited information, time, and thinking that people are actually able to bring to bear on most of their choices. Second, this research program uses simulation models of these simple decision heuristics, in conjunction with empirical data from experiments and field observations, to test the effectiveness of the heuristics in different situations and their implications at the population level. …