COMMENTARIES Attachment, Caregiving, and Parental Investment
Total Page:16
File Type:pdf, Size:1020Kb
Psychological Inquiry Copyright © 2000 by 2000, Vol. 11, No. 2, 84–123 Lawrence Erlbaum Associates, Inc. COMMENTARIES Attachment, Caregiving, and Parental Investment David C. Geary Department of Psychology University of Missouri at Columbia Bell and Richard’s position is very similar to Mac- gent on current conditions; for instance, if food is too Donald’s (1992) argument that attachment involves at scarce to ensure the survival or normal development of least two independent systems. The first is a fear-based offspring, then parents will often abandon these off- system that is essentially the same as that originally de- spring (Clutton-Brock, 1991). Stated somewhat differ- scribed by Bowlby (1969), and the second is a ently, from an evolutionary perspective, parental warmth-based system that is very similar to the investment is expected to be expressed contingent on caregiving system described by Bell and Richard. Both social (e.g., population density) and ecological (e.g., systems of attachment, as related to the parent–child availability of food) factors and on parental condition relationship, can be understood in terms of parental in- (e.g., health, social status). When parents invest in off- vestment (Trivers, 1972, 1974), as is described in the spring, some aspects of this investment are obligate, first section. The second section addresses a few mis- that is, essential for offspring survival, and other as- conceptions about evolution and proximate and ulti- pects may be expressed more conditionally, or mate causes. facultatively. For the latter, the investment may not be essential for survival, but if provided, it results in other Parental Investment benefits to offspring, such as an improvement in later social, and thereby reproductive, competitiveness. Parent–child attachment, whether involving prox- The long developmental period of humans and the imity-related systems or caregiving-warmth, is readily necessarily heavy cost of human parental investment understandable in terms of the more general topic of strongly argue that this investment is an evolved fea- parental investment; that is, parent–child attachment is ture of human social behavior, as indicated by Bell and a manifestation of the evolution of parental invest- Richard and others (e.g., Bowlby, 1969; Lovejoy, ment. Trivers (1974) defined parental investment as re- 1981; MacDonald, 1992). As with other species, it is sources (e.g., time, food, etc.) that are provided to likely that the selection pressure for human parental in- offspring at a cost to the parent; costs can be reproduc- vestment was reduced child mortality risks and per- tive (e.g., a delay in conceiving the next offspring) or haps improvements in the later social, and thereby in terms of the health and survival of the parent reproductive, competitiveness of children (Geary, (Clutton-Brock, 1991). This is not to say that each and 2000). The proximity-seeking feature of attachment every parental behavior is directly related to the par- described by Bowlby (1969) may reflect a form of ob- ent’s survival or later reproduction. Rather, the sys- ligate parental investment, whereas the tems that orient parents to their offspring, as in caregiving-warmth system described by Bell and maintaining proximity and promoting parental invest- Richard and by MacDonald (1992) may reflect a more ment (e.g., in terms of time and material resources), are conditional form of parental investment. costly to parents and would not evolve unless they pro- Features of proximity seeking, such as offspring vided a reproductive benefit to parents. In nonhuman distress calls, are found in many species of primate and species, the primary reproductive benefit of parental mammal (Hofer, 1987) and reflect a way of soliciting investment is an increase in offspring survival rates parental investment that has a long evolutionary his- (Clutton-Brock, 1991). tory. For instance, many features of proximity seeking, An evolved bias to invest in offspring does not in such as stranger anxiety and separation anxiety, are any way mean that all parents at all times will invest in found in all human societies and are manifested in the their offspring (Daly & Wilson, 1981). For many non- same way and appear at about the same age in one of human species, parents will often abandon offspring or our closest relatives, the chimpanzee (Pan troglodytes; otherwise reduce levels of parental investment, contin- Bard, 1995; Eibl-Eibesfeldt, 1989). The apparently ho- COMMENTARIES mologous attachment patterns in humans and chim- some conditions (Daly & Wilson, 1981)—with a long panzees suggest that this form of human parental evolutionary history. The caregiving-warmth feature investment has at least a 6 million–year evolutionary of attachment is less common across species and, thus, history, the estimated age of the ancestor common to likely has a much shorter evolutionary history. More- humans and chimpanzees (e.g., Vrba, 1985). In fact, over, the human caregiving and warmth feature does the ubiquity of proximity-related features of attach- not appear to be an obligate form of parental invest- ment across many species and the increased mortality ment in humans but rather appears to be expressed risks associated with separation from the primary care- facultatively, that is, only under certain social and eco- giver (e.g., Goodall, 1986) strongly suggest that this logical conditions (MacDonald, 1992). aspect of attachment predated hominid evolution. The caregiving-warmth feature of parental invest- Proximate and Ultimate Causes ment, in contrast, is not a feature of attachment in most other mammals or primates and, in fact, is absent in The ultimate selection pressures for any form of pa- many human societies (Geary, 1998; MacDonald, rental investment—obligate or conditional—are im- 1992). Although the proximate mechanisms are not provements in offspring survival rates and, in some fully understood, it appears that high levels of conflict species, including humans, an improvement in the so- within the wider society or within the family result in cial and later reproductive competitiveness of off- reductions in parental empathy and responsiveness to spring (Clutton-Brock, 1991; Geary, 2000). The children and in harsh child-rearing practices (e.g., associated proximate causes constitute all of those painful physical punishment). At the same time, most cognitive, social, and emotional systems that result in of these parents show the proximity-related behaviors the administration of parental investment, independ- (e.g., responding to distress signals) described by ently of whether this investment is subjectively com- Bowlby (1969; MacDonald, 1992). Although these fortable or cost free to the parent. Bell and Richard harsh child-rearing practices are sometimes described argue that “no rational self-interested person would as abusive and pathological, the possibility that these voluntarily pay the emotional and monetary costs of are adaptive and facultatively expressed responses to parenting” (this issue). This statement represents a harsh social conditions needs to be seriously consid- confusion of ultimate and proximate mecha- ered. In fact, MacDonald argued that harsh child rear- nisms—even subjectively taxing proximate costs, such ing “shuts down” the neurobiological and associated as anxiety, distress, and lost resources, will evolve, if emotional systems that support interpersonal warmth they result in a reproductive advantage and thus results in a more guarded, aggressive, and ex- (Clutton-Brock, 1991). In other words, genetic self-in- ploitative social style. Although maladaptive in some terest—of which parental investment is but one exam- contexts, this type of social style is functional in other ple—and here-and-now personal self-interest (e.g., social contexts—in theory, those contexts that promote personal comfort) are not the same. harsh parental child rearing. In fact, selection could support heavy emotional It appears that caregiving, as described by Bell and and other costs of parental investment if these costs re- Richard, and warmer parent–child relations are more sulted in behaviors that reduced the mortality risks of commonly found in high-resource, low-conflict social children. As an example, parental grief associated with ecologies and in settings with low mortality rates and a the loss of a child and the associated examination of relatively even distribution of resources among the lo- “how did this happen” could prompt behavioral cal population (Belsky, Steinberg, & Draper, 1991; changes that reduced risks to later children. Moreover, MacDonald, 1992; Wilson & Daly, 1997). In these set- there are other mechanisms, such as fear when the tings, a cooperative social style—one characterized by child is threatened, empathy as described by Bell and warm and reciprocal social relationships among Richard, and child characteristics (e.g., cute) that pro- adults—may be more adaptive than the guarded and mote parental investment (Trivers, 1974). On a per- aggressive social style described above. In this view, sonal level, this investment often exacts emotional and cooperative social relationships among adults, com- monetary costs on the parent, to the benefit of the child. bined with living in a low-risk and high-resource envi- But if this investment increases the chances that these ronment, result in the facultative expression of the children will reach adulthood and have children of features of caregiving described by Bell and Richard. their