Evolutionary Developmental Psychology - Wikipedia
Evolutionary developmental psychology (EDP) is a research paradigm that applies the basic principles of evolution by natural selection, to understand the development of human behavior and cognition. It involves the study of both the genetic and environmental mechanisms that underlie the development of social and cognitive competencies, as well as the epigenetic (gene-environment interactions) processes that adapt these competencies to local conditions.
EDP considers both the reliably developing, species-typical features of ontogeny (developmental adaptations), as well as individual differences in behavior, from an evolutionary perspective. While evolutionary views tend to regard most individual differences as the result of either random genetic noise (evolutionary byproducts) and/or idiosyncrasies (for example, peer groups, education, neighborhoods, and chance encounters) rather than products of natural selection, EDP asserts that natural selection can favor the emergence of individual differences via "adaptive developmental plasticity." From this perspective, human development follows alternative life-history strategies in response to environmental variability, rather than following one species-typical pattern of development.
EDP is closely linked to the theoretical framework of evolutionary psychology (EP), but is also distinct from EP in several domains, including: research emphasis (EDP focuses on adaptations of ontogeny, as opposed to adaptations of adulthood); consideration of proximate ontogenetic; environmental factors (i.e., how development happens) in addition to more ultimate factors (i.e., why development happens). These things of which are the focus of mainstream evolutionary psychology.
Broad Theoretical Assumptions of EDP:
- All evolutionarily-influenced characteristics in the phenotype of adults develop, and this requires examining not only the functioning of these characteristics in adults but also their ontogeny.
- All evolved characteristics develop via continuous and bidirectional gene-environment interactions that emerge dynamically over time.
- Infants and children are prepared by natural selection to process some information more readily than others.
- Development is constrained by genetic, environmental, and cultural factors.
- Infants and children show a high degree of developmental plasticity and adaptive sensitivity to context.
- An extended childhood is needed in which to learn the complexities of human social communities.
- Many aspects of childhood serve as preparations for adulthood and were selected over the course of evolution (deferred adaptations).
- Some characteristics of infants and children were selected to serve an adaptive function at specific times in development and not as preparations for adulthood (ontogenetic adaptations).
Developmental Adaptations
EDP assumes that natural selection creates adaptations for specific stages of development, rather than only specifying adult states. Frequently, EDP researchers seek to identify three such adaptations:
Deferred Adaptations
Some behaviors or traits exhibited during childhood or adolescence may have been selected to serve as preparations for adult life, a type of adaptation that evolutionary developmental psychologists have named "deferred adaptations". Sex differences in children's play may be an example of this type of adaptation: higher frequencies of "rough-and-tumble" play among boys, as well as content differences in fantasy play (cross-culturally, girls engage in more "parenting" play than boys), seem to serve as early preparation for the roles that men and women play in many extant contemporary societies, and, presumably, played over human evolutionary history.
Ontogenetic Adaptations
In contrast to deferred adaptations, which function to prepare individuals for future environments (i.e., adulthood), ontogenetic adaptations adapt individuals to their current environment. These adaptations serve a specific function during a particular period of development, after which they are discarded. Ontogenetic adaptations can be physiological (for example, when fetal mammals deriving nutrition and oxygen from the placenta before birth, but no longer utilize the placenta after birth) and psychological. David F. Bjorklund has argued that the imitation of facial gestures by infants, which has a predictable developmental window and seemingly different functions at different ages, shows evidence of being an ontogenetic adaptation.
Conditional Adaptations
EDP emphasizes that children display considerable developmental plasticity, and proposes a special type of adaptation to facilitate adaptive developmental plasticity, called a conditional adaptation. Conditional adaptations detect and respond to relevant environmental cues, altering developmental pathways in ways which better adapt an individual to their particular environment. These adaptations allow organisms to implement alternative and contingent life history strategies, depending on environmental factors.
Related Research
Social Learning and the Evolution of Childhood
The social brain (or Machiavellian) hypothesis posits that the emergence of a complex social environment (e.g., larger group sizes) served as a key selection pressure in the evolution of human intelligence. Among primates, larger brains result in an extension of the juvenile period, and some authors argue that humans evolved (and/or expanded) novel developmental stages, childhood and adolescence, in response to increasing social complexity and sophisticated social learning.
While many species exhibit social learning to some degree and seemingly possess behavioral traditions (i.e., culture), humans can transmit cultural information across many generations with very high fidelity. High fidelity cultural learning is what many have argued is necessary for cumulative cultural evolution, and has only been definitively observed in humans, although arguments have been made for chimpanzees, orangutans, and New Caledonian crows. Developmentally-oriented researchers have proposed that over-imitation of behavioral models facilitates cultural learning, a phenomenon which emerges in children by age three and is seemingly absent in chimpanzees.
Cooperation and Prosociality
Behaviors that benefit other members of one's social group, particularly those which appear costly to the prosocial or "altruistic" individual, have received considerable attention from disciplines interested in the evolution of behavior. Michael Tomasello has argued that cooperation and prosociality are evolved characteristics of human behavior, citing the emergence of "helping" behavior early in development (observed among 18-24 month old infants) as one piece of evidence. Researchers investigating the ontogeny and evolution of human cooperation design experiments intended to reveal the prosociality of infants and young children, then compare children's performance with that of other animals, typically chimpanzees. While some of the helping behaviors exhibited by infants and young children has also been observed in chimpanzees, preschool-age children tend to display greater prosociality than both human-raised and semi-free-ranging adult chimps.
Life History Strategies and Developmental Plasticity
EDP researchers emphasize that evolved strategies are context dependent, in the sense that a strategy which is optimal in one environment will often be sub-optimal in another environment. They argue that this will result in natural selection favoring "adaptive developmental plasticity," allowing an organism to alter its developmental trajectory in response to environmental cues.
Related to this is the idea of a life history strategy, which can be conceptualized as a chain of resource-allocation decisions (e.g., allocating resources towards growth or towards reproduction) that an organism makes. Biologists have used life history theory to characterize between-species variation in resource-allocation in terms of a fast-slow continuum (see r/K selection theory), and, more recently, some anthropologists and psychologists have applied this continuum to understand within-species variation in trade-offs between reproductive and somatic effort.
Some authors argue that childhood environment and early life experiences are highly influential in determining an individual's life history strategy. Factors such as exposure to violence, harsh child-rearing, and environmental unpredictability (e.g., frequent moving, unstable family composition) have been shown to correlate with the proposed behavioral indicators of "fast" life history strategies (e.g., early sexual maturation, unstable couple relationships, impulsivity, and reduced cooperation), where current reproduction is prioritized over future reproduction.
https://en.wikipedia.org/wiki/Evolutionary_developmental_psychology
An Introduction to Evolutionary Developmental Psychology
Karin Machluf, James R. Liddle, David F. Bjorklund,
2014
Abstract
Evolutionary developmental psychology represents a synthesis of modern evolutionary theory and developmental psychology. Here we introduce the special issue on evolutionary developmental psychology by briefly discussing the history of this field and then summarizing the variety of topics that are covered. In this special issue, leading researchers provide a collection of theoretical and empirical articles that highlight recent findings and propose promising areas for future research.
Introduction
Evolutionary and developmental theory have had a tumultuous history, occasionally being viewed as detached, incompatible fields of study. However, this was not the case when the theory of evolution by natural selection was originally proposed by Darwin (1859), who acknowledged in The Origin of Species the relationship between development and his theory, painstakingly describing the process of embryology and using it as part of his indisputable evidence for evolution. Emphasizing the importance of development, Darwin (1860) once wrote, “Embryology is to me by far the strongest single class of facts in favor of change of forms, and not one, I think, of my reviewers has alluded to this.”
The separation of the two fields was, arguably, due primarily to the discovery of genetics and the Modern Synthesis (Huxley, 1942) and the perceived implications of this revised version of evolutionary theory. The field became strictly “gene-centric,” incorporating Mendelian genetics into the theory of natural selection. Although this resulted in the general dismissal of development, it was a massive advancement for the theory of evolution. The Modern Synthesis reflected the official acceptance of evolution by natural section by the scientific community. Unfortunately, development became an afterthought, perfectly highlighted by Richard Dawkins' (2006/1976) assumption that “The details of embryological developmental processes, interesting as they may be, are irrelevant to evolutionary considerations” (p. 62).
The field of evolutionary psychology was born when pioneering psychologists realized that modern evolutionary theory could be applied to cognitive processes, and thus could potentially explain and predict many aspects of human behavior (see Buss, 1995; Daly and Wilson, 1988; Tooby and Cosmides, 1992). Understandably, the primary focus of mainstream evolutionary psychology was on adult behavior initially. After all, adults do the “stuff” of mating, arguably the critical measure of evolutionary success.
This focus on adult behavior and cognition served the field well. It allowed a deeper insight into the question of why humans behave the way they do, rather than just answering how do humans behave. Development, although interesting and necessary for reaching the crucial adult period, was seen as incidental as it did not seem to aid in answering these important “why” questions.
The survival of infancy and childhood is no easy feat, though; surviving in childhood is just as risky, if not more so, than surviving in adulthood. In fact, the likelihood of a newborn dying before reaching adolescence has historically been approximately 50% in traditional societies (Volk and Atkinson, 2008), and was likely higher for our ancestors. This makes childhood the “crucible” of evolution (Volk and Atkinson, 2008), such that any cognitive or behavioral adaptations that increase the chance of surviving from childhood to adulthood should be favored by natural selection. The realization that natural selection operates at all stages of the lifespan, and possibly operates more strongly at some stages, especially early in development, led to the formation of evolutionary developmental psychology (see Bjorklund, Ellis, and Rosenberg, 2007; Bjorklund and Pellegrini, 2000, 2002; Burgess and MacDonald, 2005; Ellis and Bjorklund, 2005; Geary and Bjorklund, 2000).
Evolutionary developmental psychology was defined by Bjorklund and Pellegrini (2002) as:
the study of the genetic and environmental mechanisms that underlie the universal development of social and cognitive competencies and the evolved epigenetic (gene-environment interactions) processes that adapt these competencies to local conditions; it assumes that not only are behaviors and cognitions that characterize adults the product of selection pressures operating over the course of evolution, but so also are characteristics of children's behaviors and minds. (p. 4)
In other words, this field represents the application of the basic principles of evolution to contemporary human development, postulating that natural selection operates throughout ontogeny. It seeks to answer the question of how inherited behaviors and cognitions get expressed in the phenotypes of individuals across the lifespan.
Integrating Evolutionary and Developmental Theory
A strict evolutionary approach usually encounters the problem of genetic determinism, the idea that genes directly cause, or determine, behavior (e.g., Lickliter and Honeycutt, 2003; Spencer et al., 2009) in that genes (perhaps, the basic units of inheritance) influence evolved behavior and cognitions, suggesting that there is little one can do to change “human nature.” Although evolutionary psychologists explicitly reject this view and acknowledge the interaction between genes and the environment, evolutionary developmental psychology specifies this relationship in more detail by adopting a developmental systems approach (Gottlieb, 2002, 2007), which states that genes and the environment interact at all levels of organization, from one's genes through society. Central to the developmental systems approach is the concept of epigenesis, which Gilbert Gottlieb (1991) defined as “the emergence of new structures and functions during the course of development” (p. 7). New structures or behaviors are the result of the bidirectional relationship between all levels of biological and experiential factors, with function at one level influencing function at adjoining levels and constant feedback in between. Because the experiences of every individual are unique, there should be substantial plasticity (i.e., individual differences) in development. Most individuals, however, share many features. Evolutionary developmental psychology posits that this is because individuals inherit a species-typical environment, as well as a species-typical genome. Development follows a species-typical pattern given that individuals within the species grow up in environments that are similar to those of their ancestors.
An evolutionary developmental perspective posits that an extended childhood is necessary to acquire the skills needed for the complexities of the human social world. Human children have a longer juvenile period than any other mammal, suggesting that there is a substantial benefit associated with this costly trait, such as allowing for the development of a large brain capable of acquiring the skills necessary to navigate the social world (Bjorklund, Cormier, and Rosenberg, 2005; Dunbar, 1995, 2010). The intricacies of the social world are highly varied, and acquiring the ability to compete and cooperate with other complex humans takes time.
Additionally, since natural selection operates throughout ontogeny, and not just when individuals are reproductively viable, evolutionary developmental psychology posits the existence of adaptations specifically associated with infancy and childhood. Rather than simply serving as preparation for adulthood, or representing incomplete versions of adult characteristics, some traits were selected for because they serve an adaptive function at a specific time in development. These are known as ontogenetic adaptations (Bjorklund, 1997). Ontogenetic adaptations emerge at different times in development and adapt the child for challenges specific to that time. These adaptations may then disappear when they are no longer functional. Deferred adaptations, on the other hand, are those properties of infancy and childhood that were selected for their function in preparing children for adulthood (Hernández Blasi and Bjorklund, 2003). These adaptation can be seen as “adult training,” and help children explicitly learn the skills necessary for adulthood.
Lastly, given the uncertainty of survival through childhood and the varying conditions throughout development over evolutionary history, evolutionary developmental psychologists argue that children have evolved behavioral and cognitive flexibility in order to direct their development in anticipation of adult environments. These take the form of what is termed conditional adaptations; that is, adaptations that are dependent on conditions of the immediate environment and serve to direct children's subsequent development (Boyce and Ellis, 2005).
Although evolutionary psychologists were initially reluctant to incorporate developmental ideas into their theories and research (and vice versa), the role of developmental thinking in explaining important aspects of human evolution has increased over the past decade. A recent special issue in Developmental Psychology (Ellis and Bjorklund, 2012, Vol. 48) examining development under risky and supportive environmental conditions provided a host of new and informative findings from an evolutionary perspective to a developmental audience. In a similar vein, this special issue serves to highlight the recent literature that integrates evolutionary and developmental perspectives, and present it to an evolutionary audience.
Overarching Topics of the Special Issue
Childhood context: Early family
This special issue begins by highlighting the classical findings that catalyzed the field of evolutionary developmental psychology. Webster, Graber, Gesselman, Crosier, and Schember (this issue) present a meta-analysis examining the age of menarche in girls from father-absent homes. Menarche is used as a clear indicator of the initial pubertal process in girls, approaching the benchmark of reproductive age. The timing of girls' (and all organisms') reproductive viability is, according to life history theory, an important milestone. In line with an evolutionary developmental perspective, life history theory states that a tradeoff between resources on somatic (physical) development versus reproductive efforts exists because a person cannot concurrently maximize all features of evolutionary fitness. Somatic development factors include physical growth, brain maturation, and social learning. Reproductive factors include sexual development, mating behaviors, gestation, and parenting. Choices along this somatic-reproductive continuum are made across a given lifespan, and these choices make up an organism's life-history strategy.
Early menarche suggests a different life-history strategy for girls than later menarche. Belsky, Steinberg, and Draper (1991) found that early environments can regulate and predict later reproductive strategies, at least in females. Their theory, termed psychosocial acceleration theory, later the basis for differential susceptibility, proposed that experiences in early childhood influence children's somatic and behavioral development, which subsequently affect pubertal timing and reproductive strategies that serve to match an adaptive life history strategy to the local environment.
From this framework, the early emergence of reproductive ability suggests that the early environment is substantially different (e.g., more stressful, less predictable; Ellis et al., 2012) than the environments experienced by girls with a later emergence of menarche. One measure of stress in early environment that is found to be of particular importance is father absence. The meta-analysis reported by Webster et al. (this issue) examines the variation in age of menarche as a function of father absence, providing further support for these principal findings, while underlining some new directions of inquiry that can further elucidate these effects.
Chasiotis, Bender, and Hofer (this issue) extend the findings that early environmental factors can serve to alter the context of childhood by examining both parental socioeconomic status (SES) and number of siblings as indicators of early environmental stress. Their primary measure is differences in implicit parenting motivation, a preverbal and, therefore, possibly evolutionarily relevant motivation for parenting behaviors. One of the most important trade-offs involves investment in one's offspring, suggesting that parental motivations, specifically implicit ones, may add to our understanding of the evolutionary importance of early childhood experiences. Furthermore, in order to steer away from simply examining W.E.I.R.D. populations (Henrich, Heine, and Norenzayan, 2010), Chasiotis and his colleagues collected data from Chinese, Cameroonian, Costa Rican, and German populations. The findings of this paper suggest that other factors contributing to early environments should be examined in order to get a fuller picture of the factors influencing children's life history strategies.
Navigating the social world
Although parental influences are highly important, they only serve as one part of a bigger picture in understanding the evolution of childhood. Humans evolved an extended childhood partially to allow for the child to be able to navigate through the complexities of the human social realm. Navigating the peer group represents a significant adaptive problem, and balancing and coping with conflict, competition, and cooperation are hypothesized to be focal developmental achievements of childhood.
Hawley (this issue) uses a life-history framework to present a theoretical model of competitive behaviors in the peer group (in childhood and adulthood), resource control theory, which posits that both aggressive (i.e, coercive) and prosocial (i.e., cooperative) behaviors serve adaptive functions when strategically implemented in the appropriate contexts. Her reformulation highlights the misconceptions of prosocial behaviors (its confusion with altruism or altruistic motivations) and aggressive behaviors (its confusion with negative, maladaptive outcomes that should always be eliminated). Similarly, Ingram (this issue) examines the function and development of indirect and direct aggression and how the expressions of aggression shift across development. Martin, Davies, and MacNeill (this issue) further the discussion of children coping with challenges and conflicts in the peer group by examining how children deal with hostile peer relationships and guard themselves from interpersonal threat. Conversely, O'Brien (this issue) examines an evolutionary model for the development of prosociality. He proposes a model consisting of two psychological mechanisms, one domain specific and the other domain general, that underlie the evolution of prosociality.
Toward consilience
The field of evolutionary psychology in general represents an important step toward consilience, or the unification of different branches of knowledge (Wilson, 1999). In addition to connecting the study of human behavior to evolutionary theory, it also has the potential to serve as a unifying framework across the currently disparate subfields of psychology (Shackelford and Liddle, 2014). Evolutionary developmental psychology furthers this endeavor, both by unifying evolutionary and developmental theory and by providing a more nuanced framework for unifying the psychological sciences.
Although this special issue as a whole serves as an illustration of progress toward consilience, the last several articles emphasize this goal in unique ways. Pandeirada, Pires, and Soares (this issue) present empirical work intersecting the fields of evolutionary, developmental, and cognitive psychology by investigating memory functioning in children. More specifically, they test the “survival processing” function of memory, in which memory performance is enhanced by encoding information with respect to its relevance in an imagined survival scenario (Nairne, Thompson, and Pandeirada, 2007). This article represents an important addition to the survival-processing effect literature not only by testing children, which has been done rarely up to this point, but also by testing a new cultural group, thereby expanding the generalizability of the results.
Rottman (this issue) propels consilience in a different way, by further integrating evolutionary and developmental approaches to human behavior and illustrating how each approach can inform the other. Whereas evolutionary developmental psychology often consists of applying an evolutionary perspective to better understand developmental phenomena, Rottman emphasizes the utility of the less common, converse approach: applying developmental evidence to inform and evaluate claims about evolved function. This approach is illustrated in this article by focusing on evaluating claims about the evolved function of disgust. By analyzing disgust in terms of its developmental trajectory and the flexibility of the inputs that elicit disgust, Rottman re-evaluates the functional hypothesis that disgust evolved to allow humans to avoid ingesting pathogens, and in doing so illustrates how this approach can be applied to arguably any topic within evolutionary developmental psychology.
Greve, Thomsen, and Dehio (this issue) discuss how play, which they argue to be a crucial deferred adaptation, might improve individuals' reproductive success. They argue that play provides children with the opportunity to be socially successful, which in turn is predictive of being reproductively successful. Using a cross-sectional questionnaire study, they are able to conclude that free play in childhood is a predictor of later social success, which they terme “the Fitness-Effect.”
Finally, Rosati, Wobber, Hughes, and Santon (this issue) further emphasize the goal of consilience by applying a comparative developmental approach to human cognition. This approach has the potential to advance our understanding of human cognition by investigating differences in the pace and pattern of cognitive development across species. Rosati et al. focus their analysis on object reasoning, foraging skills, and social cognition, but they also discuss how a comparative developmental approach can aid in tackling currently unsolved questions regarding human cognition, such as the development of theory of mind.
Conclusion
Evolutionary and developmental theory have not always been on the same page, but now more than ever researchers are acknowledging the importance of both ontogeny and phylogeny and working to understand the complex ways in which they interact to influence behavior across the lifespan. Both evolutionary psychologists and developmental psychologists can benefit from considering the ideas put forth by the unified field of evolutionary developmental psychology, and we hope that this special issue serves as a helpful collection of these ideas and their application across a variety of topics of interest to both camps.
References
https://journals.sagepub.com/doi/10.1177/147470491401200201
Basic Principles - (body-plan genes & modularity)
Evolutionary developmental biology is not yet a unified discipline, but can be distinguished from earlier approaches to evolutionary theory by its focus on a few crucial ideas. One of these is modularity: as has been long recognized, plants and animal bodies are modular: they are organized into developmentally and anatomically distinct parts. Often these parts are repeated, such as fingers, ribs, and body segments. Evo-devo seeks the genetic and evolutionary basis for the division of the embryo into distinct modules, and for the partly independent development of such modules.
Another central idea is that some gene products function as switches whereas others act as diffusible signals. Genes specify proteins, some of which act as structural components of cells and others as enzymes that regulate various biochemical pathways within an organism. Most biologists working within the modern synthesis assumed that an organism is a straightforward reflection of its component genes. The modification of existing, or evolution of new, biochemical pathways (and, ultimately, the evolution of new species of organisms) depended on specific genetic mutations. In 1961, however, Jacques Monod, Jean-Pierre Changeux and François Jacob discovered within the bacterium Escherichia coli a gene that functioned only when "switched on" by an environmental stimulus.[4] Later, scientists discovered specific genes in animals, including a subgroup of the genes which contain the homeobox DNA motif, called Hox genes, that act as switches for other genes, and could be induced by other gene products, morphogens, that act analogously to the external stimuli in bacteria. These discoveries drew biologists' attention to the fact that genes can be selectively turned on and off, rather than being always active, and that highly disparate organisms (for example, fruit flies and human beings) may use the same genes for embryogenesis (e.g., the genes of the "developmental-genetic toolkit", see below), just regulating them differently.
Similarly, organismal form can be influenced by mutations in promoter regions of genes, those DNA sequences at which the products of some genes bind to and control the activity of the same or other genes, not only protein-specifying sequences. In addition to providing new support for Darwin's assertion that all organisms are descended from a common ancestor, this finding suggested that the crucial distinction between different species (even different orders or phyla) may be due less to differences in their content of gene products than to differences in spatial and temporal expression of conserved genes. The implication that large evolutionary changes in body morphology are associated with changes in gene regulation, rather than the evolution of new genes, suggested that the action of natural selection on promoters responsive to Hox and other "switch" genes may play a major role in evolution.
Another focus of evo-devo is developmental plasticity, the basis of the recognition that organismal phenotypes are not uniquely determined by their genotypes. If generation of phenotypes is conditional, and dependent on external or environmental inputs, evolution can proceed by a "phenotype-first" route, with genetic change following, rather than initiating, the formation of morphological and other phenotypic novelties.
https://psychology.fandom.com/wiki/Evolutionary_developmental_biology
Evolutionary Developmental Psychology:
A New Tool for Better Understanding Human Ontogeny
Carlos Hernndez Blasia & David F. Bjorklundb
Abstract
Evolutionary developmental psychology (EDP) is described and contrasted with previous (e.g., sociobiology) and other contemporary (e.g., mainstream evolutionary psychology) approaches to applying evolutionary theory to human behavior. We argue that understanding the ‘whys’ of development will help us acquire a better understanding of the ‘hows’ and ‘whats’ of development, and that in addressing the ‘whys’ an EDP perspective has the potential to provide a fuller understanding of human ontogeny. To this end, we propose five ways of applying EDP to contemporary issues of psychological development.
These include;
(1) classifying developmental features according to their evolutionary or functional status,
(2) proposing hypotheses and microtheories to explore the function of developmental traits,
(3) collecting data from different sources to test developmental evolutionary hypotheses,
(4) describing the phylogenetic and sociocultural history of human developmental features and
(5) designing 'evolutionary experiments’.
We argue that an EDP approach should not be seen as replacing other, more proximal, explanations of development, but rather that an evolutionary perspective should be incorporated in all accounts of human ontogeny. —Copyright © 2003 S. Karger AG, Basel...
What Is Evolutionary Developmental Psychology?
What today is called evolutionary psychology (EP) is an outgrowth of earlier movements in sociobiology, ethology and behavioral ecology that applies the basic principles of neo-Darwinian evolution to explain contemporary human behavior. According to EP, the human mind has been prepared by natural selection, operating over geological time, for life in a human group.
As such, according to Buss [1999], EP should be especially committed to answering four key questions:
(a) Why is the mind designed the way it is?
(b) How is the mind designed & what are its mechanisms?
(c) What are the functions of these mechanisms, and how are they organized?
(d) How does environmental input interact with these mechanisms to produce behavior?
Within this framework, evolutionary developmental psychology (EDP) can be viewed as a more specific theoretical perspective that has been broadly defined as the application of the basic principles of Darwinian evolution, particularly natural selection, to explain contemporary human development. It involves the study of the genetic and environmental mechanisms that underlie the universal development of social and cognitive competencies and the evolved epigenetic (gene-environment interactions) processes that adapt these competencies to local conditions; it assumes that not only are behaviors and cognitions that characterize adults the product of selection pressures operating over the course of evolution, but so are characteristics of children's behaviors and mindsí [Bjorklund and Pellegrini, 2002, p. 4].
From this point of view, EDP can be considered simultaneously as
(1) a general psychobiological framework to understand development,
(2) a source of experimental hypotheses and questions about development and
(3) a perspective to produce and test interpretations about developmental outcomes from a phylogenetic point of view.
The basic principles assumed by EDP can be summarized as follows [Bjorklund and Pellegrini, 2000, 2002].
(a) - The extended juvenile period of H. sapiens was favored by the need (and the time necessary) to master an increasingly complex social-technological envi- ronment. This extended youth had implications for the evolution and development of the brain as well as for psychological development.
(b) - Evolution favors ontogenetic diversity (variation), because humans live in a wide range of environments, and this requires flexible cognitive and behavioral systems to survive.
(c) - Concerning the effects of natural selection on ontogeny, EDP holds that;
(1) many aspects of childhood serve to prepare the way for adulthood and were selected over the course of evolution ñ we refer to these as deferred adaptations; many sex differences in social and cognitive abilities are good examples of deferred adaptations***;
(2) there have been different selection pressures on organisms at different times in ontogeny, and some characteristics of infants and children were selected in evolution to serve an adaptive function at that time in development and not to prepare them for later adulthood ñ we refer to these as ontogenetic adapta- tions [Oppenheim, 1981];
(3) there are aspects of childhood that did not evolve to solve any recurring problem and have not been shaped by natural selection but are a consequence of being associated with deferred or ontogenetic adaptations (ontogenetic by-products) or are simply random effects attributed to mutations, changes in the environment or aberrations of development (ontogenetic noise). This could be the case, for example, of the belly button (by-product) and the shape of one's belly button (noise), respectively [Buss et al., 1998].
***By using the term deferred adaptation, we do not mean to suggest any teleological implications, as if adaptations in childhood anitcipate adult needs. Rather, such adaptations likely function throughout life, adapting juveniles to their niche in childhood but also to the lives they will likely lead as adults. This is most apt to occur, we argue, when environmental conditions/pressures of the juvenile and adult period are similar, or even continuous (as social group composition would likely be in small groups of hunters and gatherers).
This is consistent with what we believe is the majority view among researchers in cognitive psychology, cognitive development and intelligence, that human cognition is multifaceted, consisting of both relatively domain-general and domain-specific abilities [Bjorklund, 2000; Fodor, 2000; Sternberg, 1997].
(d) - Many, but not all, evolved psychological mechanisms are proposed to be domain specific in nature [Fodor, 1983].
Consistent with contemporary thinking in much of cognitive science [Pinker, 1997], evolutionary psychologists [Buss, 1995; Tooby and Cosmides, 1992] have emphasized that humans (and other animals) evolved specific cognitive abilities to deal with recurring problems faced by our ancestors (e.g., obtaining food, acquiring a mate). Language abilities are often used as examples of domain-specific mechanisms. From this perspective, humans did not evolve general, all-purpose problem-solving faculties that can be applied across domains to any and all circumstances. We concur with the significance of evolved domain-specific abilities, but an EDP approach argues that domain-general mechanisms, such as speed of processing and working memory, also underwent selective pressure over the course of human evolution [Geary and Huffman, 2002].
(e) - Behaviors, cognitions and physical features that arise and change from infancy to old age emerge from an interaction of evolved mechanisms and the envi- ronment. As such, developmental patterns are not conceived as genetically predetermined (regardless of whether they are universal or not) but as a result of an evolved epigenetic process that adapts human competencies to local conditions, as described, for example, by the developmental systems approach [Gottlieb, 2000; Oyama, 2000].
(f) - Because the living conditions in which our species evolved (the environment of evolutionary adaptedness) are far different from the information age environments in which humans now live, many of our speciesí evolved behavioral and cognitive adaptations are not well suited to modern life and may actually be maladaptive.
As a whole, we see EP, and particularly EDP, as an overarching theory or perspective that can and should be applied to all realms of psychology and its ontogeny. From our view, all accounts of human behavior should include the question does this make sense from an evolutionary perspective?
Developmental science (as other disciplines concerned with historical processes) has traditionally assumed that knowing the past helps in understanding the present and in predicting the future. This is no less true, we argue, for phylogeny. Knowing the evolutionary history of a species can help explain present and future behavior, including the amelioration of some ëproblemí behaviors (e.g., child abuse, male-on-male violence, rape, reading/math disabilities) [Bjorklund and Bering, 2002; Bjorklund and Pellegrini, 2000; Geary and Bjorklund, 2000]. We argue that EDP can be a useful tool to achieve such purposes. However, at the same time, we propose that an EDP approach should not be seen as replacing other theoretical perspectives that attempt to account for the proximal causes of behavior. Rather, evolutionary developmental accounts should be seen as adjuncts to other theoretical accounts (and vice versa) [Bjorklund, 1997].
EDP uses the extant knowledge of how development and evolution proceed and integrates it into a single, hopefully coherent, perspective. This perspective is based on a number of other well-developed theories, both in ontogeny and in phylogeny, is subject to falsification and to modification as new information/ideas are introduced and can generate/test specific lower-level theories and hypotheses. In some cases, we will surely oversimplify both development and evolution, and per- haps in other cases make the processes more complicated than they actually are. But we strongly believe that the application of evolutionary ideas to the study of human development, with a critical evaluation of such research and theory, will advance our science immeasurably and may serve as a common ground for devel- opmental researchers studying disparate topics.
https://www.jstor.org/stable/26763760?seq=1#metadata_info_tab_contents
