The pleistocene mind: A critical review of evolutionary psychology, and an introduction to intelligent design psychology.

Researchers and scientists in evolutionary psychology, a new theoretical perspective within the field of psychology, have proposed striking insights into human behavior based on our long evolutionary past. These insights and proposals have gained support over the past decade among psychologists, but they have also been roundly criticized. According to proponents, the field of evolutionary psychology seeks to synthesize modern evolutionary theory with the latest psychological findings, informed by the field of evolutionary biology. This new field of evolutionary psychology claims to have discovered insights about our universal human nature, pointing to our supposed millions of years of evolution during the Pleistocene era as the main designer of our minds. Evolutionary psychologists point to such universal phenomenon as feelings of shame, cheater-detectors, standards for female beauty, mate selection, and child abuse by step-fathers as evidence for specialized brain circuits that were designed by evolution. Ad apted to a life on the savannas, the human mind is composed of these functionally specialized circuits, and to fully understand behavior today we must understand the pressures of savanna life. Critics of this new discipline, including philosophers, scientists, and evolutionary biologists, have responded with serious counterpoints. This article provides a brief overview of the field and the arguments brought against EP, including evaluating both the empirical evidence and the theoretical underpinnings. Implications for those favoring a theistic worldview are also discussed, and an introduction is given to a new field called Intelligent Design Psychology.

Evolutionary psychology (EP) is a newly developing theoretical perspective within the field of psychology that has seen much growth over the past decade. According to key proponents (e.g., Buss et al., 1998) the field of evolutionary psychology "seeks to synthesize the guiding principles of modern evolutionary theory with current formulations of psychological phenomena" (p. 533). Barkow, Cosmides, and Tooby (1992) state that evolutionary psychology "is simply psychology that is informed by the additional knowledge that evolutionary biology has to offer, in the expectation that understanding the process that designed the human mind will advance the discovery of its architecture" (p. 3). Understanding the process that designed the mind is of central importance to EP, as our own particular mind architecture is shared with all other humans, and in fact underlies all of human behavior. EP believes that if we map out and understand this architecture, the longstanding riddles of human behavior will begin to make sen se.

Over the past decade, research in this new field has thrived, surprising to some only in the sense that it has taken so long. Darwin (1859/1958) himself ended his Origin of Species with the notable prediction that psychology would one day be based on his new theory and that "in the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation" (p. 346). This second Darwinian-based revolution has now dawned. The author of this country's most adopted introductory psychology textbook has given EP prominent space in recent revisions (i.e., Myers, 2001), devoting numerous pages to the new perspective and its findings. The number of articles and textbooks on the subject is also growing rapidly, and includes the influential Barkow, Cosmides, and Tooby's (1992) text The Adapted Mind, and the more recent How the Mind Works by Pinker (1997). There are also a host of academic articles and expanded reviews on EP (e.g., Badcock, 2000; Buss, 1995, 1998, 1999; Cosmides & Tooby, 1997; Crawford & Krebs, 1997; Tooby & Cosmides, 1992; Wright, 1995). The annual conference of the Human Behavior and Evolution Society (HBES) and the journal Ethology and Sociobiology, among others, serve the researchers in this growing field. As new academic departments spring up (e.g., the largest may be UC Santa Barbara's Center For Evolutionary Psychology), the future growth potential seems to finally validate Darwin's prophetic claim of 1859.

With such growth, however, has come concern. A number of recent works are critical of the field, within psychology (e.g., Looren de Jong & Steen, 1998; and others as found in this issue) and from those outside of the field. Evolutionists from other disciplines, such as Gould (2000) and Rose & Rose (2000) have referred to EP as "one of the most pervasive of present-day intellectual myths" (p. 1), claiming it is "not merely mistaken, but culturally pernicious" (p. 4). One critic has compared those in EP to religious missionaries "advocating a set of principles that define the meaning of life and seeking to convert others to their beliefs" (Nelkin, 2000, p. 23). The harshest critics come from evolutionary biologists, feminists, and some philosophers of science who recognize many of the difficulties inherent in trying to "inform psychology" via the "additional knowledge that evolutionary biology has to offer." Some of their criticism is appropriate and revealing, as it deals with the meaningful philosophical and scientific problems associated with the views of EP. Many of these critics are also reacting to the implications that are inherent in EP's theoretical and meta-theoretical perspectives (i.e., methodologies implicit in using biological concepts, such as adaptations). Admittedly, some of these implicit ideas threaten some rather cherished worldviews, like the powerful role of culture in shaping human behavior, and result in politically motivated reactions. Although both scientific and political criticisms will be noted in this paper, most of the attention will be given to the scientific (and/or philosophical) criticisms.

Psychologists interested in the integration of psychology and theology, regardless of their stance on the evolution-creation debate, would do well to take note of this newly emerging field. Whether one is a young-earth creationist or a theistic-evolutionist, the claims of EP are revolutionary, and there is much with which to disagree. However, it will be argued here that while many assumptions are counter or even hostile to a theistic worldview, there are some investigative strategies and findings of EP that can co-exist with a theistic approach and may counter-intuitively aid scientists who are proponents of an intelligent design approach. The intent of this paper is to provide an objective overview of the main points made by this emerging field, along with the implications and criticisms that have been leveled against it. There will also be a discussion of the main research investigations that distinguish the field, and the ramifications that arise when theorists apply a Darwinian evolutionary approach to t he field of psychology. The implications for theists in general and Christians psychologists in particular will be discussed, including the challenges and possible benefits, for proponents of an intelligent design psychology.

THE GOALS OF EVOLUTIONARY PSYCHOLOGY

Even as a recently emerging field, EP has made extraordinary gains in getting its ideas and findings across to both the academic community and the popular media. Still in its infancy, EP is primarily an American phenomenon, and analogous to the field of psychology in general, it is more popular here then in Europe, Asia, and third world countries. The field's most vocal adherents are well known, at least within academic circles, and have garnered respect, as well as criticism, for their ardent and what some believe are zealous views of EP. The main leaders are the UC Santa Barbara husband and wife team of John Tooby, an anthropologist, and Leda Cosmides, a psychologist. Joining them are Steven Pinker (e.g., author of How the Mind Works), David Buss, Richard Dawkins (e.g., author of Selfish-Gene Theory), E.O. Wilson (e.g., author of Sociobiology), and the husband and wife team of Margo Wilson and Martin Daly. Although there are other EP supporters whose views differ slightly, the above have received the most a ttention, and their ideas and findings will be the focus of this paper. As they begin to investigate the riddles of the human mind and behavior, EP makes far-reaching claims that distinguish itself from other fields within psychology. Thinking on a much broader and grander scope, EP supporters believe that their approach will revolutionize not only psychology, but also all of the social sciences in the process. EP believes it provides the necessary framework for unifying the social sciences with the natural sciences. Are these grand beliefs a simple boasting of a young, undisciplined field, or are they more serious indicators of marked delusions of grandeur? Critics have come down harshly on the field. Many believe that EP's attempt to redirect the focus of the social sciences to the more biologically leaning natural sciences is misguided and unnecessary (Looren DeJong & Steen, 1998), claiming that biology is not as unified as EP would have it. Other critics are even harsher.

Evolutionary psychology is based on the belief that humans share a universal evolved brain architecture, composed of functionally specialized computational devices that solved early adaptive Pleistocene-type problems. The aims of this movement are to promote the discovery of how these adaptive problems and their solutions explain current cultural and social phenomenon. The goal of this section is to examine the claims and the critiques of the major tenets of EP. Primary among these are: (a) a heavy reliance on an adaptationist approach, modeled from evolutionary biology; (b) a rejection of the "standard social sciences model;" (c) an emphasis on the modularity of the brain; and, (d) a belief in the universality of human nature. While there are other outstanding claims, these are the most central, and each will be discussed.

The Adaptationist Program

"Evolutionary psychology can be thought of as the application of adaptationist logic to the study of the architecture of the human mind" (Cosmides &Tooby, 1997, p. 11).

Evolutionary psychology starts with Charles Darwin and his theory of natural selection as the powerful casual mechanism that enables macro-evolution: the genealogical connection of all living organisms, which is better known as common descent. Humans, like all other living things, are simply one of many endpoints in a descent that started via modification of form, behavior, and function of simple organisms. Given central importance in this view is the principle of natural selection, which is the key mechanism of evolution. According to this principle, variations in organisms that contribute to reproductive success or enhanced survival rates will be genetically passed on to future generations. For example, our cravings for fats and sweets originated as Pleistocene adaptations. These adaptations, now fixed features of our architecture, allowed for better survival during times of famine. Today with easier access to processed foods high in sugars and fats, such cravings result mostly in increased obesity rates.

As a result of natural selection being for the most part hidden from scientific observation because it is so slow, its results or effects are indirectly inferred from the attributes of organisms that give it reproductive or survival advantages. These attributes are known as adaptations or, in other words, inherited characteristics that arise in a species through natural selection because they facilitate reproduction. They are genetically inherited and have the primary function of solving adaptive problems. The hallmarks of adaptations (Buss et al., 1998) are qualities like complexity, economy, and precision, which point to special design instead of evolving by chance alone. For example, Pinker (1994) argues that language has qualities, like complexity and precision, that point to evidence of special design.

Adaptations play a central role in the research strategies and overall program for EP (see Buss et al., 1998 for a summary). The goals of EP are to discover and map the adaptations that comprise our brain architecture. This architecture allowed our ancestors to survive and reproduce by helping them to solve adaptive problems. It is now for the most part fixed, and it is currently the focus of EP research strategies. For example, avoiding poisons leads not only to a fear of snakes, but according to EP, may also explain pregnancy sickness (e.g., teratogens can harm babies in the womb, so avoiding novel foods which may be poisonous, increases survivability-see below).

Adaptationist programs have been criticized by a number of people. Gould (2000) has criticized this strategy, stating that "selection cannot suffice as a full explanation for many aspects of evolution, for other types and styles of causes become relevant, or even prevalent, in domains both far above and far below the traditional Darwinian locus of the organism" (p. 106). Looren DeJong and Steen (1998) are also critical of using an adaptionist approach, calling these evolutionary explanations empirically empty schemata. They criticize EP's reliance on the biological concepts of adaptation and fitness by stating that these are not even representative of unitary concepts in biology. Gould (1991) suggested that exaptations might be a more important concept for EP.

Exaptations and spandrels. Some evolutionary psychologists have thus begun to explore whether some human behaviors are better explained by exaptations and spandrels rather than by adaptations (Buss et al., 1998). According to Gould (1991) exaptations refer to features that are now useful to an organism "that did not arise as an adaptation for its present role, but was subsequently co-opted for its current function" (p. 43). Bird feathers originally evolved for thermal regulation but have been coopted for a completely different function (i.e., flight). The term spandrel is an architectural term that refers to the spaces, like the nooks and crannies, that are "left over" in the structural features of a building. These side effect features did not result from adaptations, but they arose as side consequences of other features and they presume to include "modern" things like reading, writing, art and religion. Gould (1991) has commented that evolutionary psychologists would do well to study spandrels and exaptatio ns when explaining human religious or artistic behavior, for instance, because these behaviors are by-products of the complex human brain, rather than specific adaptations. Gould recognizes that natural selection and adaptation would need "fatal revisions" to account for the intricacies and complexities of human life. He thus proposed that psychologists would be better off employing the tools of spandrels and exaptations rather than adaptations, or at least in conjunction with adaptations, to account for the richness in human behavior (see Buss et al., 1998 for a response to Gould). Kirkpatrick (1999) followed up with the suggestion that religion is better thought of as a byproduct than as an adaptation, and proposed an evolutionary approach to the study of the psychology of religion.

Buss et al. (1998) concede that exaptations can be theoretical beneficial, but that the efficacy of an adaptationist program is found in the results, or in this case, the increasing number of valid findings and insights. Although Gould (2000) and others (e.g., Looren de Jong & Steen, 1998) continue to criticize this EP strategy, the principles of adaptation and natural selection are given prominent positions and powers as the "designers" and "architects" of both the human mind and behavior.

EP as past oriented. Another assumption of EP is that the evolved structure of the human mind is adapted to the way of life of Pleistocene hunter-gatherers, and not necessarily to our modern circumstances. Their focus then is on the selection pressures that caused the design of an adaptation, like the African savanna, which is referred to as the environment of evolutionary adaptedness. A favorite saying of EP is that our modern skulls house a stone aged mind. Presumably we have not had enough time to evolve fears of modern technologies, such as the car. Cosmides and Tooby (1997) believe that natural selection slowly (e.g., over 10 million years) sculpted our brains "favoring circuitry that was good at solving the day-to-day problems of our huntergatherer ancestors" (p. 10).

The argument goes something like the following Natural selection takes a long, long time to sculpt things like minds. Due to our species having lived as hunter-gatherers for most of our (supposed) 10 million-year existence, stone age priorities produced a brain/mind better equipped at solving African savanna problems, such as getting dinner while avoiding being dinner. We have not had enough time to develop solutions to modern problems, such as navigating freeways or programming VCR's. Hence, we more readily develop phobias of snakes rather than automobiles, even though cars pose a much larger threat than snakes do in most modern cities. For this reason Cosmides and Tooby (1997) state that EP is relentlessly past-oriented.

Rejection of the Standard Social Sciences Model (SSSM)

"The entities now commonly evoked to explain the mind-such as general intelligence, a capacity to form culture, and multipurpose learning strategies--Will surely go the way of protoplasm in biology and of earth, air fire and water in physics" (Pinker, 1997, p. 27).

Throughout psychology's history a number of themes have given shape to the field. For example, one important theme that characterizes the field of psychology is its diversity, both in content and perspectives. This "loosely federated intellectual empire" prevents easy categorization and analysis (Stanovich, 1998). The various subdivisions of the American Psychological Association--currently there are 49 divisions, each with their own additional subdivisions-attest to the wide diversity. There has been little hope in finding a grand theoretical unification, and possibly the only coherence the field does display relates to its adherence to the scientific method (Stanovich, 1998).

EP is attempting to change this by proposing that unification is not only possible, but that it is only a matter of time before all of psychology is subsumed under it's evolutionary paradigm. From the perspective of Buss (1995), the traditional distinctions between the sub-disciplines of psychology are arbitrary, misleading, and detrimental to progress because they divide the human mind and behavior in arbitrary and unnatural ways. The solution, Buss says, is that psychologists must focus on adaptive problems and their solutions. Such a focus would provide a "natural means of cleaving nature at its joints and hence crossing current disciplinary boundaries" (Buss, 1995, p. 27). The first step needed to accomplish this cleaving requires EP advocates to weigh in with its views on an old issue-the nature-nurture debate.

Nature-Nurture dichotomy and the SSSM. Does biology or experience influence intelligence more? Are our personalities formed at birth or molded by our culture? Are psychological disorders merely neurological or psychological? The nature-nurture issue represents a long-standing and often contentious debate. According to EP, this debate is malformed and ill conceived, and hence they reject such dichotomies. Cosmides and Tooby (1997) believe the pendulum is situated such that most people in the social sciences believe that biological evolution has been superseded by cultural evolution. The idea that human behavior is highly malleable, it is influenced by the environment and culture is called the "Standard Social Sciences Model" (SSSM) by EP. They believe it is the reining orthodoxy in today's mainstream anthropology, sociology and most of the fields of psychology.

According to Cosmides and Tooby (1997) the SSSM is problematic and must be discarded. The SSSM purports that the contents of our mind derive from the social world and consist mostly of a few, general purpose mechanisms. These mechanisms, such as " 'learning,' 'induction' 'intelligence,' 'imitation,' 'rationality,' 'the capacity for culture,' or simply 'culture'" (Cosmides & Tooby, 1997), are content-independent and they govern how we learn language, recognize emotional expressions, and think about incest. They operate uniformly regardless of the content they are operating on.

The social world organizes and injects meaning into individual minds, but our universal human psychological architecture has no distinctive structure that organizes the social world or imbues it with characteristic meanings. According to this familiar view [SSSM] the contents of human minds are primarily (or entirely) free social constructions, and the social sciences are autonomous and disconnected from any evolutionary or psychological foundation. (Gosmides & Tooby, 1997, p.3)

EP believes our minds are composed of many specialized, content-dependent mechanisms (see below), and believes that the SSSM has a radically defective view of the human mind and needs to be discarded. In their view, our universally shared and evolved brain architecture, composed of numerous mechanisms, implies that a unified theory is not only a possibility, but also an inevitable necessity. It also implies that culture and cultural variability (e.g., our customs, food preferences, etc.) depend on a foundation of evolved mechanisms for their very existence.

This reduction of cultural influences to a dependence on psychological mechanisms is the key for EP in its forceful rejection of the nature-nurture dichotomy. According to Buss (1995) culture, learning, and intelligence do not even constitute alternative explanations to the computational devices EP proposes: "Instead, they represent human phenomena that require explanation. The required explanation must have a description of the underlying evolved psychological mechanisms at its core" (p. 14).

As one might imagine, many in the social and natural sciences do not take too kindly to arguments that summarily dismiss the long cherished notions of things like culture, learning, and intelligence. Benton (2000) questions the simplistic reductionism inherent in EP's view, arguing that it eventually leads to biological determinism. Rose (2000) questions the whole EP argument for tearing down the SSSM by calling it "a straw man tactic" (p. 142).

The central issue is not whether the current sociocultural influences actually shape and influence human behavior. Rather, are they powerful and independent enough to be scientifically useful concepts? EP believes these concepts themselves require explanations, and EP supplies the only framework necessary to accomplish this. A modularity view of minds/brains designed by natural selection is the only appropriate focus of study for psychology. Yet, what is the nature of these modules that EP relies on so heavily?

The Modularity of the Brain

"The mind is system of organs of computation, designed by natural selection to solve the kinds of problems our ancestors faced in their foraging way of life, in particular, understanding and outmaneuvering objects, animals, plants, and other people" (Pinker, 1997, p.21).

According to Pinker (1997) "the mind is an organ, a biological gadget" (p. 155). Pinker presents what he calls a computational theory to explain the workings of the mind/brain, while Buss (1995) uses the term "psychological mechanisms." The evolved cognitive structure, which is also called Darwinian algorithms, of this organ is a central focus of research for EP. Cosmides and Tooby (1997) believe these algorithms, or reasoning and regulatory circuits, place psychology as a branch of biology that studies the brain, even though these mental modules are not mapped directly onto specific brain structures. They propose that our brains are functionally specialized, like a computer or a Swiss army knife. It is composed of many diverse neural circuits designed to solve different, recurring adaptive problems, which in return affects the reproduction of individual organisms. The precise number of these functionally specialized modules or circuits that humans possess is unclear, but the quantity is thought to be quite l arge. There are potentially so many that Samuels (1998) refers to this as the "massive modularity hypothesis."

In general, this modularity approach divides human behavior, emotions, and mental operations into discrete mental modules or organs. For example, all humans utilize common mechanisms to develop things such as language, the use our perceptions of the sensory world, the desire to live in social groups, physical attraction, as well as a host of other sexual practices. These modules are primarily "cognitive" and deal in the language of information rather than "energy." Emotions for EP are module, adaptations that work together with the other cognitive circuits, and they are primarily designed to "propagate copies of genes that built them rather than to promote happiness, wisdom or moral values" (Pinker, 1997, p. 370).

The central task of EP, according to Buss (1995) is to discover, describe, and explain the nature of these mental organs, and to articulate their functions. Buss et al. (1998) give numerous illustrations of the various psychological mechanisms that have been discovered by EP researchers and the specific adaptive problems that they were designed by selection to solve. For example, a "fear of snakes" module functions to help us avoid poison. Another popular mechanism is a "mate-preference module," dubbed the "men like pretty girls and women like wealthy men" organ by EP followers and critics alike. Utilizing this mechanism helps us select highly fertile mates. Another widely cited mechanism is a cheater-detection module studied by Cosmides (1989), which is used in social exchange situations (see the section below on current findings).

The modularity approach, initiated by Fodor (1983), is heavily relied upon by EP and it has been criticized by many. In this issue, Johnson, Herzel and Collins (2001) raise significant concerns about EP's ability to account for certain phenomenon, like reading, and call into question the theoretical commitment of EP to modularity. Nonetheless, these modules are a key focus for EP researchers, whose task it is to understand how they function in solving adaptive problems. Find out what the early pressures were on our species, or in other words 'the specific problems of survival or reproduction, and you can describe and understand their current operations. The hypothesized existence of such mechanisms is hardly revolutionary because most psychological research assumes similar mechanisms exist. Concepts such as learning, rationality, intelligence, and even at times culture all imply that there are underlying hypothetical mental mechanisms at work. However, what sets EP apart is the belief that we can only truly u nderstand these underlying mechanisms or modules by a detailed exploration of our evolutionary past, especially by focusing on the evolutionary pressures that shaped such functioning.

A Universal Human Nature

Leo Tolstoy (1877/1997, p. 3) wrote that "happy families are all alike; every unhappy, family is unhappy in its own way" (p.3).

"There are compelling reasons for the view that our basic psychological mechanisms are likely to be species typical, shared by most or all humans"(Buss, 1995, p. 11).

EP claims that all human behavior is predicated on the basis of our human nature, which was formed around a half million years ago during the Pleistocene era, and that this nature has undergone little change since then. Our human nature, EP believes, is universal and mostly fixed; thus, our minds were designed by evolutionary forces during our early, yet commonly shared history on the vast savannas. To understand the Pleistocene epoch and the forces at play at that time is to understand human nature today. According to Tooby and Cosmides (1992) this single, universal design stems "from our long-enduring existence as hunter-gatherers ... the interesting, complex functional design features of the human mind evolved in response to the demands of a hunting and gathering way of life ... (I)n considering issues of functionality, behavioral scientists need to be familiar with how foraging people lived" (p. 5).

This central assumption of EP, the belief in the psychic unity of humanity, implies that we share not only a common biology but also common behavioral tendencies. For evolutionary psychologists, this "pan-human" nature exists primarily at the level of evolved psychological mechanisms, not at the level of expressed cultural behavior. According to Buss (1995) all manifest behaviors depend on these underlying psychological mechanisms. As discussed above, regardless of culture, humans find attractive features in women that typify reproductive potential, such as health and youth. The mate preferences of males and females are similar in that we each desire to select mates representative of high fertility. According to EP, this "mate" module is be universally true and it is stamped in by the powerful work of adaptation. It is an integral part of our cognitive architecture, shared by all other humans and based on genetics. Buss et al. (1998) claims that the mate preference module has been documented in 37 different c ultures worldwide.

Evolutionary psychology and sociobiology. These views are not without controversy because they lead to implications about the role of learning and culture, they reprise the "biology as destiny" notion of sociobiology, and they question the malleability of humans. To claim that humans have mechanisms that are stamped-in, shared by all, and powerfully influence behaviors, such as what we prefer in a mate, makes many feminists cringe. Resurrecting the old venom and dusting off the previous arguments used against the 1970's style sociobiology movement, critics of EP are once again preparing for battle.

Although many in EP are attempting to distinguish themselves from human sociobiology, it is difficult to do this when the key proponents of sociobiology are some of the intellectual leaders in the EP movement-individuals like Richard Dawkins and E.O. Wilson. Critics like Nelkin (2000) and others have difficulty distinguishing the two. Many feminists and past critics of sociobiology distrust EP, believing it reinforces inequalities and old gender stereotypes. They are turning their attention to arguing against it by focusing on its similarities to sociobiology and the inherent problems of such views (see also Fausto-Sterling, 2000). Previous complaints about social Darwinism that were concerned with biological determinism apply just as significantly to EP as they did to sociobiology, according to critics.

One of EP's responses has been to draw strong boundaries between the two fields. Buss (1995) claims that sociobiology advocates the view of humans as "fitness maximizers" or, in other words, the goal is to maximize the replication of our genes relative to others, whereas EP sees humans as "adaptation executors." For EP, psychological mechanisms are central and according to Buss, neglected by sociobiology in favor of an analysis of the patterns of social organization, such as the nature of polygyny vs. monogamy in the human mating system.

Another response form those in EP has been to simply acknowledge the overlap and dig in for battle (e.g., Pinker, 1997). E. O. Wilson (1998), the father of sociobiology, perceives few differences and calls EP the politically correct title for sociobiology. He believes that "in the interest of simplicity, clarity, and--on occasion--intellectual courage in the face of ideological hostility, evolutionary psychology is best regarded as identical to human sociobiology" (Wilson, 1998, p. 163).

Evolutionary psychology and behavioral genetics. The universal views of EP are also used to distinguish the field from behavioral genetics, which followers of EP also take pains to point out. Behavioral genetics is more interested in differences between people, and it frequently utilizes twin studies and adoption studies in their attempt to unravel the threads of environment and genes. A behavioral geneticist would want to know the extent to which differences between people of a given race, culture, or environment can be accounted for by the differences in their genes. From an EP perspective, there is little to be gained by an exploration of race or culture, because as mentioned previously, these concepts depend on underlying psychological mechanisms. Thus, according to Cosmides and Tooby (1997), two individuals do not differ in personality because one has the genetic basis for an adaptation that another person lacks, as we share a universal architecture.

Current Findings and Areas of Investigation of Evolutionary Psychology

According to one academic EP program (i.e., the EP program at UC Santa Barbara), the current areas of investigation for researchers revolve around the discovery and mapping of the adaptations that comprise the evolved species-typical architecture of the human mind. These include finding the mechanisms that evolved for incest avoidance, cooperation, exchange, threat, and inter-group conflict. There have been a number of interesting and controversial findings presented by researchers who have used the framework of EP as a heuristic guide. Common topics of study include sex differences, human sexuality, mate-selection, and the function of emotional responses such as jealousy, disgust, and love. Some of the most interesting findings (see Buss, 1995, 1998) include pregnancy sickness as an adaptation to teratogens, gender differences in jealousy responses (Buss et al., 1998; Daly & Weghorst 1982), and the detection of cheaters (Cosmides, 1989). Even though some of the most controversial findings deal with mate sele ction and gender differences (e.g., Buss, 1995; Gangestad & Simpson, 2000; LeCroy & Moller, 2000), this paper will only discuss the issue of jealousy, as another paper in this issue (Looy, 2001) covers this area more thoroughly.

Jealousy has been studied using an EP approach and has provided insightful findings. Researchers using an EP heuristic predicted (Buss et al., 1998; Daly & Weghorst, 1982) that the inputs that activate jealousy would differ from men to women. According to Buss (1995) men do not know with 100% certainty the paternity of his offspring, and there is a reproductive threat that comes from the possible sexual infidelity of a mate. Hence, it was surmised that men would find any possible sexual indiscretions by their mates to be distressing. Due to the fact that women know that they are the mother of their children, typically they find the possible emotional infidelity of their mates more threatening. Women could lose their men's attention, commitment, and resources that are needed for raising children because these resources could be diverted to other women. Hence, women would find that mates forming emotional attachments to others more upsetting than sexual infidelities. Research findings confirmed such differences and they have been replicated in various cross-cultural samples.

Wilson and Daly (1987) have identified mechanisms that deal with "preferential allocation of resources," citing it as the cause of child abuse by stepparents. They claim that there is a 40% higher rate of abuse of preschoolers in families with stepparents than in families with both genetic parents. In fact, it is claimed that "stepparenthood" is the strongest risk factor ever identified for child abuse. In explaining why a stepparent is 40 to 100 times more likely than a biological parent to kill a child, Pinker (1997) states that stepparents are not crueler than anyone else, but parenthood is one-sided: "Parents give, children take. For obvious evolutionary reasons, people are wired to want to make these sacrifices for their own children but not for anyone else... The antagonism of stepparents to stepchildren is simply the standard reaction of a human to another human" (p. 434).

Cosmides (1989) work on cheater detection procedures has produced some interesting findings as well. Utilizing a reciprocal altruism (e.g., "You scratch my back and I'll scratch yours") paradigm, she predicted that certain cognitive machinery must be in place for social exchange to work (see also Cosmides, 1989; Cosmides & Tooby 1992). Namely it was predicted that humans have evolved an ability to detect cheating, specifically when others accept benefits without giving back in return or paying the appropriate costs. Results from a number of well-designed studies showed that people do detect cheaters in social exchange situations better than they can detect other sorts of violations.

Possible Impacts of Evolutionary Psychology on Christian Psychology

There are a number of implications these recent EP investigations and findings have for Christian psychologists, and in this section a few of these will be briefly noted. Although the specific findings of EP and their impact will not be discussed here due to space issues, the more general critical reviews of EP and some possible areas for agreement will be discussed. Also, the possible impact for those who support an intelligent design approach to the sciences will he considered.

Of course, to assume that all Christian psychologists, and for that matter all EP supporters, believe the same thing when it comes to evolution would be patently inaccurate. When it comes to the creation-evolution debate, numerous perspectives can be taken, and each perspective will respond differently to the current EP movement. I will sidestep the majority of the broad issues, and even the subtle nuances, and refer readers to works that detail these views more explicitly (e.g., Moreland & Reynolds, 1999). However, whether one is young-earth (i.e., recent) creationist, an old-earth (i.e., progressive) creationist, a theistic (i.e., fully-gifted) evolutionist, or still uncertain, the claims of EP are radical and require studied contemplation, which is one of the guiding purposes behind the publication of this special JPT issue.

Briefly, it is submitted here that the progress EP is making on some fronts may ultimately aid a design approach to psychology. This new approach, referred to here as Intelligent Design Psychology (IDP), can benefit from some victories gained by proponents of EP. Despite the fact that the two perspectives start with radically different assumptions and by most accounts are antagonistic, there are elements of an EP approach that might ultimately aid an intelligent design perspective of psychology, and a few of these will be highlighted here.

The implications of a universal nature. In general, it can be argued that the progress EP makes in questioning the SSSM in attempting to validate their evolutionary approach may ultimately aid the reception and viability of an IDP. For example, EP has as their goal the uncovering of the workings of the human mind and behavior based on the assumption of a universal, designed human nature.

For Christians and theists, the universal nature of humans is one that includes a spark of the divine. The human soul is unique in contrast to animals in that we have been created in the image and likeness of God. Thus, we bear a congruent similarity to God, and even though we are fallen and sinful, we possess moral faculties and can engage in moral actions (see Moreland, 2001). It is believed that humans share much in common with this Designer, as we are endowed with a conscious and the knowledge of good and evil (a cheater detection algorithm?). As sinful creatures, however, we possess a nature that leans toward selfishness, and EP would seem to concur with our self-centered nature. Bufford and Garrison (1998) have noted that this similar belief in a flawed human nature is one area in which EP and Christianity appear to be compatible.

Investigative strategies. Both the EP and the IDP approaches are concerned with historical questions, inferences, and explanations. As Myers (1994) noted, "advocates of design and descent alike seek to postulate antecedent causal events or event scenarios in order to explain the origin of present phenomenon" (p. 94). The investigative strategies used for detecting this nature are potentially similar for both EP and IDP, such as reverse engineering. This approach allows for the identification of the standards for recognizing special design-economy, efficiency, complexity, precision, specialization, and reliability. Good engineering solutions to adaptive problems point to special design, and if humans are in fact products of an intelligent designer, then we should be able to find evidence for such hardwiring. Some of this hardwiring would include psychosocial constraints, according to Dembski (1998). Certain EP findings, such as the cheater detector and gender differences modules, seem to point to such constrai nts and to hardwiring, whether put there by EP's designer (i.e., adaptation and selection) or a theist's Designer.

Design arguments. The most famous use of a design argument is the 19th century theologian William Paley, who utilized a design argument to prove the existence of God by noting the complexity of biological organisms. He argued that only a grand designer could create such complex things (i.e., the watchmaker analogy). Charles Darwin, on the other hand, saw a natural mechanism that was blind and unconscious (i.e., "the blind watchmaker"). The difference is the emphasis on the power of blind, historical forces to shape an organism's structure and function, versus the force of God. By most accounts Darwin won, and the design argument faded away. Recently, however, some scientists have brought it back, newer and better (e.g., Dembski, 1999). By separating out naturalistic philosophy from science, the IDP movement shows how searching for intelligent design is a legitimate exercise for scientists and it can be empirically detectable. Although the history and current use of the design argument is a topic for another p aper, the relevance here is that EP supporters have resorted to a similar argument and they are fighting a battle from within the academic community. EP's designer is natural selection and adaptation over vast periods of time, and they hope to allow for the inclusion of this argument in explaining complex human behavior and adaptations. Their success would seem to be beneficial for those who propose an IDP perspective. IDP's designer is God, a personal, powerful, transcendent agent who created and designed human beings through direct (i.e., primary) causative mechanisms (see Moreland, 1994; 2001). How much time He used in doing this, either one literal day or longer, is under continual debate.

As an example, in explaining the discovery of a supposed cheater detection module, Cosmides and Tooby (1992) appeal to a design argument. The cognitive machinery inherent in cheater detection appears to be so specialized that Cosmides and Tooby believe it is domain specific and functionally distinct. They label this a "social contract algorithm" and present it as evidence for design:

The programs that cause reasoning in this domain have many coordinated features that are complexly specialized in precisely the ways one would expect if they had been designed by a computer engineer to make inferences about social exchange reliably and efficiently: configurations that are unlikely to have arisen by chance alone. (Cosmides & Tooby, 1992, p. 20)

They utilize references to intelligent agents that are similar to a computer engineer, even though the gist of the argument is put forth as to counter the role of chance. And though certainly not the intent of Cosmides and Tooby, this approach has implications for Christian psychologists interested in utilizing intelligent design arguments.

The ultimate question is not only whether EP is successful in appealing to a design argument, but also whether such an argument is a helpful heuristic to explore future research from an IDP perspective. This is the focus of other papers in these two special issues (e.g., Grace & Moreland, 2002; Moreland, 2001)

Critical reviews of evolutionary psychology. Perhaps the most vocal and recent critics of Darwinian evolutionary theory in general, from a theistic perspective, have been those individuals associated with the Intelligent Design (ID) movement. Critical of the assumptions of a naturalistic science approach (i.e., naturalism), those in this movement have been somewhat successful in getting their views across, even to the sometimes hostile mainstream academy. Foremost among these critics have been Philip Johnson, who is a UC Berkeley professor and author of Darwin on Trial and The Wedge of Truth, Michael Behe, who is at Lehigh University and author of Darwin's Black Box, Paul Nelson from the University of Chicago, Steve Myers from Whitworth College, and William Dembski, who is from Baylor University and author of Intelligent Design.

Much of the impetus for this intelligent design movement has been to both expose the naturalism and scientism's leanings and the assumptions of Darwinian evolution, and to present a competing research program based on the notion of an intelligent designer. The main ideas associated with this approach can be found in any of the above mentioned texts, as well as in these special JPT issues (2001/2002). Grace and Moreland present a more detailed account of ID and Intelligent Design Psychology (IDP) and some possible implications for phenomenon like consciousness. Moreland examines the philosophical claims of a naturalistic EP, and he provides an excellent critique and comparison with a Christian IDP approach. In general, the concerns raised by the ID movement about the naturalistic Darwinian evolutionary account apply just as appropriately to the new field of EP.

There are some who believe that EP and religion are highly compatible (e.g., Kirkpatrick, 1999) and that EP even presents opportunities for Christian apologetics (e.g., Zimmer, 1998), though these appear to be minority opinions. Bufford and Garrison (1998) also point out EP's compatabilities for Christians, but they are less optimistic than Zimmer. They discuss valid areas of conflict and caution against a premature embracing of EP. Though other Christians critical of EP have registered brief responses (e.g., Colson & Pearcey, 1998; Jones, 1995), the field is new enough to have escaped more serious reflection. No doubt that will soon change if EP continues growing in popularity.

CONCLUSION

EP is seeing tremendous growth over the last decade or so. From new adherents and programs to interesting insights and findings, it has the potential to capture an even larger audience, both in academia and the broader public. Its assumptions of a fixed, universal human nature, its utilization of design arguments, and its far-reaching claims (e.g., on sex differences, the role of culture, etc.) account for the pointed and highly contentious criticisms leveled at them. Indeed, the surprise is that this criticism is from those who would seem to be natural allies--fellow Darwinian evolutionists.

The formal gauge as to the value and ultimate staying power of any new theoretical approach is whether it better accounts for and organizes existing findings, it provides new insights and directions for future research, and it can predict counter-intuitive results. EP is showing signs that it is to be taken as a serious contender and that it will be around for awhile. An informal gauge of the potential of a new theory may also be indicated by how many high powered critics it attracts, and EP is attracting them like flies.

The criticisms of EP spring from many motives, some appropriate for academia (i.e., scientific or philosophical motives), and some not (i.e., political motives). An example of a valid criticism is Rose's (2000) uncertainty about the validity of EP's scientific assumptions by stating:

For those conscious that scholars of prehistory work with highly fragmentary evidence, from shards of bones, fossils and very occasionally entire bodies ... the belief that late twentieth-century people can know the human psychological architecture of our early ancestors with any degree of certainty and accuracy is difficult to take seriously. (p. 141)

Evidence of criticism more politically motivated occurs when some rather cherished worldviews are threatened, like the powerful role of culture in shaping human behavior. This results in politically oriented criticisms, which, for example, liken EP proponents with "religious" types, a comparison Nelkin (2000) makes. Rose (2000) also resorts to such a comparison:

The new fundamentalist Darwinism looks to claim its place among the other contemporary religious certainties of fundamentalist Islam, Christianity and Judaism, offering certainty in uncertain and troubled times. In today's pick-and-mix culture, evolutionary psychology proposes itself as yet another possible opiate for the people. Freud and Marx are dead--so long live Darwin. (p. 149)

Whether the criticism is politically, theoretically, or scientifically motivated, it indicates a perspective that is getting its views acknowledged. It makes one wonder whether it might also be interpreted as evidence that EP is questioning assumptions, utilizing methods, or discovering truths that could just as easily lend support to a theistic worldview--an apparently unpalatable thought for some.

AUTHOR

GRACE, CHRISTOPHER R. Address: Rosemead School of Psychology, 13800 Biola Avenue, La Mirada, CA 90639. Titles: Associate Professor of Psychology; Chair, Undergraduate Psychology Department; Associate Provost, Biola University. Degree: PhD, Experimental Social Psychology, Colorado State University. Specializations: Social psychology, science and Christianity, prosocial behavior.

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