For many people, culture and biology provide alternative explanations for human behavior. This dichotomy is false. Culture is as much a part of human biology as large molars with thick enamel. In this talk, I defend five propositions which I believe fo rm the basis of an evolutionary account of human culture:

Does group size and city size have an influence on our predisposition to imitate behaviour? In a previous test of Boyd and Richerson's (1985) conformist transmission model it was found that group size needed to be greater than three in order to elicit imitative behaviour. This present study examines the relationship between the size of a stimulus group looking up at a building and the response of passersby in a town (pop. 153,000). The initial aim was to examine the effect of stimul us group sizes of three, four and five (cf. Milgram, Bickman and Berkowitz 1969). It was found that there was a significant linear effect of size of stimulus group and the number of people looking up. No one stopped alongside a stimulus group of three. Th ese results differ from Milgram et al's (1969) New York study but are compatible with Mullen, Copper and Driskoll's (1990) findings that the influence of models of a behaviour is greater in cities of larger size. Two further studies were undertaken to asc ertain the impact of city size. One study took place in a city (pop. 1,017,000) and the other took place in a village (pop. 2,500). The results are discussed in terms of a predisposition to imitate group behaviour and Boyd and Richerson's (1985) conformis t transmission model.

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A psychometric study was performed to evaluate the convergent and discriminant validities of the hypothetical constructs of reciprocity, revenge, and honor, as proposed by both evolutionary and social psychologists. A sample of 544 undergr aduates at the University of Arizona completed an 80 item questionnaire that was constructed to test the theory that a basic and genetically determined instinct for reciprocity may be cognitively elaborated at various increasing levels of sophistication u nder appropriate social conditions to yield more complex ideologies of equity and social exchange. Eight common factors were constructed and validated: 1) Positive Individual Reciprocity, 2) Negative Individual Reciprocity, 3) Positive Group Reciprocity, 4) Negative Group Reciprocity, 5) Positive Individual Honor, 6) Negative Individual Honor, 7) Positive Group Honor, and 8) Negative Group Honor. These common factors relate to theoretical constructs proposed in the previous literature. For example, Positi ve Individual Reciprocity is comparable to Axelrod & Hamilton’s (1981) "Tit-for-Tat" strategy, whereas Negative Individual Reciprocity is comparable to Triver’s (1971) concept of "Spite." Also, Positive Individual Honor is comparab le to Alexander’s (1987) "Indirect Reciprocity," while Negative Individual Honor is comparable to Nisbett’s (1987) "Culture of Honor." The covariance structure of the empirical interrelationships of these various constructs will be mat hematically modeled and presented. Verbal explanations will also be provided.

Cultures like species have unique phylogenetic histories. Unlike biological traits within species, however, cultural traits may possess unique phylogenies. These divergent histories within a single population result from the exchang e of cultural information among groups. Thus character conflict in cultural data may represent real phylogenetic information. Iterated parsimony is a method for capturing this information and reconstructing the multiple histories within each culture. I ha ve used simulation experiments to test the effectiveness, consistency, and robusticity of the iterated parsimony methodology. These results indicate varying effectiveness, ranging from better than 90% separation by transmission pattern (when most assumpti ons are valid) down to near total failure (when key assumptions are invalid or the dataset contains relatively little information).

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Researchers have long recognized the central role of love and anger in romantic relationships and the paradoxical coexistence of these seemingly opposite emotions. We propose that variations in characteristic levels of love and anger experienced in dif ferent mating relationships (a) track specific, largely independent fitness-relevant classes of benefits and costs in those relationships and (b) adjust behavior in ways that increase the individual's capacity and tendency to respond adaptively to those b enefits and costs. We hypothesize that individuals who experience relatively strong feelings of love will be involved in relationships that provide relatively high levels of fitness-enhancing resources and will experience relatively frequent activation of behavior-regulating mechanisms that function to enhance relationship commitment (e.g., sexual exclusivity). Conversely, individuals who experience relatively strong feelings of anger toward their partners during conflict will be involved in relationships characterized by relatively high levels of strategic interference and will experience relatively frequent activation of behavior-regulating mechanisms that function to reduce that interference (e.g., aggression). In research with college-age dating coupl es, we found support for the model; variations in levels of strategic facilitation by one's partner predicted the self's feelings of love but not anger, and variations in levels of strategic interference by one's partner predicted the self's feelings of a nger but not love. In turn, variations in feelings of love predicted levels of commitment-promoting behavior but not levels of partner-directed aggression, and variations in feelings of anger predicted levels of partner-directed aggression but not levels of commitment-promoting behavior. Despite this independence, the love and anger systems converged to predict relationship satisfaction.

Humans evolved in a world of groups in which individuals not only had to make decisions in which they trade off their own welfare against that of others, but had to assess the impact of these trade-offs on the formation, consolidati on, and maintenance of the cooperating groups they were members of. We argue that a set of evolved, specialized cognitive procedures is activated in the context of perceived group interactions which lead to systematic adaptive patterns in the ways in whic h people weigh individual/group cost/benefit trade-offs — decisions that are inconsistent with rational choice theory, but make sense given the adaptive consequences that these choices would have in a world of small groups and coalitions. We found that su bjects are more tolerant of uncooperative behavior by ingroup members than outgroup members during the early phase of group formation, but were less forgiving and more willing to punish uncooperative behavior by ingroup members than outgroup members after the group had persisted for a longer period of time. Subjects were willing to incur a cost to punish others, and even though within the experimental situation this would not improve their situation in subsequent interactions. In addition, we explored the ways in which the perceived relative status of the groups in the locally constructed experimental context affected participants decisions. Results violate both classical rational choice theory and simple reflexive theories of ingroup favoritism that negl ect an analysis of the complex adaptive problems involved in the formation and maintenance of coalitions.

Previous attempts to estimate cultural transmission mode have focussed on economic and social variables (Guglielmino et al. 1995, Pocklington and Breden 1997). Little is known about the 'coherence' or 'units' involved in complex sociocultural phenomena . We develop our understanding of cultural transmission mode through the study of one particular cultural element which is 1: widespread, 2: easily defined as coherent and independent, and 3: composed of many characters that themselves vary. Homologs of a folktale, the 'Moon Spots Myth', were collected from the literature. Gene frequency data on the populations where the myth was found was collated from the Human Population Genetics Database (maintained by Eric Minch of Stanford University). Latent Semant ic Indexing was used in order to extract relevant 'meme' like fragments from the myths (Best 1997, Pocklington and Best 1997). The vector space representation of the myths was transformed into a pairwise 'mythological distance' matrix. The genetic data we re transformed into an Fst genetic distance matrix. Longitude and latitude coordinates were similarly transformed into a distance matrix. A multiple regression model extension of the Mantel test (Mantel 1967, Smouse et al. 1986) was used to assay for tran smission mode using the method of Pocklington (1996).

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Mate selection preferences were investigated as a budget allocation problem. In two studies, participants designed their ideal mates by selecting various levels of attributes, paying for their selections with a specified budget of mate dollars. In each study, low, medium, and high budgets were used. I examined males’ use of physical attractiveness thresholds and females’ use of resource acquisition thresholds as screening devices to solve the adaptive problem of being adequately attracted to those potential mates who have a reasonable probability of contributing reproductive value in one’s environment. Each gender should most value cues to reproductive contribution at low budget levels, where mate choice is greatly constrained. As budget levels increase and thresholds for reproductive contribution are met, males (females) should value physical attractiveness (resource acquisition) less, and this should be reflected in a decreasing proportion of their budget allocated to physical attractiveness (resource acquisition). I also studied the hypothesis that thresholds and preferences are adjustable to the social environment, and are calibrated with one’s own mate value, which in turn depends on one’s own level of potential reproductiv e contribution. Participants were rated on their physical attractiveness and asked to report their net worth/income to determine the proposed dependent variables.

A growing body of research on human reasoning indicates that certain types of situations or contents can engage inference procedures that are adaptively designed for reasoning about those domains. Areas previously studied includ e social exchange (reciprocal altruism), threat and bluff detection, and food aversion. Using similar methods, the possibility of an adaptively specialized inference procedure for evaluating social groups, or coalitions, was explored. Cues of coalition me mbership — coalitional markers — were given in conjunction with coalitions, within reasoning situations. It was predicted 1) that inference procedures would treat markers as physical manifestations of membership, and 2) that indications of deception regar ding markers would systematically and adaptively alter inferences towards the detection of deception. The results indicate that cues and reference categories need to be considered as factors in reasoning tasks, and that coalitional markers and coalitions may be important examples of this phenomenon.

Food sharing among hunting societies can be seen, in part, as a means of buffering risk, and is not entirely explicable in terms of kin selection or reciprocal altruism. By sharing food more widely than can be reciprocated, the most proficient hunter m akes himself a valuable resource to his social group—a resource which is difficult to replace and, therefore, which other group members are highly interested in retaining. This interest translates into the hunter-gatherer equivalent of disability insuranc e for the best hunter by motivating group members to aid him should he become incapacitated for a prolonged period due to injury or illness. The adaptive problem posed by unpredictable periods of incapacitation is not, of course, restricted to the best hu nter in a group, nor is extensive meat sharing the only benefit an individual can provide. One would therefore expect species-typical adaptations motivating humans to identify and cultivate skills needed to provide difficult-to-replace benefits to their s ocial group. Ethnographic evidence from contemporary tribal societies suggests that certain cross-cultural social roles recurrently fulfill this objective (e.g., the exceptional warrior, the savvy strategist, the shaman). We focus here on two such roles, the artisan and the storyteller, arguing that over the course of human evolution, individuals who cultivated valuable skills were more likely to receive aid during—and thereby survive—periods of incapacitation due to injury or illness.

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Many social psychological studies have shown that attitude similarity has strong rewarding properties, and is an important determinant of attraction and of the willingness to altruistically help another individual. Recently it has been sho wn that attitudes differ considerably in their heritability. On the basis of inclusive fitness theory, it is argued in this paper that the ultimate cause of the attraction inducing property of attitude similarity is that such similarity is a cue to geneti c relatedness. In line with this assumptiom, it was predicted that individuals would be more willing to engage in help that could save the life of another individual if the other had similar rather than dissimilar attitudes, but only if it concerned herit able attitudes. The study was conducted among 77 adults with a mean age of 44. In a 2 (high vs low attitude similarity) X 2 (high vs low heritability of attitudes) within subjects design. Subjects were asked to respond to four different profiles of target individuals that were constructed on the basis of the participants' own attitudes. The results confirmed the predictions. Moreover, it was found that participants assumed the highest degree of genetic relatedness with target individuals who had similar a ttitudes high in heritability.

A computational analysis of the psychological processes underlying cooperation and altruism reveals that humans likely have processes that 1) involve relatively complex evaluations of the relatedness between individuals, including r epresentations of the uncertainty of relatedness (relational uncertainty), and 2) use these evaluations in decisions about helping and cooperating with others. Grandparent-grandchild relationships offer an interesting test case for these propositions beca use putative relatedness is constant across grandparents, but relational uncertainty is not. Grandparents range from being completely certain about the genetic relatedness of putative grandchildren (maternal grandmothers are certain about their genetic re latedness to their daughters, and are certain about their daughters’ genetic relatedness to their own children), to being doubly uncertain (paternal grandfathers are uncertain about their genetic relatedness to their sons, and are uncertain about their so ns’ genetic relatedness to their own children). Three studies examined the pattern of grandparent to grandchild investment, and investigated the cues involved in evaluating relational uncertainty. Results suggest that people form representations of relati onal uncertainty and use these representations in their investment decisions. Discussion will focus on the implications for understanding kin relationships, and on the implications for a general model of cooperation and altruism.

A model of the characteristics of sexual aggressors is described and relevant data are presented. It includes: A) configuration into three major constellations of many characteristics identified as correlates of sexual aggressors; B) a functional, evol utionary-based analysis of the psychological mechanisms underlying these three constellations; and C) a discussion of hypothesized natural selection processes operating on such characteristics. The following is a brief elaboration on each of these issues:

A) Sexual aggressors' characteristics. Sexual aggressors' characteristics coalesce into three constellations consisting of 1) a mating orientation likely to create a conflict of interests with females (i.e., a short-term mating strategy), 2) an "a ssociative network" of characteristics labeled hostile masculinity that includes emotions (e.g., hostility) and attitudes (e.g., acceptance of violence) priming coercive tactics for dealing with strategic interference or conflict, and 3) a general persona lity orientation to assert one's own interests at the expense of others (i.e., emphasizing dominance at the expense of nurturance). While each of these three constellations makes a unique contribution to the likelihood that a man will be sexually aggressi ve, their confluence is particularly suited to facilitate such aggression.

B) Functional analysis of characteristics. Sexual coercion may be viewed within a larger frame of male strategies involving "converging" or "diverging" interests with those of females. Men's 's experiences beginning early in life affect the calibr ation of the relevant mechanisms so that they become more suited for particular strategies. Data are described indicating that 1) a short term sexual strategy is associated with harsh early environments (as suggested by Belsky et al., 1991, this linkage m ay be explained by early reproduction conferring selection advantages in such harsh environments), 2) hostile masculinity characteristics are associated with high perceived rejections by women (a linkage hypothesized because such characteristics are desig ned to "energize" coercive acts that can overcome strategic interference), and 3) nurturance relative to dominance personality characteristics are affected by individual and cultural socialization (hypothesized to vary as a function of the extent to which the ecological conditions confer selection advantages to traditionally masculine vs. feminine characteristics).

C) Selection, individual mechanisms and/or confluence of systems. Data are reviewed suggesting that the minds of many men who are not aggressing sexually in current environments nevertheless reveal an attraction to such aggression. Further, system atic comparisons of these men with actual aggressors, including convicted rapists, show expected similarities in key areas. I suggest that the capacity to engage in sexual coercion contributed to male reproductive success with sufficient frequency to have played a role in natural selection and consider how selection may have operated at the levels of individual mechanisms and at their confluence.

Path modeling was used to investigate the relationship between characterological and experiential factors in the prediction of patterns of sex crime perpetration in adolescent males. Characterological factors included various measur es of personality and psychosocial adjustment, and experiential factors included childhood sexual victimization and post-abuse family support. The results indicated that a younger age at time of victimization, a greater number of incidents of abuse, a lon ger period of waiting to report the abuse, and a lower level of perceived family support post-revelation of the abuse predicted future sex crime perpetration. It was also found that adolescent sex offenders evidenced deficits in self-sufficiency and had m ore pessimistic explanatory styles than nonsexually-offending controls. Self-sufficiency was defined as reflecting attitudes of self-confidence, independence, assertiveness, and self-satisfaction. With regard to pessimism, the sexually offending youths sh owed a greater tendency than controls to assign internal, stable, and global attributions for the occurrence of negative events in their lives. The results of this study were interpreted as supporting a conceptualization of juvenile sex offenders as youth s who are lacking in social competencies and who are perhaps competitively disadvantaged in the social and sexual arenas relative to their peers by both early environmental challenges and exacerbating constitutional deficits. This form of coercive sexuali ty may thus represent a conditional adaptive strategy involving elements of reactive heritability.

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The definition of altruism currently accepted in evolutionary biology requires that an organism incur a fitness cost in the course of providing others with a fitness benefit. New insights can be gained, however, by exploring the imp lications of an adaptationist version of the "problem of altruism" as the existence of complex functional organization designed to deliver benefits to others whether such delivery is costly or not. Such an analysis makes clear that there potenti ally may be, in a species, many distinct and separable sets of adaptations for altruism designed to deliver benefits to different targets for quite independent reasons. We believe that reciprocal altruism and kin-selected altruism are only two pathways ou t of a larger set, and discuss how some other pathways may be modeled. These models allow one to understand aspects of the design and social dynamics of human friendship and mateship that are otherwise mysterious, such as why overt and explicit reciprocat ion is taken as a sign of the absence of friendship.

A path model was developed relating adolescent sex offending to other forms of antisocial deviance. The sample consisted of 82 males (ages 13-18) from inner-city New York, charged with or convicted of a sex crime. Four major common fac tors were constructed: 1) Psycho-Social Deficiency (PSD), measuring psychological and social functioning (e.g., depression, physical, mental, and emotional development); 2) Non-Criminal Sexuality (NCS), measuring legal but abnormal sexual interests or "pa raphilias" (e.g., transvestitism, fetishism, masochism); 3) Non-Sexual Criminality (NSC), measuring non-sexual offenses (e.g., vandalism, burglary, robbery, violent nonsexual assault, arrests for nonsexual offenses and use of weapons); and 4) Sexual Crimi nality (SC), measuring explicitly sexual offenses (e.g., rape, child molestation, frottage, voyeurism, exhibitionism, number of arrests for sexual offenses, type of offense committed and amount of aggression used). Significant direct and indirect pathways were found leading from PSD to SC through both NCS and NSC successively, each time facilitated by interactions with PSD. The causal order specified remains equivocal, but these results are consistent with and empirically support otherwise non-obvious pre dictions of evolutionary theory, telling a pathetic tale of repeated frustration and failure in various competitive sexual strategies, leading to an escalation of increasingly extreme means of obtaining sexual gratification, yet also suggesting preventati ve intervention at a major root cause of this cascade of consequences, PSD.

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Within Australia, views of Aboriginal social organization, particularly the relationship between land-using and land-owning groups, have been at something of an impasse since the demise of Julian Steward’s model of the patrilineal band some thirty year s ago. We suggest that part of the reason for the demise of Steward’s model and the failure to generate a theoretical replacement lies in an inadequate understanding of the factors that structure the composition of local groups. We utilize theory from evo lutionary ecology and data collected among the Alyawarra of central Australia to argue that a portion of the variability in local group composition results from preferences in residential choices made by women.

Using the example of helping behaviors (in which one individual incurs a cost and confers a benefit on another), this paper presents evidence that evolutionary accounts of particular cognitive, affective, and social processes are cr itical to understanding phenomena not explained by current biological models of helping: the anonymous helping of strangers and why individuals incur an immediate certain cost for a delayed uncertain benefit (McGuire, 1989). The data presented in this pap er show that different processes (empathy, guilt, self-esteem, others' opinions, social norms, etc.) operate differentially in different types of help (casual, substantial personal, emotional, and emergency helping [McGuire, 1994]). Understanding h elping thus entails an investigation of the phylogenetic and ontogenetic origins and proximate operation of each of these processes. Implications for individual (and group) differences in behavior are explored: for example, empathy and impulsiveness are e ach strong predictors of a different subset of helping behaviors but the most impulsive people may not be the most empathic. Furthermore, each of the psychological and social processes implicated in helping have effects in other evolutionarily critical be havior systems, such as aggression, attachment, parenting skills, desirability as a friend or mate, vocational or status achievement; these simultaneous multiple behavioral effects must be considered in ultimate (fitness) accounts of each process. The goa l of this paper is to provide evidence that behavior and mechanisms are like the length and breadth of Dawkins' rectangle: mutually dependent and equally important to an understanding of the whole.

The existence of preferential same-sex mating in human males presents an evolutionary puzzle because the behavior leads to reduced reproductive success. Evolutionary theory and available literature will be used to analyze a novel hypothesi s, called the parasite strategy model. The parasite strategy model proposes human male homosexual behavior to be the result of host manipulation by a sexually transmitted parasite. The parasite strategy model is able to explain important correlates of mal e homosexuality including: a) why the probability of a male becoming homosexual increases for each older brother the male has, b) the concordances for homosexual orientation between monozygotic and dizygotic twins, c) the poor childhood relationship that homosexual males report having had with their father, d) the cross cultural positive correlation between the frequency of male homosexuality and the degree of polygyny, and e) the heterosexual response to male homosexuality typically called homophobia. Th e parasite strategy model is able to explain how human male homosexuality can exist over evolutionary time.

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High levels of male parental investment are a distinguishing characteristic of humans versus other primates or mammals. It has been argued that the appearance of this behavioral trait is an important event in hominid evolutionary history, allowing the extension of the juvenile dependent period well beyond weaning and facilitating a learning period during which the complex skills and knowledge needed to exploit a high-quality, but unpredictable feeding niche could be acquired. Nevertheless, we find mark ed differences in the levels of investment that fathers provide their children both within and between extant human societies.

The Hamiltonian extension to Darwinian theory leads to the general expectation that individuals will direct investment in their kin to the recipient whose reproductive value will be most positively impacted after discounting by the coefficients of rela tedness. Could psychological mechanisms have evolved that would have been able to keep track of how investments might impact the changing reproductive values of a large network of genetic kin of various degrees of relatedness? It may be more likely that h uman kin investment decisions are guided by simpler rules-of-thumb that result in near optimal patterns of kin investment in most evolutionary environments. Competing predictions about male kin investment patterns are presented.

A strategy of reciprocity based on the quality, rather than the quantity, of altruism is evolutionarily stable. Although the strategy rests on pairwise interactions, the psychological mechanism which results could lead to apparently indiscriminate bene ficence, i.e. behavior often referred to as "group altruism."

The model is tested using the Dictator Game paradigm from economic psychology. Participants in this game are typically quite generous, in contradiction to the prediction from economic theory. In a between subjects design, participan ts exhibited varying levels of generosity, in accord with this evolutionary model.

This paper reviews evidence supporting the hypothesis that the development of gynemimesis (Money and Lamacz, 1984) or "sissy boy Syndrome," (Green, 1987) is based upon a unique psychoneuroendocrionology which has a genetic basis maintained in human populations via kin selection. Historical, anthropological, and archaeological evidence reveals that male sexual inversion (i.e. transsexualism, "effeminate" male behavior) was institutionalized in primitive culture shamanism for sufficient time for this religious institution to have been the dynamic element in what Lumsden and Wilson (1981) have described as a coevolutionary process of genes, mind, and culture. Reasoning from the work of Geschwind and Galaburda (1987), it is proposed that prodigious talent shown by many young males with this personality may also be a manifestation of the same neurohormonal organization, and the talent may offset disadvantages of reproductive fitness of the individual.

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The senior author has been quantifying kinship relationships within and between communities of Yanomamö Indians using genealogical data and a computer program called KINDEMCOM. Given relatively complete genealogies of a 'group' , KINDEMCOM searches for and quantitatively documents detectable kinship relatedness among communtiy members and makes possible the comparison of what kinds of kinship relationships exist in the community. Contact with missionaries has resulted in a consp icuous diminution of Yanomamö 'kinship density' due to the influx of new members. Recent studies of Siberian tribesmen, Cree Indians of the James Bay area, and Haitian peasants will be compared to Yanomamö data and the issue of "tests of kin sel ection theory" discussed.

Research was designed to measure positive affect of children within the context of a four player competitive/cooperative game-like situation. Children were observed playing a game which required both cooperative and competitive beha vior in order to obtain a desirable goal. The experimental design is such that in order to view a movie cartoon a child must enlist the aid of two of the other three children in the group, thus forcing the fourth child to become a bystander. Individual me asures of positive affect while playing the game were compared to group measures of equality of cartoon viewing time. Comparisons between sexes and cultures were also made.

Homo sapiens sapiens is perhaps the only animal species that concerns itself with theories of causality. If we are to judge by the example of contemporary (including the past century) foraging societies, the knowledge and understanding of why things happen—such as these ideas exist within cultural contexts—has been key to the survival of every subsistence-oriented individual since the beginnings of human history. The successful hunter, for example, has long know n that natural instinct and acquired skill are of secondary importance when compared to his fundamental concept of luck. He knows that luck is not a matter of chance, but a predictable result based on proper attitudes and behaviors. I n this paper, the underlying principles of luck and related human behaviors are examined as mentifacts, as culturgens, processed according to what Lumsden and Wilson have defined as the epigenetic rules—"the genetically determine d procedures that direct the assembly of the mind (1981:7)."

Migration studies are commonplace in history, anthropology, and demography, yet few behavioral ecologists have explicitly studied human dispersal (Koenig 1989; Clarke and Low 1992; Clarke 1993). This gap means that most studies of human mi gration are at a societal level and leave unanswered many questions of interest to evolutionary biologists. For instance, why would individuals give up the apparent benefits of living in their natal areas, and how can we understand the variation between i ndividuals in the likelihood and timing of dispersal? Using historical records from New England and Utah genealogical libraries, I have reconstructed family histories for people from the small farming town of Oakham, Massachusetts (1750-1850). With this d emographic database, I examine the extent of dispersal from Oakham and the impact of life-history traits such as sex, age, birth order, and reproductive status on dispersal