Craig T. Palmer

Human rape: Adaptation or by‐product?

This paper examines two alternative evolutionary explanations of human rape. One explanation sees human rape as a facultative male reproductive tactic. The other explanation sees human rape as an evolutionary byproduct of certain evolved differences in the reproductive strategies of human males and females. These two explanations generate alternative testable predictions concerning cross‐species, cross‐cultural, and modern societal data on rape. Existing evidence is found to be insufficient to warrant an adaptive explanation of rape per se in humans. The question of whether the search for adaptations needs to be shifted from behavioral categories to the underlying psychological mechanisms is discussed.

Kin-selection, reciprocal altruism, and information sharing among Maine lobstermen

Abstract In this paper, the sharing of information about the location of lobsters among lobstermen in two Maine harbors is described. First, why the sharing of such information is likely to entail an economic loss for the transmitters is explained. Then, the extent to which the principles of kin-selection and reciprocal altruism can account for the sharing of information is determined. Many cases of information sharing in one of the harbors do not appear to be the type of kin-directed or reciprocal acts expected to be produced by kin-selection or reciprocal altruism as they are usually conceived. The behavior of these lobstermen may be the result of the advantages of maintaining a complex web of social relationships among them. Failure to appreciate the complexity of such relationships in some fishing communities is suggested to be a major shortcoming in the economic models previously used to explain information management among commercial fishermen. I conclude that a more complex model of reciprocal altruism is needed to account for the information sharing among this group of Maine lobstermen, and perhaps many other human social groups.

Sexual access to females as a motivation for joining gangs: An evolutionary approach

Previous theories of gangs have largely ignored a crucial aspect of the motivation young males have for joining gangs: a desire for increased sexual access to females. We first argue that an understanding of the evolutionary psychology of sex and reproductive competition can account for the typical age and sex compositions of gangs. We then review the anecdotal evidence from the gang research literature concerning the role of sexual access to females in the motivation of males who join gangs. Finally, we present an analysis of a unique study of a sexually transmitted disease (STD) outbreak that occurred in Colorado Springs, Colorado, between 1989 and 1991. This analysis revealed that the 57 male gang members involved in the outbreak had a significantly (p < .03) higher average number of sex partners than did the 63 male non‐gang members who were also involved in the outbreak.

Rape in nonhuman animal species: Definitions, evidence, and implications

This paper examines the controversial issue of rape in nonhuman animal species. Many existing studies on nonhuman rape appear to suffer from inappropriate definitions and questionable interpretations. Many existing critiques of these studies are limited by their own misunderstandings of evolutionary theory. An attempt is made to reduce the resulting controversy by defining rape in a way that can be applied to nonhuman animals, without provoking unwarranted implications about human rape. Applying this definition to existing studies indicates that behavior meeting the definition of rape does exist in several nonhuman species. However, comparisons of these species do not provide clear implications for either proximate or ultimate explanations of human rape.

Religion as an identifiable traditional behavior subject to natural selection

Abstract This article puts forth a definition of religion that refers only to identifiable elements. Previous definitions typically refer to beliefs in supernatural—i.e., unidentifiable—phenomena. These definitions neglect the fact that beliefs in general may be just as difficult to identify with the senses as the content of religious beliefs, i.e., alleged supernatural beings and powers. This article thus argues that the only thing identifiable that is distinctly religious is a certain type of behavior; more specifically, a certain type of talk. Further, although a statement about the existence of something supernatural is necessary for talk to be considered religious, such a claim by itself is not identifiably religious. Religious behavior can rather be defined as the communicated acceptance of a supernatural claim, a claim whose accuracy cannot be demonstrated by the senses. The accuracy of this definition can be tested by examining whether it is consistent with the way the words “religion” and “religious” are actually used. If this definition is found to be consistent with the use of these words, the study of religion becomes subject to the scientific principles used to study other forms of behavior. These principles include the theory of evolution by natural selection.

Human kinship as a descendant-leaving strategy: A solution to an evolutionary puzzle

Abstract Ethnographic examples are used to demonstrate three aspects of human kinship altruism that can be explained neither by the standard evolutionary explanations of altruism (i.e., kin selection, and reciprocal altruism) nor the controversial theory of group selection. First, humans favor closer kin over more distant kin even at genealogical distances where kin selection is essentially nonoperative. Second, this favoring of “close” distant kin over “distant” distant kin is prescribed by tradition and does not depend on the greater likelihood of reciprocal altruism from the closer kin. Finally, the favoring of “close” distant kin over “distant” distant kin does not depend on co-membership in the same social group. To explain this universal aspect of human social behavior, an alternative evolutionary explanation of altruism—referred to as the “descendant-leaving strategy model”—is presented.

Categories and gatherings: Group selection and the mythology of cultural anthropology

Abstract If the term “group selection” is to have any meaning beyond mere semantics, it must refer to situations where individuals live in groups. Although the terminology of cultural anthropology suggests that humans live in bounded and enduring gatherings that might serve as group “vehicles” of selection, we argue that none of the terms asserted to be such an entity (i.e., clans, lineages, villages, bands, tribes, populations, societies, and cultures) fulfill this requirement. This is because these terms refer to: (1) reified abstractions, (2) groups only in the sense of categories of people instead of groups in the sense of people gathered together, or (3) gatherings that are much too fluid and fuzzy in their membership to be “vehicles.” Following Murdock (1972), we refer to this obsession with groups as “anthropologys mythology,” and we suggest that it is the result of our evolved capacity for categorical perception. Although classifying phenomena into categories is useful in many situations, it has hindered our understanding of human social organization and human evolution.

Evolution of sex differences in spatial cognition

Psychological research has now clearly demonstrated that there is a significant difference between men and women in their performance on certain spatial tasks. Evidence further suggests that this difference has a neurological basis. This hypothesis is well enough established to have inspired several additional hypotheses concerning the evolutionary origin of the difference, including hypotheses emphasizing male hunting, female foraging, and male reproductive strategy. In this article we examine these hypotheses by placing them against the evidence for the neurological basis for the sex difference and the archaeological evidence for the evolution of spatial thinking in general. Given the probable source of the neurological difference in the timing of fetal testosterone, hypotheses that emphasize selection for female cognitive abilities are handicapped from the start. The hypotheses favoring male hunting and male reproductive strategy stumble when evaluated in light of the timing of the evolution of spatial cognition; archaeological evidence for the proposed selective behaviors and for the spatial abilities in question (e.g., mental rotation) do not correspond in a way that would permit a link between them. We conclude that none of the proposed adaptationist hypotheses fit the evidence as it currently exists, and that the modern sex difference in spatial cognition is almost certainly an evolutionary by-product of selection for optimal rates of fetal development.

Introductory Psychology Texts as a View of Sociobiology/Evolutionary Psychology's Role in Psychology:

Sociobiology and its descendant evolutionary psychology (EP) have struggled to gain ground within the social sciences over the past 30 years. While some have heralded the Triumph of Sociobiology (Alcock, 2001), others have critiqued it as a poor approach to understanding human behavior and would prefer that a Darwinian perspective remain outside the domain of human social sciences. We attempt to assess just how successful (or not) it has been by examining how it has been covered in introductory psychology textbooks over the past 30 years. Our findings indicate that a Darwinian perspective has gained influence and acceptance within the field of psychology over the past three decades. However, we also find that EP as a sub-discipline is often perceived as narrowly defined and limited to research on mating strategies. We address how these perceptions may affect the future of EP, and possible steps needed to increase both the acceptance and importance of evolutionary theory to psychology.

Once Upon a Time: Ancestors and the Evolutionary Significance of Stories

Evolutionary theorists attempting to explain forms of literary narrative appear to agree on the general premise that such use of language ‘reflects and articulates the vital interests of human beings as living organisms’ (Carroll 2001, 9). This leads to the view that literature ‘reflects our nature—basic human motives like mating, parenting, gaining social status, acquiring resources’ (Carroll quoted in Max 2002). Most literary critics see literary narrative as a product of the ‘evolved human mind’ and our ‘complex mental architecture’ (Boyd 1998, 4–5), and as a ‘cognitive process’ (Scalise Sugiyama 2001a, 221). While it is undoubtedly true that our complex mind is involved in literary narrative, scholars disagree about whether or not literary narrative may have an evolutionary function (see Pinker 1997) and, if it does, what that function might be. Carroll (2001, 22) argues that literary narrative satisfies a need for ‘cognitive order’, but we agree with other theorists who argue that literary narrative can directly or indirectly influence behaviour. Alexander (2005, 314) proposes that the arts evolved to make ‘contributions to our patterns of social scenario building through consciousness and foresight’. These scenarios, he continues, ‘are obligate passports to social success’. Scalise Sugiyama (2001a, 223–24) proposes that literary narrative’s function was to alleviate some of the costs of ‘information acquisition’. Given that first-hand experience can be so costly, she argues, the function of narrative would be to provide listeners ‘with information useful to the pursuit of fitness’ (p. 223). We agree with Alexander and Scalise Sugiyama that stories can affect the behaviour of listeners and that some of these effects are on the survival and reproduction of listeners. This is consistent with Jakobson’s observation that in any act of verbal communication ‘The ADDRESSER sends a message to the ADDRESSEE’ (1960, 353; emphasis in original). We also agree with Arnheim (1998, 63) that the behaviour