No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
... From an evolutionary perspective, sexual jealousy is understood as an emotion that motivates the protection of a valued relationship from rivals (Buunk, 1997;Symons, 1979;White, 1984). In the context of romantic relationships, jealousy appears as an emotion designed to protect the romantic pair-bond (Fernandez, 2017;Fletcher et al., 2015) preventing the diversion of reproductively relevant resources toward interlopers (Buss et al., 1992). ...
... Reacting with jealousy when there is a suspicion of losing a partner is less costly than actually losing a valued reproductive partner or their resources (Buss & Haselton, 2005;Foster et al., 2014;Schmitt & Buss, 2001). Hence, Symons (1979) and Buss et al. (1992) hypothesized that sexual selection favored cognitive biases to dissuade a possible betrayal from a partner and increase the protection of the mating bond. With SDJ emerging as the result of sexual asymmetries in the allocation of resources for reproduction between the members of the romantic couple (Trivers, 1972). ...
... With SDJ emerging as the result of sexual asymmetries in the allocation of resources for reproduction between the members of the romantic couple (Trivers, 1972). Specifically, women are the sex that incur the more significant obligatory investment during reproduction (i.e., in nutrient-rich eggs, internal female fertilization, internal gestation of 9 months, and postpartum lactation as described in Symons, 1979). These higher obligatory reproductive costs imply that women actively attempt to monopolize a mate's resources so that they can be channeled toward them and their offspring (Buss, 2013;Fernandez, 2017). ...
Evidence is abundant that evolution by selection has produced sex differences in the design of adaptations to solve the problems surrounding reproduction. A prime example is the design of human jealousy, which research suggests is triggered by distinct evoking acts that are specific challenges for women and men in their exclusive reproductive bond. It follows that jealousy would be directed toward driving away interlopers who could potentially threaten the bond with the romantic partner or increase mate retention efforts in response to sex-specific threats. To explore this possibility, we use as a methodological innovation an economic game for the evocation of jealousy. With a modified dictator game, we showed men and women in a committed relationship, conditions in which the partner or an intrasexual rival allocates money to (investing condition), or obtains money from (receiving condition), the partner or an opposite sex third party that they recently met. A sample of 56 heterosexual couples (n = 112) participated in a laboratory setting. Our results show the different scenarios of this dictator game exerted the expected evocation of jealousy (controlling individual differences), with women being more jealous by the partner’s allocation of resources to a rival, and men reporting slightly more jealousy by their partner receiving money from a rival. We discuss the implications of this method to advance the comprehension of the adaptive function of sex differences in jealousy, the use of economic games, and possible modifications to improve the similarity of the game to a real assessment of actual male jealousy.
... Thus, in reproductive terms, the costs of a short-term sexual relationship typically outweigh the benefits for women more so than for men (Li and Kenrick 2006;Symons 1979). Although each individual offspring provides equal reproductive benefits to both parents, they present much higher costs to women if they result from uncommitted sex. ...
... Women have therefore evolved to be more selective about potential mates relative to men, as failure to procure the long-term commitment of a mate who provides protection and resources would have been particularly detrimental to survival for impregnated ancestral females, who lived without the benefits of modern food production, public health, medicine (Daly and Wilson 1983), and social welfare. On the other hand, reflecting their rather minimal physiological constraints, men evolved to have greater eagerness for short-term casual relationships and desire for sexual variety than women (Buss and Schmitt 1993;Kenrick et al. 1990;Symons 1979). ...
... When seeking long-term mates, men value physical attractiveness more than women do, whereas women value social status and resources more than men do (e.g., Buss 1989). Because women's fertility declines relatively quickly as a function of age, men's reproduction is constrained by access to reproductively valuable or fertile mates (Symons 1979;Trivers 1972). Identifying fertile and healthy mates is thus a primary adaptive problem in both long-term and short-term mating for men. ...
... EP theorizing on sexual aggression includes models that vary along the dimension of specialized to general explanations for the behavior. Symons (1979) first discussed extensively whether adaptations or by-products of adaptations produce rape. Adaptations are naturally selected (i.e., they resulted in increased ancestral reproductive success). ...
... By-products are incidental characteristics that did not evolve because they solved adaptive problems. For example, male nipples, which have no design functionality, are by-products of the adaptive value of nipples in women (Symons, 1979). Symons (1979) concluded that the available data were insufficient to conclude that rape is a facultative adaptation in humans. ...
... For example, male nipples, which have no design functionality, are by-products of the adaptive value of nipples in women (Symons, 1979). Symons (1979) concluded that the available data were insufficient to conclude that rape is a facultative adaptation in humans. Rather, rape may be a by-product of male adaptations that produce sexual arousal and adaptations that motivate coercion to secure desired goods. ...
... Thus, whereas women evolved to be more cautious and selective than men when considering potential mates, men evolved to be more sexually opportunistic and eager for short-term, casual sex than women (Buss & Schmitt, 1993). Therefore, perceptions of sexually receptive women, particularly when they are physically attractive which serves as a cue to fertility (Symons, 1979), may induce men (but not women when viewing sexually receptive men) to become present-focused and more receptive to potential sexual opportunities. ...
... Finally, although both high-ISC men and women discounted more after seeing attractive targets in the high-competition condition, we did not examine sexdifferentiated mechanisms that might underlie these responses. According to evolutionary theories of mating (Symons, 1979), women's desirability appraisals are driven more by social status indicators, whereas men's appraisals arise from health and fertility cues. Testing these specific pathways will clarify our findings while validating broader mate preference theories. ...
Studies have shown that men discount the future and prefer immediate-but-smaller over delayed-but-larger rewards when exposed to mating opportunities (e.g., attractive opposite-sex targets) or threats (e.g., same-sex competition) whereas women's discounting in response to similar cues appears mixed, suggesting that mating-motivated discounting is primarily a male phenomenon. Importantly, this line of research has not yet examined the role of individual difference variables as well as how the attractiveness of potential mates and perceptions of competition jointly influence discounting rates. We conducted a novel test of the effect of trait intrasexual competitiveness (ISC) using dating profiles varying on target attractiveness and same-sex competition to observe their interactive effects on participants' discounting. Results showed that when targets were attractive , higher ISC was associated with steeper discounting for both men and women, and this association was stronger when competition was high rather than low. ISC still predicted discounting when targets were low in attractiveness but competition was high; high ISC did not predict discounting only in the low attractiveness and low competition condition. These findings reveal ISC as a factor that leads women to discount as much as men, and that high-ISC individuals may be more responsive to competition than to target attractiveness.
... Features not present early in life are automatically assumed to be "learned," not the product of natural selection. One key problem with this line of reasoning is that it mistakenly pits learning and evolution against each other as if they are competing explanations, when in fact they are not (for an extended discussion of the compatibility between learning and evolution, see e.g., Lewis et al. 2017;Symons 1979;Tinbergen 1963). The other key problem is that there is simply no basis for the arbitrary assumption that the products of natural selection must be present at birth. ...
... To paraphrase Don Symons, the evolutionist should focus on psychology and information processing. When he ignores these in favor of observable behavior, he is like the drunk looking for his key under the lamppost: he knows he dropped it in the dark, but under the lamppost the light is better (Symons 1979). ...
... Pornography is a genre focused on short-term mating, largely targeted to a male audience; while the romance and erotica genres are largely targeted toward and consumed by females, typically involving contexts that are more long-term mating focused (Salmon & Symons, 2001). Short-term mating is facilitated by a drive for sexual variety (Symons, 1979) and the pornography industry provides just that via close ups of a variety of different attractive female bodies and faces, particularly faces that give the impression that they are enjoying the acts that they are engaged in, including being the recipient of ejaculate on the face, images of which convey information about her attractiveness, enjoyment, and his pleasure in their activities. ...
... While some researchers (Salmon & Symons, 2001;Symons, 1979) have suggested that there are no substantial differences between gay male pornography and pornography produced for heterosexual men, other than the sex of the actors, as they both tap into basic male short-term sexual psychology, Salmon and Diamond (2012) tested this in a content analysis of pornography targeted toward homosexual and heterosexual males. There were, in fact, few differences, except that external ejaculations were more frequent in the gay male pornography yet they were more frequently deposited on the face in heterosexual pornography and the body in gay male films. ...
The persistent debates over pornography have often focused on differences between males and females, not only in the frequency of consumption or the type of material consumed, but also on the different ways that individuals may perceive sexually explicit images and respond to them. Some of these differences may be due to sex differences in a number of factors including sexual strategies, pathogen or sexual disgust, and own mate value as well as within sex differences in these factors. Previous studies have demonstrated that perceptions of sexually explicit images are influenced by the sex of the target in the image and the target’s emotional affect, as well as sex of the respondent, their sexual orientation, short-term mating orientation, and disgust measures. However, these previous studies were conducted with participants from the United States alone. This study compared the findings from these US samples to those from non-Western ones (Philippines and Brazil) in order to examine the replicability across cultures of the US results as well as whether some variables (religiosity, for example) account for more or less of the variance in perceptions in different populations. Results indicated that there were some differences in terms of the amount of variance in perceptions explained by different variables across populations. Participant and stimuli related variables explained more variance in the Philippines while individual difference variables accounted for more variance in Brazil.
... Even when differences are observed between gay and heterosexual men, such as in the level of sociosexualityrelated behavior (Schmitt, 2007;Silva Júnior et al., 2023), these differences may not reflect distinct underlying mating psychologies. Instead, they could result from varying opportunities for engaging in uncommitted sex, as suggested by Bailey et al. (1994) and Symons (1979). According to evolutionary theory, mating psychology has likely been shaped by natural selection due to its reproductive advantages in ancestral environments. ...
Male sexual functioning is a prerequisite for conception and consequently for reproduction and is thus a crucial mechanism from an evolutionary and social perspective. Previous studies reported better sexual functioning in coupled compared to single individuals. However, it is not clear whether sexual functioning increases or decreases with a short-term casual sexual strategy, which is another possibility, along with a long-term strategy. Furthermore, sexual orientation may represent yet another mating strategy that may influence sexual functioning. Here, we aimed to test the possible associations between male sexual functioning and sexual strategies, as measured through sociosexuality, relationship status, and sexual orientation. We hypothesize that due to its relationship with the evolved motivation of mate acquisition and mate retention, both stable relationships and sociosexuality would be positively associated with male sexual functioning. We did not expect significant differences in sexual functioning among men with different sexual orientations. We sampled 427 healthy men of different sexual orientations (203 heterosexuals, 77 bisexuals, and 147 gay men) who completed the Male Sexual Function Index (MSFI) and its subscales of desire, arousal, erection, orgasm, and satisfaction; the Sociosexual Orientation Inventory-Revised; and sociodemographic questions. A multivariate general linear model showed that, compared to single individuals, partnered individuals reported greater MSFI-arousal, MSFI-erection, MSFI-orgasm, and MSFI-satisfaction. Sociosexuality and sexual orientation only weakly predicted MSFI domains. Male sexual functioning thus seems to be moderately associated with a long-term mating strategy and can thus serve for relationship maintenance rather than for acquiring new partners.
... For instance, psychopathy may be less predictive of future problematic behavior in girls and may not have as strong of ties with the sexuality variables included in our study (Colins et al., 2022;Visser et al., 2010). Because reproductive constraints among males and females affect sexual behavior differently among the sexes (Buss, 2017;Symons, 1979), it may be relevant to examine more closely how female psychopathy can be understood if male psychopathy is to be considered a male mating strategy. Does this mean there is also a female mating strategy that underlies female psychopathy? ...
Purpose
Sexual behavior plays a prominent role in adult descriptions of psychopathy, and research shows associations between psychopathy in males and distinct aspects of sexuality, including impersonal, precocious, and coercive sexuality involving reproductively mature sexual partners. Evolutionary perspectives have suggested that consistent links with these sexual outcomes may reflect a male mating strategy that can result in reproductive success. But fewer studies have examined the various aspects of sexuality and psychopathic traits during adolescence, a time when reproductive strategies may become entrained.
Method
Using a mixed sample of 156 criminal justice-involved and at-risk community male adolescents (Mage = 17.4, SD = 1.2), we examined associations of the Psychopathy Checklist: Youth Version with impersonal, precocious, coercive, and mature (i.e., sexual interest in reproductively mature females) sexuality.
Results
Psychopathic traits were associated with each aspect of sexuality, including impersonal, precocious, coercive sexuality as well as increased likelihood of showing a sexual interest in reproductively mature adult females.
Conclusion
The results suggest that psychopathy in adolescent males is associated with a unique pattern of sexuality like that seen in adult males and may suggest the beginnings of a young male mating strategy whose pattern of impersonal and coercive sexuality may continue into adulthood.
... Previous studies have also shown that women tend to identify with actors in sexual stimuli, i.e., that they imagine themselves in the depicted sexual interactions (Chivers, 2017;Symons, 1979). It seems that women who watch videos showing other people enjoying sexual pleasure can identify with these cues and project themselves into such scenarios (Chivers, 2017). ...
Research has repeatedly shown marked differences in men’s and women’s sexual response patterns; genital response in men tends to be elicited by cues that correspond to their sexual preference (preferred gender), while women’s genital response is less sensitive to gender cues and more sensitive to the presence and intensity of other sexual cues (e.g., sexual activities). We tested whether the cue of copulatory movement in a general sexual context elicited a genital response in androphilic women but not in gynephilic men. If so, women should react to stimuli depicting not only the non-preferred gender but also other animal species differing in phylogenetic distance to humans. We studied the genital and self-reported arousal of 30 gynephilic men and 28 androphilic women to two sexual videos depicting penetrative human sexual intercourse (female-male and female-female) and nine videos depicting animal copulation. Neither women nor men showed genital or subjective sexual arousal to non-human sexual stimuli. Moreover, both sexes demonstrated a highly cue-specific pattern of arousal. Our results suggest that copulatory movement displayed in non-human species is not a sexual cue that can elicit genital or subjective sexual arousal in humans.
... Gay men engage in sexual behavior much more frequently than do lesbians and have many more partners (e.g., Schäfer, 1977;Blumstein & Schwartz, 1983; see also Peplau & Fingerhut, 2007). The comparison suggests that heterosexual relations often involve a sexual compromise between men and women (Symons, 1979). ...
Sexual violence is explained using a social psychological theory of aggression that emphasizes bounded rationality. The approach challenges feminist approaches that examine violence against women in isolation and attribute it to sexism. It suggests that sex differences in sexuality lead men to attempt to influence women to have sex using various means. Sex differences in physical strength create opportunities for them to use violence while chivalry encourages them to act like “gentlemen.” Research on the age of victims, sexual arousal, self-reported motives, legalized prostitution, and modus operandi support the commonsense notion that most incidents are sexually motivated. As a result of sexual motivation, rape is as much a crime against teenagers as it is a crime against women. However, evidence suggests that some rapes–like other violent crimes– are motivated by real or imagined grievances. The role of grievances is supported by research on self-reported motives and justifications, and the offender’s use of gratuitous violence during the incident. It is argued that sexual assault can be explained by bounded rationality and well-established social psychological processes.
... Sex differences in neurobiology, cognition, and personality are the subject of intense research and scientific debate (e.g., Archer, 2019;Cahill, 2017;Del Giudice, 2009;Hyde, 2014;Schmitt et al., 2017). Examining sexual orientation differences vis-à-vis basic sex differences inform our understanding of sexual orientation diversity, while also providing clues about male-and female-typical mating cognition, strategies, and sexual behavior (Bailey et al., 1994;Symons, 1979). Past research has established reliable sex differences in sub-clinical narcissism, psychopathy, and Machiavellianism-a cluster of socially exploitative personality traits whose persistent co-occurrence has led to them being called the "Dark Triad" (DT) (Muris et al., 2017). ...
The present study sought to investigate sex and sexual orientation differences in several traits related to sexuality and sexual behavior. Examining sexual orientation differences alongside basic sex differences to help identify correlates of sexual orientation diversity, and whether individuals with varying degrees of same-sex attraction show concurrent sex-atypical shifts in other domains. Males tend to score higher than females in the Dark Triad (DT) traits of sub-clinical narcissism, psychopathy, and Machiavellianism. Similarly, females tend to be more cautious than males in their attitudes and desires toward casual sex activity (i.e., sociosexuality). These sex differences may be related to the propensity for individuals to become easily sexually excited, which is higher in males, or to instead inhibit sexual arousal, which is higher in females. In a large undergraduate sample (N = 2047), we replicated expected sex differences in DT traits, sociosexuality, and sexual excitation/inhibition. We found that non-heterosexual females were “male-shifted” in some of these traits, but these shifts tended to be strongest among mostly heterosexual and bisexual individuals. Furthermore, we found that within-sex variation in sociosexuality, sexual excitation, and sexual inhibition was not related to sexual orientation in a linear fashion. Instead, sociosexuality and sexual excitation were related to sexual orientation in a curvilinear (inverted-U) fashion, especially among females. The fact that traits correlated with bisexuality and homosexuality were somewhat distinct is consistent with the idea that different developmental pathways may lead to these discrete sexual attraction patterns.
... Bateman's three principles, particularly through their influence on Trivers' (1972) characterization of the relationship between parental investment and sexual selection, were central to the founding of human sociobiology (Alexander 1974;Chagnon & Irons 1979) and evolutionary psychology (Symons 1979). ...
Human evolutionary demography is an emerging field blending natural science with social science. This edited volume provides a much-needed, interdisciplinary introduction to the field and highlights cutting-edge research for interested readers and researchers in demography, the evolutionary behavioural sciences, biology, and related disciplines.
By bridging the boundaries between social and biological sciences, the volume stresses the importance of a unified understanding of both in order to grasp past and current demographic patterns. Demographic traits, and traits related to demographic outcomes, including fertility and mortality rates, marriage, parental care, menopause, and cooperative behavior are subject to evolutionary processes. Bringing an understanding of evolution into demography therefore incorporates valuable insights into this field; just as knowledge of demography is key to understanding evolutionary processes. By asking questions about old patterns from a new perspective, the volume—composed of contributions from established and early-career academics—demonstrates that a combination of social science research and evolutionary theory offers holistic understandings and approaches that benefit both fields.
Human Evolutionary Demography introduces an emerging field in an accessible style. It is suitable for graduate courses in demography, as well as upper-level undergraduates. Its range of research is sure to be of interest to academics working on demographic topics (anthropologists, sociologists, demographers), natural scientists working on evolutionary processes, and disciplines which cross-cut natural and social science, such as evolutionary psychology, human behavioral ecology, cultural evolution, and evolutionary medicine. As an accessible introduction, it should interest readers whether or not they are currently familiar with human evolutionary demography.
... The same e ect was not observed for men, which could be explained in terms of social status (Bozin & Yoder, 2008). From an evolutionary perspective, however, women's greater sociality compared to men in this context could re ect that group membership had greater reproductive bene ts for women due to their greater parental investment (Symons, 1979). In other words, in most situations women could provide better care for their o spring in a group rather than alone, and it was therefore more adaptive for them to respond to ostracism (and other forms of stress) in an a liative manner (Taylor, 2012). ...
This book provides a cutting-edge overview of emotion science from an evolutionary perspective. Part 1 outlines different ways of approaching the study of emotion; Part 2 covers specific emotions from an evolutionary perspective; Part 3 discusses the role of emotions in a variety of life domains; and Part 4 explores the relationship between emotions and psychological disorders. Experts from a number of different disciplines—psychology, biology, anthropology, psychiatry, and more—tackle a variety of “how” (proximate) and “why” (ultimate) questions about the function of emotions in humans and nonhuman animals, how emotions work, and their place in human life. This volume documents the explosion of knowledge in emotion science over the last few decades, outlines important areas of future research, and highlights key questions that have yet to be answered.
... Males choose physical characteristics that are indicators of fertility for the continuation of the lineage. Symons (1979) counts flawless and smooth skin, white teeth, shiny hair, full lips and clear eyes, a lively gait and a lively body in the clues he obtained (Yıldırım, 2007). ...
According to attachment theory, once an attachment style is determined as secure or insecure in early childhood, it shows little variation later in life. In this process, secure attachment is stated as a healthy communication. Insecure attachment style has been
associated as a determinant of psychopathology in later life. Anxious/ambivalent attachment, which is one of the insecure attachment styles, has been associated with anxiety disorders. It has also been associated with avoidant attachment behaviour disorder, which is a form of insecure attachment, and other expressive pathologies. Between secure attachment and Romanticism and Spouse Attitude, between living together, idealization and full trust, significant positive, avoidant attachment and Romanticism and Spouse Selection Attitude, living together, love is sufficient, effort, idealization and opposite poles between meaningfully positive, anxious attachment and idealization A significant positive correlation was found between and opposite poles.
Keywords: Attachment styles, spouse attitudes
This chapter discusses the importance of addressing sexuality within psychotherapy to enhance overall treatment outcomes. It emphasizes the need for therapists to conduct thorough sexological assessments and integrate sexual health into clinical practice. This chapter covers essential concepts such as biological sex, gender identity, sexual orientation, and the multidimensional nature of human sexuality. It also explores the relevance of attachment, metacognition, and the therapeutic relationship in understanding and treating sexual dysfunctions. Practical guidelines and a clinical case example illustrate how to effectively incorporate sexology into psychotherapy.
The chapter explains how the concepts of physical and sexual attraction differ from each other. The materials of the chapter describe the ideas and research on beauty and physical attractiveness.
The chapter demonstrates how attractive physical appearance influences overall interpersonal attraction. Evolutionary, ecological, social, cultural, and psychological perspectives show that the values and notions of physical attractiveness depend on many of these contextual factors. The studies reviewed in the chapter have demonstrated variability in preferences for physical appearances across cultures.
The chapter presents research findings that reveal the effects of familiarity, imprinting, and exposure on the impressions of how physically attractive a person looks. The features of physical attractiveness are sexually polymorphic and differ between genders. The sections of this chapter provide an overview of the qualities of physical appearance that make a person attractive, as well as multisensory qualities of attractive appearance, including visual, auditory, tactile-kinesthetic, olfactory, and gustatory modalities of sensation and perception.
The chapter describes in detail how people experience and express physical and sexual attraction. The last section of the chapter presents varieties of sexual attraction in love that depend on sexual identities, sexual orientations, and factors influencing diversity in sexual attraction.
Wovon hängt der viel berühmte „erste Eindruck“ ab, wenn wir privat oder beruflich neuen Menschen begegnen? Und welchen Einfluss können unsere Eigenschaften und Bedürfnisse auf die Wahrnehmung einer anderen Person bei dieser Begegnung haben? Im folgenden Buchkapitel werden wir diesen Fragen nachgehen und dafür zunächst vorstellen, anhand welcher Dimensionen die Wahrnehmung fremder Personen charakterisiert werden kann. Daraufhin ziehen wir Parallelen zu den relevanten Dimensionen bei der Wahrnehmung potenzieller Partnerinnen und Partner und diskutieren die Wichtigkeit der Domänen in Abhängigkeit von Eigenschaften der betrachtenden Person. Wir werden darlegen, dass bestimmte Personen (Targets) von bestimmten Betrachterinnen und Betrachtern (Perceivern) unterschiedlich wahrgenommen werden (Target x Perceiver-Interaktion). Hierbei fokussieren wir uns auf das Geschlecht als relevante Perceiver-Variable. Weiterhin werden wir aufzeigen, dass sich die unterschiedliche Wichtigkeit in der Bewertung von Partnermerkmalen nicht nur im Selbstbericht widerspiegelt. Es liegen bereits erste Befunde vor, welche auf Target-, Perceiver-, und Target × Perceiver-Interaktionseffekte bei der automatischen Verarbeitung von Partnermerkmalen auf basaler kognitiver Ebene hindeuten. Abschließend fassen wir zusammen, welche Fragen die empirische Forschung bereits geklärt hat und welche noch offen sind. Aus unserer Sicht eröffnet sich durch ein systematisches und umfassendes Verständnis der automatischen Verarbeitung in der Personenwahrnehmung ein interessantes Forschungsfeld für die evolutionären Sozialwissenschaften, um theoriegeleitet Hypothesen über den Einfluss von „Kultur“ auf den verschiedenen Stufen der Verarbeitung, beginnend bei sehr basalen automatischen Prozessen auf der Ebene der Wahrnehmung und Aufmerksamkeit, bis zu sehr kontrollierten und verzerrten Antworten im Selbstbericht, abzuleiten und zu überprüfen.
Several hypotheses have been proposed to explain the occurrence of continual sexual receptivity and concealed ovulation in human females. In view of the large number of benefits that would accrue to females if they could sense their own ovulation, these explanations appear insufficient to explain why ovulation is concealed from females as well as from males. The hypothesis presented here is that the phenomenon occurs because of a hominid female tendency to avoid conception in biologically nonadaptive ways. This tendency was countered by natural selection by making ovulation virtually undetectable to women. The sequence of evolutionary adaptations culminating in concealed ovulation is most likely as follows. First, olfactory, visual, and pronounced behavioral cues to ovulation were lost to conspecifics. Coincidentally females evolved continuous receptivity, frequently copulating at times other than when ovulating. Finally, females lost conscious cues to their own fertility. This last step was predicated up...
Describes a technique in which organisms are provided with extended exposure to mirrors and then given an explicit test of self-recognition (through the unobtrusive application of marks to facial features visually inaccessible without a mirror). Use of this procedure with chimpanzees and orangutans in a series of studies by the present author provided evidence of self-recognition, with patterns of self-directed behavior emerging after only 2–3 days. In support of the widely held view that the self-concept may develop out of social interaction with others, the capacity for self-recognition in chimpanzees appears to be influenced by early social experience. To date, however, attempts to demonstrate self-recognition in all other species except man have failed. The phyletic limits of this capacity may have important implications for claims concerning the evolutionary continuity of mental experience. (64 ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Examines the possibility that pheromones can explain various aspects of primate reproductive and sexual behavior in the light of behavioral, olfactory, and biochemical evidence. Emphasis is on rhesus and human phenomena. Menstrual synchrony is suggested as the most promising area in which to search for pheromonal control of higher primate behavior. It is concluded that although it is probable that olfaction and olfaction-related phenomena influence behavior, it seems unlikely that chemical communication plays any significant role in the control of higher primate reproductive and sexual behavior. (3½ p ref)
Clinical work with offenders and victims is cited to support the concept of rape as a sexual deviation, as well as a sexual offense. It is suggested that rape is directed toward the sexual expression and gratification of needs that are not basically sexual, and that it represents a developmental crisis for the offender, which in turn triggers a situational crisis for the victim.
Sexual delinquency is probably on the increase in most countries; at least everywhere that statistical data are available this has been the case. This fact has aroused considerable concern among criminologists and the lay public. In the Netherlands the number of persons convicted of sexual offences amounted in 1925 to 886 and in 1954 to 2,224 — an increase of 157 per cent (table I). In England and Wales “on the average for the two years 1937 and 1938 the number of indictable sexual offences annually recorded was 4,448, whereas in 1954 the number had become 15,636, which is an increase of 252 per cent.”1 In Finland 125 sexual offences led to punishments in general courts of first instance in 1945, while in 1954 the figure was 465 — again an increase of 247 per cent.2 In Austria there was a rapid increase of sexual offences after the second world war.3
Publisher Summary Birds, in which, in the absence of lactation both sexes can play an equal role in feeding the young, monogamous mating systems are generally desirable, such that sexual dimorphisms in body size are unlikely to develop. This chapter describes the concept of sexual selection, reproduction in the gorilla, orangutan, chimpanzee, and man. Sexual selection can be subdivided into two components parts: somatic selection, the factors determining general body size, and genital selection, the factors determining the size of the gonads and external genitalia. While, somatic selection is apparently related to the mating system, and is concerned with successful competition for access to a mate, genital selection is far more complex; although influenced by mating type, it is ultimately a reflection of copulatory frequency. The chapter concludes that the most telling anatomical clues, probably, to the reproductive behavior of man and the Great Apes are the relative body sizes of the male and the female, and the relative sizes of the testis and the ovary. However, it remains to be seen whether the significance of these simple anatomical clues will be confirmed by the examination of a far wider range of species.
Male hoary marmots living in isolated colonies at Mount Rainier National Park demonstrated a significantly greater involvement with their infants than did males living in a larger, more interactive social situation. Paternal behavior correlated inversely with frequencies of extrapaternal social interaction. This pattern is seen as maximizing male fitness in each situation by providing for male defense of his reproductive interests when this is dictated by the proximity of other adults and facilitating direct paternal involvement when relative isolation reduces the advantages of extrapaternal sociality.
Book reviewed in this article:
THE ECOLOGY OF HUMAN DEVELOPMENT: EXPERIMENTS BY NATURE AND DESIGN by Urie Bronfenbrennre
Current models for the evolution of polygyny and sexual dimorphism are largely derived from data on passerine birds. These models are less appropriate for taxa such as mammals, in which males emphasize mating strategies, than for those such as passerines, in which males emphasize progeny rearing strategies. The Orians-Verner model is inadequate as a general explanation of the evolution of polygyny in mammals because many species do not meet one or more of its assumptions: that the need for male parental care is the main factor opposing the evolution of polygyny; that females choose to mate with particular males; and that the female raises her young on the resources contained in the territory of the male with which she mates. A two-factor model incorporating the concept of sexual bimaturism, developed by Wiley for grouse, is more appropriate for many mammals but still too simple. In mammals, large male parental investment is a good predictor of both monogamy and reduced sexual dimorphism, but small male in...
Approximately 62 per cent of a group of university Freshmen women reported experiencing offensive male sexual aggression during the year prior to university entrance. Proneness to sexual aggression appears associated with a lack of parental sex guidance and the absence of older male siblings. Certain characteristics of the pair relationship also increase the probability of aggression. The adjustive reactions of the offended female are strongly influenced by prior parental guidance and the severity and provocation of the aggressive episode.
Rejects the concepts of sex drive, instinct, need, and motivation on the grounds that they cannot be handled empirically or operationally (any more than phlogiston or possession by demons could be) and substitutes threshold for the release or inhibition of behavior. Chromosomes, fetal gonads and hormones, neural pathways, and genital appearance are listed as cumulative components of adult gender. Photographs of varying genital differentiation in genetic vs gonadal males and females at different ages are presented. Results of corrective therapy and/or surgery are shown. Transvestite disexual identity, transsexual reassignment, and transpositions of gender identity and role are compared. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Discusses the applicability of ethological data to the human condition and how psychiatrists and ethologists each view the other's field of study. Suggestions for preventing distortion of data from animal behavior studies are presented, and the dangers of obtaining data from 1 species and applying it to another or using it to confirm social prejudices are examined. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Failure of the behavioral sciences to develop an adequate general theory is seen as a result of the difficulty in deriving from evolutionary theory a subtheory, or set of subtheories, with satisfying applicability to the study of behavior. Efforts at general theories based on reflex concepts, or simple movements such as in orientation, have been unsuccessful in dealing with complex behaviors. Recent arguments that selection is focused at the level of the individual organism suggest the additional inadequacy that such theories fail to emphasize the selective compromises that exist at suborganismic levels. Evolutionary theories about behavior have tended to concentrate chiefly on patterns of historical change (phylogenies) without stressing adaptive (= reproductive) strategies, or have generally viewed adaptiveness erroneously as focused at group, population, or species levels. Human society is discussed briefly, in a context of selection focused at the individual level, considering six principal aspects: group-living, sexual competition, incest avoidance, nepotism, reciprocity, and parenthood. An effort is made to combine the approaches and data of biologists and social scientists in analyzing reciprocity in social interactions.
Comparative observations in a captive setting of the sexual behavior of wild born and reared Pan troglodytes and Pan paniscus revealed important and unexpected behavioral differences between these two closely related species. The external genitalia of the female Pan paniscus is rotated anteriorly, copulation takes place throughout the cycle in Pan paniscus, and homosexual copulation is a common occurrence. Vocal and gestural exchanges often precede and accompany copulation in Pan paniscus but not in Pan troglodytes. Feeding and food sharing elicit copulatory activity on virtually every occasion in Pan paniscus, but not in Pan troglodytes. Copulatory positioning among Pan paniscus is marked by considerable variability, including en face ventro-ventral positioning. These observations suggest that, at least in aspects of sexual behavior, the pygmy chimpanzee displays greater malleability and greater dependencyupon complex non-verbal signaling. In Pan paniscus, copulatory behavior is more closely intertwined with other forms of social interaction such as food sharing. The sexual behavior patterns of the pygmy chimpanzee, while still quite distinct from those of man, nevertheless display a greater degree of similarity to the sexual patterns of our own species than do those of any other living non-human primate.
1.
The sexual behaviour of a chimpanzee community in the Gombe National Park, Tanzania, was studied intensively for 16 months. Additional information came from 15 years of demographic and behavioural data accumulated by Jane Goodall and members of the Gombe Stream Research Centre.
2.
The mating system of the Gombe chimpanzees is flexible and comprises three distinct mating patterns: (a) opportunistic, non-competitive mating, when an oestrous female may be mated by all the community males; (b) possessiveness, when a male forms a special short-term relationship with an oestrous female and may prevent lower-ranking males from copulating with her; and (c) consortships, when a male and a female leave the group and remain alone, actively avoiding other chimpanzees. While males took the initiative in possessive behaviour and consortships, females had to cooperate for a successful relationship to develop.
3.
Data from 14 conceptions indicated that the majority of females (9) became pregnant while participating in the restrictive mating patterns, possessiveness and consorting. It could be established definitely that seven of these females were consorting during the cycle in which they conceived. As 73% of the 1137 observed copulations occurred during opportunistic mating, 25% during possessiveness, and only 2% during consortships, there was no correlation between copulation frequency and reproductive success.
4.
Adult males showed differential frequencies of participation in the restrictive mating patterns. Male age, dominance rank, and the amount of agonistic behaviour directed to females showed no correlation with participation in the restrictive mating patterns. The following male characteristics did show significant, positive correlations with involvement in the restrictive mating patterns: (a) the amount of time spent in the same group as oestrous females, (b) the proportion of that time spent grooming oestrous females in groups, and (c) the frequency with which males shared food with females. While dominance ranks of the adult males showed no consistent correlation with involvement in the restrictive mating patterns, it was clear that the most dominant male did gain an advantage. He was the only male able to monopolise oestrous females by showing possessive behaviour.
5.
Consortships appeared to be the optimal reproductive strategy for males (with the exception of the most dominant) and females, as they gave males the highest probability of reproductive success, and allowed females to exercise choice. However, there appeared to be disadvantages associated with consort formation; the greatest of these was the increased risk of intercommunity encounters. While all individuals have the potential to practice each mating pattern, the strategy actually used at any moment will be determined by variables both within the individual, e.g. age, physical condition, dominance position; and by social factors in the group, e.g. general stability of male dominance relationships, presence of a strong alpha male, existence of special male-female relationships.
Eighteen Soviet female patients with the late-treated virilizing adrenogenital syndrome are described. In contrast to previous studies, homosexual experience and fantasies were not reported. In concordance with previous studies, there was the suggestion of enhanced intelligence as a function of increased levels of prenatal androgen.
Homo sapiens is unique among primates in that it is the only group-living species in which monogamy is the major mating system and the only species in which females do not reveal their ovulation by estrus. These unique traits can be explained in terms of natural selective and cultural selective theory applied at the level of the individual. The relative amount of parental investment by the sexes is an important correlate with the type of mating systems found in animal species. In human history the evolution of increased hunting abilities, bipedality, relatively altricial young and the concomitant dependency on the male for food by the female are viewed as the factors allowing and favoring increased male parental investment. The same scenario can explain the evolution of extensive female parental care in humans. Monogamy is the result of the male's investment being increased to approximate equality with that of the female and the male's attempt to insure his paternity. The incipient hunting activities of Australopithecus and small cranium would indicate polygyny at this stage of hominid evolution. The increase in hunting activities and brain size of Homo erectus may have favored monogamy. Polygyny may have reappeared to some extent with the evolution of Homo sapiens sapiens 40,000 B.P., but perhaps not until 15,000–11,000 B.P. did disparity in resources controlled by males allow some males to exceed the polygyny threshold. The loss of estrus in the female is regarded not as a precondition to pair-bonding, but as a means for increasing the likelihood of successful cuckoldry of the male after monogamy has been established. The human social setting of monogamous pairs in close proximity greatly reduces the costs of infidelity.
SINCE the publication of my work on Hereditary Genius in 1869, I have written numerous memoirs, of which a list is given in an earlier page, and which are scattered in various publications. They may have appeared desultory when read in the order in which they appeared, but as they had an underlying connection it seems worth while to bring their substance together in logical sequence into a single volume. I have revised, condensed, largely re-written, transposed old matter, and interpolated much that is new; but traces of the fragmentary origin, of the work still remain, and I do not regret them. They serve to show that the book is intended. to be suggestive, and renounces all claim to be encyclopedic.. I have indeed, with that object, avoided going into details. in not a few cases where I should otherwise have written with fulness, especially in the Anthropometric part. My general object has been to take note of the varied hereditary faculties of different men, and of the great differences in different families and races, to learn how far history may have shown the practicability of supplanting inefficient human stock by better strains, and to consider whether it might not be our duty to do so by such efforts as may be reasonable, thus exerting ourselves to further the ends of evolution more rapidly and with less distress than if events were left to their own course. The subject is, however, so entangled with collateral considerations that a straightforward step-by-step inquiry did not seem to be the most suitable course. I thought it safer to proceed like the surveyor of a new country, and endeavour to fix in the first instance as truly as I could the position of several cardinal points. The general outline of the results to which I finally arrived became more coherent and clear as this process went on;. they are briefly summarised in the concluding chapter.
This article presents a graphical approach to the genetical theory of sex change (similar to one recently applied to the evolution of simultaneous hermaphroditism). The graphs will help clarify a set of predictions to be tested against data from Pandalid shrimp. These shrimp are protandrous hermaphrodites (reproduce first as males). The goal is to use the genetical theory to predict the age of sex change. Since these shrimp show much geographic variation in this age, they provide a good opportunity to test the evolutionary model.
R. A. Fisher (1930) was perhaps the first to realize that the key to sex ratio evolution lay in the almost trivial fact that (under diploidy) everyone has one mother and one father; that in terms of autosomal genes males and females contribute equally to any zygote formed. This paper shows that his observations proves a useful key to a host of other sex related problems. It is for this intuitive reason that fitness measures for the alteration of sex function are often of the general form W = m̂/m + f̂/f. In such a measure male and female function are assigned equal weight. It is somewhat surprising that this notion continues to hold under haplodiploidy (at least from the mother's viewpoint). There is much that this paper has ignored--inbreeding, fluctuating or stochastic environments, etc. A treatment of many of these is much beyond me. It will be quite interesting to know how well the m̂/m + f̂/f notion holds up to alterations in the basic models proposed here.
Mammals exhibit a variety of density-dependent reproductive variables
that enable them to come into equilibrium with their environment. These
include the age at puberty, extent of embryonic and foetal death,
neonatal mortality rate, and the duration of lactational anoestrus or
amenorrhoea. These are all female-oriented mechanisms; most mammals are
polygynous, and as the female has the greatest energy investment in
reproduction she is the limiting resource. Unfortunately, man as a
species has chosen to eliminate these constraints, so that we are now
without any natural checks and balances on our rate of population
growth. We will be entirely dependent on artificial forms of
contraception for evermore. Since natural selection has always operated
in the past to maximize reproductive potential, women are
physiologically ill-adapted to spend the greater part of their
reproductive lives in the non-pregnant state. Tomorrow's contraceptives
need to be chosen with great care, as they will have a considerable
impact on our general health and social well-being.
An adaptationist programme has dominated evolutionary thought in England and the United States during the past 40 years. It is based on faith in the power of natural selection as an optimizing agent. It proceeds by breaking an oragnism into unitary 'traits' and proposing an adaptive story for each considered separately. Trade-offs among competing selective demands exert the only brake upon perfection; non-optimality is thereby rendered as a result of adaptation as well. We criticize this approach and attempt to reassert a competing notion (long popular in continental Europe) that organisms must be analysed as integrated wholes, with Baupläne so constrained by phyletic heritage, pathways of development and general architecture that the constraints themselves become more interesting and more important in delimiting pathways of change than the selective force that may mediate change when it occurs. We fault the adaptationist programme for its failure to distinguish current utility from reasons for origin (male tyrannosaurs may have used their diminutive front legs to titillate female partners, but this will not explain why they got so small); for its unwillingness to consider alternatives to adaptive stories; for its reliance upon plausibility alone as a criterion for accepting speculative tales; and for its failure to consider adequately such competing themes as random fixation of alleles, production of non-adaptive structures by developmental correlation with selected features (allometry, pleiotropy, material compensation, mechanically forced correlation), the separability of adaptation and selection, multiple adaptive peaks, and current utility as an epiphenomenon of non-adaptive structures. We support Darwin's own pluralistic approach to identifying the agents of evolutionary change.
The sexual interactions of 10 pairs of rhesus monkeys were observed during a control and an experimental menstrual cycle of each female. During the experimental cycle the females were treated with an antiandrogen, flutamide. Daily peripheral serum levels of estradiol, testosterone, and progesterone in each female were determined by radioimmunoassay. Sexual behavior did not correlate reliably with female serum concentrations of any hormone measured nor with the menstrual cycle stage. Administration of the antiandrogen to the females did not affect the sexual behavior of the pairs, although female serum levels of estradiol and testosterone were reduced. It was concluded that although female ovarian hormones may influence rhesus sexual interactions under some circumstances, the normal hormonal fluctuations during the menstrual cycle need not regulate this behavior; a knowledge of an intact rhesus female's hormonal condition does not allow accurate predictions about behavior displayed during laboratory pair tests with a male.
Daily administration over a period of 6 weeks of increasing doses of dexamethasone sodium phosphate (DEX) to seven long-term ovariectomized female stumptail monkeys significantly lowered circulating levels of testosterone without reducing any aspect of the females' sexual behavior or that of their male partners. Since treatment with DEX failed to suppress serum testosterone levels completely an additional experiment was performed in which the sexual behavior of five ovariectomized stumptails was compared before and after bilateral adrenalectomy, combined with chronic administration of both gluco- and mineralocorticoids. Serum levels of both testosterone and estradiol were reduced to very low levels in females after ovariectomy and adrenalectomy, yet no significant depression of females' sexual performance or that of their male partners occurred. Subsequent sc administration of estradiol or estradiol + testosterone in Silastic capsules to ovariectomized, adrenalectomized stumptails had little effect on sexual interaction. In a third experiment five ovariectomized stumptails which initially were relatively unreceptive and unattractive to males were given first testosterone and then testosterone + estradiol sc in Silastic capsules. One of the three indexes of females' receptivity increased significantly after testosterone; however, no other essential aspect of sexual interaction was affected. These findings suggest that sex steroids are normally not required in the female stumptail macaque for activation of preceptive and receptive sexual behaviors or for maintenance of sexual attractivity.
The reproductive behavior of captive female rhesus monkeys living in a large social group was examined to determine what patterns of proceptive behavior occur and how they are distributed throughout the menstrual cycle. Ten intact adult females and six vasectomized adult males were observed during the breeding season. The males were housed separately overnight and released into the social group for a 4-hr observation period. The female menstrual cycles were monitored by daily capture for vaginal swabbing. A total of 18 cycles in which females showed estrous behavior between intervals of menstruation were observed for nine females between October 4 and February 4. A composite of all the cycles revealed a significant rise in proceptive behavior during the follicular period culminating in a midcycle peak, with an abrupt cessation of female sexual invitations during the early luteal period. The specific patterns of proceptive behavior observed consisted primarily of female-initiated proximity and following of males. Solicitation patterns such as sexual presentation, hand slap, head bob/duck, and threat out were displayed to a lesser extent. Overall, these data suggest that underlying endocrine events strongly influence the behavior of female rhesus monkeys living in a complex social environment and that social factors such as dominance rank do not appear to override these hormonal variables.
Sociobiology is discussed as an extreme example of the adaptationist program. This program attempts to describe all aspects of living organisms as optimal solutions to problems set by the environment and by the biology of the species. Sociobiology first describes human nature by generalizing about human behavioral universals, then asserts that these traits are controlled by genes and then provides an adaptive story to explain why individuals with these traits would leave more offspring. The theory takes no account of problems of correct description and makes four errors: Arbitrary agglomeration, reification, conflation, and confusion of levels. As a result, the human behavior described bears no necessary resemblance to actual biological traits. The theory depends upon assertions of genetic control that have no basis in experimental fact. Sociobiologists have made no critical evaluation of the extremely poor knowledge of human genetics. Finally, the assumption that all characteristics are adaptations is never examined by sociobiology. There are many alternative evolutionary forces besides direct adaptation for establishment of characters. These include genetic drift, multiple selective peaks, lack of correspondence between the result of natural selection and optimal solutions, pleiotropic gene action, allometry and developmental noise. If sociobiology is to become a real science instead of idle speculation, it must abandon the tautological adaptationist program which is untestable.
The effects of endogenous fluctuations in ovarian hormones during the female's menstrual cycle on heterosexual interaction was studied in groups of stumptail macaques. When 5 different trios of females were paired for 5 consecutive weeks with each of 5 males no aspect of male-female interaction changed as a function of phase of the menstrual cycle. Moreover, males usually preferred to copulate with the same female of each trio in consecutive tests, regardless of the ovarian condition of any of the females. It appeared that the most dominant females in the trios were sexually most preferred. Subcutaneous implantation of silastic capsules containing progesterone into the sexually most preferred females of each trio affected neither the males' sexual preference, nor the behavior of these females, nor the behavior of sexually non-preferred females in each trio. Likewise, progesterone in sexually preferred females had no effect on male-female interaction in pair tests. It is concluded that in stumptail macaques social factors are more important than ovarian hormones in regulating heterosexual interaction.
The recent rise of a high-ranking adult male chimpanzee to the alpha male position of the Gombe National Park's Kasakela chimpanzee community is reported. The male Figan is the fourth individual to assume this status in the wild chimpanzees' social hierarchy during Goodall's 16 year study in Tanzania. The paper describes the overthrow of the previous top-ranking male, and the manner in which Figan has maintained his new position after the take-over. Emphasis is placed upon his relationship with his elder male sibling, Faben, and the second highest-ranking male in the community, Evered.
RENSCH1,2 showed, more than 20 years ago, that sexual dimorphism in body size tends to increase with increasing body size in various arthropod and avian taxa. Recently, the same positive relationship has been suggested for mammals in general3, and primates in particular4. Based on their findings on primates, Clutton-Brock et al.4 discussed several possible functional explanations for this relationship, but considered none of them wholly satisfactory. In particular, they rejected the hypothesis that positive allometry in sexual dimorphism in weight may be the product of an association of size and polygyny; they did not present statistical data to that effect, however. I argue here that, on the contrary, there is a strong relationship between polygyny and positive allometry for sexual dimorphism in body size. The evidence is based on an analysis of the relationship between the scaling of sexual dimorphism in body weight and the breeding system for 53 primate species, which in most cases coincide with those chosen by Clutton-Brock et al.4 for their study. The findings are incorporated into a multifactorial system on the evolution of sexual dimorphism in body size.
This study was designed to test the hypothesis that women exhibit peaks of sexual activity at ovulation, as would be predicted from estrous effects in animals. Married women who used contraceptive devices other than oral contraceptives experienced a significant increase in their sexual behavior at the time of ovulation. This peak was statistically significant for all female-initiated behavior, including both autosexual and female-initiated heterosexual behavior, but was not present for male-initiated behavior except under certain conditions of contraceptive use. Previous failures to find an ovulatory peak may be due to use of measures of sexual behavior that are primarily determined by initiation of the male partner. Women using oral contraceptives did not show a rise in female-initiated sexual activity at the corresponding time in their menstrual cycles, probably owing to the suppression of ovulatory increases in hormone secretion by the oral contraceptives.