Male, Female: The Evolution of Human Sex Differences

by David C. Geary

Univ. of Missouri, Columbia. New approach to the sexes, explaining the differences between men and women rather than describing them. Covers sexual selection, paternal investment, evolution and development of the mind, and more. For researchers and practitioners. Halftone illustrations.

Genres: Psychology, Science, Evolution, Biology, Gender, Nonfiction, Sexuality

397 pages, Hardcover

First published January 1, 1998

About the author

David C. Geary is a cognitive developmental and evolutionary psychologist with interests in mathematical learning and sex differences. After receiving his Ph.D. in 1986 from the University of California at Riverside, he held faculty positions at the University of Texas at El Paso and the University of Missouri, first at the Rolla campus and then in Columbia. Dr. Geary is currently a Curators' Professor and a Thomas Jefferson Fellow in the Department of Psychological Sciences, and served as department chair from 2002-2005. He has published more than 240 articles and chapters across a wide range of topics, including cognitive, developmental, and evolutionary psychology, education, and medicine, including three sole-authored books, Children's mathematical development (1994), Male, female: The evolution of human sex differences (1998, now in second edition. 2010), and The origin of mind: Evolution of brain, cognition, and general intelligence (2005), and one co-authored book, Sex differences: Summarizing more than a century of scientific research (Ellis et al., 2008). He is co-editing a series of five books on Advances in Mathematical Cognition and Learning with Drs. Dan Berch and Kathy Mann Koepke. The first volume, Evolutionary origins and early development of basic number processing should be published in late 2014 or early 2015. He has given invited addresses in a variety of departments (anthropology, biology, behavior genetics, computer science, education, government, mathematics, neuroscience, physics, and psychology) and Universities throughout the United States, as well as in Canada, Europe and East Asia.

Reviews

[Mansoor · Rating 5 out of 5]

Everything You Always Wanted to Know About Sex Differences but Were Too PC to Ask
...
روانشناسی تکاملی همچون پتکی بر سر ایدئولوژی‌های خیالباف-فمینیسم و سوسیالیسم و لیبرالیسم-فرود می‌آید و تک‌تک افسانه‌هایشان را رسوا می‌کند. بیخود نیست که فمینیست‌ها، چپ‌ها و لیبرال‌ها هرچه در توان دارند به کار می‌بندند تا نتایج این قبیل پژوهش‌ها را پنهان یا سانسور کنند

[Falk · Rating 4 out of 5]

Geary writes in the Preface: “Since the publication of the first edition, the literature on human sex differences and on related topics, such as the evolution of sexual reproduction, has increased substantially. This required a thorough rewriting of all of the chapters, including breaking topics that were covered in a single chapter in the first edition into two chapters in this one, as well as adding new chapters. With the expanded coverage and more thorough organization and integration across chapters there was no room (in terms of page limitations) to include a chapter on implications for modern societies. However, I do cover the gist of these topics—sex differences in academic competence (e.g., reading, mathematics), behavioral (e.g., accidents) and psychological disorders (e.g., depression), and occupational outcomes (e.g., achievement level)—in the afterword.” – Make sure you pick up the second edition of this book.

The book starts out with an overview of basic mechanisms of natural selection and the evolution of sex before moving on to the evolution of sex differences in different species of birds, mammals, insects, fish, etc. in the light of Darwin’s theory of sexual selection, and finally applies it to the evolution of sex differences in hominids. The main part of the book is focused on sex differences in humans. - Geary argues that gorillas may provide a better model for the family and kinship structure of our hominid ancestors than does e.g. chimpanzees:
“Unlike men, male chimpanzees and bonobos show little to no paternal investment. And unlike women, female chimpanzees and bonobos show conspicuous estrous swellings and mate promiscuously. On the basis of these and other differences, Geary and Flinn (2001) proposed that modern humans' ancestors might have been more similar to our distant cousin, the gorilla (see also Lovejoy, 1981). This is because moving from a gorilla-like pattern to the current human pattern would require fewer evolutionary changes than needed to move from a chimpanzee-like or bonobo-like pattern to the human pattern.” (p. 138) “Unlike the unrestricted mating of female chimpanzees (during estrous) or bonobos, and a corresponding low level of paternity certainty (de Waal & Lanting, 1997; Goodall, 1986), adult male and female gorillas often form long-term social relationships. DNA fingerprinting indicates that male lowland gorillas show high levels of paternity certainty (greater than 95%; Bradley et al., 2004).. (...) The genetic findings indicate that the male-kinship structure for lowland gorillas is close to that currently found with humans (Bradley et al., 2004). The primary difference is the degree of cooperation among adult males as related to coalitional competition. Such coalitions could easily evolve from the social structure described by Bradley et al. The formation of more closely knit male kinships would result in greater proximity of males and through this the creation of the multimale, multifemale communities found in all human societies..” (p. 139)

I find it interesting that three people gave the book a very low rating (one star) at Amazon - for widely different reasons. One person criticized it for justifying “current politically correct presumptions,” which wouldn’t have surprised me since this book is published by the APA. I didn’t find much of that however. I did note that Geary does tend to make caveats quite often, but this is mainly when the findings aren’t clear enough, or because research specifically focusing on sexual selection is sometimes lacking. This lack however, is possibly due to said political correctness, but it’s hardly something you can put blame on Geary for. There is however, some degree of difference between to two editions of this book, which is worth noting in this connection, because at the time of the new edition (2009) much more data was available, and the last chapter of the first edition, dealing with “Sex Differences in Modern Society” was dropped, possibly not only due to lack of space but simply because it had become more or less redundant. It seems much will in fact hinge on which edition is reviewed. - One of the other Amazon reviewers again criticized the book for being “biological determinist” and the third simply dismissed the book suggesting you read some feminist literature instead. – So, in addition to the evolution vs. creationism debate, you can join the evolution vs. feminism debate - if you have some time to waste, that is. Or, lacking time to waste, you can simply read e.g. Geary’s empirical work on evolution and sex differences.

Geary deals methodically and comprehensively with such different areas as intrasexual competition, mating strategy and choice, parenting (one chapter is devoted to the evolution of fatherhood), prenatal and child development, and finally sex differences in brain structure and cognition. There are copious references, all of them provided in parentheses throughout the text, and often over several lines. This breaks up the text too often for my liking, but on the whole there’s far more to like about this book than not. In brief, this is a massive work of impressive scope and erudition.

I’ll end with a quote from the author’s Afterword: “Evolution is not just another psychological, sociological, or anthropological theory; it has proven to be the unifying meta-theory for all of the biological sciences. Eventually, all psychological, sociological, and anthropological models will need to be reconciled with the principles of natural and sexual selection. One can choose to be part of the discovery process or one can let these forthcoming scientific advances pass one by.”




This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

[Mooncalf · Rating 4 out of 5]

This books provides very strong reasons to believe that there are biological differences between the human sexes.

[Juny · Rating 4 out of 5]

En una época de wokismo, posmodernismo, negacionismo, la pseudocientífica teoría queer y los famosos «estudios», es muy importante estudiar de forma fiable y libre de falacias sobre la selección sexual, los sexos y la reproducción sexual. Si se quiere cambiar el mundo, primero debemos entendernos —y no negarnos— a nosotros mismos.

Un libro excelente y muy necesario. Muy serio sobre estos temas, muy informativo y muy al día sobre las últimas y más influyentes investigaciones y estudios. Va desde la selección sexual y las diferencias sexuales en otros animales hasta conectar ya con los humanos; desde la dinámica de la selección sexual en los humanos ancestrales hasta la actualidad; desde los desencadenantes en el entorno y la historia de la vida de los individuos hasta los efectos de la biología en nuestro comportamiento y decisiones. Y muchas más cosas interesantes sobre la selección sexual. Hay algunas partes que se hacen pesadas, pero en general es un libro muy ameno para el lector, y es pan comido si ya se tienen conocimientos previos sobre el tema. El libro pasa directamente a mi lista de recomendados.

- - -

In an age of Wokism, postmodernism, denialism, pseudo-scientific queer theory, and the famous "studies," it is very important to study in a reliable way and free of fallacies about sexual selection, the sexes and sexual reproduction. If the world is to be changed, we must first understand —and not deny— ourselves.

An excellent and much needed book. Very serious about these issues, very informative and very up to date on the latest and most influential research and studies. It goes from sexual selection and sexual differences in other animals to already connecting to humans; from the dynamics of sexual selection in ancestral humans to the present day; from triggers in the environment and life history of individuals to the effects of biology on our behavior and decisions. And many more interesting things about sexual selection. There are some parts that get heavy, but overall it is a very enjoyable book for the reader, and is a breeze if you already have prior knowledge on the subject. The book goes directly to my recommended list.

[Graham Seibert · Rating 5 out of 5]

A rigorously academic book. Encyclopedic, scrupulously noncontroversial treatment of a sensitive subject.

David Geary is a thorough, authoritative expert on the evolution of sex differences throughout the animal kingdom, and especially human beings. His bibliography is huge. I counted well more than a thousand authors, including a Who's Who of the best known science writers of the age. Here are some of the names I have reviewed and respect: Baumeister, Darwin, Dawkins, Diamond, Dunbar, EiblEibesfeldt, Fossey, Giedd, Goodall, Gould, Haidt, Hamilton, Hrdy, Irons, Kanazawa, Leakey, MacDonald, Pinker, Ridley, Robbins, Rubenstein, Scarr, Tiger, Tobias, Tooby, Trivers, Wade and Wilson.

The first part of the book deals with sexual evolution in the animal kingdom, then among primates and among anthropoid apes and humanoids. The second part addresses the evolution of traits that we observe in modern man. The chapter titles are:

Chapter 1: Beginnings
Chapter 2: Natural Selection and the Evolution of Sex
Chapter 3: Sexual Selection
Chapter 4: Sexual Selection and Life History
Chapter 5: Sexual Selection in Primates and During Human Evolution
Chapter 6: Evolution of Fatherhood
Chapter 7: Choosing Mates
Chapter 8: Competing for Mates
Chapter 9: Evolution and Development of the Human Mind
Chapter 10: Sex Differences in Infancy and at Play
Chapter 11: Sex Differences in Social Development
Chapter 12: Sex Differences in Folk Psychology
Chapter 13: Sex Differences in Folk Biology and Folk Physics

Sexual and asexual reproduction are found throughout the plant and animal kingdoms. Asexual reproduction has its advantages, chief among which is that it does not require the organism to find a mate. The major disadvantage of asexual reproduction is that it has no mechanism to support diversity within the gene pool. Most mutations are disadvantageous and need to be eliminated. Conversely, beneficial mutations should be conserved. With asexual reproduction it is an all or nothing proposition. Any mutation gets reproduced with the entirety of the genome. A population lacking genetic diversity is vulnerable to changes in the environment, a phenomenon that happens all the time.

Sexual reproduction is favored by just about every advanced animal species. Most plants as well, although they may have the facility to reproduce by sending out runners (banyan trees) or leaf in branch cuttings (walnuts, navel oranges) also take advantage of sexual reproduction at some point in their cycle.

Mate choice is part and parcel of sexual selection. In a good many species the males battle with one another for access to females. One of the interesting things to come out in this book is the extent to which the supposedly passive females are able to take active control of their reproduction by one means or another. In many bird species the females overtly choose the male with whom they will mate. In other species the females mate with whom they must, but have evolved mechanisms to covertly choose whose sperm will impregnate them.

In most species one sex makes a greater investment in the offspring than the other. It is usually, but not always, the female. Whichever it is, the sex that makes the greatest investment in offspring tends to be the choosiest about selecting a mate.

Mating may be a matter of a moment or a lifetime. Different strategies of evolved to support each kind of pairing up. Among monogamous animals, the males typically assist in raising the young. They are typically about the same size as the females. They typically have smaller genitalia and less testosterone, inasmuch as they do not have to fight for sexual access.

Our primate ancestors have generally been polygynous. Dominant males controlled as many females as they could and did their best to control their mating. DNA testing demonstrates that try as they might, orangutans and chimpanzees are not totally successful in keeping their mates from straying. Nonetheless, among primate species the males tend to be significantly larger than the females. Another evolved suite of attributes among species that feature dominant males is that males reach sexual maturity later than females, males are brightly colored, and males' childhood play involves practicing dominance battles with other males.

A point to which Geary often returns is that gorillas are the exception. The male gorilla guards his harem and participates somewhat in taking care of his children. The male to male competition in which he is involved has to do with territory. There is only one silverback at a time in a gorilla family, and he alone has the right to mate with the females. His genitalia are just big enough to do the job; skillful lovemaking is not the key to having baby gorillas.

Human beings differ from other apes in significant ways. There is less sexual dimorphism – men and women are closer to the same size. We are more monogamous. Men participate significantly more in raising children, especially in provisioning the family as the children grow up. Female humans have more freedom to choose their mates than other species of primates, and they tend to choose men who will provide well for their children.

Humans are the only ape species in which male choice is a significant factor. In human societies culture and custom require the male to remain with the female. Men do not want to be saddled with losers. Moreover, since they are often compelled to be monogamous, they want to choose the mate offering the best possible genetic material and the promise of fidelity and attention to the young.

To repeat, Geary made every effort to make this book as balanced and uncontroversial as possible. The research he cites and the conclusions he draws are very careful and mainstream. Anybody seeking useful quotations to employ in the battle of the sexes would do well to look elsewhere. Roy Baumeister, cited by Geary, manages to be more exciting, though remaining scientifically objective, in Is There Anything Good About Men?: How Cultures Flourish by Exploiting Men. Jack Donovan focuses mainly on men, and how we evolved to be who we are, in [[ASIN:B007O0Y1ZE The Way of Men]]. Lastly, Roger Devlin enthusiastically joins battle with the feminists in [[ASIN:1935965891 Sexual Utopia in Power]]. There is a book for every appetite. Geary is for the serious academic in search of the considered opinion of the experts and a rich bibliography of same.

[Alan Marchant · Rating 3 out of 5]

The simple thesis of David Geary's stodgy meta-analysis is that sex differences within the human species are the result of sexual selection, a second-order manifestation of Darwinian natural selection. Credit the author with consistently, even doggedly repeating and defending this thesis in the face of frustratingly ambiguous evidence in every particular. What the study actually demonstrates is the existence of significant innate differences between male and female in all facets of life - physical, social, reproductive, competitive, cognitive, etc. This significant contribution is obscured however by repeated professions of allegiance to the cultural goal of minimizing to the extent possible any social, political, and economic differences between the sexes.

[Rin]

this wasn't what I was looking for.

[Maya Crowley · Rating 4 out of 5]

I had to read this book for my class I hope I get in A in the class or imma change the rating to 1 star