Sex Differences: Nature, Nurture or Nothing

Psychology 101: The 101 Ideas, Concepts and Theories that Have Shaped Our World - Adrian Furnham 2021

Sex Differences: Nature, Nurture or Nothing

It is hard for a woman to define her feelings in language which is chiefly made by men to express theirs. (Thomas Hardy, Far From the Madding Crowd, 1890)

We have more than a ’sneaking suspicion’ that the female of the species is not only more deadly but also more intelligent than the male. (D. Wechsler, The Measurement of Adult Intelligence, 1939)


Psychologists often have to be courageous, naive or unwise to research or write about sex differences. Sex differences in intelligence is one of the ’hottest’ topics of research, and psychology researchers have been attacked and sacked on the basis of their views. However, to assert there are sex differences in anything causes a quick and dramatic backlash.

Many people want to believe that men and women are equal, not only in potential, but also ability, and certainly rights. They argue that, even if there are small but actual, verifiable ability differences, they should not be explored or explained because of the divisive effect that it has on both sexes. In other words, do not research or dispute this issue: it only leads to bad things.

There remains a great deal of popular debate about such things as the sex-linked glass ceiling, cliff, escalator and the ’sticky’ floor, all of which imply career opportunities are quite different for men and women. It is clearly true that men are paid more than women often in the same job and often when they are equally, if not more, productive. It is quite easy to understand their outrage.


Many studies over many years have demonstrated sex difference in children from an early age. They have shown that boys are more interested in block-building and vehicles; girls prefer doll play, artwork and domestic activities. Boys like rough-and-tumble play; girls tend to be more sensitive and sedentary. Boys show narrow interests; girls a wider range, including boy-typical activities (asymmetrical sex-typing). There is evidence of voluntary gender segregation (same-sex playgroups) which is true for both boys and girls. Boy groups are larger and more concerned with dominance issues; girls play in groups of two/three and are more sharing — concerned with fairness.

Girls acquire language earlier than boys and remain more fluent throughout life. Girls develop larger vocabularies, use more complex linguistic constructions, enunciate and read better. Boys are less communicative and use language instrumentally (to get what they want).

Brain localization of language is more bilateral for females than males (MRI & lesion studies).

Some of these findings will be hotly disputed. But even if some small but consistent findings are acknowledged the debate shifts into why they exist. This is the nature—nurture issue.


Another curiosity is the apparent contradiction between popular and scientific writers. There are many popular books (e.g., Men are from Mars; Women are from Venus) that portray a simple evolutionary perspective that describe, and even rejoice in, sex differences in almost all human behaviour but particularly communication, relationships and work. These are contrasted with the measured and cautious academic books and papers that note how complex some of these seemingly simple questions are and how all the answers require numerous qualifiers.

Inevitably there are two strongly competing, opposite forces: those who stress the biology of difference (Nature) and those who stress the sociology of similarity (Nurture). The former often suggest that these differences are immutable, though we know that all innate traits can be changed with experience. While nearly everyone acknowledges that we are biopsychosocial beings, there are those who see us more as BIOpsychosocial as opposed to biopsychoSOCIAL. This all concerns explaining how and why observed differences occur.

There are those who want to argue that well-established sex differences in abilities, personality and values inevitably leads to different occupational choices as well as adaptation to those jobs. Others want to stress social forces that for a variety of ideological reasons have pre- or proscribed gender differences at work that do not exist.


Reviewers of this topic can be described as Maximizers vs. Minimizers. Maximizers want to find and explain the (many large) differences between the sexes, while the minimizers want to emphasize how few differences there are. Part of this debate can be seen in the interpretation of a statistic called ’Cohen’s d’ which is an indicator of difference. While there are conventions about how to label the difference as: no, trivial, small, medium, large and very large — even this is contested. Thus, minimizers are happy to see many differences are trivial and dismissible, as unimportant in every sense, while maximizers are eager to describe and explain all differences that they find.


But in the midst of all this heat there is light. Careful and thoughtful meta-analyses from researchers who pick over the evidence in a disinterested manner. Most acknowledge difference in certain specific abilities but point out that they are small, though they might have important consequences.

Diane Halpern (2012) in her very carefully and comprehensively researched book noted the tasks at which females excel: generating synonyms (associational fluency), language production and word fluency, computation, anagrams, memory for words, objects, personal experiences and locations, and reading comprehension and writing. She argued that the underlying cognitive processes that explain this was rapid access to, and retrieval of, information in memory. On the other hand, tasks at which males excel include: verbal analogies, mathematical problem solving, mental rotation and spatial perception, spatiotemporal tasks (dynamic visual displays), generating and using information in visual images, and mechanical reasoning and some science-related topics. She suggested the underlying cognitive processes were maintaining and manipulating a mental representation in visual—spatial working memory.

Janet Hyde has noted that there is evidence for the gender similarity hypothesis. She noted two theoretical approaches: Cognitive social learning theory explains psychological gender differences as being a result of females and males receiving different rewards and punishments for their behaviours, people’s tendency to imitate same-gender models, and cognitive processes such as attention and self-efficacy. Sociocultural theory argues that contemporary psychological gender differences have their origins in the prehistoric division of labour by gender; once males and females take on different roles, they develop the psychological qualities that equip them for those roles.

It is her conclusion that there are far more gender similarities than differences. Yet there are some large differences. For instance in 3D mental rotation tasks, where men do much better; the personality dimension of agreeableness/tender-mindedness, where women score higher than men; sensation seeking, where men score higher; a greater interest in things versus people, which is true of men and the opposite for females; physical aggression, where men score much higher than women; and some sexual behaviours like masturbation and pornography use.

There is perhaps no area in psychology, indeed the social sciences in general, that is as ideologically charged as this topic!


Furnham, A. (2007). 50 ideas you really need to know in Psychology. London: Quercus.

Halpern, D. (2012). Sex Differences on Cognitive Abilities. New York: Psychology Press.

Hyde, J. (2005). The gender similarities hypothesis. American Psychologist, 60, 581—92.

Hyde, J. (2014). Gender similarities and differences. Annual Review of Psychology, 65, 373—38.

Lynn, R. & Kanazawa, S. (2011). A longitudinal study of sex differences in intelligence at ages 7, 11, and 16 years. Personality and Individual Differences, 51, 321—4.