Aside from obvious physical distinctions, how different are men and women?  This age-old question has been the topic of extensive research and the focus of impassioned debate across many disciplines.  Psychologists pursue this question in order to establish the role of sex in the etiology of mental illness, and to contribute to the  general understanding of the workings of the mind.  Others have an agenda that addresses social concerns, for example, to challenge sexist beliefs.  Certainly, a large motivation for resolving this question is the desire to understand what goes awry in heterosexual relationships.

In the popular media, authors have capitalized on this last concern, promoting personal theories that explain these relational problems.  For example, Gray (1992) states that friction occurs between the sexes because men are solution oriented, averse to accepting help, and withdraw to solve their problems alone when under stress.   On the other hand, women need to process their emotions verbally in the presence of a sympathetic listener, and see offering and receiving help as a means for sharing love.  Tannen (1991) describes men as competitive, independent, and preoccupied with their position within a hierarchy, while the female spirit is communal, egalitarian, and seeks cooperation and intimate connection.  More recently, Mark Gungor (2007) has proposed that conflict in heterosexual relationships is a product of innate differences in the male and female brain.  He compares a woman’s brain to a buzzing “ball of wire” that is electrified by emotion, capable of storing connections between all memories in great detail.  Men’s brains store discrete, relatively limited information in separate boxes that must not touch one another.  Further, while women’s brains are always active, men seek out their “nothing” box, in which they enjoy empty headedness. 

In the social sciences, this supposition that men and women are essentially different in the ways they think, feel, relate, and act is known as the “gender differences hypothesis.”  Research exploring this hypothesis is driven primarily by three theories (Hyde, 2014): evolutionary theory, cognitive social learning theory, and sociocultural theory.  Evolutionary theory posits that gender roles are adaptive for males and females. For example, because aggressive males were more successful at winning mating privileges, aggression has been selected as a male trait.  On the other hand, women excelled at care-giving as a function of the physical investment required by them to produce offspring. As they were thusly focused on ensuring the survival of the species, women could not develop traits that would enable them to compete at male-oriented tasks.  Cognitive social learning theory states that human behavior is shaped by reinforcements and punishments.  Sensing implicit pressure to do so, children conform to the behavior of role models, and generation by generation, gender roles become more embedded in the psychology of men and women.  According to sociocultural theory (Eagly & Wood, 1999), gender differences are a function of the division of labor.  Men came to have wealth and status due to physical advantages.  Women became subordinate, and accommodated to the roles assigned to them by men.  In contrast to evolutionary psychology, sociocultural theory asserts that women came to be nurturers after they were assigned the tasks of child rearing.

Also at the heart of the study of differences is the ongoing nature-nurture controversy.  Over the years, science has addressed this debate in response to zeitgeist, seeking the truth in current cultural beliefs and theories.  For example, the feminist movement challenged the assumption of biological differences, which led to a resurgence in research focusing on nurture rather than nature (Bem, 1974; Bem, 1981; Shields, 1975; Weisstein, 1978).  Starting in the 1980’s, research on biological differences had an upswing because of a fresh interest evolutionary psychology and neuroscience. As Eagley & Wood (2013) point out, most contemporary psychologists accept that both nature and nurture play key roles in the formation of human personality, however,  researchers continue to support dichotomous views, targeting either biological or sociological variables, and rarely both at the same time.  And certainly, any finding from one camp is quickly explained by the other using its own set of theories.

What the research shows

Tens of thousands of studies employing over twelve million participants have been conducted to explore gender differences across a wide range of variables since the final quarter of the last century.  For the most part, little support has been found for the gender differences hypothesis.  In her review of 46 meta-analyses, Hyde (2005) found that 78% of gender differences on psychological variables were negligible.  As a product of this finding, Hyde developed the “gender similarities hypothesis,” which proposes that males and females are similar on most, but not all, psychological variables (Hyde, 2014). However, very little attention, if any at all, has been directed at studying gender similarities.

Out of the large number of studies conducted, only a few empirically validate differences have been considered worthy of note (Zell, Krizan, & Teeter, 2015). The following ranking (Table 1) shows the top nine psychological features that differ between males and females, from most significant to least, based on robust findings from meta-analyses. Effect sizes range from .73 (for item 1) to .39 (for item 9).

Table 1

Top Nine Largest Gender Differences

Rank	Characteristic	Finding	Author(s)
1.	Masculine vs. feminine traits	On self-report questionnaires, men endorse masculine traits more frequently than women.	Twenge, 1997
a.	Mental rotation ability	Men outperform women in tasks requiring mental transformation of two- or three-dimensional objects through spatial visualization. This difference is decreased when tests are untimed. (Voyer, 2011).	Maeda & Yoon, (2013)
b.	Noxious stimulation	Women have higher pain tolerance	Riley et al., 1998
c.	Importance of beauty in mates	Men rate attractiveness in their partners as more important than women do.	Feingold, 1990
d.	Peer attachment	Women become more attached to their peers than men do, as measured by degree of trust and openness of communication.	Gorrese and Ruggieri (2012)
e.	Interest in people vs. things	Men prefer to work with things, women prefer to work with people.	Su et al., 2002
f.	Aggression	Men become angry more often than women, especially in situations where there are slow increments in anger-inducing stimulation.	Knight et al., 2002
g.	Film-induced fear	Women show more physiological signs of fear when watching frightening films.	Peck (2000)
h.	Confidence in physical abilities	Men show more confidence in performing male-oriented tasks.	Lirgg, 1991

Note: From Zell, Krizan, Teeter (2015)

Culture mediates gender differences

Relatively complex studies have looked at context as a mediator for gendered behavior. In one analysis, Eagly & Wood (1999) challenged the idea that gender roles are universal. Their hypothesis was that the greater the inequality in power and status ascribed to either sex within a culture, the greater the difference would be in how men and women would chose their sexual partners.  They found strong correlations between the degree of gender inequality and the extent of differences in these choices. Challenging the old conjecture that men are inherently better at math than women, Else-Quest et al. (2010) looked at the relationship between the degree of job equality in various countries (as measured by the ratio of men to women in research positions) and math performance in women.  Women who lived in the countries with greater employment equality performed better in math than those in the other nations.  This finding suggests a strong relationship between attributions of competency and level of performance.

If no one is looking, gendered behavior may diminish

Other studies have looked at how gender roles are mediated by anonymity. For example, as noted in Table 1, men are typically more aggressive than women.  However, men displayed less aggression while playing a video game when they were anonymous as opposed to when the experimenters knew their identities (Lightdale & Prentice, 1994). Further, although men scored higher than women in helping behavior (Eagly & Crowley, 1986), the difference between men’s and women’s behavior declined when they were not observed by others. The authors of the study interpret this finding to be evidence that men will conform to the expectation of heroism if someone sees them, but might let themselves off the hook if no one is available to witness their heroic act.

If future studies continue to confirm that few true differences exist between the sexes, and that those that do occur have their bases in cultural norms, men and women are left with the task of understanding one another as simply human.  It is interesting to consider what this might mean for heterosexual relationships.  While it is reasonable to assume that gender equality would lead to greater harmony, this might not be the case.  Horner (1997) asserts that stereotypes generate belief systems that serve the purpose of demystifying human relationships. If this is true, than it stands to reason that men and women welcome stereotypes because they offer quick explanations for what causes strife in relationships. In terms of cognitive economics, this is a more efficient way to function.  However, the obvious disadvantage to adhering to stereotypes is that men and women never truly know one another.

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References 

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