Encouraging science.

Life is not easy for any of us. But what of that? We must have perseverance and above all confidence in ourselves. We must believe that we are gifted for something and that this thing must be attained.

--Marie Curie 

THE CAUSE OF EGALITARIANISM has come a long way since the second wave of feminism shook the 1960s. Women today have entered the workforce and set up camp, holding prestigious jobs in fields once considered solely the realm of men. And men, too, are enjoying the benefits of the erosion of once-rigid gender norms, becoming more involved in home life and child rearing.

But despite these advancements, disparities between the sexes are still evident. Certain careers, such as elementary education and computer engineering, are still largely dominated by only one sex (females and males, respectively), and women still handle most of the childcare and housework. Because the barriers to progress appear to have all but crumbled, it is common to assume that any of the remaining differences are due to innate, biological factors that naturally separate men and women. Many believe that social reform has run its course and the sun is assumed to have set on the effect of nurturing in gender equality.

Certainly nature plays a significant role in explaining differences between men and women--one can hardly deny the societal implications of women's exclusive ability to bear children--but it is important that we don't abandon nurture as an avenue for progress just yet.

Teasing out direct evidence of purely social or biological causes of sex differences is a daunting task given the complexity of our society and the difficulty of definitively inferring any cause for observable phenomena. Take mathematical performance, for example. As former Harvard University President Larry Summers infamously pointed out, men continue to lead in certain mathematical fields and he questioned if this was due to innate abilities rather than discrimination. Summers was excoriated for his comments and his glib dismissal of the role societal attitudes play in women's underrepresentation in certain fields. Nevertheless the question remains: what is responsible for this imbalance?

The conventional wisdom that pervaded society until very recently is that men are naturally gifted with mathematical and scientific ability whereas women, due to a weaker mind, struggle to keep pace. This belief was long used to justify barring women from studying mathematics and science, and from pursuing jobs in these fields. Luckily, few people of intellectual integrity accept this to be true today and much progress has been made by women in these fields since the latter half of the twentieth century. Girls now outperform boys in high school math, taking as many classes--even at the more advanced levels--as their male counterparts. In addition, almost half of all bachelor's degrees in mathematics are now earned by women, and they achieve equal grades to men. The number of women employed in the sciences has also increased over time, though the ratio of men to women in this field is still very high.

Despite these facts, differences in mathematical ability are still observable and documented, though the truth of the situation is far from the overtly sexist and overly simplistic notion that girls are bad at math. It turns out that it depends on what types of mathematical abilities we're talking about, and the results by no means favor men. To boil a very complex situation down to a generality, men appear to perform better on tasks that involve abstract reasoning and women appear to perform better on tasks that involve mathematical calculations.

Of course, the fact that these differences exist doesn't mean that they are innate. A range of environmental factors might explain them just as easily as biological ones. However, one of the most consistently documented differences between men and women--evincing what most people believe to be an innate aptitude--involves spatial ability. Specifically, men seem to outperform women in tasks that involve mental rotation, spatial perception, and spatial visualization. Or, more simply, men are better at seeing and manipulating three-dimensional objects in their mind's eye.

One of the most commonly used measures of spatial rotation ability is the Vandenberg Mental Rotation Test, in which participants are shown a series of three-dimensional objects at varying angles and must determine which are identical. Studies have shown that men are three times as likely as women to do well on tasks that measure such ability. Moreover, this difference can more or less be replicated across cultures and ages, and the size of the difference has remained stable over time, despite the strides women have made in math. It also seems there might be some hormonal influence in spatial-rotation ability: higher levels of testosterone have been associated with an increased capability in spatial manipulation.

That differences in spatial-rotation ability between the sexes might be innate is important because spatial rotation is a necessary skill for many of the elite, high-paying jobs in mathematics and the physical sciences. As we might expect based on the preceding data, women are underrepresented as tenured faculty in nearly all of the elite universities in these fields. If men truly are innately gifted at these jobs, then it wouldn't be fair to men or to society to initiate policies that would aim to redistribute half of these jobs to women, however subtle those attempts might be.

However, if women have the potential to perform just as well as men, even at the elite levels, but are denied the realization of that potential due to the unconscious bias of society, that is neither fair nor just. And, as seen in a study published in the Journal of Applied Developmental Psychology last fall, nature is far from getting the last word on the matter.

In an inspired set of experiments, University of Texas psychologist Matthew S. McGlone, working with Joshua Aronson of New York University, set out to test whether the gender difference in spatial reasoning can be eliminated or reduced. To do this, McGlone utilized important information known about how women's performance on tests can be adversely affected by the way society perceives them.

This phenomenon is known as "stereotype threat." Before they're administered a test, women who are made to activate gender stereotypes such as the "girls are bad at math" cliche (though other, less blatant examples have been known to work as well) generally perform worse than those for whom the stereotypes aren't activated. Gender stereotypes can be activated simply by asking participants to precede their test by writing an essay that primes ideas of gender differences, such as writing about differences between coed dorms and single-sex dorms.

In his study, McGlone turned this phenomenon on its head to see if there is an opposite effect to stereotype threat: If you could get women to think about their demonstrated strengths rather than their stereotypical differences, would their performance on spatial rotation tasks improve?

McGlone administered the Vandenberg Mental Rotation Test to his participants, but preceded the test by priming one group to think about their educational accomplishments. As expected, the control group of women who hadn't been primed performed worse than the male control group. However, in the group that had been primed, women's scores improved dramatically while men's scores stayed the same, considerably reducing the gender gap in demonstrated spatial reasoning performance.

"The special significance of these results is that spatial ability is thought to be one of the most sex-linked areas of math" said Aronson. "Studies indicate that spatial ability is correlated with testosterone levels, leading many people to think that girls are worse at it than boys because of biology and that these differences are fixed. Our work shows that the social context and people's mindsets may be equally important."

"The idea that something is immutable due to some biological factor can be trumped," added McGlone. "With a pretty simple manipulation, we could significantly reduce this gap ... there might be things that make all of these biological factors go away."

McGlone's study will need to be replicated and the fact remains that there is still a wealth of information suggesting that men are, on the whole, innately better than women at spatial-rotation tasks. However, McGlone's study puts a dent in the deterministic argument that gender differences in mathematical ability and other disciplines are due exclusively to biology, and indicates that by applying the results we can work towards reducing this gap, if not eliminating it. The more we find that social inequities can be mitigated, manipulated, or both, the less likely it is that a ceiling to humanity's progress exists.

Unfortunately, despite happy findings, this is certainly not a panacea for gender inequity. These sorts of studies are notoriously hard to apply in the real world; the results are too specific to have a general applicability because the specific conditions of the test cannot be replicated outside of a lab. In addition, factors such as discrimination (both overt and unconscious), other interacting innate differences, or a combination of both influence how women proceed in the world.

For example, relevant to women achieving tenured positions at universities, women are unintentionally discriminated against when they compete with similarly qualified men for jobs in mathematical fields. Studies have shown that psychology professors, when sent identical vitas of tenure applicants with the only difference being the gender of the name attached, rated average female applicants more poorly than average male applicants. This preference was shown even when the evaluator was female.

Other studies have shown that girls may be receiving subtle nudges from society to pursue or avoid certain paths based on the perceived ability of girls in fields such as math and science. One such study showed that when parents of children in the sixth grade were asked how talented their child was in mathematics, sons were judged as having more talent than daughters despite the fact that objective measures, including grades and performance on standardized tests, revealed no differences between the boys and girls. It is presumed that because of the parents' demonstrated bias they were inadvertently discouraging their daughters from pursuing or even taking an interest in math.

Other evidence suggests that women may be less likely to pursue careers in certain mathematical fields not because of a lack of ability in these areas, but because they may be biologically predisposed to prefer other careers. Women generally choose professions that involve interactions with people; men generally choose professions that involve working with objects. Thus, when considering the fact that physics and chemistry are wholly object-centered, that there is a dearth of women in these fields might not be surprising. It has been suggested that this is an innate drive based on evidence that newborn girls prefer to look at faces while newborn boys prefer to look at mobiles or other objects. The fact that this difference could be seen in babies so young suggests that the causes must be due to innate characteristics, as any effect socialization would have on these preferences would not yet have occurred.

As a whole these studies illuminate an important point about sex differences and the quest for equality in general: there are myriad factors that influence the differences between men and women, whether these differences are in mathematical ability, career choices, desires, interactions, the way they see the world, or the way they see themselves. None of the causes for these differences can be boiled down to either biological instigators or environmental ones; nature and nurture are interwoven in ways that are sometimes plainly obvious, sometimes in ways that we might never expect.

How then can we strike a healthy balance between biology and environment, and appeal to our sense of fairness? First and foremost, the most just way to evaluate people is based on their individual abilities and accomplishments rather than on the general abilities of whatever gender they espouse (remember the case of Stanford neurobiologist Ben A. Barres, who claims he received a great deal more respect from unknowing scientists after undergoing a sex change nine years ago). People are individuals first--just because empirical evidence shows a general difference between men and women on spatial-rotation ability doesn't mean every man will outperform every woman. Similarly, the fact that there might be an observed difference between men and women on mathematical calculation ability doesn't mean every woman will outperform every man on tests that involve such talents. In fact, there is far more variability among the sexes than between them. Thus, whenever possible, we must make evaluations gender-blind.

One of the most effective ways to reduce disparities in society--not just between men and women but between races and classes as well--is education. Always education. The more we know, the better able we are to realize and achieve our potential. That includes accepting innate gender differences for what they are but also recognizing our biases and enacting policies that minimize their effects. Ultimately, when we begin to understand the interplay between nature and nurture, we learn how to utilize both to create a better, more equitable world.

Karen Frantz has a B.A. from the University of Virginia and is the public relations executive assistant at the American Humanist Association.