The following blog was published in an earlier form on PLoS SciComm nearly a month ago.  But much misrepresentation of the information about this topic remains and I think the Psychology Today community is an important place to continue this conversation.

First the reality:  There are biological differences between the sexes, including average body size, upper body strength, and key aspects of reproductive physiology and endocrine patterns. There are also gender differences across the spectrum of masculine and feminine. As contemporary societies structure developmental patterns and expectations differently for boys and girls their social and perceptual surroundings shape their physiology and psychology. Gender is not just some overlay on biology, it shapes and structures our bodies and they ways we use them. However, across all possible measures there are more biological similarities than differences between sexes (same species, remember), and greater gender overlaps than discontinuities.  These differences and similarities can, and do, play roles in shaping performance on specific tasks by individuals and by classes of individuals.

However, a biological perspective on sex and gender is not what is at the heart of the Google manifesto’s claims. Rather, the manifesto makes claims about human nature---about what it means to be human and what our species is “really” like. The language used is rooted in the terms “biological difference”, “biological causes” and “evolutionary” or “evolved” psychology which in this case are code for an “innate humanness” and imply that social action, however well-intended, is not going to change who we are. It is not a scientific approach but rather an ideological one and displays a radical ignorance of what biology is and how evolution works.

The manifesto asserts that “On average, men and women biologically differ in many ways” but offers examples of general psychological differences assumed to have “biological causes”, not any examples of biological processes or specific systems. The only actual biological factor mentioned is Testosterone, a hormone shared by all humans (and most other animals) but without any understanding of the hormone and its biological and cultural complexity. What the manifesto actually refers to is a set of psychological assessments of gender difference drawing on the work of a few select researchers, some magazine articles, and Wikipedia.

The manifesto tells us that women are more open towards feelings rather than ideas, towards people rather than things, show gregariousness rather than assertiveness, and have higher rates of neuroticism/more prone to anxiety. Men have a higher drive for status and are more capable of dealing with stress and technological challenges. These general personality trends, we are told, are biological and culturally “universal” and clearly understood evolved patterns in the human species…spoiler alert: they are neither.

There are hormonal, neurological and other physiological factors in the expression of behavior associated with assertiveness, emotion, stress responses, anxiety, etc…but the real assertion in the manifesto is not about the behaviors themselves, or their biological components, but about the evolved patterns that led to them. This is about human evolution. Inherent in the manifesto is the assumption that human males and females experienced such different patterns of evolutionary pressures that they evolved different systems of response and perceptions (an extreme sexual selection model). And that is why the author believes Google’s (and society’s) attempts to develop a more level structural landscape of access across genders will fail.

The main gist of these assumptions is that male humans (at least ancestrally) experienced stronger pressures due to their role as hunters, protectors and creators/users of technology (stone tools and such) and their psychologies (and bodies) were shaped accordingly. Women, on the other hand, were under the intense pressures of childbirth and child care and getting men and kids connected and interacting, maintaining social cohesion. Thus men evolved the tendency to deal with stress and seek status more effectively (or be eaten or killed) while women were geared towards social connections, compassion and thus more susceptible to social disruption and anxiety (more emotional). 

We actually know quite a bit about human evolution and the patterns and processes that our ancestors faced.  Do these assumptions hold up? Not really.

Men made the tools? We have no evidence of any sort that there were any sex or gender differences in the creation and use of stone, wood, bone or other technologies for the vast majority of the Pleistocene (the last 2 million years or so).  Some evidence in bones and materials for gendered differences do show up in the latest Pleistocene and Holocene (~25-10, 000 years ago) especially when we see the emergence of craft specialization, domestication and sedentism.

Men hunted and fought one another and women did not? For the vast majority of human evolution we do not have clear evidence that only men hunted. In fact, for some ancient humans there is strong likelihood that both sexes did participate in hunting. And, importantly, earlier humans were substantially more robust that we are today…that is, a large percentage of females in the past were more robust than many males are today.  Plus, depending on what hunting technology you use, size and muscle density might not be critical factors. Also, the evidence of interpersonal violence is pretty minimal for much of human history, insufficient to see if there was a sex-based pattern. When we do start to see more robust evidence for lethal violence (war-like events) the distribution of injuries and evidence of participation is not biased by sex and until quite recently (last 7,000 years or so). There are no clear biases one way or the other in regards to gender representation in hunting and violence until very recently. Not to say that such differences did not exist but to assert they existed and that they were as they are today is not science, it is speculation.

Women cared for babies/children and did the social work for the group?  Females do give birth and lactate, men don’t. This is major sex difference. However, human evolution is characterized by a very idiosyncratic (for mammals and primates) pattern: extensive cooperative parenting.  Human infants, from at least 1-1.5 Million years ago, were born extremely early with substantial brain development after birth and extremely slow motor skill acquisition (the slowest of all mammals). Human infants require massive caretaking and our ancestors adapted to this pressure via increased care from diverse members of the group, including both sexes and all ages.  There is widespread agreement that cooperative care had a significant impact on the shaping of both male and female human physiology and behavioral patterns.

An evolutionary history clearly divided into women staying home caring for babies while the men made tools and hunted, both experiencing different evolutionary pressures, is not borne out by the available archaeological and fossil evidence.

Were there gender difference in the past? It is extremely likely. Do we know if they were like gender differences we see today?  No. And the majority of the current evidence suggest that male and female lives, and thus evolutionary pressures, overlapped much, much more than they diverged. This makes humans pretty distinctive relative to many other mammals and is likely one of the major factors in our astonishing evolutionary success.

This in no way denies that there are many patterns of difference between male and female gendered individuals and that those patterns can be quite relevant in many contexts of daily life. It does deny the assertion of biological and evolutionary underpinnings to the differences in capabilities for leadership and tech-based positions. Simply noting a few highly contended, and structurally very complex, generalized psychological trends as “biology” is bad science and reflects substantive ignorance of the biological and social sciences and of evolutionary processes.  

But then again, the manifesto was never about biology. It is about anger, ignorance and resentment. Its author states that women, as a gender, have made much progress and that men are more constrained by restrictive gender expectations. He claims that 95% of the social sciences and humanities are left-leaning and create myths that are unsupported (like the gender wage gap and the theory of social construction) thus biasing social and corporate actions in favor of some (women and minorities) and against others (white men).

Sound familiar? Given the political and social state of our country, the widespread ignorance of biological and evolutionary processes, and the author being from a class of people who are used to having inherent structural benefits in the American system (and now fear losing them), it is not at all surprising that the Google manifesto was written as it was.

Scientists, especially biological and evolutionary scientists, cannot allow the ignorant and erroneous misuse of “biology” as a tool to control and repress. We have seen the effects of this too many times in our own society and in many others. At the same time, we cannot shut down debates and discussions about difference and similarities…these are needed now more than ever. What we can do is participate, offer knowledge, data and insight from scientific investigations to correct errors, to reject lies, and to provide access to understanding everywhere we can.

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