Undressing Lamarckian Evolutionary Psychology

Evolutionary Psychology is a branch of psychology that attempts to explain psychological behaviours and traits as products of natural selection. It seems to be one way for psychology to gain scientific acceptance - by adopting evolutionary biology, the principles of which it generally plays fast and loose with. Unfortunately, its place in popular culture is cemented by best selling books and questionable research paradigms that affirm intuitively sound but wildly inaccurate conclusions regarding gender differences. Claims by evolutionary psychology advocates have serious credibility issues amongst many scientific researchers (including all my professors). You simply can not adopt the blueprint for modern biology for psychology while ignoring the scientific logic behind it. My informed opinion (bias) comes from having been a human biology major and a psychology specialist, and from the courses I had taken on the subject, including Sex, roles & behaviour, and Evolutionary Psychology.

There is not a good argument to be found in the realm of behavioral biology for why American Women shop while their husbands sit on the bench in the mall outside the women's fashion store fantasizing about a larger TV on which to watch the game.

The above quote is by Greg Laden, a biologist who studied Efe Pygmies in the Ituri Forest, of Zaire. He blogs about science and culture over on ScienceBlogs conglomerate website. I recently came across his post on evolutionary psychology titled, "Why do women shop and men hunt?" It is an essential reading, so I'm going to cut and paste the main relevant arguments for you to skim through (comments in between provided by me; italics are added for emphasis):

• What's your politics? "[T]he validity from an individual's perspective of the various arguments that men and women are genetically programmed to be different (in ways that make biological sense) is normally determined by the background and politics of the observer and not the science."

• Evolution in brief: "Organisms have genes that vary (the variants are called alleles). Sometimes a variant arises that, when interacting with the environment, confers a negative or positive effect. Those that confer a positive effect with respect to the process of passing on genes to future generations are over-represented (on average) in the next generation while those that confer a negative effect are under-represented. If the strength of this selection is sufficient and random effects do not overpower it, there may be a shift in allele frequencies over time."
  
  It is by chance that a positive interaction between gene expression and environment takes place and is increasingly represented in the next generation. An interaction between gene expression (phenotypic variation) and environment averaged over time is the key here. Evolution is slow and the environment interacts with gene expressions rather than genes.
  
  "The link between phenotypic variation and the underlying genetic variation is almost always assumed and hardly ever documented directly."

• The basic biology: "[H]umans are the result of evolution over two million years or so of the Pleistocene [...] The Pleistocene is, among recent geological time periods, considered to be the most variable in terms of climate change, and thus, overall ecology, habitat distributions, etc. There is no expectation that any given population making up part of a species like humans or their close relatives would have had any long term consistency in natural environment. [...] [H]abitat determines social structure in humans, with technology as a major factor. [...] There is also variation in important social norms beyond that which can be explained easily by ecology." There is no one social environment in which we evolved over millions of years. There goes evolutionary psychology.

• Brain science: "It is very possible that module-like structures in our neocortex arise during development, de novo, in each of us, and that these modules are similar across groups (but perhaps different sometimes by gender) because of overall similar developmental trajectories."

• Gender differences, artifacts? "There are dozens of reported gender differences, with piles of research demonstrating them. But when we look more closely, we often see that the either a) the methodology of the research sucks or b) the gender difference, while likely real, changes, goes away, or even reverses as times change, suggesting that the difference is (was) cultural."

• There are some differences, sometimes. But not due to a direct link to genes. " Testosterone poising of neural tissue (indirectly) during development probably accounts for the fact that there are almost no male simultaneous translators. The neural ability to do this difficult thing is retains in some females but lost in almost all males during puberty. That is not genes coding for neural connections, but it is genes coding for different endocrine systems which then, through a series of negative and positive feedback systems, cause hormonally mediated changes in the body (including the brain)."

Basically, men are not from Mars and women are not from Venus. We are all genetically humans. Our behaviours are the results (so many paths to take!) of the interactions between our gene expressions and our developmental and cultural environment. Where we are different, it is more likely related to hormonal environment we were/are exposed to, or our social conditions, rather than our genes or our ancestral social behaviour. If there's a kind of evolution psychologists should focus on, it's the cultural one. The hunter gatherer scenario as as universal environment from which we got our traits is highly disputable. To continue championing a Lamarckian-like idea (that behaviours of individuals acquired during a life time are passed on to the next generation - in this case, behaviours acquired during a particular period in human history) of sex differences in our complex human society is to go against basic evolutionary principles and biological research. I know some people like to stoke the nature-versus-nurture battle (even though at this point most would agree it's likely a combination of both, and a direct causal gene-behaviour relationship is unlikely in most cases), but at some point, you need to stop trying to grab the headlines by pandering to the public's erroneous but intuitively familiar hunches. After all, isn't there some sort of duty to practice good science? You know, as proclaimed scientists and all?

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