The social sciences have sought to explain all customs and social arrangements as a product of the socialization of children by the surrounding culture: a system of words, images, stereotypes, role models, and contingencies of reward and punishment. A long and growing list of concepts that would seem natural to the human way of thinking (emotions, kinship, the sexes, illness, nature, the world) are now said to have been "invented" or "socially constructed"...
According to the doctrine, any differences we see among races, ethnic groups, sexes, and individuals come not from differences in their innate constitution but from differences in their experiences. Change the experiences--by reforming parenting, education, the media, and social rewards--and you can change the person. Underachievement, poverty, and anti-social behavior can be ameliorated; indeed, it is irresponsible not to do so ("The Blank Slate," p. 6).
There is certainly some truth to the theory. Consider how the concept of gender has been changed in recent years. I can remember when girls basketball was played when each team played with two sets of five players--one on offense, one on defense--because women were seen as the "weaker sex" and physically incapable of running up and down the basketball court. Thankfully, this "socially constructed" belief has gone the way of the Do-Do bird, as have other more pernicious beliefs (e.g., the superiority of the Aryan race).
At the same time, the theory's proponents often make absurd claims. Take, for instance, the case of David Reimer, a Canadian man who was raised by his parents as a girl after he suffered an accident that occurred during a circumcision went awry. The psychologist John Money oversaw the case and reported that the "experiment" of raising Reimer as a female was a success, and many social scientists interpreted this as evidence that gender is primarily learned (i.e., it is a social construction). However, by the time Reimber was 15, he began living as a male and after undergoing an operation, he got married and had kids. However, the psychological damage he suffered as a child led to bouts of extreme depression, and he eventually committed suicide.
According to Pinker, regardless of the evidence, the blank slate theory has become "the secular religion of modern intellectual life" (p. 3), primarily because it's seen as providing the intellectual justification for and the means by which values that most of us hold dear (e.g., equality of the sexes, races, etc.) can be promoted through social engineering. In fact, many believe that without such intellectual justification, society could devolve back into a world where oppression and discrimination are justified (p. 139), and this, according to Pinker, is why some social scientists continue to defend the theory, explaining away any and all evidence mustered against it:
The fact that [the theory] is based on a miracle--a complex mind arising out of nothing--is not held against it. Challenges to the doctrine from skeptics and scientists have plunged some believers into a crisis of faith and have led others to mount the kind of bitter attacks ordinarily aimed at heretics and infidels. And just as many religious traditions eventually reconciled themselves to apparent threats from science (such as the revolutions of Copernicus and Darwin), so... will our values survive he demise of the Blank Slate (p. 3).Unfortunately, hard-core social constructionists continue to stroll the halls of academia (which is about the only place they can still find employment), force-feeding their unsuspecting students with fundamentalist zeal. But then again, why should they let empirical evidence get in the way of a theory that confirms their biases and justifies their causes?
(As an aside, Peter Berger and Thomas Luckmann referred to earlier should not be grouped with hard-core social constructionists. While they obviously believe that some things are social constructions, they don't believe that all thing are. Berger, for instance, doesn't believe that God is a social construction and is, in fact, a Christian).
Eventually, though, these social constructionists have to come to terms with the evidence (or they will become increasingly irrelevant), and a good place to start is the anthropologist Donald Brown's list of universal human traits ("Human Universals"). Pinker's book should also be a must read, but for the less ambitious, his TED talk (see below) is excellent. Like all TED talks, it's approximately 20 minutes long. It isn't as complete as his book, but then again it's not nearly as long either.