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The Blank Slate

The Modern Denial of Human Nature
Steven Pinker 

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The main goals of this book are:

  • To refute the “standard social science model” that human behavior is 100% explained by socialization and there is no such thing as human nature.
  • To argue that recent results concerning connectionist AI, neural plasticity and the surprising success of removing half of a child's cerebral cortex do not show that the blank slaters were right after all.
  • To argue that it is a mistake to believe that (if it were only true) the blank slate would lead to morally superior outcomes in terms of avoiding prejudice, resurgent Nazism, etc.

As is usually our attitude toward the smarty-pants stance, we generally agree with the factual claims, but not the attitude.

Human Nature Exists

We believe that humans do have genetically determined behavioral predispositions—Humans would be unique among animals if they did not. Due to their large brains, humans must be born when quite immature. This fact has allowed people to imagine that the brain of an infant is a “blooming buzzing confusion” without form and void. Consider animals whose lifestyle requires a functional newborn (herd animals such as the zebra.) In this case the newborn is able to walk and navigate by sight and smell within minutes (so that it can follow mother.) More subtle studies of human infants have shown that they have considerable powers of visual perception and of intuitive physics such as object permanence and collision causing prompt rebound.

It seems the “standard social science model” that the author is refuting is in fact a straw man that hardly anyone believes. We also found ourselves agreeing somewhat with many of the quotes from social scientists about the autonomy of culture from biology, which he seemed to feel were patently ridiculous. The idea that cultural evolution proceeds with considerable autonomy and can pursue its own its own goals (possibly to the detriment of what one would reasonably consider to be the individual's interest) is compatible with the idea that there is a genetically determined human nature.

Connectionist AI

Some connectionists have evidently argued against human nature on the grounds that they have shown it is unnecessary. Likely they are wrong about genetically programmed capabilities being unnecessary, definitely they are wrong about the absence of innate capabilities. But in the author's debating zeal, he seems to deny that discoveries from Artificial intelligence have anything to tell us. We believe that connectionist AI has a great deal to tell us about how the mind works, especially the unconscious, see Representational Opacity

Experience Changes the Brain

In his discussion (and dismissal of) neural plasticity he has a wonderful rant that we wholeheartedly agree with. This is related to the X proved real fallacy. He notes that findings from FMRI that experience affects brain operation, that neurons grow in adults, etc., are completely consistent with having genetic behavioral tendencies, and can only be surprising to someone who is an unconscious Cartesian:

The fact that the brain changes when we learn is not, as some have claimed, a radical discovery with profound implications for nature and nurture or human potential. Dimitri Karamazov could have deduced it in his nineteenth-century prison cell as he mulled over the fact that thinking comes from quivering nerve tails rather than the immaterial soul. If thought and action are the products of the physical activity of the brain, and if thought and action can be affected by experience, then experience has to leave a trace in the physical structure of the brain.

So there is no scientific question as to whether experience, learning, and practice affect the brain; they surely do if we are even vaguely on the right track. It is not surprising that people who can play the violin have different brains from those who cannot, or that masters of sign language or of Braille have different brains from people who speak and read. Your brain changes when you are introduced to a new person, when you hear a bit of gossip, when you watch the Oscars, when you polish your golf stroke—in short, whenever an experience leaves a trace in the mind. The only question is how learning affects the brain. Are memories stored in protein sequences, in new neurons or synapses, or in changes in the strength of existing synapses? When someone learns a new skill, is it stored only in organs dedicated to learning skills (like the cerebellum and the basal ganglia), or does it also adjust the cortex? Does an increase in dexterity depend on using more square centimeters of cortex or on using a greater concentration of synapses in the same number of square centimeters? These are important scientific problems, but they say nothing about whether people can learn, or how much. We already knew trained violinists play better than beginners or we would never have put their heads in the scanner to begin with. Neural plasticity is just another name for learning and development, described at a different level of analysis. [see Level Confusion

All this should be obvious, but nowadays any banality can be dressed up in neurospeak and treated like a great revelation of science. According to the New York Times headline, “Talk therapy, a psychiatrist maintains, can alter the structure of the patient's brain.” I should hope so, or else the psychiatrist would be defrauding her clients. “Environmental manipulation can change the way [a child's] brain develops,” the pediatric neurologist Harry Chugani told the Boston Globe. “A child surrounded by aggression, violence or inadequate stimulation will reflect these connections in the brain and behavior.” Well, yes; if the environment affects the child at all, it would do so by changing connections in the brain. A special issue of the journal Educational Science and Technology was intended “to examine the position that learning takes place in the brain of the learner, that pedagogies and technologies should be designed and evaluated on the basis of the effects that they have on student brains.” The guest editor (a biologist) did not say whether the alternative was that learning takes place in some other organ of the body like the pancreas or that it takes place in an immaterial soul. Even professors of neuroscience sometimes proclaim “discoveries” that would be news only to believers in the ghost in the machine: “Scientists have found that the brain is capable of altering its connections. … You have the ability to change the synaptic connections within the brain.” Good thing, because otherwise we would be permanent amnesiacs.

This neuroscientist is an executive at a company that “uses brain research and technology to develop products intended to enhance human learning and performance,” one of many new companies with that aspiration. “The human being has unlimited creativity if focused and nurtured properly,” says a consultant who teaches clients to draw diagrams that “map their neural patterns.” “The older you get, the more connections and associations you should be making,” said a satisfied customer; “Therefore you should have more information stored in your brain. You just need to tap into it.” Many people have been convinced by the public pronouncements of neuroscience advocates—on the basis of no evidence whatsoever—that varying the route you take when driving home can stave off the effects of aging. And then there is the marketing genius who realized that blocks, balls, and other toys “provide visual and tactile stimulation” and “encourage movement and tracking,” part of a larger movement of “brain-based” childrearing and education. […]

These companies tap into people's belief in a ghost in the machine by implying that any form of learning that affects the brain (as opposed, presumably to the kinds of learning that don't affect the brain) is unexpectedly real or deep or powerful. But this is mistaken. All learning affects the brain. It is undeniably exciting when scientists make a discovery about how learning affects the brain, but that does not make the learning itself any more pervasive or profound.

Oh wouldn't it be nice

One of the recurring themes on the nurture side of Nature Versus Nurture debate is that it would be nice if there was no genetically determined human nature, because then humanity would be infinitely perfectible. Of course, nobody argues that the world must conform to our wishes, but some have argued that human malleability is so desirable and innate human nature so abhorrent, then if there is any doubt, then the only responsible position is to assume malleability. The author quite rightly challenges this. Any error has consequences. It is true that the consequences of assuming malleability where there is none are different than the consequences of assuming inevitability when there is potential for progress, but one is not clearly morally superior to the other.

For example, some have claimed that the innatist views of evolutionary psychology are abhorrent because they resemble the views of the Social Darwinists and Nazis. He raises the nice debating point that it seems that considerably more people were killed in the genocides in the Soviet Union, China and Cambodia, than were killed by Hitler, and these countries had an ideology of the malleability (and perfectibility though coercion) of human nature. As Roy Baumeister observes in Evil, the main precondition for large-scale institutional evil like the Holocaust is idealism in service of a higher cause. Be very afraid of any ideology that tells you it knows how to radically transform the human condition.

A similar argument has been used to challenge claims that there are genetically determined differences between the aptitudes, interests and motivations of the sexes. While complete sameness of the sexes would argue for moral equivalence, it is obvious to anyone who is not overly educated that men and women are not the same. Moral equality of the sexes is the equality of opportunity (fairness and lack of prejudice) rather than the equality of outcome. See Sex Differences.

Does Parenting Make any Difference?

He strongly endorses the interpretation of Behavioral Genetics popularized by Judith Rich Harris in The Nurture Assumption. In short, this is that parents have been given way too much credit and blame for how kids turn out, that in fact parents have relatively little influence over many aspects of personality, intelligence and behavior. This is probably still true to some degree, and certainly in the not-so-distant past it was widely accepted that schizophrenia was caused by bad mothering. However, we think it is going way too far to say that parenting makes no difference (see Behavioral Genetics.)

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books/blank_slate.txt · Last modified: 2014/01/30 10:58 by ram