She explicitly sets aside situations of overt, deliberate discrimination, which historically have been, and still are, the ones most of humanity inhabits. (It's easy to see why women don't become successful lawyers if they get beaten for trying to leave the house.) Rather, she wants to "explain women's lack of achievement in situations where nothing seems to be wrong" (p. 1). It is partly for this reason that she confines herself to white, college-educated Americans. The other reason is that she wants real statistical, experimental knowledge about people, rather than just anecdotes, and while we're abysmally ignorant of humanity in general, white, college-educated Americans are almost as well understood as leopard frogs and zebra fish (but still not a patch on what we know about mice, fruit-flies or intestinal bacteria). There are anecdotes in the book, and some good ones too (I particularly liked the one about the New York Times crossword puzzle), but they are illustrations, not arguments. Anyone who has read extensively on "women's issues" will realize that this alone puts Valian's book among the elect.
There are two ways to approach this such questions of large-scale social phenomena. One is to try to explain them by other, equally large-scale social phenomena. Sometimes --- in macroeconomics, for instance --- this can be very useful, but it's rarely intellectually satisfying. To really understand what's going on, we need to see how mechanisms in the psychology of individuals, and their interactions with each other, cause the big effect (here, too few women in positions of power and prestige). The belief --- or perhaps the demand --- that all social phenomena should be explained this way is called "methodological individualism," and we have, in these reviews, traipsed around these issues before. I think it's not merely a true doctrine but a truism; apparently so does Valian, since she never bothers to justify herself before producing a model example of methodological individualism at work; never even uses the phrase. (Perhaps this is because she's a cognitivist intruding into sociology.) Let's start by looking at the mechanisms she invokes: gender schemata and the accumulation of advantage.
Schemata (Valian prefers "schemas") are mental representations of the categories into which we parse our experience, and our beliefs about what those categories are like (what's typical, what the range of variation is, etc.). The existence of schemata is well-documented and fairly uncontroversial in most areas of cognition. (Little in cognitive science is completely uncontroversial, but that we have schematoid things in our minds comes pretty close.) In particular, we have schemata about the genders. These include the inarguable anatomical differences of the slot A vs tab B variety which distinguish the biological sexes, but go far beyond them, and it's easy to demonstrate that these non-anatomical parts of the schema varying across time, space and class. (It has been equally schematic to believe that women are naturally lustful and that they are naturally frigid; that men are naturally austere and subdued and that it is only natural and proper for men to revel in ornament and display; that women are emotional while men are rational, and that women are cold-blooded while men can be moved by finer sentiments. And so on and so forth.) --- When I say things like "our schemata are X," I mean "schemata which are X are very common among American professionals"; schemata are individual possessions. This is not to say that the content of our schemata are not influenced by those around us, particularly those who teach us before we are old enough to know better, and Valian gives two chapters over to the inculcation of gender schemata.
Forming schemata is natural, inevitable and useful; there's no point to treating the world as ever new and unprecedented when it's really quite repetitious. The problems arise when schemata are inaccurate in general, when they are inaccurate in particulars, and when they assume illegitimate normative force. To take those in reverse order: the expectation that women are more likely than men to sew is (at present) accurate; this in no way should imply that women who don't sew are defective, or that men who like to crochet are twisted. (These normative effects seem to be stronger for the male schema than the female; to give a small but revealing example, women can wear shirts and trousers; men, except for Scotsmen on special occasions, cannot wear skirts.) Women are on average shorter than men; but one can show that this leads to systematically underestimating women's height, even when shown pictures of both men and women beside fixed bench-marks. This effect --- general expectations over-riding particular facts --- is particularly strong when dealing with rare cases; also when pressed for time. Generally this helps "economize thought," but here it means that the first women to enter a field will find themselves most schematically treated. Finally, many beliefs which are part of our schemata (as, men are naturally more ruthless than women) are simply not so. All of these deviations from rationality are what Valian calls "nonconscious." The word is perhaps not a happy one, but I can't myself think of a better compromise between, on the one hand, suggesting that people consciously go through trains of reasoning on the order of "Judging by that table, the woman in this photo has to be about six feet tall; but women are generally shorter than men; call her five foot ten", and the motivated irrationalities burbling out of a Freudian swamp suggested by "unconscious" or "subconscious."
Having established the existence and strength of gender schemata, Valian then shows that women are schematically not competent professionally; women who manifestly possess the traits needed for competence are un-schematic, i.e. unfeminine. One effect of this is that women get less credit for the same accomplishments and attributes than men do --- which is especially the case when there are no objective scales for these accomplishments, and evaluators rely on their personal feelings, experience, and the like. Valian even documents many traits which help men's careers but hurt women's, for instance a reputation for assertiveness. (This ties back in to the normative force of schemata. When was the last time you heard of somebody that "She's a bitch, but she gets things done"?)
So here we have a mechanism at work in people's minds, particularly when they deal with other people. By itself it could account for some of the retardation of women, but Valian has another trick, another mechanism, which explains the growth of this retardation over time and as one moves up the levels of the professions. She calls the mechanism "accumulation of advantage."
It is a fact of professional life that our business consists mostly of talking (and writing) to one another, and that one person's words rarely carry exactly as much weight as another's. Before we act on or believe what co-workers say, we have to take them seriously; to take them seriously we have to listen to them. Before we bother listening to them in the first place, we have to think they're the kind of people worth bothering with. The quality of being judged worth bothering with (and taking seriously and following) has, surprisingly, no vernacular name; "prestige" comes pretty close, and Valian uses it, though it doesn't quite fit, and she also speaks of "advantage". People are usually pretty well-agreed on judgments of worth-bothering-withness, though lots of office politics revolves around the disputes. In any event, the peculiar --- but readily-observed --- fact about prestige is that one gets it by being bothered with, listened to, taken seriously, and followed, and that one loses it by failed attempts at these (much more than by doing nothing, though even that is often not neutral). This is of course what sociologists have, since Robert Merton, called the Matthew Effect (Matt. 13:12: "For whosoever hath, to him shall be given, and he shall have more abundance: but whosoever hath not, from him shall be taken away even that he hath"); or positive feedback, if you like electronics; or a virtuous circle, if you like to be old-fashioned in your jargon. (This is well understood by one of our best contemporary novelists, L. M. Bujold, one of whose characters calls advantage "forward momentum.") Many successfully ambitious people, as Valian notes, have an intuitive understanding of this, and take care to accumulate the small successes which support large ones, and avoid the small failures which undermine them. (I wish I could be that strategic.)
It's not hard to see where this is heading. Even small systematic biases in starting positions --- in judgments of advantage of people without reputations --- will quickly amplify; and gender schemata provide just such a bias, often not such a small one. They also make it harder for women to be successful in professional encounters and evaluations all down the line. If the membership of one level of the profession is picked from those with the highest standing in the level below --- which is pretty much the case --- then we have a case of repeated biased sampling, and it's elementary to work out that this quickly leads to fixation. (Actually, repeated sampling leads to fixation even without bias, but that's another story.) In other words: there only has to be a very slight day-to-day bias against women in mundane professional life for the heads of the professions to be all male. The glass ceiling is built out of unnumbered petty occasions of paying more attention to Jack than to than Jane.
Now, an important part of methodologically sound science is ruling out alternative explanations of phenomena. Valian does a fine job of this as well, particularly the two most likely to appeal to critics, namely meritocracy and biology.
The first rival explanation is that professional life is genuinely meritocratic, and that women simply have less merit (are less well-prepared, less skilled, etc.), and consequently do not do as well. To the extent that "human capital" and similar sorts of merit can be estimated, it is true that female professionals have less merit than men. But even when this is controlled for --- when e.g. we track the careers of men and women with the same qualifications --- there is still a discrepancy between men and women, and it is not in the women's favor. So, while women really do have less of what the professions reward, they don't have so little of it as to explain the divergence between them and men. This also brings us back to the question of why women begin their careers with less human capital.
The other main rival is biology. There's a very strange and almost dualistic use to this word, where the endocrine system and the gonads are biological, but the brain and learning are not. (The entry for "Biology" in the index reads: "See Hormones.") This dualism won't stand examination; but let's bow to popular usage. The best current research indicates that there are cognitive differences between men and women, which are apparently not due to differences in the social environment. It also indicates that they are quite small, and quite irrelevant to schooling and professional life. They are largest and most clearly hormonal for spatial visualization and mental rotation. Valian shows that even this doesn't mean that girls have to do worse in geometry than boys, if it's taught properly, and it certainly doesn't mean they have to do worse in math over all. It seems likely, on evolutionary grounds, that there are other psychological differences between the sexes, one sort of software (so to speak) going with the concave hardware, another with the convex. On exactly the same evolutionary grounds, however, it's extremely far-fetched that one sex has a biological advantage in professional life, since that's one of the most artificial ecological niches yet invented on this planet; everyone should be equally maladapted to it.
Assuming Valian is right (and I really do think she is), what are the available remedies? Valian's recommendations fall under four broad heads. First of all, people --- men and women both --- need to realize that gender schemata and the accumulation of advantage exist and make a big, harmful difference. They also need to learn how gender schemata work, so they can change their practices to minimize their importance, and check themselves when they start to lapse into schematic thinking. Valian stresses that this should not be confused with "awareness training," which she thinks is probably counterproductive, and I can testify is often extremely irritating. (People are more likely to accept changes in their habits of work and even thought if it's presented as a matter of patching a nonconscious cognitive bug than as one of rooting out unconscious sexism.) Second, women need to learn to act strategically --- "be impersonal, friendly and respectful ... build power ... seek information ... become an expert ... get endorsed by legitimate authority ... negotiate, bargain, seek advancement" (pp. 323--327). Of course many men would benefit from acting thus (I certainly don't do enough of it myself), but we're expected to behave that way, and women are not. Third, institutions must recognize the existence of this problem and find ways to deal with it --- which is to say, the people in charge of institutions must. Switching to objective performance criteria, for instance, will help, since more personal, intuitive evaluations are also more influenced by schemata. Her fourth recommendation logically belongs under the third, institutional heading, but it's controversial enough to get special treatment: affirmative action. Since evaluations are biased, in the statistical sense, against women, a man and a woman who are equally rated are probably not equally qualified; the woman is probably more qualified. Failing elimination of the bias in evaluation, a countering bias in the decision rule will actually restore meritocracy. Setting the compensatory bias is of course tricky; it is likely to be too small.
One of the more piquant arguments against affirmative action is that it makes its beneficiaries feel bad about themselves. I'm tempted to argue (following Popper) that happiness ought not be the aim of policy, and that if these people have to take a hit to their self-esteem so that others, and even they themselves, have a fair shot at success, so be it. Valian, characteristically, has dug up the germane studies.
The implications of [the experiments] is that the negative psychological effects of affirmative action are caused not by affirmative action itself but by the already-existing negative views that men and women hold about women. The very process that makes affirmative action necessary --- men's and women's underestimation of women's performance because of gender schemas that selectively attribute professional competence to males --- also makes affirmative action psychologically costly for women. [p. 287]People, it seems, really don't sweat getting a special break if they think they deserved success anyway. (Consider preferential admission of children of alumni at colleges.) Knowing this suggests ways to reduce those psychological costs; I'm almost fond enough of can't-make-an-omlette rhetoric to be disappointed.
Psychologists are notorious for writing badly; but while nobody would read Valian for the pleasures of her style, she is clear and comprehensible, keeping jargon to a minimum and citations unobtrusive. I've not touched on a lot of her material, like the very shrewd chapters on self-perception and self-evaluation, and said nothing at all about many fascinating side-lights, such as the demonstration (pp. 179f) that far too few middle-class white men were failures in life during the mid-century; but I've gone on about the book for long enough as it is. I'll finish up by advising everyone very strongly to read it, and by quoting a passage (pp. 330f) that summarizes a big chunk of Valian's message:
The sentiments in the phrase --- "to succeed a woman has to be twice as good as a man; fortunately, that isn't difficult" --- are wrong. Not only is it difficult, it is impossible. Men and women are, on average, equal in ability. Only a tiny fraction of women could be twice as good as the average successful man, just as only a tiny fraction of men could be twice as good as the average successful woman...Valian has made a significant contribution to achieving that modest, important goal.
Rather than role models, people need access to information, opportunity and recognition. People need fairness. Fairness does not guarantee that people will always be rewarded according to their merits, but that no one will be unrewarded more often than someone else because of membership in a particular group. Fairness means that an average woman has as great a chance of success as an average man.