I think you are right, that it's hard to show a pattern of discrimination. It's still a risk, and lawsuits like the age discrimination case at Google keep it in general awareness that it's something to be concerned about.

When I talk about EEOC laws with people, there is often a knee-jerk reaction toward them being "completely unexpected and uncontrollable." I can understand this, because labor rights and civil rights are so undervalued in US discourse, where the interest is more on profit and job production. EEOC training in many companies is woeful, so people end up being more scared of it than they should.

I don't understand why managers don't get real EEOC training. I've read through a dozen or so court cases, and they are all consistent and understandable. If manager are really worried, and acted rationally, then why don't they seek out the education which would greatly limit that risk?

(The answer is obvious. I don't think people are really rational in that way. But you think they do.)

In practice, what happens is the 'rational human' analyzes use what appear to be a post hoc argument that a variance from the expect optimal result is due to a personal preference for a different weighting scheme. People like religion because they place a high value on the sense of community or spirituality the practice gives. People like to discriminate because the social standing is worth the effect of a suboptimal market, etc. There's nothing which cannot be justified with "weighted very highly", making it a weak concept.

The evidence you gave looks like the sort of crap one finds with a Google search, which is easy to match. A Google Scholar search for 'anti discrimination laws effectiveness' found:

http://ilr.sagepub.com/content/56/2/244.short - Using census data from the Integrated Public Use Microdata Series, the author assesses the impact of fair employment legislation on black workers' relative income, unemployment, labor force participation, migration, and occupational and industrial distributions. In general, the fair employment laws adopted in the 1940s appear to have had larger effects than those adopted in the 1950s, and the laws had considerably smaller effects on the labor market outcomes of black men than on those of black women.

http://www-siepr.stanford.edu/conferences/gender05/racesex_s... - we find robust evidence that state equal pay laws for women–which
predated federal legislation establishing both equal pay and equal
employment for women–reduced relative employment of both black women
and white women. With respect to race, we find some evidence of
positive effects of race discrimination laws on earnings of blacks
relative to whites, although no evidence of employment effects.

That second one starts "The question of the effects of sex and race discrimination laws on relative economic outcomes for women and blacks has been of great interest since the Civil Rights and Equal Pay Acts passed in the 1960s." so I presume there is a lot of literature on the topic.

If discrimination is an irrational act, then how come there has been so much of it through the centuries?

Take a look at colonist power structures. The foreign power (Britain, France, Germany, etc.) has a very small population in the country. They are outnumbered. What they do is put a minority in charge of the next rung of the power hierarchy. These people gain power and prestige by maintaining the colonial system.

At the bottom are the majority in population, even though they are the minority in power.

For a real-world example, https://en.wikipedia.org/wiki/Rwandan_genocide#Colonial_era :

> The Berlin Conference of 1884 assigned the territory to Germany[22] and began a policy of ruling through the Rwandan monarchy; this system had the added benefit of enabling colonization with small European troop numbers.[23] European colonists, convinced the Tutsi had migrated to Rwanda from Ethiopia, believed the Tutsi were more Caucasian than the Hutu and were therefore racially superior and better suited to carry out colonial administrative tasks.

This is a relatively stable system where the rational market response - the market favors those with the most market power - causes the discrimination to persist for decades. One result for Rwanda was the Rwandan genocide, which presumably was also the result of rational actions.