Income inequality in the United States has grown substantially since the 1970s, to the point where today the bottom 20 percent of the nation’s households have 5 percent of total income, the top 10 percent about 50 percent, and the top 1 percent more than 20 percent. The question is whether such a high level of inequality is likely to reduce what is called “relative mobility,” or the likelihood that members of one generation of a family and members of the next generation will end up at different points in the income distribution. You are very likely to earn more than your father; the question is how likely are you to be higher (or lower) in the income distribution. If he is in the bottom quartile, for example, how likely are you to be in the next higher quartile?
Income inequality in the parents’ generation might be expected only to create income inequality in the next generation. Whether income inequality will affect relative mobility will depend on why income inequality in the current population is so high. One possibility is that, because of increased assortative mating as a result of declining discrimination and of the efficiency of online search for potential mates, there are greater differences in IQ across families than there used to be. Another possibility—closer to a certainty—is that as a result of automation in the broadest sense, the economic returns to IQ have risen relative to the returns to strength and stamina, which are the qualities important to such vocations as factory work, construction, mining, and farming.
The combination of assortative mating with higher returns to IQ could have dramatic effects on relative mobility if the effect was to insulate to a significant degree a prosperous family’s children from economic risk. And it may be. The adults in high-IQ families are disproportionately represented in the jobs (professional, managerial, financial, and so forth) that pay well, and their income can and often is used to give their children a boost—for example in the form of payment of tuition to high-quality (and very expensive) private schools, payment to tutors, a variety of other educational enrichments, and entry into high-quality colleges without need for their children to borrow to finance college (or graduate or professional school) and thus assume debt. Colleges like to admit kids from high-income families, seeing such kids as future donors. And high-IQ parents are likely to produce high-IQ children, further enhancing the children’s attractiveness to first-rate colleges. These factors, which loom larger the greater the inequality in the income distribution, because that inequality creates a highly affluent tier of families (a proximed by the income shares of the top 10 percent and within that group the top 1 percent) are likely to reduce relative mobility, by securing a disproportionate number of the top college and university admissions and top jobs for children of the intellectual-economic elite.
These factors can be offset to a significant extent by immigration, because immigrants tend to be more ambitious, bold, and determined than the average member of their nation of origin; refugee immigrants are often drawn from the elite of their nation of origin. First-generation immigrants tend not to have a high income, but to endow their children with the attitudes and abilities that enable the children to achieve economic success. Certainly the United States has benefited greatly in recent
years from immigration from countries like China, India, and South Korea. But relative mobility that is the consequence of the artificially depressed income of first-generation immigrant families does nothing to promote relative mobility for the children of low-income native-born Americans.
A 2011 study by Scott Winship for the Brookings Institution reports that the likelihood that an American will rank higher in the income distribution than his parents is lower than in most other wealthy countries. The report states: “If being raised in the bottom fifth [of the income distribution] were not a disadvantage and socioeconomic outcomes were random, we would expect to see 20 percent of Americans who started in the bottom fifth remain there as adults, while 20 percent would end up in each of the other fifths. Instead, about 40 percent are unable to escape the bottom fifth. This trend holds true for other measures of mobility: About 40 percent of men will end up in low-skill work if their fathers had similar jobs, and about 40 percent will end up in the bottom fifth of family wealth (as opposed to income) if that’s where their parents were.” Income inequality is greater in the United States than in our peer countries, and may be responsible for our lower relative mobility. In the limit, an income distribution that produces a very wealthy top tier of earners and a very large bottom tier of poor or low-income families may reduce movement between the tiers in subsequent generations.
Becker points to Headstart and other government programs as possible counters to the effect of income inequality on economic opportunities for children of families that are rank low in the income distribution. This raises the question whether there may be a more efficient way of dealing with the problem of relative mobility than spending government money. A natural starting point would be to increase the very low federal income tax rate (15 percent) on dividends and capital gains, which is a significant factor in the increase in income inequality.