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.Withoutknowing this demand, we find it difficult to relate IQ scores, wholly orin part, to the dollars of salary they may generate.Nature versus NurtureAny mention of IQ and what it means brings to mind the ancient bat-tle over nature versus nurture.As a wise man once said, we will needan 11-foot pole to touch this one, since we would not touch it with a10-foot one.Scientific estimates of the proportions of ability due to heredity or en-vironment have been put forth.Unfortunately, these seeminglyreasonable estimates are frequently demolished, using the same scien-tific tools used to build the original estimates.As a result, it is close toimpossible for us to say anything useful in a quantitative way on thissubject.In 1889, Francis Galton said,12 "Each peculiarity in a man is shared byhis kinsman, but on the average to a less degree." Since IQ tests werein the future, his statistician friend, Karl Pearson, devised a simple test.He measured the heights of fathers and sons.Pearson found that althoughtall fathers have tall sons, the average height of sons of a group of tallfathers is less than their fathers' heights.13 In other words, there is aregression, or going back, of sons' heights towards the average heightsof all men.What does this have to do with IQs, income, or anything inparticular?Many of us know affluent suburbs around our cities and towns.Letus assume that there is a relationship between IQs and income, and thusmany of the adults in these well-off suburbs have high IQs.If the law of regression is true, their children should have lower IQs,on average, than their parents.But in almost all regions of the country,we notice a curious phenomenon.The high school graduates with thehighest scholastic honors (e.g., National Merit Scholarships or ScholasticAptitude Test [SAT] scores close to the maximum) tend to be concen-trated in these well-to-do suburbs.Yet if the regression rule holds, these students should do less well thantheir parents had in school.We can conclude that while the regressionto the mean works for heights, over which one's environment exerts littleWHY AREN'T YOU SMART? 153control, it does not seem to apply to scholastic achievement or even IQ.Score one more point for environment.PUTTING IT ALL TOGETHERAbout all we can say to this point is that there are a number of factorsthat could, in principle, predict income.They include native ability, lengthand quality of education, family background, and others.They blend ina complicated way, the details of which are not known.How they com-bine to predict incomes for the very highest income earners is evenmurkier.The crude analogy we can draw is that of a massive computer that willtry to predict our personal incomes for the rest of our lives.It asks usfor thousands of bits of information, some of which seem relevant, andothers which do not: how long we went to school; our coat size; the namesof our parents; what we were doing on the night of January 25, 1954;our grades in English; how much we have in the bank; and more.It putsall this information together in a detailed equation, and prints out theanswer.Yet we have only a vague idea of what the equation is, or whichof the scraps of information we supplied were actually used.One of the major studies to try to sort out all the variables was byJencks.14 In the words of Sahota1:The general conclusion of the study was that neither family environmentnor cognitive talent [reasoning ability] nor school quality determines signifi-cant proportions of educational inequalities; and that none of these factorsnor educational attainment nor occupational status significantly alters in-come inequalities.Apart from inheritance of property, economic suc-cess is largely the result of 'luck and peculiar competencies' over whichgovernment has no control.Education cannot achieve non-educational[economic] goals.What fraction should go to nature and what fraction to nurture? Ac-cording to this massive study, no more than 45% and no less than 55%,respectively.While the proportion ascribed to heredity (less than 45%)may not seem that much, it is by far the largest component of all the in-fluences on future earnings.Like the Prime Minister in the British cabinet,it is primus inter pares (first among equals).What can we learn from these and other comprehensive studies? Thecomplex of factors that determine the future earnings of a small childseem, at least in our present state of knowledge, to be analogous to aspider web.Some of its threads are stronger and thicker than others, andhelp to hold it together.These correspond to ability, family background,and other major factors.Some threads are thin; they correspond to lesser154 HOW RICH IS TOO RICH?quantities such as the child's place of birth, perhaps the university at-tended, and so on.The threads are joined in a way which yields onlya little to our probing.But one factor can overwhelm the entire structure:a strong gust of wind, corresponding to the unknown variable of luck.MATHEMATICAL EXPLANATIONSThe economists who formulated the theories noted above approachedthe subject via the front door.They wanted to find the factors that deter-mine future earnings, regardless of the exact shape of the income curve [ Pobierz całość w formacie PDF ]