The reasons for this fifth episode comes two months after the publication of the fourth are many and varied, and most personal, but at least one of these reasons, however, is intrinsic to the subject: I would have liked summarize the characteristic features of biological determinism applied to the study of intelligence, his age begins roughly with the 30s, and new conceptual forms that would emerge in particular the rapid development of genetics and statistics at that time. I have read and reread, and Well, I could not find anything. No new conceptual elaboration, no particular theoretical innovation ... has always continued to repeat the same mistakes at the beginning of the century by Goddard and associates, "improving" in the light of new genetic knowledge, and treating them with more sophisticated statistical techniques. But the concepts and logic underlying the errors do not change ever. In
Intelligence and Prejudice, SJ Gould ago to begin this phase of history with the invention of the statistical technique of factor analysis, which allows you to summarize in a few major components of very large matrices of correlations between different measures. Charles Spearman, psychologists and statisticians in London, he developed this technique specifically for the study of the reactive mind. He found that all the tests (eg. Spatial, verbal, numerical, etc.). Have a certain positive correlation (ie that those who manage well in a kind of test is intended, generally, to obtain good results in others). The axis on which the project all the positive correlations (I try to slip into a more succinct as possible on the mathematical treatment) is the first principal component, which Spearman called g, or general intelligence. He felt so real that they had identified the real measure of intelligence, a kind of "energy", measurable and scalable, which fed all mental activity, and finally gave a theoretical basis for the Intelligence Quotient, a measure hitherto Wizard only by blind empiricism: the IQ test is valid as a measure g, the new philosopher's stone of psychology. I will not go into technical details, and I will only say that an American psychologist LL Thurstone, starting in 1935, razed the g Spearman simply distributing the same matrix of correlations in the groups as homogeneous as possible, on multiple axes different from their equivalent, representing, in our example, the distinct spatial ability, verbal, numerical, etc.. The statistical changes introduced by Thurstone explained exactly the same amount of information, with the surprising effect that the first principal component, the most valuable and "objective" Spearman's g, the measure of "true" intelligence, simply ... disappeared.
The motto that guides the valuable work of statisticians, to whose work we all have to gratitude, is that if something exists, it must somehow be measured. You just have to be careful not to get carried away and assert arbitrarily transitive property: the one that produces a statistical value is not necessarily a real entity. The debate between Spearman and Thurstone was on fire, but summed up, in a nutshell, in mutual accusation of having taken for a specific property of our minds that this was merely a mathematical abstraction. Both accusations were easily prevailed over the defenses. As flawed
error of reification (treating an abstract concept such as the concrete entity) in a similar way to that of Spearman, Thurstone's interpretation could be considered today to be awarded a posthumous revenge, with the conception of Gardner's multiple intelligences currently in vogue. But
g Spearman raged long, and as a single, innate, and classified, provided a convenient tool for measuring people with a single number, and their arrangement along a single scale of value.
Spearman was convinced that intelligence was hereditary, with no proof, but simply because it was variable among individuals (just like Goddard), shared the racist conventional conceptions of the time (however, stressed that individual variations in intelligence within races largely hung over the small mean differences between races), and was a supporter of the Immigration Restriction Act in the U.S. 1924 ( see section 4), but nell'infuriare contentions on social and political implications of his publications, was held on the sidelines after all, remained a psychologist, and his primary concern was the understanding of intelligence.
His most faithful disciple, and his successor, in 1932, professor of psychology at University College London, Sir Cyril Burt, was always obsessed instead dell'innatismo idea, which remained his obsession since his first publication (1909) until his death (1971). Initially, he adopted the idea of \u200b\u200ban intelligence unit, innate and heritable (as he had inherited from his teacher ... Spearman), simply as a pure dogma immune from discussion, and then defended it with a fervor more and more excited , and increasingly frustrated by the lack of reliable data to support. To see what I mean, just know that he tried to organize experiments on samples of boys, the first of which compared a group of children of small traders of a primary school with pupils from the upper classes of a prestigious school. I get proof that the scions of good families were more intelligent than those of the middle class. Apart from the pathetically small sample (43 children in all), his "proof" that this difference was hereditary and not due to environmental conditions is reduced: 1) a series of arguments, specious up to ridicule, that the conditions environment in which children had been living should not have too much influence on the test results, 2) the fact that the intelligence of children is correlated with that of their parents. And this could be interesting to have an argument, except that the intelligence of the parents ... was never measured: Burt estimate based on their occupation and income. The circularity of the argument is even surprising for its sloppiness: it seeks to show that intelligence is inherited and not dependent on the socio-cultural conditions, and to do this using the socio-cultural conditions as a measure of intelligence.
In the remainder of his career, the experience did not help at all to eliminate prejudices the conclusions. In 1937, he published an accurate statistics on children who had lost years in school (which I consider as a proxy for low-to-intelligence). In the various suburbs of London, he found very strong correlations between the percentage of boys in school and delay factors such as number of households below the poverty level; overcrowding unemployment juvenile mortality. Environmental influences should be apparent, but the conclusion was reached that Burt bizarre social groups create less intelligent than the suburbs worst, and poor children are dumb because children whose parents remained poor because obtuse.
And here we have to do a couple of interesting observations. The first: Cyril Burt was a famous and respected scientist, and other fields created works fine, and when was the inheritance of intelligence and down the blinders and its conclusions were an annoying inaccuracy. Yet few of his contemporaries criticized him and attacked him, in spite of all logic errors were evident. This teaches us something about how society reacts when the error is useful to give a veneer of objectivity to a commonly shared dogma?
Second, Burt is not never too interested in the differences in intelligence between races, which always considered negligible, and its true mission was to demonstrate that social stratification was justified on the basis of innate biological differences.
In the United States made by Torie hereditary intelligence support to the division of society into racial groups, and discrimination of immigrants, in England, in the heart of capitalist Europe troubled by the October Revolution, Burt uses the same tool for justify inequality between social classes: a case be?
and inheritance dell'intellgenza should be used to justify reduced social mobility, the children of the rich are rich because the more intelligent of the poor. Burt
But now he realized very well dell'irrisolvibilità combination of biological inheritance and cultural heritage, so any strong correlation between the values \u200b\u200bof IQ of parents and children in the same way he could support the two interpretations of the extreme environmental factors exclusively or only genetic factors, and of course all the infinite range in between.
A single case could allow a resolution between genetic and environmental causes: monozygotic twins, that is genetically identical, separated shortly after birth and reared in environments different. The problem, of course, is the scarcity of cases. There are few published studies: one on only 12 pairs of twins, one out of 19, another of Shields, provides up to 44 pairs of twins, and is the only one to provide details about the life of these people are usually brought up by relatives narrow, or friends, or neighbors, you know and frequent, in some cases live in the same way. It 's hard to say whether it's twins "separated" and that actually live in different environments.
Cyril Burt stunned the world by publishing a series of studies on 53 well pairs of twins separated at an early age, which fully confirm the erditabilità of IQ. Even far away, the twins had Burt QI always very similar. Burt did not release details about their lives, and indeed no one has seen the original raw data, were destroyed in a small fire in the laboratory. The only primary source of publications were papers with data that are already partially developed, that Burt jealously kept in the drawer until his death.
When Burt died in 1971, and his papers were examined, discussed the most sensational scientific fraud in history: the 53 pairs of twins were invented, their IQs were fictitious, their perfect correlations in place at the table, and they were even invented employees who had collected the data around the world.
The prestigious and respected Sir Cyril Burt, who was defeated and frustrated, had pushed his desperate defense heritability of intelligence beyond legal.
