For Herrnstein and Murray publishing The Bell Curve in 1996, the cognitive elite comprised those of:
IQ 125 and above, or 5% of the population - that is one person in twenty.
But for Cyril Burt writing in 1924^, the cognitive comprised those of:
IQ 150 or above, or 0.1% of the population - that is one person in a thousand.
So Burt's elite was fifty times more elite than Herrnstein and Murray's!
A small part of this difference is due to Burt using the 'mental ratio' method of calculating IQ - which is that an IQ of 150 is attributed when a child's performance in intelligence testing is the same as the average child fifty percent older (up to a plateau of about 14-16 years old) - for example when an 8 year old performs at level of an average 12 year old.
By contrast, H&M use the 'percentile' method of calculating IQ - which tests a (supposedly population-representative) sample of subjects and puts their results into rank order and then fits onto this a normal distribution curve with 100 IQ points as the mean average and a standard deviation of 15 - such that the IQ of an individual is a statement of their percentile position if the normal distribution assumptions are assumed to be true and if extrapolation beyond the available data is regarded as valid.
(I will soon post a comparison and critique of ratio versus percentile methods of measuring IQ, especially higher than average IQ, separately.)
But this accounts for only about 5 IQ points difference in Burt's standard (i.e. Burt's IQ of 150 would be approx. equal to H&M's IQ of 146).
There just is a very big difference in the size of the cognitive elite; and an equally profound difference in the kind of jobs that people of different intelligences ought to be doing.
('Ought' - that is - from Burt's late 19th-early 20th century Left-wing Fabian eugenic meritocratic perspective of optimal rational efficiency.)
Burt has eight grades of intelligence, which I will here express in terms of rounded percentiles.
1. Top 0.1 % - Higher Professional: appropriate for university scholarships and honours degrees - occupations include university academics, doctors, lawyers, higher administrators in business and civil service.
2. Top 2 percent - Lower Professional: appropriate for secondary (high) school education, but not for college or university. Occupations include elementary school teachers and higher level clerks.
3. Top 15 percent - Clerks and Highly Skilled Workers: higher elementary education, leaving school about 14 years old; the occupations are of 'intelligent, but moderately routine character' - such as highly skilled manual workers and most clerks.
4. Top 50 percent (above average, but below the above groups - comprising about 35% of total population) - Skilled workers and most Commercial Positions: occupations in skilled labour such as shopkeepers, small scale tradesman, shop assistants for large firms.
5. The approx 35-40% who fall just below the average (that is, IQ roughly between 85 and 100) - Semi-skilled Labour: such as (I guess) underground coal miners, shipyard workers, steel workers, farm foremen.
6. Those above the bottom 4% but below the group of semi-skilled (that is, IQ roughly between 70 and 85) - Unskilled Labour - (I guess) farm workers, navvies, most labourers.
7. & 8 The bottom 4% described as "Casual Labour, Imbeciles and Idiots": are those who are more or less mentally handicapped - some can be basic domestic servants and rural labourers, most are incapable of work and presumably live under family care or in institutions.
What is striking about Burt's classification is how minute are the elite; and what a high intellectual standard, compared with nowadays, he expects would be required for each level of occupation.
This fits with my idea that nowadays we are living in an over-promoted society
Compared with about a century ago, the average cognitive competence of occupational strata has decline by at least one of Burt's categories, sometimes more like two categories.
Part of this is due to the inflationary expansion of the upper categories - which means that people have higher level occupations in name, but not in terms of what they actually do; and part of it is due to the decline in general intelligence over these period, such that the proportion of the population in each high level category has declined.
For example, intelligence at Burt's highest level was attained by one in a thousand as measured in 1924; but this level would now probably now be attained by only one in five or ten thousand (or less).
Burt envisaged a society with a small and very able cognitive elite, selected and allocated afresh each generation; and the mass of people doing manual labour and routine clerical jobs.
Yet we apparently see in the modern West is a society in which only a small proportion do manual labour (due to increased use of machines and computerization) and a third or more of people do what appear to be higher level jobs in Burt's categories 1 and 2.
I think the meritocrats of Burt's era would interpret this in terms of a massive expansion of make-work - instead of making unemployed the mass of the manual and routine clerical workers displaced by mechanization and computers, they have been allocated pretend work at a higher level than they are competent to accomplish.
What the early meritocrats would not have envisaged, since they lived in a much more honest society than ours, was that we could have this current situation of massive over-promotion, gross inflation of occupational status, and incomprehensibly vast erosion of the value of educational qualifications - and yet to deny outright that this is the case: indeed to pretend that the average person in a given category is smarter, better educated and more competent!
^Burt C. The principles of vocational guidance. British Journal of Psychology. 1924; 14: 336-352.