James White Debunks TBC

In my continuing assault and relentless attack on "The Bell Curve" and the kind of pseudo science it represents, I will go over IQ tests, what they are and how they are conducted or should be conducted.

The most reliable tests for humans (Tests which compute an IQ analog for Computer programs are different in some respects) are generally administered face-to-face and one-to-one by a psychologist trained in how to administer the test. The test is a mixture of sub-tests which examine a variety of cognitive skills which can be roughly divided into verbal, spatial and memory. Some are spoken or written questions [e.g. those tapping general knowledge or vocabulary] while others are manipulative tasks [such as the request to put colored (no racial slur) blocks together to make them look like a sample diagram, put pieces of jigsaw together or choose which of several alternate diagrams completes the series].

The results from each item are added together and a sub-test score derived. [Provided the person's brain is functioning normally there is usually only small variations in level between the sub-tests.] The results from each sub-test are added together and a score computed from the average of these. It's quite common to compute separate scores for Verbal, Performance and Memory IQ. [Again, if there is much difference between these scores the person's brain is not functioning properly.] The "IQ" which most people refer to is the average score of the Verbal and Performance scales which has been adjusted for age and gender [also known as a Full Scale IQ]. Note that these tests are normed for both gender and age, they are not normed for race. One reason for gender norming is that females until recently came up in a different culture from men and consequently did not score as highly on the average as males.

The IQ tests we use in my business are the Wechsler scales: the WAIS [Wechsler Adult Intelligence Scale], the WISC [Wechsler Intelligence Scale for Children] and the WMS [Wechsler Memory Scale] (for Adults). Other well-known scales are the BAS [British Ability Scales] and the NHAIS [Naylor-Harwood Adult Intelligence Scale {Australian}]. These scales are regularly updated because they go out of date as the culture changes [especially items on verbal scales]. Note here that there is recognition that IQ tests are culturally loaded in spite of the claims made in TBC to the contrary.

To give you some idea of the range of things covered here is a list of the WAIS sub-scales. It shouldn't be difficult to figure out which ones are most likely to vary with the culture and why. Also there is much fiction about IQ tests out there in the lay world. One of the biggest, which was promulgated by TBC, is that IQ test scores are immutable from childhood through adulthood. This is absolutely and positively false.


Information: a test of general knowledge {test of ability to learn} Comprehension: test of social understanding and adaptation Arithmetic: simple mental arithmetic (timed) Similarities: "How are x and y alike?" {test of abstract verbal ability} Digit Span: "Repeat these numbers after me:" {test of immediate memory} Vocabulary: list of words to define {test of ability to learn language}


Block Design: two dimensional pattern construction (timed) Object Assembly: simple jig saws (timed) Picture Completion: "What is missing in this picture?" (time limit) Picture Arrangement: cartoon frames to put in logical order (timed) Digit Symbol: copy the right symbols underneath the numbers (timed)

You can see that not only are IQ tests culturally loaded but time plays a big part in the score you get. These people who come into this group and pronounce that IQ tests have no cultural component do not really know what they are talking about. Another thing is that there are some really bad IQ tests out there so it matters where you get tested and by whom. One reason for the bad tests is that is quite expensive to really run IQ tests such as the Wechsler series so people come up with cheap and dirty methods of estimating IQ. The tests are best at identifying feeble minded people and people with mental disorders which is what they were originally designed to do. IQ tests are an excellent way to identify dyslectics for example. Dyslectics usually score between 80 and 90 because their spacial abilities are defective. Dyslectics however can be very high achievers in society. Some notable dyslectics were: Alexander Graham Bell, Thomas Edison, Henry Ford and Albert Einstein!

TBC talks about relative performance of whites and blacks on IQ tests. It makes many false claims such as that IQ tests are not culturally biased and that IQ test scores are immutable both of which are false. The final point I would make about IQ tests is that the tests Murray and Herrenstein refer to as IQ tests are not really IQ tests. What they are referring to are the Armed Forces Entrance Exams. These tests among other things measure the quality of the schooling you received.