Intelligence: A Very Short Introduction

Intelligence: A Very Short Introduction - Ian J. Deary An excellent introduction into the subject. Deary concentrates on statistical studies and meta-studies to delve into those questions that seem to vex people about intelligence.

Starting with 'general intelligence' and working through the types of brain activity that make it up and the mechanisms through which it can be tested (where it can be tested), Deary then explores what happens to our intelligence as we get older (It stays in the same ballpark area for a lot of people for all their life), how intelligence impacts an individuals life and opportunities (Deary suggests you are better off being more intelligent), and then gets into the whole Nature VS Nurture debate - It is clear where Deary thinks this balance should lie (it's genetic).

Finally Deary summarises what has been said, by referencing the "intelligence knowns and unknowns" report produced by the American Psychological Association (see Wikipedia Article, which, as it happens, contradicts some of what Deary has said.

Deary ends by listing the unknowns, which are (these taken from the actual report):


1) Differences in genetic endowment contribute substantially to individual differences in (psychometric) intelligence, but the pathway by which genes produce their effects is still unknown. The impact of genetic differences appears to increase with age, but we do not know why.

2) Environmental factors also contribute substantially to the development of intelligence, but we do not clearly understand what those factors are or how they work. Attendance at school is certainly important, for example, but we do not know what aspects of schooling are critical.

3) The role of nutrition in intelligence remains obscure. Severe childhood malnutrition has clear negative effects, but the hypothesis that particular "micro-nutrients" may affect intelligence in otherwise adequately-fed populations has not yet been convincingly demonstrated.

4) There are significant correlations between measures of information processing speed and psychometric intelligence, but the overall pattern of these findings yields no easy theoretical interpretation.

5) Mean scores on intelligence tests are rising steadily. They have gone up a full standard deviation in the last fifty years or so, and the rate of gain may be increasing. No one is sure why these gains are happening or what they mean.

6) The differential between the mean intelligence test scores of Blacks and Whites (about one standard deviation, although it may be diminishing) does not result from any obvious biases in test construction and administration, nor does it simply reflect differences in socio-economic status. Explanations based on factors of caste and culture may be appropriate, but so far have little direct empirical support. There is certainly no such support for a genetic interpretation. At present, no one knows what causes this differential.

7)It is widely agreed that standardized tests do not sample all forms of intelligence. Obvious examples include creativity, wisdom, practical sense and social sensitivity; there are surely others. Despite the importance of these abilities we know very little about them: how they develop, what factors influence that development, how they are related to more traditional measures.


Or in other words, there is little agreement on anything when it comes to understanding on intelligence, or perhaps little appetite for the political fallout of measuring intelligence at all. Still, I have found it to be a most interesting subject, and this book to be accessible and enlightening. Only didn't get a 5 because of the cop-out at the end!