Intelligence (English, Hans Eysenck)

Great on Intelligence, Good on Creativity, But Poorly Edited

At the time of his death in 1997, Hans Eysenck was the most-cited living psychologist in the world. His speciality was on intelligence and personality, and this book—written immediately before his death—is an outstanding summary of the state of intelligence research in the late-1990s. The book is still relevant today, because the past two decades have only solidified and clarified the findings Eysenck presented.Eysenck shows that intelligence (1) has a biological basis, (2) is an extremely important trait for occupational, educational, and social success, and (3) IQ tests accurately measure intelligence.The second half of the book is spent on creativity. This section is less interesting—partly because creativity is more difficult to define and test than intelligence, partly because a lot of creativity research is so unconvincing (for example, reading biographies of famous creative people and then "diagnosing" them with various mental illnesses), and partly because Eysenck's sympathy with the paranormal leads him to argue that a potential correlation between low solar activity and high human creativity means that low solar activity causes creativity.However, Eysenck does note that mental illness is likely a spectrum, and that many creative types have what could be termed "very low-level schizophrenia and depression." These findings have been greatly buttressed in recent years, especially by Robert Plomin. There is no sharp dividing line between having a mental illness and not having one. Instead, there is a spectrum. For example, with schizophrenia: on one side we have completely uncreative types, on the other side we have schizophrenics, and between the two we have varying degrees of creativity.Lastly, the book is poorly edited. There are several typos, and some outright flabbergasting inaccuracies—on page 136, Eysenck says that only 4% of Americans are Catholic.