Under The Microscope

IRRATIONALITY: THE ENEMY WITHIN, by Stuart Sutherland; Penguin, 1994; 360 pages; NZ$25 approx.

This book, by University of Sussex psychology professor Stuart Sutherland, aims to demonstrate to the lay reader that people are much less rational than might be assumed, and to show some important reasons for human irrationality. Sutherland bases his arguments partly on evidence from psychological experiments, including some classics from the fields of social and cognitive psychology. He also includes many real-life examples, often from the professions.

A central theme of the book is that irrational conclusions and decisions are often caused by inherent biases in human thinking, rather than by purely emotional factors. Particular emphasis is given to the tendency to place undue weight on concrete, recent, and dramatic instances, because these come most readily to mind. Sutherland shows how this bias affects many areas of thinking, including decisions made by professionals such as doctors and managers, as well as judgements of risk.

The book also looks at emotional and social causes of irrationality. These include tendencies towards obedience and conformity, other forces operating in groups and organisations, and the need to feel that one's beliefs and actions are consistent.

Several chapters deal with specific common types of faulty thinking, such as ignoring, distorting, and selectively forgetting evidence which conflicts with one's beliefs or prior decisions, and drawing the wrong conclusions about causes and connections. One chapter discusses the fallibility of human intuition; another considers how errors in thinking contribute to belief in the paranormal. In the final chapter, Sutherland speculates that the fundamental causes of irrationality lie in evolution and the design of our brains. He also considers how we can make ourselves more rational.

The book is easy to read, written in a lively style, and full of fascinating, if sometimes alarming, examples of human irrationality.

Helen Pennington lectures in the Psychology Department at Massey University.