SIMON BARON-COHEN

Simon Baron-Cohen is in the Departments of Experimental Psychology and Psychiatry, Autism Research Centre, University of Cambridge, Downing Street, Cambridge CB2 3EB, UK.

Emotion: The Science of Sentiment
by Dylan Evans
Oxford University Press: 2001. 204 pp. £9.99, $15.95

This is a fun little book, no bigger than your palm, and with a bright pink cover, summarizing in a popular science format what we know about emotion. Dylan Evans is a researcher at the Darwin Centre at the London School of Economics, and his account is, predictably, about the evolution of human emotions. Highly accessible, this little gem deserves to sell well.

CORBIS

Let it out: all the important aspects of everyday life are governed by emotion.

Typically, only about 5% of what we teach on undergraduate psychology courses is emotion, the remainder being cognition. This is despite the fact that all the important stuff in our everyday lives is determined by emotion. Evans' agenda is to redress this balance, and, given how student-friendly this little book is, we can hope to see emotion become more central in behavioural neuroscience research.

Evans admits that his book leaves out a fair bit. For example, it doesn't touch on individual differences or on development. You might think that these are two big omissions, for many of the interesting questions centre on why you and I experience our emotions differently, and on the role of development in creating these individual differences. Psychotherapists will therefore find that this book contains little of relevance to their clinical work.

But the strength of the darwinian approach is to sweep aside individual differences in an effort to highlight the universals. Universals are compelling, because we can then rule out the role of culture and focus on the products of evolved biological systems. This is Evans at his best. Following Paul Ekman, the psychologist most well known for his comparative studies of emotion in Western and non-Western cultures, Evans lays out some central examples of emotion that you will find the world over, and for which one can make a convincing argument for their adaptiveness.

The obvious case of an emotion being adaptive is fear. Those of our ancestors who experienced too little fear may have stood for too long at the edge of a cliff or staring into the face of a lion, and their genes would in all likelihood have died with them. Ancestors who experienced too much fear may have been equally unlikely to reproduce if they were too afraid to even venture out of their cave. A midway level of fear seems therefore to have been adaptive and optimal. Evans makes similar arguments for other emotions, such as revenge, guilt, embarrassment, romantic love and sexual jealousy, as well as the usual ('basic') list of emotions - happiness, sadness, fear, anger, surprise and disgust.

I was somewhat surprised that there was no comprehensive list or taxonomy of emotions. It may be that Evans decided, wisely, to avoid grappling with this, given the controversies that exist in this field. There is no consensus as to how to classify emotions, because the dimensions along which they could be sorted rely on which features of a given emotion a researcher highlights. But this does not mean a taxonomy of emotions cannot be attempted and defended. In our lab, for example, we have been collecting emotion words in the adult English lexicon and have now classified close to 1,000 discrete emotions into 23 mutually exclusive categories. But Evans's excellent introductory book makes clear that we have a long way to go before we can give a full account of the richness of human emotions in terms of both their evolved and their experiential components.