Book Review: The Invisible Gorilla

Chabris, C., & Simons, D. (2010). The invisible gorilla and other ways our intuition deceives us. London: HarperCollins. Psychology is a much misunderstood discipline. If you go into a high street bookstore, you will find the psychology section stuffed with self-help manuals and in all probability located next to the section on witchcraft and the occult. This is partly the fault of the Dewey Decimal Classification, which sandwiches Psychology firmly between Philosophy and Religion. For those who regard experimental psychology as a scientific discipline with affinities to medicine and biology this is a problem, and some psychology departments have dissociated themselves from the fluffy fringes of the discipline by renaming themselves as departments of cognitive science or behavioural neuroscience. An alternative strategy is to reclaim the term psychology to refer to a serious scientific discipline by demonstrating how experimentation can illuminate mental processes and come up with both surprising and useful results. This book does just that, and it does so in an engaging and accessible style. The book starts out with the phenomenon referred to in the title, and which the authors are best-known for, i.e. the Invisible Gorilla experiment. This has become well-known but I won't describe it in case the reader has not experienced the phenomenon. Richard Wiseman has a nice video demonstrating it. This is perhaps the most striking example of how we can deceive ourselves and be over-confident in our judgement of what we see, remember or know. In all there are six chapters, each dealing with a different 'everyday illusion' to which we are susceptible. My personal favourites were the last two chapters, which consider why people continue to believe in notions such as the damaging effect of MMR vaccination, or the beneficial effects of brain training for the elderly. Sceptics tend to dismiss those who persist such beliefs in the face of negative evidence, and denigrate them as stupid and scientifically illiterate. Chabris and Simons, however, are interested in why scientific evidence is so often rejected and consider why it is that anecdotes so much more powerful than data, and why we are sucked in to assuming there is causation when only correlation has been demonstrated. My one disappointment was that they did not say more about the reasons for wide individual variation in people's scepticism. After a rigorously sceptical undergraduate course in experimental psychology at Oxford, I assumed that all my peers on the course would be sceptics through-and-through, but that is far from being the case: I have intelligent friends who learned all about the scientific method, just as I did, yet who now are adherents of alternative therapies or psychoanalysis. I find this deeply puzzling, but it makes me realise that the satisfaction I find in the scientific method is in part due to the fact that it resonates with the way my brain works, and there are others for whom this is not so. In sum, I enjoyed this book for the insights it gave into how people think and reason, and for its emphasis on the need to adopt scepticism as a mind-set. Its avoidance of jargon and clear explanations give it broad appeal, and it would make an ideal text for undergraduates entering the field of experimental psychology, because it illustrates how a good experimenter thinks about evidence and designs studies to test hypotheses.