The Invisible Gorilla

Christopher Chabris and Daniel Simons (HarperCollins, £16.99)

This popular psychology book is written by two professors of psychology with good academic reputations and a healthy respect for scientific method. Their title refers to a fascinating experiment that they devised involving a gorilla walking across a basketball game (people don’t notice the gorilla if asked to count the number of passes made), and it’s all about the way we naturally give attention to a scene. If you haven’t seen it yet, then Google the book’s title to find out why the video features in many presentations about how our brains work. The authors have written about the ways that our intuition deceives us through six everyday illusions that influence our lives: attention, memory, confidence, knowledge, cause and potential. Each one is unpicked in a chapter, using examples and details of experiments, with references to back up the authors’ conclusions.

Their chapter on the illusion of memory starts with an incident which led to the sacking of a well-known basketball coach, when it was claimed that he had choked a student. Coach and student had vivid memories about what had happened, as did several witnesses. All the accounts differed.

Interestingly, some time later a video of the incident was discovered, so there was hard evidence to compare with the accounts. All the accounts were wrong, to a degree.

This example leads to a discussion of the reliability of witness accounts in criminal trials, the work of Hollywood script supervisors who try to ensure continuity in movies, and our own flawed memories of significant events. Just where were you when you heard about 9/11?

A later chapter on the illusion of cause shows us that we might need to be circumspect when responding to new information because of pareidolia, the mind’s tendency to perceive patterns in randomness. Diana Duyser thought that she had found the likeness of the Virgin Mary in a grilled cheese sandwich.

Happily for her, she auctioned it on eBay, to someone with more money than sense, for $28,000.

However, jumping to conclusions can have far less amusing consequences, as the MMR vaccination scandal showed, when the number of children infected with measles increased following unfounded fears that MMR had causal links to autism.

This is an interesting and amusing book that made me far less sure about the way that I think.