Jason G. Goldman writes: In his 2011 book, The Tell-Tale Brain, neuroscientist V. S. Ramachandran says that some of the cells in your brain are of a special variety. He calls them the “neurons that built civilization,” but you might know them as mirror neurons. They’ve been implicated in just about everything from the development of empathy in earlier primates, millions of years ago, to the emergence of complex culture in our species.

Ramachandran says that mirror neurons help explain the things that make us so apparently unique: tool use, cooking with fire, using complex linguistics to communicate.

It’s an inherently seductive idea: that one small tweak to a particular set of brain cells could have transformed an early primate into something that was somehow more. Indeed, experimental psychologist Cecilia Hayes wrote in 2010 (pdf), “[mirror neurons] intrigue both specialists and non-specialists, celebrated as a ‘revolution’ in understanding social behaviour and ‘the driving force’ behind ‘the great leap forward’ in human evolution.”

The story of mirror neurons begins in the 1990s at the University of Parma in Italy. A group of neuroscientists were studying rhesus monkeys by implanting small electrodes in their brains, and they found that some cells exhibited a curious kind of behavior. They fired both when the monkey executed a movement, such as grasping a banana, and also when the monkey watched the experimenter execute that very same movement.

It was immediately an exciting find. These neurons were located in a part of the brain thought solely responsible for sending motor commands out from the brain, through the brainstem to the spine, and out to the nerves that control the body’s muscles. This finding suggested that they’re not just used for executing actions, but are somehow involved in understanding the observed actions of others.

After that came a flood of research connecting mirror neurons to the development of empathy, autism, language, tool use, fire, and more. Psychologist and science writer Christian Jarrett has twice referred to mirror neurons as “the most hyped concept in neuroscience.” Is he right? Where does empirical evidence end and overheated speculation begin? [Continue reading…]