Why does the stereotype of a scientist with mad hair, big spex, white coat endure and how does this image relate to what 21st century scientists actually look like and do? For more than 60 years researchers have explored stereotypes of scientists. During this time they have attempted to isolate the small number of essential, simplified criteria that represent a scientist. This work began in the 1950s when two cultural anthropologists, called Margaret Mead and Rhoda Métraux, drew on the perceptions of American high-school students to produce a image of a scientist. Their findings, published in the journal Science, described a stereotype that still features in some forms of popular culture. The Open University's Dr Richard Holliman reflects on the findings of a research project called 'Invisible Witnesses' to explore these questions. In so doing he considers some of the implications of the 1950s stereotype for how scientists are perceived in the public sphere.