An American experiment in 2006 showed that even experienced fingerprint experts can be swayed by contextual information. Six experts were shown marks that each one had analysed before. But this time they were given certain details about the case – that the suspect was in police custody at the time the crime was committed, for example, or that the suspect had confessed to the crime. In 17 per cent of these secondary examinations, the experts changed their decision in the direction suggested by the information.
