Witnesses Can Catch Criminals By Smell: Study

A new study has found that our sense of smell may be just as reliable as sight when it comes to identifying a criminal. For example, if you got a whiff of a man’s body odor right as he ran up and snatched your purse, you may be able to pick him out of a line-up based on his smell.
Police often use human eye-witnesses, and even ear-witnesses, in lineups, but to date there have not been any human nose-witnesses. Dogs have been used to identify criminals through body odor-identification in court, but it is commonly thought that the human sense of smell is inferior to that of other mammals.
Move over sniffer dogs, people who witness a crime may be able to identify criminals by their body odor, suggests new research. Nose-witnesses can be just as reliable as eye-witnesses, revealed the findings. Professor Mats Olsson, experimental psychologist at the Karolinska Institutet in Sweden, said, “We wanted to see if humans can identify criminals by their body odor.”
To find out more about human odor memory following stressful events, Olsson and his team investigated how well we identify body odor in a forensic setup.
In their first experiment, participants watched video clips of people committing violent crimes, accompanied by a body odor that they were told belonged to the perpetrator.
They also watched neutral videos, with a similar setup. Then they identified the criminal’s body odor from a lineup of five different men’s odors, showing correct identification in almost 70% of cases.
“It worked beyond my expectation,” explained Olsson. “Most interestingly — participants were far better at remembering and identifying the body odor involved in the emotional setting.”
In another test, the team conducted the same experiment but varied the lineup size – three, five and eight body odors – and the time between observing the videos and undertaking the lineup – 15 minutes up to one week.
In lineups of up to eight body odors, participants were still able to distinguish the criminal. The accuracy of their identification did reduce with the larger lineup size, which is in line with studies on eye and ear-witnesses.
The results also showed that the ability to distinguish the criminal’s body odor is significantly impaired if the lineup is conducted after one week of having smelt the offender’s body odor.
“Our work shows that we can distinguish a culprit’s body odor with some certainty,” said Olsson. “This could be useful in criminal cases where the victim was in close contact with the assailant but did not see them and so cannot visually identify them.”
The new findings are published in the journal Frontiers in Psychology.