Our Sense of Smell May Be the New Way to Identify Culprits
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For millennia humans have relied on dogs for security. Their keen sense of smell provided protection around the ancient campfire and alerted to intruders in the dark ages. Even now, the olfactory abilities of our canine brethren detect explosives, seek out fugitives, and identify criminals. A new study published in Frontiers in Psychology reveals, however, that we humans may also have a bit of hidden power in our snouts.
“Police often use human eye-witnesses, and even ear-witnesses, in lineups but, to date, there have not been any human nose-witnesses,” says Professor Mats Olsson, experimental psychologist at the Karolinska Institutet in Sweden. “We wanted to see if humans can identify criminals by their body odor.”
While dogs have been used to identify criminals in courts, until now humans were thought to lack a sufficient sense of smell to perform the same trick. Olsson’s research shows that humans do indeed have the ability to distinguish individuals by their distinct body odours.
Smell is strongly associated with emotional processing and is linked to areas of the brain corresponding to memory and emotions – the amygdala and the hippocampus. To investigate the link between memory recall and smell following stressful events, Olsson and his team tried to determine how well humans distinguish body odour in a forensic setting.
In their first experiment, subjects viewed a video of a violent scene and were introduced to an odour that they were told belonged to the perpetrator. They were also shown neutral videos with a similar setup. They then identified the suspect’s smell from a lineup of five different men’s smells, correctly recognising it in almost 70 percent of cases.
In following tests it was revealed that accuracy did decrease with a larger sample size. However, this is in line with studies done on eye- and ear-witness identification abilities. Olsson’s studies also reveal that the ability to recognise the suspect’s smell was greatly reduced a week following the initial viewing.
“Our work shows that we can distinguish a culprit’s body odor with some certainty,” concluded 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.”
