Just one whiff of another person’s body odor could be enough to fall in love, according to new research.
And it could also be key to the way humans bond and decide whether they like someone else, suggests the study.
Some animals use odor from a very early age to create attachments to family members – and humans could develop relationships in a similar way, according to the research.
Scientists say that means our response to other people’s odors could be a key mechanism in human bonding, falling in love and deciding whether we like someone.
Now researchers at the University of California San Diego have found out how our brains react to these odors shedding light on the root of attraction.
Co-author Dr. Davide Dulcis, said: “You can imagine how important this is for social preference and behavior.”
“We have innate responses in relationships, falling in love and deciding whether we like someone. We use a variety of cues and these odorants can be part of the social preference equation.”
Scientists had long known about such animal kinship attachments, some known as “imprinting,” but the mechanisms underlying them have been hidden in a “black box” at the cellular and molecular levels.
Dulcis said the findings represented a “key” element of the kinship mysteries and can help with the understanding of social attraction and aversion in a range of animals and humans.
The study looked at how young tadpoles, which are known to swim with family members in clusters, swim with their kin.
They focused on familial olfactory cues, signals which allow animals including humans to “smell” chemical signals from others.
They found these were a mechanism which made two to four-day-old tadpoles swim with family members over non-family members.
The neurobiological studies carried out over eight years, also revealed tadpoles exposed to early formative odors from those outside their family were also inclined to swim with the group that generated the smell – widening their social preference beyond their own true kin.
The researchers discovered that this change is rooted in a process known as “neurotransmitter switching.”
The dopamine neurotransmitter was found in high levels during normal family kinship bonding but switched to the GABA neurotransmitter in the case of artificial odor kinship, or “non-kin” attraction.
Dulcis said: “In the reversed conditions there is a clear sign of neurotransmitter switching, so now we can see that these neurotransmitters are really controlling a specific behavior.”
Dr. Nick Spitzer, who co-authored the study, added: “Social interaction, whether it’s with people in the workplace or with family and friends, has many determinants.”
“As human beings we are complicated and we have multiple mechanisms to achieve social bonding, but it seems likely that this mechanism for switching social preference in response to olfactory stimuli contributes to some extent.”
The research, published in the journal Neuron, has been given as an example of how a baby lamb separated from its family can locate its kin – despite members of a huge flock looking virtually identical.