Rats were used in the study, which looked at smell and bonding
New research into how animals bond with each other could shed light on the causes of autism and anxiety disorders, according to an Edinburgh scientist.
Researchers pinpointed how a key hormone, known as vasopressin, helped animals recognise each other by smell.
Edinburgh University experts found animals could no longer recognise each other when the hormone failed to work.
They said the study may offer clues about the way humans make emotional connections with each other.
The ability to recognise other individuals by smell is said to be crucial in helping animals establish strong bonds with other animals.
The researchers, working with scientists in Germany and Japan, studied the way rats familiarised themselves with other rats using their sense of smell.
They put an adult rat in an enclosure with a baby rat and left them to sniff and interact with each other.
After a short separation, they placed the baby back in the adult's enclosure, together with an unknown baby.
Adult rats whose vasopressin had been blocked failed to recognise the baby they had already met.
Professor Mike Ludwig, who led the study, said: "This study gives us a window into understanding the biological basis of social interactions.
"Normally, vasopressin supports the forming of 'social memories'.
"But if it is lost, disturbed, or interrupted then the animals are unable to recognise other individuals by their odour.
"Some studies, including ours, suggest that when the vasopressin system in the brain is not working properly, it may prevent people from forming deep emotional bonds with other individuals or might underlie conditions such as autism and social phobia."
The research was funded by the Biotechnology and Biological Sciences Research Council (BBSRC).
Professor Janet Allen, BBSRC director of research said: "Research that helps us to gain a fundamental understanding of how our brains work is vital if we are to know what is happening when something has gone wrong."