People with Autism Spectrum Disorder (ASD) are less likely to know when others are surprised, which may be an important discovery into understanding the condition.
Scientists have found that the part of the brain that tracks other people's expectations in a situation does not function the same in those with ASD.
The research was conducted by an international team from Trinity College Dublin, as well as ETH Zürich, Oxford University and Royal Holloway, University of London.
"A number of brain regions are activated when something unexpected happens. But there is a special part of the brain that signals when something surprising happens to other people," researcher Dr Joshua Henk Balsters said.
The area of the brain is called the gyrus of the anterior cingulate cortex (ACCg).
"We found that individuals with an ASD are less accurate at identifying other people's expectations, but they also lack the typical response in the ACCg when surprising things happen to other people," he said.
The study monitored brain activity in several subjects using MRI scans. They played a game were they chose between two coloured doors - one door had a euro behind it while the other did not.
Dr Balsters explained: "However, on a selection of trials this colour change was misleading, so participants were surprised when they expected to win a euro but didn't, or unexpectedly won a euro.
"Sometimes the person in the MRI scanner chose the door and would be surprised to win or not win money, and sometimes the person in the MRI scanner watched while someone they met outside the scanner, or a computer, chose a door."
They found that people with ASD found it difficult to determine whether someone else was surprised at what they found behind the door.
Irish autism groups commended the "very valuable" research saying it could guide future therapies and lead to improved social skills for anyone with ASD.
"From our viewpoint the social skills deficit that people with an ASD experience is the result of a developmental delay and as such developmental therapies can improve social interaction," Ronan Maher, programme director of Cluas, said.
The findings have been published in the journal 'Brain', by the Oxford University Press.