A new study at the University of Hertfordshire has found out how to tell if someone doesn't like the Christmas present that you give them.
In the run-up to the festive season, they've filmed people unwrapping gifts to see if their behaviour gives them away.
Karen Pine, Professor of Developmental Psychology, who undertook the research, explained what the study involved.
"There were two parts to the study," she said.
"One part was a survey asking people about gifts that they've had that they haven't liked, and what they've done about it. We also did a much closer study in the lab videoing people when they were opening presents that they didn't like and looking at the non-verbal behaviour.
"People always try and say the right things, there's a lot of social pressure to say the right things and to give the impression that we do like a present and our words tend to be quite positive, but the real feelings tend to leak out in our non-verbal behaviour."
Professor Pine revealed that the research showed that if a present has gone down badly, people will tend to hide it away.
"We looked at what people did when they opened a present that they didn't like," she explained.
"One thing that they would do is not look at the person who gave it to them, because if there is any tell tale sign on your face, you don't want that person to see it. People would avoid making eye contact with the person who gave them a gift they didn't like.
"With the gift itself, they would re-wrap it fairly quickly, to put it out of sight, whereas if they liked a gift it would stay out in the open for longer, they would interact with the gift or we even found that if there were other people in the room they would always show it to them if they liked it, they would even hold it up rather like a trophy - but none of that went on if they didn't like a gift. They certainly wouldn't show it to other people."
Professor Pine explained why she had decided to undertake the study.
"I'm very interested in non-verbal behaviour and a lot of my research at the University of Hertfordshire is about gestures and what we give away with our body language," she said.
"I'm also very interested in consumer behaviour. I've written a book called Chiconomics which is about women and money and I know that people spend a lot of money at Christmas which is absolutely wasted on presents that people don't want to receive.
"So really I was just pulling together those different strands of my research into what I thought was an interesting topic.
"I think we need to go back to the old values about what a gift is really for," she added, "it is a token of appreciation or affection for a person.
"A lot of people told us that they didn't mind having a cheaper present if a lot of thought had gone into it and people told us that they wouldn't mind a homemade present. So really we don't need to be spending a lot of money on presents, just maybe put a bit more thought into what we give people."