Picture the scene. A bunch of you, including kids and grandparents, are sat around the coffee table on Boxing Day nibbling on turkey sandwiches and playing Trivial Pursuit.
You're asked a tough question on science and nature. It's on a scoring square and answering correctly will put you in the lead. You pause, stutter, and then drag some distant memory of an old David Attenborough programme from the darkest recesses of your mind.
"Um, that would be the common Peruvian bullfrog," you say. Your sister looks visibly deflated. "Have you been reading the answers again?" she moans, in a tone that you know means the common Peruvian bullfrog is a bullseye.
You smile sweetly and calmly add a green cheese to your counter...then jump up from the sofa and do a celebratory jig round the room while high-fiving your nieces and nephews and singing "We are the Champions" at an annoyingly loud volume.
Sound like you? Here's why men love to win.
The latest research
Are men really ultra competitive, or is this another myth that's used to hammer home the aggressive, macho, not-far-removed-from-apes male stereotype?
Um, unfortunately, it seems many of us really are ultra competitive.
The latest research even suggests we're competitive with our kids. The study of 2,000 parents by Lego Games found that dads were far more likely than mums to go all out to win when playing board games with children.
By contrast, mums were more likely to let their kids win if it made life easier. It probably would. The study also found that two-thirds of young children throw a tantrum if they don't win.
"We need to remember that playing games is all part of the fun at Christmas time and it's about spending time together and having fun, not having arguments," said Jo Merton, spokesperson for Lego Games.
But one in five parents - and more dads than mums - admitted they'd never let their kids win when playing games with them, and more than a third thought it was character-building to not come top in everything.
It could be that dads simply hate losing, but it may also be that they want to impress upon children the idea that you can't win at everything, and that tasting defeat is part of life.
Are men naturally competitive?
Other studies have confirmed that men are the more competitive gender. In one experiment at the University of Pittsburgh, researchers asked both men and women to add up two columns of digits, paying them for their efforts.
But while in one test participants were paid simply by the number of sums they'd completed in a set time limit, in another the subjects were put in a tournament where only the fastest problem-solver got paid anything.
After the tests the subjects were given feedback and asked to choose whether, for the final round, they'd prefer to get paid for each problem solved or to compete in a tournament.
It turned out that, even though the genders were equally matched when it came to their adding abilities, twice as many men opted to fight it out in a tournament in the final round.
Men respond better to competition
It could be that men are competitive because they react better to the competition. In winner-takes-all situations, men enjoy the challenge of being that winner.
That was tested when psychologists at the University of San Diego asked men and women to solve maze puzzles on a computer. Like the Pittsburgh experiments, they were paid either a piece rate or according to a winner-takes-all tournament.
Under the piece rate, men did slightly better than women, solving 11.2 puzzles on average compared with 9.7 for women. But in tournament conditions, men's figures leapt to 15 puzzles completed on average, while the female rate stayed much the same as before.
In other words, men got better when a competitive element was added. For women, the competitive element made little difference to their performance.
"The main finding is that in competitive situations where only the best person in the group is rewarded, males react with extra effort, while females do not," said the study's authors.
Are men born to win?
So is male competitiveness genetic, or learnt? Is it down to nature, or nurture?
Some experts would argue the latter. As children, aggression and competitiveness is more likely to be frowned on in girls and encouraged in boys. Boys are taught that taking part is good, but winning is better.
That view is backed up by studies of a few societies where women are in charge. In matriarchal societies women tend to be more competitive, suggesting that the behaviour is learnt rather than ingrained in our genes.
Why do men love to win?
So why do men love to win? Partly, because society encourages us to be winners from an early age. That's not just on the sports field (or round the Boxing Day coffee table), but in maths tests, or when comparing salaries or qualifications, or in our careers.
But from the research it seems that maybe men don't so much love to win as love to compete. Winning might be the icing on the cake, but it's the competition we crave. And if, as experiments suggest, it makes us perform more ably, maybe there's no harm in that.