Here’s my Q&A column from the WSJ this week — and if you have any questions for me, you can tweet them to @danariely with the hashtag #askariely, post a comment on my Ask Ariely Facebook page, or email them to AskAriely@wsj.com.

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Dear Dan,

At a holiday potluck that I attend each year, the hostess asks each guest to bring a specific dish. We always wind up with too much food, but the hostess never asks us whether we would like to take any leftovers home. I think that the food I made and brought should be considered mine. So who do the leftovers belong to, the hostess or the cook/guest?

—Sigrid 

This is a tricky one. Usually, if we are invited to someone’s house for dinner and bring, say, a bottle of fine whiskey, we wouldn’t expect to take the rest of the bottle back home with us. But a potluck isn’t your standard dinner party, and it isn’t clear what rules apply. You gave the food, which was accepted by the host—but she did so on behalf of the group, which didn’t finish it.

Ethics aside, I see three practical ways to resolve the problem. First, you could make something that is physically hard to separate from the dish in which you brought it. If, for instance, you brought crème brûlée in a large ceramic dish, you’d make it clear that the dish was yours, and because it would be difficult to separate it from the leftover dessert, you would get to take them both home.

Alternatively, you could bring your contribution in two containers, hand one to the host and tell her that you have another container in case your fellow diners polish off the first one. You wouldn’t have to hand over the second part of your offering unless it turned out to be needed, and you’d have a decent shot at getting to take it home.

Or you could whip up a crowd-pleasing recipe that you happen not to like. The point of a potluck is to have fun with friends, not to fret about who gets what at the end. So just make something you don’t care for. You won’t care who inherits the leftovers, and you’ll enjoy the party more.

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Dear Dan,

I went to the bathroom at a new restaurant in town only to find a large, modern-looking stainless-steel urinal, without partitions, which put everyone in plain view of his fellow patrons. I tried to finish my business quickly and get out of there. Am I the only one made uncomfortable by such arrangements?

—Greg 

Actually, many men are made uneasy by such bathroom settings, but I suspect that you didn’t finish your business any faster.

In 2005, my students and I carried out an experiment at MIT. Sometimes, we had one of our students stand at the middle urinal in the men’s room, pretending to go and waiting for unsuspecting visitors. Other times, we didn’t have anyone from our team at the urinals. In all cases, we had a student hiding in a nearby stall with a recorder.

That let us pick up two aspects of urination: its onset (from the time a subject situated himself at the urinal to the moment when we first heard liquid sounds) and its duration (until those sounds stopped).

We found that men took longer to get going when they had company nearby, presumably because of social stress. But once they started, they finished faster—again, presumably because of stress and the desire to get out of there. The total amount of time was slightly slower than when men were left alone.

Of course, our participants were undergraduates with splendid bladder control, so we might need to repeat this study with a more mature population.

See the original article in the Wall Street Journal here.