Gift cards vs. cash
In our daily lives, a lot of purchases have the element of guilt along with them, Ariely said. If you give cash or a credit-card-sponsored gift card that can be used anywhere, your friend may be tempted to use it on groceries or gas or some other necessity that doesn't make it feel very "present"-like anymore.
Ariely's intuition is that if you give a gift card that must be used at a particular store, restaurant or entertainment venue, it may eliminate the guilt a person would feel about spending money to treat herself or himself. In fact, you're essentially creating an experience for the person by coaxing them into going to a particular place that they might not otherwise go.
A spa gift certificate is a popular example, Ariely said. "If you can only spend it on things that you would otherwise not allow yourself to buy, then it's more valuable," he said.
For men vs. women
There has been some research to suggest that men and women view gifts differently. Jeff Huntsinger, assistant professor of psychology at Loyola University in Chicago, and colleagues did a study published in Social Cognition in 2008 on how gifts influence relationships.
Researchers did a series of experiments with men and women where people were led to believe either that they had received a good or a bad gift from their romantic partner, and then state their views about their partner and their relationship.
It turned out that regardless of whether the gift was good or bad, women believed their boyfriend was similar to them and that the couple would stay together for a long time. Men, on the other hand, had a more negative reaction in the "bad gift" setting, being more likely to view their girlfriends as dissimilar and to predict that the relationship would end sooner.
This should not be generalized to the public at large, as this is just a single study, and it's unclear what its implications are, Huntsinger said. But perhaps for relatively modest gifts, women receiving bad presents may not view them quite as negatively as men. More research is needed to say for sure.
"What's interesting about gifts is that they can act as a marker that we understand the other person," Huntsinger said.
Making everyone happy
It's important to determine whose happiness you're trying to maximize when you give a gift, Ariely said. If it's the recipient's happiness, give what that person would like the most. If it's your own happiness, give whatever makes you happiest to give. And if it's the happiness of the relationship that you're most concerned about, Ariely says, consider: Under what conditions would this person remember and think about you?
If you're buying multiple gifts for a single person, such as a spouse of a child, you can try a mix of requested and "surprise" presents, Epley said. But he's more pessimistic about those wild-card gifts.
"As long as you recognize that those gifts are really for you, as much as they are for the receiver, then I think that's fine," he said. "Just don't be disappointed if they don't appreciate your thoughts."