In a 1971 study, experimenters asked a subject to rate paintings alongside a confederate who pretended to be part of the study. During a break, the confederate would leave and come back with two sodas, offering one to the subject as a no-strings-attached gift. If the subject offered reimbursement, the confederate would refuse it.

Unfortunately, there are no free lunches, and strings are always attached. Later on in the experiment, the confederate asked the subject if he’d be willing to buy raffle tickets for a fundraiser his old high school was doing. Perhaps it is not surprising that the gifted sodas resulted in subjects buying more raffle tickets than they would have otherwise. After all, the average subject wanted to reciprocate the gift.

It was unexpected that the subject ended up spending more on the tickets than the cost of the soda, attempting to “out-gift” the confederate. In addition, researchers found that the degree to which the subject liked the confederate as a person was not as big of an impact as the social obligation to reciprocate the gifting. 

The current idea is that the power of reciprocity is deeply ingrained in our brains. There’s an inherent sense of balance in our minds and it makes us uncomfortable to experience imbalance. Eventually, it does seem that we get over it — had the confederate tried selling the raffle tickets a week later, research suggests that the effect would disappear. But in the moment, we want to make right and don’t like feeling indebted to others, even strangers.

Oddly, this phenomenon extends beyond the personal sphere. In a study from 1986, subjects witnessed two exchanges: one fair and one unfair. They were offered the choice of either giving $5 to the person who initiated the fair exchange or $6 to the person who initiated the unfair one. The catch? However much the subject gave away, he also got to keep. In other words, he could receive an extra dollar if he rewarded the cheater.

Did they do it?

Overwhelmingly, no. The majority of the subjects, 74 percent, accepted a $1 dollar penalty in order to do the right thing. There’s nothing personal at stake — the cheater didn’t cheat the subject, just a stranger — but there is something innate about fairness that makes us want to reward it. 

This is why, unless we resort to trickery, like donating anonymously or inventing Santa Claus, there seems to be no such thing as an altruistic gift. This isn’t because people always expect reciprocation for the gifts they give — it’s because we have a difficult time accepting gifts without providing something in return.

We also don’t tend to like people who won’t give us the opportunity to reciprocate. When given a loan with no expectation of return, subjects actually rated the one providing the loan less positively than if there was an included obligation to return the funds. Things get even stranger when you look at the results across three countries with very different economic and social perspectives — capitalist U.S., socialist Sweden and Japan, where obligation is heavily associated with assistance — as one study did in 1973.

The findings naturally make things more complicated than the simple “give a gift get a gift” model. In the U.S. and Japan, when the loaner not only demanded the borrowed money back, but charged interest, the subject liked him less, but in Sweden, the subject actually liked them more. 

In other words, while gift giving may be a human universal, as is the concept of fairness, the effects may vary wildly from culture to culture.

But research shows that even here in the U.S., while a gift may be a nice gesture, it comes with some uncomfortable baggage. As we head home for the holidays and unwrap packages filled with new socks rather than the Xbox One we really wanted, it’s probably best to try and hide the disappointment behind an equally unwanted gift offered in return.

After all, it’s the thought that counts, especially if that thought involves including a gift receipt.