Google “successful Thanksgiving” and you will get a lot of different recommendations.  Most you’ve probably heard before: plan ahead, get help, follow certain recipes. But according to new research from Florida State University, enjoying your holiday also requires a key ingredient that few guests consider as they wait to dive face first into the turkey: a belief in free will. What does free will have to do with whether or not Aunt Sally leaves the table in a huff? These researchers argue that belief in free will is essential to experiencing the emotional state that makes Thanksgiving actually about giving thanks: gratitude.  

Previous research has shown that our level of gratitude for an act depends on three things: 1) the cost to the benefactor (in time, effort or money), 2) the value of the act to the beneficiary, and 3) the sincerity of the benefactor’s intentions. For example, last week my 4-year-old daughter gave me a drawing of our family. This act was costly (she spent time and effort), valuable (I love the way she draws herself bigger than everyone else in the family), and sincere (she drew it because she knew I would like it).

But what if I thought that she drew it for a different reason? What if I thought that she was being coerced by my wife?  Or if I thought that this was just an assignment at her pre-school? In other words, what if I thought she had no choice but to draw it? I wouldn’t have defiantly thrown it back in her face, but I surely would have felt differently about the sincerity of the action. It would have diminished my gratitude.

This belief in the ability of others to freely choose different courses of action is the essence of belief in free will, and it is the reason why the researchers hypothesized that there would be an intimate relationship between this philosophical disposition and experiencing gratitude. They decided to test this hypothesis in four studies, first investigating whether people who are higher in their belief in free will also tend to experience more gratitude, and then whether manipulating people’s belief in free will would change the amount of gratitude they feel for acts of kindness.

Indeed, the more participants believed in free will (as measured by this) the more they tended to experience gratitude (as measured by this). To manipulate participants’ belief in free will, the researchers borrowed a methodology from previous work that has participants write or read anti- free will sentences, pro- free will sentences or neutral sentences. For example, participants in the anti-free will condition would read and summarize sentences such as “Science has demonstrated that free will is an illusion” or “Everything a person does is a direct consequence of their environment and their genetic makeup.” Participants in the pro-free will condition would do the same for sentences such as “I demonstrate my free will every day when I make decisions” and “Ultimately people cannot blame their actions on anything other than themselves.” 

Three studies supported the authors’ predictions, showing that participants who had been exposed to the anti-free will statements reported experiencing less gratitude when a) thinking about past experiences in their lives for which they felt grateful, b) when they read a hypothetical description of an act of charity, and c) when they were the actual recipients of a favor from an experimenter in the lab.

Importantly, these effects were driven by how sincere participants thought benefactors’ motivations were.  The more they thought that benefactors “didn’t have to do that” the more gratitude they reported.

Of course, none of these studies have a thing to do with whether or not we actually have free will, the effect simply depends on our belief in its existence. And this belief predicts more than just gratitude. Other studies have shown that people low on this belief are more likely to cheat on experimental tasks, to be more aggressive and less helpful and show increased conformity. Thankfully, only 2% of the population reports not believing in free will, and hopefully none of them will be sitting around your Thanksgiving table. But if so, just pass the potatoes the other way.