The research, conducted by scientists from the UK, USA and Canada, looked into the relationship benefits of shared social identity, which in part is formed by a shared knowledge of popular culture.
259 people in long term relationships (the average relationship length was 16 months, and the minimum length was four months) participated in the study.
They were asked about how many hours each day they spent together, the number of mutual friends they had, and the quality of their relationship.
While the study found that those couples with fewer mutual friends had less of a shared social identity, it was discovered that watching television together acted as an effective substitute.
The study explains how shared social interactions can build a strong relationship:
As intimacy deepens, couples increasingly share aspects of their lives. These shared experiences allow people to incorporate aspects of their partners into their sense of self, effectively expanding the boundaries of their identities to include their partner’s traits, skills, and resources, a process known as ‘‘self-expansion’’
Similarly, 'fictional social worlds' have benefits for your relationship.
The study concluded:
In particular, sharing media with a partner may allow people to compensate for lacking a shared group of friends with their partners. In other words, sharing media may allow people who lack a shared social network to foster a shared social identity with partners that deepens interdependence and promotes closeness.
So snuggle up and watch another 10 hours of Netflix. It will make up for the fact your partner won't introduce you to their friends, and why you never talk to each other unless it's to ask for a pee break.