The study couldn't delve into causative factors, Cacioppo said.
Emphasising this link to online dating, the website says that “while you’d expect interracial marriages to become more likely as the US population becomes more diverse, it doesn’t match the rate at which the change is occurring”.
This research found that people tend to partner up with other people “loosely connected” to their real-world social network, the website says.
So while most people generally avoid dating their closest friends, the site says, they are “highly likely to date people linked with their group of friends”.
The rise of dating websites and apps such as Tinder has been so rapid that it is now the “second most common way for heterosexual couples to meet”, and the most popular platform for homosexual couples, says a report in MIT Technology Review.
Digital dating has many “knock-on effects” for how society functions, says Alphr - not least because it makes it far easier for people from different cultures and social backgrounds to meet.
These couples tended to be happier in their relationships than couples who met offline, the researchers report this week in the journal Proceedings of the National Academy of Sciences.