How many of your Facebook friends could you count on in a crisis? A recently published University of Oxford study suggests it’s less than 3 percent.

Robin Dunbar, PhD, professor of evolutionary psychology, and his colleagues randomly queried 3,375 people ranging from 18 to 65 years of age across the United Kingdom to test whether or not using social-media networks translated into having more friendships.

The findings, published in Royal Society Open Science, show the average Facebook user they surveyed had 155 friends, but would ask just four of these virtual acquaintances for help in real life.

(For comparison, a 2014 Pew Research Center survey found that half of all adult Facebook users had more than 200 friends while 39 percent had between 1 and 100).

In the 1990s, Dunbar first theorized that we have cognitive limits to the number of relationships we can maintain (150) because of the limited volume of our neocortex, the part of the brain responsible for generation of motor commands, conscious thought, and language. Anthropologists H. Russell Bernard and Peter Killworth argue the median average is 231.

Dunbar further believes that our circle of friends consists of four “circles of acquaintanceship,” starting with an inner circle of five intimates, and scaling in factors of three to 15, 50, and 150. As the number of people increases, the intimacy level decreases.

The respondents surveyed in Dunbar’s latest study considered only 27.6 percent of their Facebook friends as “close.” However, they stated that they could depend on four people in their friend’s list during a crisis and that about 14 of them would express sympathy.

The researchers argue their new data “confirms the existence and size of the two innermost layers of the social network.” They identify these groups as the support clique and sympathy group.

Dunbar, like many relationship experts such as Andrea Bonior, PhD, author of The Friendship Fix, argues that in-person communication is a key to maintaining relationships.

So if you want to have more friends you can rely on in a crisis, focus on being that friend. This means taking the time to show up in someone’s life and not just their newsfeed.