Entering a romantic relationship could mean losing two close friends, according to researchers from the University of Oxford.
"On average, we have five intimate friends," said lead scientist Professor Robin Dunbar. "And when you get involved with someone romantically, who mainly comes from outside that circle, then you are left with a total of four."
The research, an internet-based questionnaire with 540 people taking part, also found that being involved in two romantic relationships at the same time did not mean that people lost four friends. Instead, they only lost two again: the legal partner is not considered in the inner core circle anymore.
Layers of friendships
People in general have four layers of friendship in their social circle: intimate friends, good friends, friends and acquaintances. The total number of your social network is limited to 150 people, known as 'Dunbar's number'. This is the maximum number that your brain can cope with.
Numbers after 150 are usually people you have a one-way relationship with and can perhaps only put a name to the face. However, relationships seem to deteriorate over time, especially when you lose contact with the other person.
Non-human friends
The individuals in your inner core circle are not necessarily human. The study showed that people also consider their pet, favourite plant, characters from the fictional world, as well as religious icons, as their 'intimate' friend.
"Humans have a tendency to give objects a human-like mental state and then become emotionally engaged," Professor Dunbar explained. "For example, we often hear people referring to the sea as being angry or storming".
Having said that, networks are usually biased. Women tend to have more women friends and men more male friends. Professor Dunbar believes that losing your two closest friends is usually related to a conflict of interest of the same gender - something that the team would like to examine next.