This post was written by Nikita Mehta, MSc, and Matthew Apps, Ph.D., with edits from Patricia Lockwood, Ph.D., and Jo Cutler, Ph.D.
Ending social interactions can be tricky. How do you decide when to end a phone call with a friend, move on to talk to someone else at a social event, or slowly drift away from a chat with your colleagues? Conversations don’t always end when we want, whether it’s being stuck in a boring discussion or having to end a chat about juicy gossip too soon. But how does our brain decide to end a social interaction to move on to someone else? This is an important question because individuals with symptoms of depression and loneliness are known to experience atypical social interactions, so we need to know how people might make these choices to leave. A recent study examined how people make such decisions, finding that people spend longer with fairer people but also adjust how long they spend with people based on how fair other people are on average in their social environment. Strikingly, this resembles how animals make decisions when foraging for food.
When an animal is foraging for food, such as collecting berries from bushes, they have to decide when to leave their current location (a “patch”) to move on to find food elsewhere. Typically, when they enter a new patch, there is an abundance of food available. However, as the animal consumes the food, there is less and less left in the patch leading to a choice: When should they leave if they want to get as much as food as possible? To make this choice accurately, the animal must think about how much food they are getting right now in the patch. But also, how likely are they to find another patch that is full of food, and how much of a cost is there to traveling to find another patch? If there are very few patches full of food, or if traveling to find food is hard work, then the best thing to do is stay a bit longer in the current patch.
This strategy will get them more food over........