According to researcher Matthew Brashears, assistant professor of sociology, people recall social ties that both involve at least three people who know each other and kinship labels such as "aunt" twice as well as they remember ties that do not, even though triad kinship networks are far more complex.
"Humans are able to manage big, sprawling, complicated social networks essentially because we don't remember big, sprawling, complicated social networks," Brashears said.
"We remember simplified, regular structures that bear a reasonable similarity to what those networks look like."
"In cases where the relationships don't fit the pattern, we remember the pattern and the few exceptions, instead of remembering all the ties simultaneously, he said."
About 300 study participants read paragraphs describing a group of people and how they relate to each other.
Some paragraphs included kinship labels and some didn't. Other paragraphs included closed triads - where three people each know each other - while other paragraphs did not.
The participants were then asked to recall as many of the ties as possible.
When the paragraphs contained both kinship labels and closed triads, the participants' recall improved by 50 percent compared with participants whose paragraphs included neither - even though the kinship and triad paragraphs contained nearly twice as many relationships.
Moreover, participants did worse when trying to recall paragraphs that had kin relationships but no triads. "It's like trying to remember a random number sequence by using the 'increase by two' rule," he said.
"Our ability to remember and manage socials ties - and build bigger groups of people - had to do with coming up with new and interesting ways of compressing that information," Brashears said.
"It's about how we structure our groups and how that allows us to remember them, as opposed to just sheer cognitive horsepower," he added.