In a new study that uses fruit as the loot, UC Berkeley researchers found that chimps steal less from their friends, and that friendship status affected the emotional expression of both victim and thieves. Closely bonded chimps swiped pineapple pieces from one another less frequently than those with weaker relationships. Additionally, victims were quicker to calm down when the thief was a friend, and thieves showed less hostility when stealing from a bonded pal than from a non-friend. The new research deepens our understanding of the emotional underpinnings of our social lives.

The new study, just published in leading international journal Science Advances, outlines that researchers have developed a “speech clock” that can estimate a person’s chronological age from hundreds of acoustic and linguistic characteristics of their speech. The difference between a person’s actual age and their speech-predicted age (called the speech age gap) was also associated with multiple independent markers of biological aging, brain health, cognition, social adversity, and dementia.