In news that will surprise absolutely no one who has ever eaten a meal because their friend was enjoying theirs, scientists have found that orangutans base their food choices on whether others appear to be having a good time. Groundbreaking.

Researchers studying captive orangutans discovered that when the great apes heard recordings of their peers laughing before searching a bowl for a treat, they valued the reward more highly. The study, published in the journal Biology Letters, involved six orangutans at two zoological institutions and was led by Erica Cartmill, a professor of anthropology and cognitive science at Indiana University.

Cartmill said the work is part of a larger project exploring whether animals feel joy and what the implications of those emotions are for cognition and learning. "One of our big motivations … is building on human research that shows that emotion has important effects on rational thought - and that they aren't two separate things; they really influence one another," she said. "We wanted to extend that to animals - in this case to orangutans."

The experiment went like this: the orangutans were first trained to search through bowls to find food treats. They were then presented with two bowls. One contained a tasty morsel buried under a harmless substance such as moss or sawdust, while the other contained a different material but no treat. Crucially, just before the bowls were presented, the researchers played a recording - either the sound of orangutans playing and laughing, or environmental sounds such as wind. The soundtrack depended on which of the two substances covered the food that day.

On the fifth day, the team presented two bowls, each containing a treat buried beneath one of the two food-covering substances. The orangutans were asked to pick a bowl. Across multiple trials, the apes overall preferred the bowl containing the substance associated with the laughter soundtrack, with four of the six orangutans showing a clear preference.

Cartmill suggested the preference could be rooted in the laughter putting the orangutans in a more positive emotional state when they learned to associate the substance with food. Dr Adriano Lameira, a primatologist and evolutionary psychologist at the University of Warwick who was not involved in the work, described the results as fascinating. "Effectively, hearing others clearly having a good time, orangutans placed their food order: 'I will have what they are having, please!'" he said.

Cartmill added that the results suggest it is not only the quantity or frequency of a reward that matters when learning associations. "What our work is showing is that it's also about the state of the animal when they are learning that association," she said. "Who you are in that moment - the context, the emotional states, what you're feeling, what you're thinking about - can also influence and can carry over in how you remember these things that you've learned."

The findings could have applications to humans, including in educational environments. "Students might learn at similar rates if they are in a good mood or not, but our research suggests that they would value information more if they learn it when they are in a good mood," Cartmill said. She added that could help understand why some information is more trusted or why students choose to continue studying certain subjects. "If a student is anxious when they are learning maths for example, it might impact whether they prefer maths versus other subjects when choosing what to pursue in the future," she said.

So there you have it: orangutans are just like us, choosing snacks based on the laughter of their friends. Next up: a study confirming that bears prefer food associated with the sound of picnics.