Scientists have previously established that the apes have excellent long-term memories to help them remember the best places to find food. Now, though, they wanted to explore how chimpanzees’ working memory performs.
Working memory – sometimes compared to a mental sketchpad or sticky note – is essential. It allows us to hold new information in our heads and not lose track of what we’re doing. For example, remembering the beginning of this sentence as you reach the end of it.
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To test the chimpanzees’ working memory, scientists from the University of St Andrews, the Max Planck Institute and the University of Veterinary Medicine Vienna set out a selection of small, opaque containers and hid food inside some of them, while the chimps watched. The apes then pointed out which box held the food, and if they guessed right, they got to eat it.
After each choice, the containers were hidden for 15 seconds. To retrieve the maximum amount of food, the chimps needed to remember which boxes they’d already searched, which tested their working memory.
The team made the activity steadily more difficult by adding more containers and by moving them around between searches. The chimps that performed best remembered four food items, but one young animal managed more than seven.
They further tested the chimps by getting them to perform a similar activity at the same time. Just like humans, the apes performed worse when they were forced to multitask.
“Our findings suggest that chimpanzees perform similar to seven-year-old children in an intuitive working memory task that does not rely on extensive training,” says Christoph Voelter, who led the research.