A new set of controlled experiments, reported in Science, suggests that apes can imagine and engage in pretend play — a capacity long thought to be uniquely human. The results come from three tests with Kanzi, a 43-year-old enculturated bonobo at Ape Initiative, and the authors suggest the ability to understand pretend objects may date back 6 to 9 million years to our common ancestors.
Coauthor Christopher Krupenye of Johns Hopkins University and Amalia Bastos, formerly at Johns Hopkins and now at the University of St. Andrews, designed tea party–style tasks. In the first experiment two transparent cups and an empty transparent pitcher sat on a table. The experimenter pretended to pour juice into both cups, then pretended to empty one cup and asked, "Where's the juice?" Kanzi usually pointed to the cup that still contained pretend juice, even after the cups changed place.
The second experiment introduced a real cup of juice alongside a pretend cup; when asked what he wanted, Kanzi pointed to the real juice almost every time, reducing the likelihood that he treated the pretend cup as if it contained unseen liquid. The third test used grapes and jars and produced similar results. Bastos said, "Kanzi is able to generate an idea of this pretend object and at the same time know it’s not real," and Krupenye called the findings "game-changing." The team plans wider tests of other apes and animals and to study future thinking and understanding others' minds.
- Johns Hopkins Provost’s Postdoctoral Fellowship Program
- Templeton World Charity Foundation
- CIFAR Azrieli Global Scholars
- Diverse Intelligences Summer Institute (Early Career Award)
Difficult words
- enculturate — to teach or adapt someone to cultural practicesenculturated
- imagine — to form a picture or idea in the mind
- engage — to take part in an activity or action
- capacity — the ability or power to do something
- transparent — allowing light to pass through clearly
- ancestor — a person related to you from an earlier generationancestors
- generate — to produce or create something
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How would finding pretend play in apes change our view of differences between humans and other apes?
- What other simple tests could researchers use to check whether other animals understand pretend objects?
- If apes can imagine pretend objects but know they are not real, how might that affect how we care for them in zoos or sanctuaries?
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