Overview
- An international team reported in Science that chimpanzees changed choices to favor later, stronger evidence across a structured series of five experiments.
- Twenty chimps at Uganda’s Ngamba Island Sanctuary made evidence-consistent choices in about 80 percent of trials, with roughly 18 of 20 individuals showing the pattern.
- When weak cues were followed by strong counter-evidence, chimps switched choices, but they typically held to their initial choice when the order was reversed.
- In more complex tests, chimps organized information hierarchically in a three-container task, treated repeated cues as redundant, and updated when second-order evidence defeated earlier signals.
- Researchers are now collecting data from two- to four-year-old children and planning broader primate comparisons, with separate exploratory work probing how chimp decisions respond to others’ choices.