The youngsters swiftly removed the morsel by following the lead of the experimenter, but the chimps and orangs bit, scratched and pummeled the container in a number of mostly futile attempts.

• 举例来说，在一项测试中，受试者必须从一根管子里取出一块食物，人类幼儿会跟随实验人员的提示，熟练地取出食物，但黑猩猩和红毛猩猩则是又咬又抓又敲著容器，尝试了许多次也不得其法。