Science. 1978 Dec 1;202(4371):991-4. doi: 10.1126/science.202.4371.991.
Sarah, an adult "language"-trained chimpanzee, made accurate same-different judgments on quantities of liquid and solid matter and conserved both types of quantity despite a transformation in an irrelevant property (shape). Control tests showed that she judged on the basis of inference rather than perceptual evaluation of the quantities. She failed to make accurate same-different judgments on the basis of number, and she was not tested for conservation of this type of quantity.
成年“语言”训练的黑猩猩莎拉能够准确地对液体和固体物质的数量进行相同-不同判断，并且在无关属性（形状）发生变化的情况下，两种类型的数量都得到了守恒。控制测试表明，她是基于推理而不是对数量的感知评估来进行判断的。她无法准确地对数字进行相同-不同判断，也没有对这种类型的数量守恒进行测试。
