In the Hearts of the Beasts

Animals cannot use words to explain whether they feel emotions, and scientific opinion on the subject has been divided. Charles Darwin believed animals and humans share a common core of fear, anger, and affection. Today most researchers agree that animals experience comfort or pain. Around 1900 in the United States, however, where intelligence was the dominant interest in the lab and field, animal emotion began as an accidental question. Organisms from insects to primates, already used to test learning, displayed appetites and aversions that pushed American psychologists and biologists in new scientific directions. The hands-on empiricism of American scientists contributed to the experimental foundation of the international field of animal emotions.