Wolfgang Köhler
Köhler concluded that the chimps had not arrived at these methods through trial-and-error. American psychologist Edward Thorndike claimed this was the basis of all animal learning: his law of effect. Instead, the chimps had an insight (also known as an “aha experience”). They saw the answer mentally, then they got the bananas in a way which was, in Köhler’s words, “unwaveringly purposeful”.