How did Clever Hans solve arithmetic problems?

Question

Quizplus · Accepted Answer

Clever Hans was able to solve arithmetic problems by watching the examiner for subtle cues. This is known as the Clever Hans effect or the observer-expectancy effect, where people unconsciously give cues to the subject without even realizing it. In the case of Clever Hans, the examiner would unintentionally give subtle cues, such as tilting their head or making a slight movement, when Hans reached the correct answer. Hans would then stop tapping his hoof when he picked up on these cues. This phenomenon was later discovered and studied by psychologists.

How Did Clever Hans Solve Arithmetic Problems