Question

select the text from the paragraph that best helps you understand that propensity means tendency. there may be more than one correct choice.

to determine whether hanss performance was simply a ruse, the german board of education sent a team of scientists to observe von osten and his horse. the team concluded that there were no tricks involved in the horses shows. however, oskar pfungst, a psychologist associated with the team, eventually realized that hans did not possess any mathematical acumen. instead, he was just picking up on subtle changes in peoples body language and using these cues to arrive at the correct number of taps. pfungst showed that people tend to make faint movements, such as tilting their heads slightly upward, when they expect to hear a certain answer. this propensity to provide unconscious behavioral clues has become known as the clever hans effect. scientists are now very careful to take this effect into consideration when designing experiments.

Explanation:

To understand "propensity" means "tendency", we look for text showing a tendency. The sentence "Pfungst showed that people tend to make faint movements, such as tilting their heads slightly upward, when they expect to hear a certain answer" uses "tend to" (meaning tendency), and the following "This propensity..." refers to that tendency. So this text helps.

Answer:

Pfungst showed that people tend to make faint movements, such as tilting their heads slightly upward, when they expect to hear a certain answer.