Cats can judge unseen people’s positions in space by the sound of their voices and thus react with surprise when the same person calls to them from two different locations in a short span of time. Saho Takagi and colleagues reached this conclusion by measuring cats’ levels of surprise based on their ear and head movements while the cats heard recordings of their owners’ voices from two speakers spaced far apart. Cats exhibited a low level of surprise when owners’ voices were played twice from the same speaker, but they showed a high level of surprise when the voice was played once each from the two different speakers.
According to the text, how did the researchers determine the level of surprise displayed by the cats in the study?
Explanation
Context: Researchers found cats can judge where unseen people are by sound. Saho Takagi and colleagues measured cats' surprise by watching their ear and head movements when cats heard their owners' voices from different speakers. Cats were less surprised when the voice came from the same speaker twice, but more surprised when the voice came from two different speakers.
Answer: A) They watched how each cat moved its ears and head.
Why? The passage directly states: "measuring cats' levels of surprise based on their ear and head movements." A is a direct restatement of this method.
Traps:
- B) "They examined how each cat reacted to the voice of a stranger" → the study used owners' voices, not strangers' voices
- C) "They studied how each cat physically interacted with its owner" → the owners were never physically present; they played recordings
- D) "They tracked how each cat moved around the room" → the measurement was ear and head movements, not room movement