A group of randomly selected people watched a speaker give a lecture on environmental ethics to a large and concentrated audience, and another group of randomly selected people watched the same speaker give a lecture to a small and unconcentrated group of people in the same way. The former group thought that the speaker thought deeply and confidently, while the latter group thought that the speaker's expression was vague and lengthy. The above materials best refute which of the following statements? ['the same social behavior may give different feelings to different people in different social backgrounds.', 'a randomly selected group of people may reach a consistent understanding of the personal qualities of the speaker in a specific social environment.', "a listener's comment on the speaker's speech may be influenced by the attitude of others.", "People's judgment of the speaker's personal qualities depends mainly on his content and the way he speaks."]