Forty-one Detroit-area residents were given perceptual tests in which they were asked to choose from a set of resynthesized vowels the tokens that they felt best matched the vowels they heard in the speech of a fellow Detroiter. Half of the respondents were told that the speaker was from Detroit, whereas half were told that she was from Canada. Respondents given the Canadian label chose raised-diphthong tokens as those present in the dialect of the speaker, whereas those given the Michigan label did not. Respondents given the Michigan label chose vowels that were quite different from the Northern Cities Chain-Shifted variety present in the speaker's dialect. Because the "speaker's" perceived nationality was the only aspect that varied between the two groups of respondents, this label alone must have caused the difference in the selection of tokens. This indicates that listeners use social information in speech perception.