A reverse causality model treating mass media use for public affairs information as a result rather than as a cause of political behavior was tested utilizing surveys of 190 Mexican-American, 176 black, and 225 white adults. The criterion variable used in each sample was frequency of television and newspaper use for public affairs information. The major predictor variables measured were diffuse support (general allegiance to the United States), political participation, and sense of political efficacy (the feeling that individuals can play a part in bringing about political and social change). Analysis of the findings revealed that political participation significantly predicted mass media use for public affairs information among all three groups. Respondents who were politically active were more likely to use newspapers and television for public affairs information than those who were not. The evidence for the other two political socialization variables was less conclusive. It was concluded that reverse causality models in political socialization and mass media research have some validity, especially for white populations. (FL)