Gallup public opinion poll information was examined in conjunction with the Television News Index to study the influence of network television news on public opinion; results indicated that, contrary to a belief common among social scientists, public opinion is highly affected by network TV news. A two-fold theory based on the principles of obtrusiveness and duration is offered to explain why previous research had failed to find a significant level of media influence. Findings of this study support the view that applied anthropologists, urban ethnographers, and others, would do well to consider the impact of the mass media on the group they are studying. (CMV)