AGENDA-SETTING EFFECTS OF TELEVISION-NEWS COVERAGE AND THE EFFECTS DECAY CURVE

Some fundamental concepts in agenda-setting are related to a simple cognitive memory decay process. Accounting for issue obtrusiveness and amounts of prior coverage, predictions for the size of the relationship between declining accumulated television coverage and issue salience are derived. Levels of declining accumulated coverage are estimated by applying an exponential decay function to the prominence of daily television coverage. This function presumably models simple forgetting of coverage that occurs within individual audience members. Three issues (inflation, Iran, and the Soviet Union) were investigated over an 1,826-day period, using the daily prominence of television coverage obtained from television news archives and daily salience of the issues interpolated from monthly archived poll data. The size of the relationship between accumulated coverage and issue salience was found to decrease with the amount of coverage of an issue prior to the beginning of the study period. A new unobtrusive issue (Iran) was found to have the strongest agenda-setting effects and more rapidly declining coverage effects than other issues.