This document summarizes several theories related to media effects:
1) The bullet theory examines how early electronic media like film and radio were used for propaganda and their powerful, uniform effects on public attitudes.
2) Selective influence theories propose that people selectively expose themselves to, process, and remember media messages based on their existing attitudes and beliefs.
3) Uses and gratification theory posits that people actively use media to fulfill needs and select media based on what will satisfy those needs in competition with other information sources.
4) Cultivation theory examines how heavy television viewing shapes people's perceptions of social reality compared to light viewers and reality.