The mass media occupy a high proportion of our leisure time: people spend, on average, 25 hours per week watching television2, and they also find time for radio, cinema, magazines and newspapers. For children, watching television takes up a similar amount of time to that spent at school or with family and friends. While school, home and friends are all acknowledged as major socializing influences on children, a huge debate surrounds the possible effects of the mass media and findings both in favour and against effects are controversial. The question of effects is typically raised with an urgency deriving from a public rather than an academic agenda and with a simplicity which is inappropriate to the complexity of the issue (we do not ask of other social influences, what is the effect of parents on children or do schools have an effect which generalizes to the home or do friends have positive or negative effects?). The possibility of media effects is often seen to challenge individual respect and autonomy, as if a pro-effects view presumes the public to be a gullible mass, cultural dopes, vulnerable to an ideological hypodermic needle, and as if television was being proposed as the sole cause of a range of social behaviours. Such a stereotyped view of research tends to pose an equally stereotyped alternative view of creative and informed viewers making rational choices about what to see. Overview articles often describe a history of progress over the past seventy years of research which alternates between these two extremes -- first we believed in powerful effects, then came the argument for null effects, then the return to strong effects etc. -- a history whose contradictions become apparent when old research is re-read with new eyes. Contemporary media studies sometimes defines itself through its rejection of the language of effects research -- criticising the laboratory experiment, the logic of causal inference, and psychological reductionism. This rejection is, I will suggest in this chapter, in part justified and in part overstated.