Advertising is in an odd position. Its extreme protagonists claim it has extraordinary powers and its severest critics believe them. Advertising is often effective. But it is not as powerful as is sometimes thought, nor is there any evidence that it actually works by any strong form of persuasion or manipulation.

Instead, the sequence, awareness/trial/reinforcement, seems to account for the known facts. Under this theory, consumers first gain awareness or interest in a product. Next, they may make a trial purchase. Finally, a repeat buying habit may be developed and reinforced if there is satisfaction after previous usage.

Advertising has a role to play in all three stages. But for frequently bought products, repeat buying is the main determinant of sales volume and here advertising must be reinforcing rather than persuasive.