How did advertising change life for Americans

Changed their purchase habits.

Explanation:

Advertising in America is a center subject in its economy, because changed the perception of people about what are the primary needs.

We can say that somehow, advertising marketing even create new markets which develop in people a consumerist habit, this represents a active economy, because products are always being sale and people feel the need of purchase anything new in the market.

Advertising created demand for new products, thereby changing the buying habits of Americans.