The Psychology Of Movie Trailers

The reasons movie studios give out major plot points in their trailers:

1. The audience likes to see in advance what they would be paying to see.
2. Big moments evoke a strong audience response and are therefore memorable.
3. Major plot points being revealed in the trailer makes the audience understand the product better, and makes the movie familiar and likeable, with no surprises.
4. Trailers (with the entire movie packed in three minutes) are targeted at people who may not be so tuned in and would decide on watching the movie after seeing the promo.