In a recent experiment one group of people was shown a sad video clip about the death of a boy's mentor, while another group viewed a non-emotional clip about the Great Barrier Reef.
Researchers then produced an insulated water bottle and asked how much of the $10 the participants were getting paid they'd be willing to give up in exchange for the bottle.
People who had seen the Great Barrier Reef video agreed to pay on average about 50 cents. People in the group that had been primed to feel sad offered up four times that price, more than $2 on average — but were unaware that the video had any impact on their spending.
From the Upcoming ueue, submitted by Geekazoid.
Why add Step 4? I think the other four steps pretty much cover it. :)
2. Put them in a mall.
3. Sell them something they don't need.
4. ????
5. Profit!