Interestingly, no chemical weapons were actually used. The Law of Expectancy is very powerful indeed. This incident is, of course, the opposite of the well known placebo effect. The placebo effect is best described in the following example. The Korean war brought thousands of casualties.
Children have a magical illusion that parents can do anything.
If we like the people connected with a product, we tend to have positive associations in our minds of the products they endorse. Regardless of product quality, because of the endorsement, we often will buy a product the first time based on celebrity endorsement. Bill Cosby probably helped you decide to buy Jell-O pudding, Kodak film and other products. Bo Jackson has sold a world on the idea that Nike tennis shoes are the only way to go. Ray Charles, Michael Jackson, Cindy Crawford and Michael J. Fox have got a nation drinking Diet Pepsi.