A sophisticated group will most likely know enough about phycology.

Anti depressant commercials use a serious voice for the positive effects and a relaxing voice for the bad effects. There is millions of ways to alter things to make them seem different.

My high school my history teacher said we can take a political test and it would plot us on a chart. She said sometimes they can word things different to make you think differently.

Since a lot of people aren't analytic thinkers they won't question everything. Hackers could go to websites and alter the article and the key points to change the readers views on it to where no one would notice. Most people who write articles and move on to the next on because they want to make more money won't be going back to it to see if it was altered.