The following is an educational video about math.
The above video gives every impression of being credible, right? Did it take you a long time to realize that this is actually a joke video satirizing 1970s educational school videos? If so, you have fallen victim to manufactured source credibility. If not, that's probably good, as this video is pretty obviously ridiculous.
But what if you'd been in a room full of other students, who all clapped and nodded, profoundly affected by the end of the video? And what if the professor engaged the class in a long, serious discussion about the content? Do you think you'd start to question your original impression of this video? According to Asch's conformity study, there's a 37% chance that you would. Would you engage in self-censorship during the class discussion, even though you realize they're all morons for believing this? Ask yourself these questions. How is having an awareness of your behavior in groups important in your everyday life? Thoughts?