Interesting tidbit from a video lecture from the Buddhism and Modern Psychology course I am taking on Coursera right now: Exposure to frightening stimuli predisposes us to see something neutral as threatening. In one study, subjects were made to watch an excerpt from Silence of the Lambs, and then shown photos of men from different foreign ethnic groups. Compared to the control group, these people were more likely to perceive the expressions on the faces of the ethnic men in the photos as menacing.
The lecturer, Robert Wright, explains this as the human evolutionary adaptation for survival. Fear makes us more cautious for the sake of self-preservation. Of course, this makes a helluva lot of sense. Put in the context of our modern-day reality, though, we see that we have a lot of unnecessary frightening or stressful stimuli. We are also quite stressed and unhappy with our day-to-day lives. I think we can safely connect the dots here.
So, really, how influenceable (sorry if this word doesn't exist!) are we? We always think that all of our decisions are made consciously. How true is that? Maybe we do hold less control over our mind and behavior than we originally thought, especially if we leave possible influences surrounding us unexamined.