Our current concerns tend to control our perceptions and interpretations of incoming information. If we believe the company is having financial trouble, we will interpret ambiguous data as support for that conclusion. If we believe someone likes or dislikes us, we will interpret that person's acts in a way consistent with our expectations. When you buy a blue car, you suddenly see blue cars everywhere. People seek and give weight to information that supports or harmonizes with information they already believe.
People depreciate or reject information that conflicts with beliefs or conclusions already held.
The facts do not speak for themselves. Most information is ambiguous enough to allow more than one interpretation to be put on it, and our interpretations are substantially controlled by what we already know and expect to find. However, if we are aware of these prejudices of interpretation, we can prevent them from misleading us. Information we are convinced is scarce, secret, special, or restricted takes on an automatically greater value and appears more credible than information that just anybody can obtain. You can imagine that the manipulators have long ago caught on to this particular bias, and use it to make us want something that otherwise would make us yawn.