When consumers (or any decision-maker) makes judgments about products or other things, they are subject to a number of biases. A bias is simply the tendency to see things in a certain way. We are all familiar with these biases, but they affect us profoundly.
Consider, for example, a shortcut we often use to judge a certain event. This shortcut (called the "availability heuristic") involves using vivid or accessible events as a basis for the judgment. An example would be a plane crash that results in people increasing their estimate that air travel is dangerous (even though the statistics for air travel indicate otherwise).
Another bias is the "law of small numbers" whereby people expect information obtained from a small sample to be typical of the larger population.
Another bias is "selective perception" whereby people structure information based on their own experience. This can involve people actively seeking certain information and avoiding other information. You can see this in your own behavior as you watch TV or read a magazine and actively avoid or search for certain types of ads.
One more bias deserves attention. This is called "anchoring and adjustment". Here, people will first anchor their judgment based on some initial value and then make adjustments as additional information is presented. The important aspect of this bias is that the first information people receive will bias later judgments.
Consider, for example, the question of whether people who see the poll results are affected by this information when making their own votes. According to anchoring and adjustment concepts, they are. In fact, if most people are voting yes, then they will tend to vote yes as well. But note, this is a subtle effect. You might see the results (that say strongly yes), and intend to vote strongly no. But due to anchoring and adjustment, you will bias your vote upwards and vote mildly no.