Perceptions, Stereotypes, and Choice

Jen Jen Reyonolds posted this picture on Google+.

I have been thinking about how stereotypes influence our free choice.  If we hold false assumptions about other people or institutions, then our choices will not be rational.  The only way to eliminate bad information is spend a lot of time learning about the person you are judging.  This might come at a high cost of time and alternative activities.  When one is in the market, the market moves too fast for the kind of analysis needed to make rational decisions especially when the number of actors are large.  Therefore, there will always be market failure.

Our perceptions of other people and the stereotypes we form, must be a defense mechanism of evolution.  Some of our choices are based on an evolutionary response rather than rational choice.

Given the huge amounts of market transactions, the market equilibrium establishes a mean. I am also prone to conform with the crowd's choices.  So how accurate is economics in predicting micro behavior?