An article written by Emanuela Cozzi and Lennart Overkamp in A List Apart provides both a cautionary tale and some context and useful guidance on the use of Personas in UX research.

In the real world, you’re designing for a context, not for an individual. Each person lives in a family, a community, an ecosystem, where there are environmental, political, and social factors you need to consider. A design is never meant for a single user. Rather, you design for one or more particular contexts in which many people might use that product. Personas, however, show the user alone rather than describe how the user relates to the environment.

This is a critical point to remember. People are not static 2 dimensional data constructs. They evolve and can behave very differently and make different choices depending on context. The person who is a an intimidating task master at work might be a teddy bear at home and different again among friends. Situational context and environment is a key factor in human behavior. With this in mind the authors suggest a more dynamic model for personas. I highly recommend that anyone interested in UX and user behavior read the article: