The paper ‘Is stereotyping inevitable when designing with personas‘ gives a good account on user representations and how personas risk stereotyping. The authors gives an overview of the application of personas, and discuss the psychological roots of stereotyping and why it is so powerful.
They give examples of different tactics to counter the tendency to stereotype, such as considering personas as archetypes, using transfer scenarios where users close to the intended users are studied and the knowledge transferred to the personas, using narrative style, and techniques to educate designers on stereotyping.
The paper is really good, but I find that the authors have missed to look into character creation in fiction and film as a mean to avoid stereotyping. My studies of fiction have shown that there are five areas to be adressed in order to avoid stereotyping. The description of a persona should depict the physics, background, psyche, present emotions of the persona, and portray more than one character trait.