One size doesn't fit all: diversifying "the user" using personas and emotional scenarios

It is common practice in software engineering to develop a product for the "user". The concepts of users and actors typically oversimplify the variety of people that could use a system in a given scenario. By developing the system for actors, many software engineers effectively develop the system for themselves, embodying the abstract actors with their own personalities - i.e. how would I use the system if I was this actor? A single perspective may be sufficient for situations with a well-defined workflow, however, many systems in the social and domestic domains should consider people's emotional response to systems, which impact product acceptance. To ensure that emotional desires are met and that a product appeals to the intended audience, we advocate the use of personas within emotional scenarios. Personas and scenarios can be used to explore the diversity of people's background, emotions and motivations, and how they would react emotionally to design decisions. We describe our experience using personas and emotional scenarios in three projects related to people's health, where emotions are ever present, in the domains of aged wellbeing and mental health.