Personas are artifacts commonly produced by agencies that perform research. They are key tools for creating empathy among everyone involved in the project. They consist, by definition, of an archetype that represents the needs, behaviors and goals of a particular set of users.
One of my favorite examples of personas is the diptychs of Jason Travis. While not typical personas, which are generally accompanied by a textual explanation of the archetype, they still convey a user’s state of mind through the objects they carry. In order to build something for someone, you must first put yourself in their state of mind; this is one of the definitions of empathy. In the diptych below, you can quickly gauge how the person might think based on what they are carrying. A tremendous amount of information is conveyed through these objects.
Credits: Persona 4 by ZephyrusSly