When exploring a effect of a product in a family setting, there are two perspectives that come into play. One of the family as a unit and the other of individuals within the family. So why speak to just one person? Studying small groups of friends or family using a product in a familiar setting can yield qualitative insights that improve user experience.
More on this topic from my article, Gaining insight through Dyads and Triads on using the dyad and triad methodology which has been published on UX Magazine.
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