Overextension and underextension of categories in cognitive development refers to extending names to members outside a particular domain, or not extending names to members inside a particular domain. [GEW]

Unstructured interview is an interview in which the interviewer attempts to elicit a response on topic(s) of interest, without using a script. Often produces rich anecdotal record; good for generating lists for structured interviews, but less useful for comparison. Often used with traditional elders. [MH]