Covert: Semantic: subjects listen to or view nouns and silently generate an associated verb, or subjects view a category and silently generate as many exemplars as possible; Orthographic: subjects listen to or view a letter and silently generate as many words as possible that start with that letter; Phonologic: subjects listen to or view a word and silently generate words that rhyme.
Overt: semantic: subjects listen to or view nouns and overtly generate an associated verb, or subjects view a category and overtly generate as many exemplars as possible; Orthographic: subjects listen to or view a letter and overtly generate as many words as possible that start with that letter; Phonologic: subjects listen to or view a word and overtly generate words that rhyme.
Definition contributed by BGregory about ten months ago.