The frequency of grammatical classes in the production of verbal strings under two response sets

Six groups, each consisting of 10 Ss, produced strings of 11, 22, or 33 words, under one of two sets of instructions: “structured” instructions which asked S to produce a grammatically acceptable string; “unstructured instructions” which solicited a random, unconstrained string. Each word in S's production was classified into one of six grammatical classes. For the structured instructions the rank ordering of frequency of the six classes was functors (40{\%}), nouns (25{\%}), verbs (13{\%}), adjectives (12{\%}), pronouns (6{\%}), adverbs (3{\%}). For the unstructured instructions the rank ordering of frequency was nouns (68{\%}), adjectives (12{\%}), verbs (11{\%}), functors (4{\%}), adverbs (1{\%}), pronouns (0.55{\%}). The findings were discussed in relation to three questions.