Following Instructions. Technical Report No. 4.

Twenty-four adults participated in an experiment to determine the difficulty of conditional sentences of the kinds frequently found in the instructions in government forms. The stimulus materials were 128 sentence frames of the form, "If you are X, press button Y," where X was replaced by sixteen different coordinate structures. These sentences functioned as conditional instructions, with the antecedent "if clause" expressing a reader-referenced statement on whose truth value the command was contingent. Responses were timed from sentence onset to response, and response accuracy was recorded. Results indicated that (1) whenever possible, negated or embedded clauses should be avoided in the design of instructions (e.g. "not male and not married" should be changed to "female and single"); (2) performance in following instructions varied with the type of construction used; (3) conditional instructions of the form, "If you are not A, and are B, then do X" should be rewritten as "If you are B and not A, then do X"; (4) strings of "ors" are more difficult than strings of "ands"; and (5) response time for wrong items was substantially longer than for correct items. (MKM)