This research examined two factors involved in the evaluation of pictorial symbol comprehension: context (absence versus presence of photographs depicting the probable environments where a symbol would be seen) and test method (multiple-choice with less versus more plausible distractor alternatives versus open-ended). We tested 33 pictorial symbols from various sources. The results showed that the multiple-choice test with less plausible distractors inflated comprehension scores by an average of 30% compared with the other two tests, which did not differ. The presence of context increased symbol comprehension in the open-ended test and in the multiple-choice test that had more plausible distractors. Extensive preliminary procedures demonstrated the difficulty of forming a multiple-choice test with plausible distractor alternatives. This fact, combined with multiple-choice tests' low ecological validity in reflecting the real-world task of symbol comprehension, suggests that this test should be avoided in favor of an open-ended testing procedure. It is suggested that context provides ecologically valid cues that limit the range of possible constructs that the pictorial symbol could be, raising comprehension scores. The use of context may help reduce the costs (money, time, and effort) of producing pictorial symbols with acceptable, above-criterion comprehension levels.
Samenvatting