Case-mixing effects on spelling recognition: the importance of test format.

In a multiple-choice spelling recognition test, 56 university students were more accurate on more regular than irregular words, and on lower-case than mixed-case words, with the case mixing effect greater for irregular than regular words. In Experiment 2, the same words were presented singly in correct or incorrect spellings and distortion of word shape was achieved by case mixing (32 subjects) or by alternating the size of lower-case letters within a word (32 subjects). The main effects of regularity and distortion were replicated and the effect of distortion was greater for incorrect than correct stimuli, with correctly spelled words suffering a decrement in accuracy of less than 5 percentage points. Case mixing had a greater effect than size mixing on response latencies. In Experiment 3, with comparable test procedures, case mixing interacted with regularity in the subjects analysis for the multiple choice format, but not the single presentation format. This result indicates that comparisons based on visual configuration may be an artifact of multiple-choice tests.