Naive judgments of stimulus-response compatibility

Subjects were asked to rate the usability of interface designs that varied in compatibility of stimulus-response mappings. In Study 1 subjects rated light-button layouts. In Study 2, the same subjects rated stove burner control designs. In Study 3, different subjects ranked fragments of computer command languages. In all three judgment tasks, subjects showed limited sensitivity to stimulus-response compatibility. A theory of naive stimulus-response judgments is put forward to explain the patterns of judgments in the three tasks. According to this theory, naive judges use an item-summing heuristic: Where possible, designs are compared by summing the presumed goodness of individual stimulus-response mappings. The upshot of this heuristic is that the usability benefits of configural, rule-based mappings are systematically undervalued.