Rationale
Most of the previous research into the effect of the
various message components of warning signs has been
conducted in the laboratory, usually with students and
usually using specially constructed signs. As the ecological
validity of this literature may be limited, the decision
was made to base the present study on actual warning
signs in current use in heavy industry. To assess the
utility of using students in such studies, two groups of
subjects participated, namely a group of actual workers,
who were tested in naturally occurring field settings, and
a group of students. This served two purposes: It increased
the ecological validity and hence the generalizability
of the results; and by comparing the results of the
two groups it enabled inferences to be drawn about the
utility of conducting such research in the laboratory with
students, conclusions that could then be applied retrospectively
to some of the existing literature