The effectiveness of warning signs in hazardous work places: cognitive and social determinants

Recommendations have been made that good warning signs should have a number of components: an alerting word such as danger, then statements of the hazard, of its seriousness, of the probable consequences and of how to avoid the hazard. Responses from 40 blue-collar workers and 44 students were measured to five industrial warning signs to determine the extent to which these components determine estimated sign effectiveness and behavioural intentions of compliance. Each sign was presented in five versions; the original (which in each case omitted one or more of the components), a 'full' version in which missing components were generated and inserted, and versions omitting, in turn, the hazard, consequences, and instructions statements. Previous findings concerning the importance of the signal word were supported. When signs were seen singly there was no tendency for versions with components missing to be rated as poorer. Only when all versions were seen together was the 'full' version ranked as being better, a result which is taken as reflecting the demand characteristics of the method. The results argue against strict adherence to a formula requiring specified components in a sign. Data also supported the third person effect, indicating that respondents considered others to be more vulnerable to the hazard and less likely to comply with the sign than they themselves. The finding that social factors are of considerable importance in sign compliance is discussed.