IT IS OFTEN ASSUMED THAT BEHAVIOUR IS MORE DIRECTLY DETERMINED BY SUBJECTIVE ESTIMATES OF RISK THAN BY OBJECTIVE RISK. WHILE THIS MAY BE THE CASE FOR EVENTS ABOUT WHICH THERE IS LITTLE EXPERIENCE SUCH AS NUCLEAR ACCIDENTS, IT IS CERTAINLY NOT THE CASE FOR EVERYDAY EVENTS SUCH AS THE RISKS ENCOUNTERED ON THE ROAD. FOR EXAMPLE, WE HAVE SHOWN THAT THE BEHAVIOUR OF DRIVERS IN THE PRESENCE OF CHILD PEDESTRIANS IS MORE CLOSELY RELATED TO THE OBJECTIVE RISK, WHICH IS VERY LOW, THAN TO THE SUBJECTIVE RISK, WHICH DRIVERS TEND TO THINK IS RATHER HIGH. THESE RELATIONSHIPS CAN BE EXPLAINED IN THE SAME WAY AS OTHER DISCREPANCIES BETWEEN TACIT KNOWLEDGE DEMONSTRATED IN SKILLED BEHAVIOUR AND CONSCIOUS VERBALLY ELICITED KNOWLEDGE. WHEN BEHAVIOUR IS WELL PRACTISED AND AUTOMATIC IT DOES NOT REQUIRE CONSCIOUS CONTROL. UNDER THESE CIRCUMSTANCES, CONSCIOUS VERBAL 'KNOWLEDGE' MAY BE A REFLECTION OF SOCIAL STEREOTYPES RATHER THAN HAVING ANY CLOSE RELATIONSHIP WITH THE TACIT KNOWLEDGE WHICH IS CONTROLLING BEHAVIOUR. WHEN THIS HAPPENS IT IS, AS WE ALL KNOW TO OUR COST, VERY DIFFICULT TO CHANGE BEHAVIOUR BY VERBAL INSTRUCTION OR PROPAGANDA. IT FOLLOWS FROM THIS ARGUMENT THAT THE MOST EFFECTIVE SAFETY MEASURES ARE LIKELY TO BE THOSE WHICH OPERATE DIRECTLY ON BEHAVIOUR, RATHER THAN INDIRECTLY THROUGH MANIPULATION OF CONSCIOUS ESTIMATES OF RISK.(A) THIS PAPER WAS INCLUDED IN THE PROCEEDINGS OF A CEC WORKSHOP ON RISKY DECISION-MAKING IN TRANSPORT HELD AT THE TNO INSTITUTE FOR PERCEPTION, THE NETHERLANDS, 9-11 NOVEMBER 1986. (BROWN,I, AND JANSSEN,W, EDITORS).
Abstract