When the risks are low: the impact of absolute and comparative information on disturbance and understanding in US and UK samples

When Klein, W. M. gave participants absolute and comparative risk information (crossed experimentally) they were more disturbed by being above than below average, but not by being at higher rather than lower risk. The current experiment tests whether Klein's findings extend to situations involving lower risk figures more typical of genuine health risks, assesses participants' understanding of the information, and directly compares responses of US and UK samples. Participants were presented with hypothetical information about comparative and absolute risks of deep vein thrombosis. There was a main effect of absolute risk information on disturbance and precaution intentions in the US sample, but no effects of comparative information on these measures in either sample. Understanding was poor among participants receiving both pieces of risk information. Future studies should include measures of understanding to establish whether people are failing to understand what they are told or failing to respond systematically to what they understand. Practically, the findings caution against providing comparative risk information when communicating low risk figures.