Why do people ignore warning labels?

Why don't people heed warnings on products such as alcohol, glue, and cigarettes? The answer has to do with how they weigh benefits vs. risks when making a decision, according to Mark Lehto, associate professor of industrial engineering, Purdue University, West Lafayette, Ind., an expert on warning label design. "If someone perceives a benefit in not following a certain safety rule or warning, they are likely to violate the rule or disregard the warning."

In one study, Lehto found just one of 54 subjects heeded the warning on a glue label to ventilate the room while using the product, despite its foul odor. "This study suggests that if someone's main goal is to complete a task, the benefits he perceives in finishing may outweigh the risks of skipping a safety step. Similarly, if someone's out to have a good time, the benefits he sees in having fun may outweigh the risks he sees in driving drunk. I you want people to behave more safely, you need something more dramatic than a warning label."

Increasing numbers of product liability lawsuits point to a need for improved criteria for deciding when and how to provide warnings, Lehto...