Many products, like cigarettes and medications, are stamped with warning labels alerting consumers to their risks. Common sense suggests these warnings will encourage safer choices.

But now Dr. Yael Steinhart of Tel Aviv University's Recanati Business School, along with Prof. Ziv Carmon of INSEAD in Singapore and Prof. Yaacov Trope of New York University, has shown that warning labels can actually have the opposite effect. When there is a time lag between reading a warning and then buying, consuming, or evaluating the associated products, the warnings may encourage trust in the manufacturers of potentially dangerous products, making them less threatening. Published in Psychological Science, the study findings could help improve the efficacy of warning labels.

"We showed that warnings may immediately increase concern and decrease consumption," said Dr. Steinhart. "But over time, they paradoxically promote trust in a product and consequently lead to more positive product evaluation and more actual purchases." The findings have important implications for regulators and managers in fields including consumer products, healthcare, and finance.

The best laid plans

The study is based on an idea called "the construal-level theory" (CLT), developed by Prof. Trope and Prof. Nira Liberman of TAU's School of Psychological Sciences. When thinking about objects over a period of time, people tend to construe them abstractly, emphasizing what they describe as "high-level features" and suppressing "low-level features." The high-level feature of warning labels is that they build trust in consumers by creating the impression that all the relevant information about the products is being presented. The low-level feature of warning labels is that they make consumers more aware of the products' negative side effects.

The CLT holds that over long periods of time, consumers deemphasize side effects and emphasize the feeling of trust communicated by warnings over time. Ironically, this may increase the purchase, consumption, and assessment of the associated products.