From sodas to sports drinks, sweetened beverages are a staple of the American diet, though this is not without consequences. Excessive consumption of sugary drinks is linked to a host of health problems, including diabetes, obesity, and heart disease.

To help curb consumers’ thirst for these beverages, some states and local governments have imposed special consumer taxes on sugary drinks. But beyond bolstering government coffers, do these taxes actually encourage consumers to make healthier choices? That answer depends on wher and how clearly the added cost of a tax is conveyed to the consumer.

According to new research published in the journal Psychological Science, taxes are effective at changing purchasing habits only when the customer is made aware that there is an added—yet undefined—cost at the point of sale.