So Express Scripts Inc. wants to know what truly motivates consumers to buy generic medicines.

Bloomberg News is reporting that the nation’s third- largest manager of pharmacy benefits, which is based in north St. Louis County, will open a research center devoted to studying why consumers pick a generic over a name-brand drug and other health-care choices.

Lower insurance co-pays and other financial incentives weren’t enough to get many patients to switch to cheaper generics from costlier branded medicines, the St. Louis-based company said today in a statement. Adding aggressive communication and other psychological techniques has proved more effective, Express Scripts said.

Express Scripts and other pharmacy benefit managers have been working to lower drug costs for employers. A campaign to get patients to switch to generic cholesterol drugs by communicating directly with insured employees persuaded 53 percent to switch from branded products, up from 8 percent on price incentives alone, the company said. That saved about $600 million.

The Center for Cost Effective Consumerism is enlisting academics and other experts in human behavior to find new methods to change the way people use healthcare, Express Scripts said.