When consumers taste cheap wine and rate it highly because under the belief it is expensive, is it just a placebo or has belief actually changed their brain function, causing them to experience the cheap wine in the same physical way as the expensive wine? 

People enjoy identical products such as wine or chocolate more if they have a higher price tag so a new study examined the neural and psychological processes required for such marketing placebo effects to occur. The authors conclude that preconceived beliefs may create a placebo effect so strong that the actual chemistry of the brain changes in a brain imaging analysis.

Participants in one of the studies were told they would consume five wines ($90, $45, $35, $10, $5) while their brains were scanned using an MRI. In reality, subjects consumed only three different wines with two different prices. Another experiment used labels to generate positive ("organic") or negative ("light") expectations of the pleasantness of a milkshake. Some consumed identical milkshakes but thought they would be either organic or regular; others consumed identical milkshakes but thought they would be either light or regular.

Participants showed significant effect of price and taste prejudices, both in how they rated the taste as well as in their measurable brain activity. The MRI readings related in part to specific areas of the brain that differ from person to person. These differences are also associated with known differences in personality traits. The authors were able to further determine that people who were strong reward-seekers or who were low in physical self-awareness were also more susceptible to having their experience shaped by prejudices about the product.

"Understanding the underlying mechanisms of this placebo effect provides marketers with powerful tools. Marketing actions can change the very biological processes underlying a purchasing decision, making the effect very powerful indeed," the authors conclude.

Citation: Hilke Plassmann and Bernd Weber, "Individual Differences in Marketing Placebo Effects: Evidence from Brain Imaging and Behavioral Experiments." Upcoming in the Journal of Marketing Research.