Price promotions can lower consumers’ motivation to think rationally during the purchasing process. Because the (financial) risk of making wrong decision decreases, emotions outweigh rational thinking and consumers are more likely to make a more emotional product choice. In addition, the ability to process brand-related attributes decreases: The chart on the right side shows that preference for the healthier option goes down and consumers remember substantially less product-related information when the product is sold on deal.
Source: Aylin Aydinli, Marco Bertini, & Anja Lambrecht, Price Promotion for Emotional Impact, Journal of Marketing, Vol. 78 (July 2014), 80 –96