In their article "If Brands Are Built over Years, Why Are They Managed over Quarters?" (HBR 2007) Lodish and Mela argue that "an increased response to promotions reflects a decrease in the price premium a brand can command." Explain a) why an increased response to promotions can indicate a "damage" to the long-term health of the brand, and b) under what circumstances a large incremental sales volume generated by short-term promotions can positively contribute to the brand's long-term health.