What is a factor that can cause a rightward shift in the demand curve?

A rightward shift in the demand curve signifies an increase in demand for a product at every price level. An increase in consumer tastes for a product directly influences consumer preferences, leading to greater willingness to purchase that product. When consumers develop a stronger preference or demand for a good—perhaps due to trends, advertising, or changes in cultural perceptions—they are likely to buy more of it even if the price remains the same. Consequently, this shift reflects an overall increase in demand, moving the demand curve to the right.

The other factors presented do not result in a rightward shift in demand. A decrease in consumer incomes generally leads to a reduction in demand for most goods, particularly normal goods. An increase in the supply of a good pertains to changes on the supply side rather than demand, affecting the equilibrium price and quantity but not directly shifting the demand curve. Lastly, a decrease in market competition might make a product less attractive to consumers, potentially lowering demand rather than increasing it, as consumers might seek alternatives in a competitive market.