Double take: Oliver and James as the Weasley twins in the 2003 film Harry Potter And The Prisoner Of Azkaban surrounded by their co-stars. Identical: James, left, and Oliver Phelps arrive at London's Odeon Leicester Square for the world premiere of 'Harry Potter and the Chamber of Secrets' in 2002.
An increase in demand is represented by a shift of the demand curve to the right: A decrease in from ECON 101 at Universitat Pompeu Fabra
Customer preference. Prices of related goods. Complements-an increase in the price of a complement reduces demand, shifting the demand curve to the left. Substitutes-an increase in the price of a substitute product increases demand, shifting the demand curve to the right. Income-an increase in income shifts the demand curve of normal goods to the right.