In the context of Giffen goods, what is unique about their demand curve?

Giffen goods are a unique type of inferior good for which an increase in their price leads to an increase in the quantity demanded, contrary to the typical law of demand. This unusual behavior is primarily due to the strong income effect overpowering the substitution effect. When the price of a Giffen good rises, consumers have less purchasing power, which leads them to buy more of the Giffen good (and less of more expensive alternatives), as they can afford to purchase less of the more costly substitutes.

This results in a demand curve that slopes upward, indicating that higher prices result in higher quantities demanded. This characteristic makes Giffen goods a unique exception in microeconomic theory where normally, demand curves slope downwards. Understanding this concept helps to illustrate how consumer behavior can defy traditional economic models under specific conditions.