When the price of a good drops, the substitution effect means consumers will tend to buy more of that cheaper good and less of its competing alternatives, because it is now relatively cheaper compared to other goods.

Quick Scoop: What the Substitution Effect Says

Think of the substitution effect as “switching to the better deal.” When one good’s price falls while other prices stay the same:

  • That good becomes relatively cheaper than its substitutes.
  • Consumers reallocate their spending toward the cheaper good and away from the now relatively more expensive alternatives.
  • As a result, the quantity demanded of the cheaper good increases , holding the consumer’s satisfaction (utility) constant.

So, under the substitution effect, when the price of a good drops, people substitute away from other goods and buy more of the now cheaper good.

Simple Example

  • If the price of Sprite falls and the price of Mountain Dew stays the same, Sprite becomes relatively cheaper.
  • Many consumers will buy more Sprite and less Mountain Dew, purely because of this relative price change (even if their income hasn’t changed).

This is exactly the substitution effect in action.

Core answer: Under the substitution effect, a drop in the price of a good leads consumers to substitute toward that good and increase the quantity of it they demand.✅

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.