[This is part of the series: The Complete Guide To Economics 101.]
What is the substitution effect?
The Substitution Effect is a change in consumption when a customers preferences move up or down, along, an indifference curve.
I might be indifferent between eating four pizzas or two cheeseburgers per week.
But if the price of pizza increases, I might then be indifferent between another combination involving less pizza and more cheeseburgers.