A question concerning the income and substitution effect when the wage changes
Let us assume that the substitution effect leads to more less leisure as the relative price of leasure increases, and more labor supply.
Let us also assume that the income effect works in the opposite direction. So, the individual will decide for more leisure and less labor (income effect).
Now, here is the question:
This income effect can only work in the opposite direction (more leisure, less labor) if we have the underlying assumption that leisure is a normal good, right? Such that, if income increases, I want to have more of the normal good (leisure) and less of the alternative good (labor).
An additional, necessary assumption would be that labor is an inferior good, not? Otherwise the income effect would lead in the same direction as the substitution effect.