According to the chapter, what can happen when someone's mental resources are heavily occupied?

Answer & explanation

Resisting impulses may become harder

Holding a difficult calculation in mind and resisting an impulse both require controlled attention. Occupying that attention with one task can make it harder to exercise control on another, a form of concurrent interference. This should not be confused with the stronger and disputed claim that prior self-control necessarily depletes a fixed resource for later tasks.