Final answer:
The incorrect statement is 'Motivation never changes.' Motivation is dynamic and can change over time, influenced by intrinsic and extrinsic factors.
Step-by-step explanation:
The statement about motivation that is incorrect is 'Motivation never changes.' Motivation is a dynamic and fluid process that can indeed change over time due to a variety of factors. Both intrinsic motivation, which arises from internal factors, and extrinsic motivation, arising from external factors, play significant roles in shaping our behavior towards achieving goals. Moreover, certain external rewards, whether expected or unexpected, have the potential to affect an individual's intrinsic motivation, as illustrated by the overjustification effect.