Jackson made a goal to quit smoking. Through a lot of hard work and willpower, he achieved this goal, and at the end of one full year tobacco free, bought himself a new car. This is an example of

Positive reinforcement

Explanation:

Positive reinforcement is an action taken that will straighten the behavior of a person or activity of a situation for a better or future purpose which was rewarded for a past action. Jackson, being able to keep to his goal, bought a car to reward himself. This will motivate him to be most consistent to staying away from tobacco

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