Positive motivation follows emotional pleasure, whereas negative motivation serves us to avoid emotional pain. Basically, we won’t act until the pain of not doing something outweighs the pain of doing it, and visa versa. Positive motivation stems from our desire to seek out pleasure, and propel ourselves forward when there’s a reward on offer. Those rewards can be tangible: for example, if you were offered $100 for every time you went on a run.
On the flipside, negative motivation takes shape when you have something to lose, and stems from fear. For example, you would be more likely to stick to a diet if you had to risk $500 of your own money on the promise of losing weight.