[ Rewards ]
The human brain is governed by a rewards-centre. There’s plenty of research showing the relationship between rewards and behaviour. Be it sugar, praise, booze, success, money. When we feel rewarded in any way, we want more of that.
This applies to forming habits. The trajectory is: cue-behaviour-reward-repeat. We get a cue to brush our teeth, we brush our teeth, they feel fresh, and we do it again the next day.
The key, I think, is the quantum, and timeframe of the (feeling of) reward.
There is a gap here with knowledge work. Rarely do we receive a tangible, instant reward.