Delayed Gratification and impulse control: Why waiting for what you want is better for your success and health. 

https://www.verywellmind.com/delayed-gratification-why-wait-for-what-you-want-2795429

The Marshmallow test pays off, 40 years later

https://www.nlsd.k12.oh.us.schools.bz/userfiles/294/Classes/1571/Delayed%20Gratification.pdf