Delayed gratification is easier when the decisions lie in the misty future

When people are offered the choice of $10 today or $11 tomorrow, they are likely to choose to receive the lesser amount immediately. But, when given a choice between $10 in one year or $11 in a year and a day, people often choose the higher, delayed amount. 

Scientists, evaluating fMRI on volunteers, report the emotional limbic system is preferentially activated by decisions involving immediately available rewards, but a greater relative prefrontal cortex activity is observed when subjects choose amongst longer-term options. 

The cogitating prefrontal cortex is required for people to slam the breaks on that pesky amygdala and benefit from delayed gratification.

For a more comprehensive discussion: 

https://brain2mind.substack.com/p/dont-eat-the-marshmallow