That's ONLY true _until_ self-control becomes a HABIT.

   Then it's natural and doesn't sap any extra resources.

   What they're talking about is: while you're LEARNING ONE THING
   (self-control in this _particular situation_) inhibits the
   abilities to learn OTHER things.

   Once you've learned how to not eat the marshmellows in the MRI
   machine or whatever, it won't be an inhibition situation. It'll
   be automatic and your mind is free to roam.

   The separation between "memory" and "self-control" is a category
   error. They're both forms of learning.