The more gray matter you have in the decision-making, thought-processing part of your brain (the prefrontal cortex), the better your ability to evaluate rewards and consequences," write the authors of a 2011 study that appeared in the Journal of Cognitive Neuroscience.
The sad irony is that the more you physically punish your kids for their lack of self-control, the less they have. They learn how to be controlled by external forces (parents, teachers, bosses), but when the boss isn't looking, then what?