AS the presidential candidates debate how to strengthen America, maybe they can learn from rats.

A McGill University neurologist, Michael Meaney, noticed that some of the mother rats he worked with spent a great deal of time licking and grooming their babies. Other rat moms were much less cuddly.

This natural variation had long-term consequences. Meaney’s team found that when the rats grew up, those that had been licked and groomed did better at finding their way through mazes.

They were more social and curious. They even lived longer.

Meaney’s team dissected adult rats and found that licking led to differences in brain anatomy, so that rats that had been licked more were better able to control stress responses.

So, could the human version of licking and grooming — hugging and kissing babies, and reading to them — fortify our offspring and even our society as well?