Also, they can smell different emotional states.
I could certainly believe and accept that.
I tell my boys that they are like 3-year-old kids. They understand certain things, like when to eat, potty, and the need to snuggle, but they forget somethings. Mostly the bad stuff, which is good and forgiving.
They love you no matter what, but you have to be a parent to them and praise them when they do good. Be firm with discipline and make sure they learn their lesson, then forgive them.