It MUST be genetic

I took a long walk today since it wasn't SO HOT.

My son came along for the first loop. For a while, we walked in silence. It was pleasant, but I began to wonder if anything was on his mind.

"What are you thinking about?"

"Huh?"

"What were you thinking about just now?"

He looked to the left and the right, and sheepishly said "Um.... nothing...."

The thing is, I know he was telling the truth....