The age of reason and external motivation

Someone told me that 7 is the age of reason.  I have observed that Jack seems older all of a sudden. He is reading. He likes to read and reads whenever there is a book around. He has been enjoying the Garfield cartoon books.  The popularity of cat videos on youtube reminds me that people really enjoy funny cats.

He takes his plate to the sink. He rarely has tantrums. He brings his back pack in from the car after school. He loves legos. He is HIGHLY motivated by the promise of screen time. We have started watching a 20 minute bbc show in the evenings called 'Shaun the Sheep.' We all love this show. It is laugh-out-loud funny. So with the promise of the show, the kids clean up, get ready for bed and Jack works on his homework. Alfie Kohn says this is terrible. I am raising children who will only participate with the promise of a reward. They will develop no internal motivation. For many, many years, I tried to develop internal motivation in my kids. They never helped around the house. They were not motivated by their responsibility as part of the family or ephemeral concepts like being kind. They are both motivated by the only things I fervently control - sugar and screen time. They are also motivated (albeit less so) when I tell them if they don't pick up their toys, I'll throw them away. I always follow through but they just don't care that much about most toys.