"Poor" isn't needed here. If the kid has siblings, or the family has an "opportunistic" dog, or the kid has spent time in a daycare where treats are sometimes grabbed, or ...
Or the kid is getting bored by the stupid researcher and her stupid test, and is trying to get it over with as fast as he can.
Or the kid is getting bored by the stupid researcher and her stupid test, and is trying to get it over with as fast as he can.