Marnie, one hopes they've done this with enough children to know what's going on. It's got to be a little off-putting for a kid to have a strange adult focusing on them, even with Mom in the corner. My son at 5 yrs was participating In a communications study, with me watching from another room, and after awhile I noticed he was really flagging, all that attention on just him. He'd done other studies in the same place, but this was different. I asked if he could have a break, and we ended up finishing the study a week later instead.
All this to say, your assessor sees lots of kids, and gets what's going on. And I think Rainbow is a very abstract in a good way response! If he'd started listing Crayola or Benjamin Moore color names, that would certainly be interesting, and you'd never hold back your giggles
