How do I even with this question? The whole picture is made up of small details, and the details are all in the context of the whole picture. So it's both. The answer is both and it depends on what the thing is and why you're having to concentrate on it and where you are in that process. Any project you work on will need big picture perspective to decide what things you need to do, and also need detail perspective to do those things. Any field of study will have its overarching themes and its individual examples.

Let's look another way. I know they're not talking about a literal picture (and why use metaphors in an autism test of all things?), but let's pretend they are. When I look at The Hay Wain I see an idyllic rural scene. Then I see the cart, the house, the horsemen, the dog. I see the whole picture first, then I pick out details. When I look at The Persistence of Memory, I see the face, the clock, the tree, the cliff. Then I wonder what it could mean. I see the details, then (try to) assemble a full picture. It depends. It always flipping depends.

If It gave me specifics, I could answer this. But I'm just floundering with this sort of generality. I am leaning towards Slightly Disagree, only because I am crying out for details trying to interpret this question.