Interestingly however the periphery is better at night vision and capturing movement. The movment "catches" your eye, yet paradoxically when you turn you eye directly to it, it will vanish. So when hunting for something at night you're better off not looking straight at it, but to one side. You'll actually see it more clearly.
Somehow I've found the same is true in life when pondering things that are intangible. As Poe put it:
The boundaries which divide Life from Death are at best shadowy and vague. Who shall say where the one ends, and where the other begins?
Its like my examination of my memory of Anita ... when I try to look directly, I see the periphery. Yet when I am looking at the periphery suddenly I catch a glimpse of her and when I turn my attention, it is somehow obscure.