As someone with 20/20 vision whose main interest growing up was snake-catching, I have trouble with this hypothesis. Unless a snake is basking or is already mov

As someone with 20/20 vision whose main interest growing up was snake-catching, I have trouble with this hypothesis. Unless a snake is basking or is already moving, you generally won't see it until it is underfoot. In other words, the proposed adaptations don't actually help you see a snake before it is underfoot. And as you mention, snakes are mainly interested in avoiding people. Wouldn't the dangers of uneven terrain, tripping, and falling be a better explanation of why we are good at looking down? Peripheral vision makes sense if you're also watching out for the family as you walk.