A psychology professor suggests that as people take more photos, they experience less and remember fewer details about what they had taken photos of. This is what she called a "photo-taking impairment effect."
Those parents at the park taking all those photos are actually paying less attention to their children at that moment, she says, because they're focused on the act of taking the photo. As a result they are giving away being in the moment.
"As soon as you hit 'click' on that camera, it's as if you've outsourced your memory," she says. "Any time we count on these external memory devices, we're taking away from the kind of mental cognitive processing that might help us actually remember that stuff on our own."