Damn my supraorbital ridge anyway! I spent at least half an hour tonight scouring the entire house for a small suitcase, only to find it within 3 feet of the back door—but above my eyeline. Someone (probably me) had placed the suitcase on a high shelf a couple of weeks ago. I simply didn’t think to look up. Most humans don’t. Our ancestors must not have worried too much about predators dropping from above.