Here, p alone is memory. Tilt alone is cogitation. Up/tilt is retro-cogitation -- "now what would I have done with my keys yesterday when I had my hands full of grocery bags? "

Interesting to watch dogs, birds, etc use head tilt without eyes up.
Very short term memory among the lower orders. "I will figure this situation out. But I won't even bother retrieving experience of similar situations..."

I'm not at all sure left or right tilt is significant.

All three of my kids combine eye roll with spinning in circles -- as if the answer might be an image on the ceiling with the projector whirling along on a record turntable...