What makes a moment feel like it’s been lived before?

I was walking home tonight and saw a woman on the pavement, crouched down, talking to a sparrow. The way she tilted her head—it reminded me of my mother, years ago, trying to coax a wounded bird back into a bush. I didn’t even know I was holding my breath until I exhaled. It wasn’t memory, exactly. More like a chord that had been struck somewhere in the dark, and now someone else played it. What do you think? Is it just the brain playing tricks, or is there something older in the wiring?