Three of the following are examples of learning. Which one is not?

Abigail cries when she steps on a sharp pebble.
After many hours of heated debate, Brian begins to advocate political practices he has previously opposed.
Cara suddenly recognizes how the division fact “24 ÷ 4 = 6” is related to the multiplication fact “6 x 4 = 24.”
David has been running away from German shepherds ever since he was bitten by a German shepherd two years ago.