Brad and Angie fell in love one summer when Brad used to bring his golden retriever to play in the park where Angie liked to jog. The sight of a golden retriever always makes her think about Brad. But today, as Angie ran in the park, she saw a Labrador retriever, and she immediately thought about Brad. What happened?

The Proust effect.

Explanation:

This is a type of medical explanation for the very strong recollection of memory after being triggered by sensory simulators. The fact that Brad and Angie fell in love created memories within her mind. The one thing that linked Angie to Brads thoughts was his golden retriever, there are strong emotional bonds with the sight, smell and touch.

Seeing the labrador retriever re-triggered those memories and therefore making the Proust effect come into play.