2. Smelling the shampoo or the cologne he used to wear.
Smell is the sense most directly linked to memory. Apparently, that’s because both the part of the brain that processes scent information and the part that governs emotions are located in the limbic cortex. A whiff of the same shampoo, laundry detergent, cologne, or any scent associated with him, and before you know it, you’re picturing his face.