Our brain utilizes fragrance by attaching it to something that has meaning to us. Without this attachment to experience, fragrance would hold no meaning to us. This mental connection also acts as a tool to recall information stored in the brain that has been attached to a specific fragrance. For instance, if you study for a test while smelling a certain fragrance, and then smell that fragrance while taking the test, studies have shown that you'll have better recall of the information you studied.
Identifying the fragrance that reminds us of a loved one can help us to dwell on memories of them when they're away and we're missing them. Try smelling the laundry soap your parents used when you were a child and enjoy all the nostalgic synapses firing off in your mind.
Fragrance helps our brain to store memories that we're making in real time as more vivid entires. This means that if we smell the same fragrance again later, we'll be able to have more detail attached to the memopry of important events where theat same fragrance was present.