So here’s what to consider before choosing between Brut and Old Spice. First, know this: Scent is linked to our emotions. That’s because the brain’s smell center, or limbic system, triggers learning and emotion. That comes from a leading expert in the psychology of smell, Rachel Herz, and here’s what she says about choosing a scent.  

• Go easy on a woman’s nose. Don’t bathe yourself in cologne. We have more scent receptors for smell than any other sense except vision. So if people can smell you from two feet away or more, dial back on the amount you use. Plus, women have a better sense of smell than men. So have your sister tell you honestly if she can smell you from two feet away.
• According to Herz’ research, a man’s smell is the single most important physical factor in attraction. More than your smile, your hair, your build. So don’t totally mask your own smell. So just do one spritz in the middle of your chest so she can smell the real you.
• When choosing a cologne – if a woman says, “Oooh I love Polo Sport!”,  don’t run out and buy it. Once an association to an odor has been formed, it’s difficult to reassociate that odor with something else. Translated, that means, if she likes Polo Sport, it’s probably because her ex, or her Dad, or her brother wears it and she’ll always associate the smell with other emotional experiences. So pick a similar but different cologne. The human nose can detect 10-thousand different odors – so she’ll associate the new cologne with you.
• Then, when you’re ready to debut your new cologne, make sure you do something new on your date. Why? Because an aroma is meaningless until it’s paired with an experience. So spritz your cologne and then take her to a concert – or to a hiking trial she’s never been on before. It’ll be like an olfactory scrapbook. Every time she smells that scent, she’ll remember that date.
• Finally, know this: 72% of women say they’ve cuddled up at night with a partner’s clothing. The most common reason? To remember him. So if she borrowed your sweatshirt because it was cold, let her keep it a while.