THE ATLANTIC - Helen Fisher is an anthropologist and famed love expert. She is the chief scientific adviser for Match.com. She says personality is a cocktail of hormones; love comes from the buzz of mixing them just right. Dating apps can't possibly kill romance, even if they do show us so many options. "It's the same old brain," she says. "The brain hasn't changed in 300K years." She's famous for her science books, including "Why We Love: The Nature and Chemistry of Romantic Love", which," may have been the one that brought her to the attention of Match.com. The company was looking for insight - Why does anybody fall in love with one person and not another? She created four personality styles (Builders - high in serotonin, logical, and traditional; Explorers - high in dopamine, spontaneous and daring; Negotiators - high in estrogen, empathetic and imaginative, and Directors - high in testosterone, decisive and competitive.) Those categories became the basis for Chemistry.com. When it launched in 2005, Chemistry.com competed with eHarmony and PerfectMatch.com, based on the Myers-Briggs personality test. Users filled out a questionnaire written by Fisher and were assigned primary and secondary personality styles. According to Fisher's system, builders match well with other builders, explorers with explorers, and negotiators with directors. Taking the job with Match was "one of the smartest things I've ever done with my life," she said. "Fifteen million people have taken that questionnaire." (The questionnaire was used first for Chemistry.com, then for Match's flagship site.) Today, Fisher's role at Match has more to do with data analysis and public relations than designing dating products.