Image: John Watson

Psychologist Diana Fleischman on how to train your boyfriend

The essayist-cum-podcaster argues that we’re always trying to shape each other’s behaviour—so you may as well do it wisely
July 19, 2023

Diana Fleischman, an evolutionary psychologist and daredevil essayist-cum-podcaster, is writing a book about how best to train your boyfriend. One might pity her husband, Geoffrey Miller, but for the fact that he, too, is an evolutionary psychologist. “Geoffrey is aware of what I’m doing,” she says. “Occasionally I will lose my temper, and he’ll be like”—she adopts a tone of faux-smugness—“‘This is bad training. I’m not going to do what you want.’” She laughs. “But there are things that work well. He’s incredibly sensitive to punishment, so I have to be careful about how much I use it.”

Punishment, in the way that Fleischman is describing, could be as simple as a sharp word or denying your partner attention. A reward might be “eye contact, affection—it can be changing the conversation to something that makes a person feel good about themselves. It can be sex, it can be food, all those kinds of things.” Punishment is easier than reward, Fleischman says, but rewards—fortunately for Miller—are more conducive to lasting, happy relationships.

In her forthcoming book, How to Train Your Boyfriend, Fleischman, 42, argues that we’re trying to shape each other’s behaviour all the time, so we might as well consider how to do it wisely. She believes this is particularly useful for women, who tend to have more interest in shaping men’s behaviour than vice versa.

Fleischman and Miller have other, more unorthodox, ideas about what makes for a happy relationship. They’ve been dubbed the “Polyamorous Professors”, making the case for letting one’s partner openly have a bit on the side. Allowing this flexibility, they said, can make a partnership more durable—provided the couple is smart and responsible.

I find it more interesting to have conversations with people that are a little spicy

Since then, Fleischman and Miller have got married. Brazilian-born Fleischman, who grew up in the US, has left the UK, where she lectured at the University of Portsmouth, to join Miller in New Mexico. Together they have had a baby—Vivian—with another on the way. Have Fleischman’s views on polyamory changed? “I wouldn’t be happy if [Miller] was consistently seeing somebody. He has a lot of stuff to do here at home!” she says, laughing again. “But if he had the weekend away,” she continues, “I don’t care. So we’re still probably poly, and probably will be in the future. But our relationship is incredibly stable at the moment.”

Fleischman doesn’t mind dealing in controversy. “I think I’m just disagreeable for a woman, and I also find it more interesting to have conversations with people that are, you know, a little spicy.” She recently begun hosting the Aporia podcast, where there has been spice aplenty. One of the most compelling episodes was with the neo-traditional feminist Louise Perry, where the pair debated everything from the merits of surrogacy to why couples might experiment with choking.

The topics broached in Fleischman’s podcast are conceptually very different from the take that first gave her online notoriety in 2013, when she argued that oysters and mussels, being so insensate as to be akin to vegetables, are compatible with a vegan diet. Since then, her interests have expanded in all kinds of directions—such as microbiome transplants, for instance. These are supposedly a method of improving your energy, mood or immunity by taking a pill containing a sample of someone else’s microbiome—that is, their faeces. Fleischman assisted a friend in trying such a transplant.

Are those days gone? “No, no. I do still handle poop every day, because I have a toddler. But not in the same fun-loving way.” Intellectually, though, she seems to be having as much fun as ever