Our point? That something feels natural or unnatural doesn’t mean it is. Every one of the examples above, including saliva beer, is savored somewhere—by folks who would be disgusted by much of what you eat regularly. Especially when we’re talking about intimate, personal, biological experiences like eating or having sex, we mustn’t forget that the familiar fingers of culture reach deep into our minds. We can’t feel them adjusting our dials and flicking our switches, but every culture leads its members to believe some things are naturally right and others naturally wrong. These beliefs may feel right, but it’s a feeling we trust at our own peril.
Like those early Europeans, each of us is constrained by our own sense of what is normal and natural. We’re all members of one tribe or another—bonded by culture, family, religion, class, education, employment, team affiliation, or any number of other criteria. An essential first step in discerning the cultural from the human is what mythologist Joseph Campbell called detribalization. We have to recognize the various tribes we belong to and begin extricating ourselves from the unexamined assumptions each of them mistakes for the truth.
Authorities assure us that we are jealous of our mates because such feelings are only natural. Experts opine that women need commitment to feel sexual intimacy because “that’s just the way they are.” Some of the most prominent evolutionary psychologists insist that science has confirmed that we are, at base, a jealous, possessive, murderous, and deceitful species just barely saved by our precarious capacity to rise above our dark essence and submit to civilized propriety. To be sure, we humans have hankerings and aversions deeper than cultural influence, at the core of our animal being. We don’t argue that humans are born “blank slates,” awaiting operating instructions. But how something “feels” is far from a reliable guide to distinguishing biological truth from cultural influence. (21-23)
Ryan, Christopher and Cacilda Jethá. Sex at Dawn: The Prehistoric Origins of Modern Sexuality. Harper Collins, 2010.