Is that it? We have no reason to think that the argument in favor of casual sex is correct.
The article upon which this review is based excitingly leads to new discussion about the topic and possible new research. But it is only a starting point, and it's dangerous to draw conclusions like these off the arguments Siegel made.
Before anyone jumps to the conclusion that I hate promiscuity because I'm a woman and there are evolutionary advantages to male promiscuity and to female fidelity, I want to point out that that conclusion is flawed in a number of ways which, hopefully, will likewise start new discussion. Additionally, I have no personal stake in the outcome of this one.
For now, what, precisely, is my beef? Let's enumerate:
1) Society really doesn't demand prudishness as it used to. The counterargument is that to be a young American now is to have a certain pressure exerted on you to be sexually adventurous. That might work for some people, but not for others who are chastised for being frigid. I want to see stats to prove that societal influence now is what it used to be when these assertions were originally made. I think norms have changed.
2) Building on that, who is to say that we have implicit pressure to avoid casual sex? That's an assumption, not a truth. We have a tool to measure that, and I would be remiss as a researcher with the good fortune of working with Professor Mazarin Banaji's lab to not point out that we could use an IAT to score implicit preferences. We need some numbers, not assumptions.
3) This is based on unstructured observation with conclusions drawn a priori on a subject pool of three. An empirical nightmare. With additional data fabricated, i.e., "Brandon's assertion that people do not belong together forever is correct, but too many of us fear facing that truth or consider alternatives to that permanence." There is no citation there. I don't believe it's true. Gimme stats.
As the assumptions continue, I have to point out well-cited research that shows a different side of sex: passionate love is distinguished from companionate love (Hatfield, 1988; Rubin, 1973; Sternberg, 1986, in Schacher, Gilbert, & Wegner, 2009). Sternberg famously offered a triangular theory of love, which INCLUDES passion. So, fatuous love is passion and commitment, romantic love is intimacy and passion, consummate love is intimacy, passion, and commitment (in Gazzaniga & Heatherton, 2003).
My counterargument in favor of passionate love is based on decades of well-reputed and -replicated psychological research. I'm more comfortable with that than with an unstructured phenomenological account, especially for generalizing results -- even if it is an interesting starting point for discourse and research.
So, in conclusion, we can't make dangerous conclusions, we need data before making assertions is possible, and perhaps implicit measures on attitudes towards sex and more fMRI data (e.g., dorsal anterior cingulate and anterior insula) could lend us the info we need. Let's think of Siegel's argument as a set of hypotheses we could test -- not as truths to hold sacred.
Until then, keep loving -- passionately.