Limerence Messes Up Your Rationality Real Bad, Yo

There’s a pretty basic rationality fact that I don’t see talked about much on LW despite it’s obvious relevance. So I am here to write The Canonical Rationality Post on the topic:

Limerence (aka “falling in love”[1]) wrecks havoc on your rationality.

Evolution created you to breed and raise families and stuff. It gave you complex abstract reasoning because that was a useful problem solving tool. Evolution didn’t do that great a job of aligning humans with its goals (see: masturbation is an inner alignment failure, birth control is an outer alignment failure). But, it looks like in some sense evolution was aware it had an alignment problem to solve. It gave us capacity for reason, and also it built in a massive hardcoded override for situations where no fuck you your brain is not for building rocketships and new abstract theories, your brain is for producing children and entangling yourself with a partner long enough to raise them. Now focus all your attention on the new prospective mate you are infatuated with.

To be clear, I like limerence. I put decent odds on CEV considering it a core human value. I think attempts to dissociate from your basic human drives are likely to have bad second-order consequences.

But, still, it’s been boggling how wonky my judgment gets when I was under the influence. And it’s boggling how arbitrary it felt afterwards (one day I’d be “wow this person is amazing”, and then a week later after I got some distance I looked back and thought “wow, Raemon’s thinking was so silly there”). It felt, in retrospect, like I’d been drugged.

I’m not sure how the rationality-warping of limerence compares to other major “evolution-hard-coded-some-overrides” areas like “access to power/​money/​status”. But the effects of limerence feel sharpest/​most-pronounced to me, and the most “what the hell just happened?” after the warp has cleared.

Mutual Infatuation and the Limerence Event Horizon

The place where this gets extra intense is when you and the object of your affects are both into each other. When only one of you is quietly pining for the other, your feelings might be warped but… they don’t really have anywhere to go.

But if two people both like each other they tend to ascend this graph:

The y-axis is labeled “irrationality” for succinctness, but a better label might be “your bottom-line-is-written-ness.” It’s not that you’ll necessarily make the wrong choice the further to the right you go. But the probability mass gets more concentrated into “Y’all end up dating and probably having sex”.

If for some reason you don’t actually endorse doing that, it’ll require escalating amounts of willpower to avoid it. And your judgment about how in-control you are of the situation will get worse. You may find yourself doing rationalization instead of rationality.

(Note: If you have more experience and practice managing your emotions, the Limerence Event Horizon is further to the right and you have more opportunity to change course before hooking up becomes inevitable)

Subtly Warped Judgment

What I find particularly alarming here is the subtly warped judgment line. I’ve had a couple experiences where I thought I was successfully holding someone at a distance. I knew about the Limerence Event Horizon, but I was being so careful to hold myself at a nice safe emotional distance! Alas, being slightly over the subtly-warped-judgment line is like taking one drink – sure it only impairs your judgment a little, but, the one of the things you might do with slightly impaired judgment is to take another drink. (Or, say, foster more emotional closeness with someone who you wouldn’t endorse eventually having sex with).

In my two experiences, it was clear-in-retrospect that my thinking was subtly warped (and I totally ended up romantically involved). One of the times worked out fine (sometimes dating people is great!). Another of the times it was one of the greatest mistakes of my life that I regretted for a long time.


So, like, I don’t hate love or fun or whatever. I don’t want to give people an anxious complex about allowing themselves to feel feelings. Many times, when you are feeling mutually limerent with someone… great! Falling in love is one of the nicest things. Have a good time.

But, I do think it is possible to end up mutually-attracted-to-someone for whom it’d be a bad idea to get involved with. Maybe one of you are married or have made other monogamous commitments you take seriously. Maybe the person is fun but predictably kinda a mess and you’ll end up paying a bunch of costs that end up net negative for you. Maybe those costs would be totally worth it for you, but be too costly for other friends/​family/​children/​coworkers caught in the wake.

Sometimes the issue isn’t anything about the person-you’re-into, but about other things you have going on. Maybe you’re working on a really important project you care about and right now it’d just be particularly bad right now to get distracted in the way that falling in love is super distracting. Maybe you recently hired the person-you’re-into and it’d predictably mess up your working relationship.

I don’t want to make a strong claim about how often those concerns are overriding. But, at least sometimes, it’s the wrong call for mutually-attracted-people-to-date, and in those cases there’s a lot more degrees of freedom to think clearly if you’re holding someone at a further distance than may feel intuitively necessary.

  1. ^

    I have strong opinions on the definition of the word “love” and am kinda annoyed at popular usage of “falling in love” to mean a time very early in a relationship before “love” is particularly substantive, but for this post I’m going with the popular usage.