In honor of Valentine’s Day, I’d like to take a quick look at one of the most fundamental human emotions — hate.

Wait, that doesn’t seem right. Hate? On Valentine’s Day? Isn’t V-Day supposed to be about love, Hallmark, and all of those positive, mushy feelings?

Well, sure. Of course Valentine’s Day is supposed to be about love. But are love and hate really all that different?

They both make us act irrationally. They both cloud our thinking and judgment. They’ve both sparked wars, poetry, and some of the greatest epics of all time. They both make our hearts race, our pupils dilate, and our palms sweat.

OK. So it seems like love and hate are not quite so different after all. Plenty of age-old sayings agree: “There’s a thin line between love and hate.” “The opposite of love is not hate, it’s indifference.”

There’s also a never-ending stream of support from pop culture. ‘Friends’ fans will remember when Rachel bitterly hated her co-worker Gavin… until he surprised her with a scarf on her birthday and they ended up kissing on her balcony ('There's a thin line between love and hate, and as it turns out, that line is a scarf'). Sandra Bullock and Meg Ryan have built entire film careers out of replaying different versions of the same story: Boy meets girl. Boy and girl desperately hate each other. Girl is usually neurotic and/or overwhelmingly anxious. Girl spends about half of the movie complaining to a best friend (maybe Judy Greer) about how much she hates the boy, but for some reason can’t avoid him entirely (usually because they work together or for competing businesses). Boy reveals a vulnerability or minor endearing flaw to girl. Both are madly in love by the end.

Pop culture is all for the fluidity of love and hate, but what about scientific research? Well, chick flicks may not be far off base. When neuroimaging subjects looked at the faces of people they strongly hated, the insula region in the brain was activated more than it was with neutral faces, which also happens when you look at faces that make you feel — you guessed it — passionate, romantic love. This in itself is not very informative.1 But importantly, the insula does not have anything to do with what type of emotions you experience… just their intensity. Whether those emotions are positive or negative mean nothing to that little brain region; all its activation means is that when you see a face, you feel VERY STRONGLY ABOUT THAT PERSON.

Just to demonstrate how important this brain region is to emotional intensity, when people with insula damage were asked to rate how strongly they felt about progressively more positive or negative things, they didn’t respond by feeling more and more intense about them like people with ‘normal’ brains did – instead, they stayed fairly neutral the whole time. So, the insula becomes activated whether you love or hate somebody, and it controls how strongly you feel about things or people, yet it has nothing to do with whether those feelings are good or bad. Well if your brain is trained to activate the insula every time you see the face of someone in your life who elicits a strong reaction, what if something minor happens to flip the switch from negative to positive? If something suddenly makes you start to feel positively – like you learn about a few redeeming qualities, or maybe this person buys you a scarf – the network associated with that person still includes the insula, so your feelings will still be drastically intense. This makes the switch from ‘hate’ to ‘love’ quite natural.2

Sadly for all of the Valentines out there, that ‘hate’ to ‘love’ switch can flip the other way as well. When people were asked to think about their last break-up, almost 1/3 of ex-partners specifically listed “unattractive features” that were simply negative versions of qualities that they initially loved. A woman who once found her boyfriend to be ‘funny and fun’ later disliked his ‘constant silliness.’ A man who initially found his partner ‘refreshingly innocent’ later disparaged her ‘lack of maturity.’ Most importantly, some types of qualities tend to be more ‘fatal’ to relationships than others. If you’re initially drawn to your partner because he/she is “exciting, spontaneous, and outgoing” or “different, unique, and opposite from me,” there’s a much higher risk that your opinion will flip… and that it will eventually kill the relationship. Sad, but true – while the people that we hate can easily become the people that we love, the things that we love about them often become the things that we can’t stand.

James Carville and Mary Matalin are political pundits on opposite extremes of the ideological spectrum and have managed to stay happily married since 1993. Maybe they’ve figured out the secret to keeping ‘different’ as a positive!

So let’s kick off this Valentine’s Day on an optimistic note. Instead of worrying that you will eventually view your partner’s charming overprotection as nasty nagging, try to maintain a realistic view of your loved one’s strengths and weaknesses so you can avoid the fatal ‘switch.’ When you see that hated co-worker, remember that the emotions you identify as ‘hate’ could just as easily be ‘love’ with a little more information. When thoughts of your hated ex-lover make you boil over with rage, remember that you likely feel that way because you once felt so strongly positive. And as for tonight, throw on some red clothing and turn up the thermostat. Hey, it can’t hurt.

1. For a better explanation of why this isn’t necessarily informative, simply knowing that something ‘lights up’ certain areas of the brain is not inherently interesting, especially if it’s a brain area that lights up for a lot of things. The insula in particular is related to pretty much every visceral feeling and strong emotion that exists, so it’s pretty intuitive that it would be activated for ‘hate’ or ‘love’; it’s also activated when people crave drugs, feel pain, or hear a funny joke. For a great New York Times article that goes into more detail about the insula, see here.

2. These last few sentences are mostly speculative.


Zeki, S., & Romaya, J.P. (2008). Neural correlates of hate. PLoS ONE, 3.

Felmlee, D. (1995). Fatal attractions: Affection and disaffection in intimate relationships. Journal of Social and Personal Relationships, 12, 295-311.

Berntson, G.G., Norman, G.J., Bechara, A., Bruss, J., Tranel, D., & Cacioppo, J.T. (2011). The insula and evaluative processes. Psychological Science, 22, 80-86.'

Love/Hate image by user asphyxiat3d available via DeviantArt

You've Got Mail image by user desireefawn available via Flickr


This was originally blogged at IonPsych for Valentine’s Day on 2/14/2011, and reblogged again at PsySociety on 2/14/2012.

You can see the original posts here and here.