Does Love Make You Dumber? What the Research Shows About Love and IQ

Love does not make you dumber in any lasting way that research has measured. The best evidence is that the first months of an intense romance can make it slightly harder to screen out distractions on laboratory attention tasks, while no study has ever measured anyone's IQ before and after they fell in love, and intelligence is one of the most stable traits psychologists measure in adults.

The idea has a real basis. New love grabs attention and raises stress hormones, and a painful breakup can fill the day with intrusive thoughts. This page covers what the attention studies found, what the brain-imaging work behind "love is blind" shows, why the effects look temporary, and how intelligence shapes who people fall for in the first place.

The most direct test comes from Leiden University. Henk van Steenbergen and colleagues recruited 43 students who had been in a romantic relationship for less than six months. Before the tasks, participants listened to love songs and recalled a romantic moment with their partner, which was meant to bring their feelings to the surface. They then completed two standard tests of "cognitive control", the ability to focus on what matters and ignore what does not. In a Stroop task you name the ink colour of a word while ignoring the word itself, and in a flanker task you respond to a central arrow while ignoring the arrows beside it.

Students who scored higher on the Passionate Love Scale were less efficient at ignoring the irrelevant information on both tasks. Put simply, the more in love they were, the worse they were at filtering distractions. The authors suggested that a new lover's thoughts keep drifting to the partner, leaving fewer resources for the task in front of them.

The sample was small and the design was correlational. The outcome was also a reaction-time measure of attention, which is a long way from an IQ score. When Sandra Langeslag and van Steenbergen tested 83 newly in-love young adults a few years later without the love-song warm-up, they did not find the predicted link between how infatuated people were and their interference control. They concluded that any cost may appear mainly while people are actively thinking about their beloved.

Attention is also pulled toward the partner. In an earlier brain-wave study, Langeslag's group showed people photos of their beloved, a friend and an attractive stranger. The beloved's face produced a larger "late positive potential", a brain response linked to motivated attention, than either of the other faces. Being in love seems to reorder priorities more than it removes ability.

The phrase got its neuroscience in the early 2000s. Andreas Bartels and Semir Zeki at University College London scanned 17 people who described themselves as deeply in love while they looked at photos of their partner and of friends. Viewing the partner activated reward-related regions and reduced activity in parts of the prefrontal cortex and the amygdala. In a follow-up comparing romantic love with mothers viewing their own children, both kinds of attachment quieted a shared set of regions tied to negative emotion, social judgment and "mentalizing", the work of judging other people's intentions.

The authors proposed a push-pull system: attachment switches off the circuits we use to judge others critically while switching on reward. That is a reasonable account of why people overlook a partner's faults. It is a claim about judging one person, measured in a scanner with small samples. It says nothing about the reasoning abilities that IQ tests measure.

A widely shared claim links love and creativity. A 2009 paper by Jens Förster and colleagues reported that reminders of love boosted creative thinking. The University of Amsterdam later requested its retraction over statistical concerns, and in 2016 the journal attached a Statement of Institutional Concern to it, so it should not be treated as evidence.

Two small Italian studies are often cited for the idea that infatuation resembles an obsession. Donatella Marazziti and colleagues measured the serotonin transporter on blood platelets in 20 people who had fallen in love within the previous six months, 20 unmedicated people with obsessive-compulsive disorder and 20 controls. Both the in-love group and the OCD group had lower transporter density than controls, which the authors linked to the intrusive, repetitive thinking common to both states.

A later study by Marazziti and Canale compared 24 recently in-love people with 24 who were single or in long relationships. The in-love group had higher cortisol, a stress hormone. When retested 12 to 24 months later, the hormonal differences had disappeared. These are small samples measuring blood markers, but they fit a picture of early love as a temporary, arousing state. Stress itself has short-term effects on attention and memory, which our page on IQ and stress covers.

Breakups are the other side. In a survey of 192 university students after a recent breakup, those with the most distress reported more intrusive thoughts, more trouble controlling them, more sleep disturbance and more symptoms of depression and anxiety. Anyone who has tried to study after a breakup will recognise the pattern. Depression, poor sleep and rumination can lower performance on cognitive tests while they last, so a person tested in the weeks after a painful breakup might score below their usual level. That is a temporary drop in test performance. It is not a change in underlying intelligence, and scores recover as the state passes.

Langeslag's lab has also studied how people recover. When heartbroken participants reappraised their ex-partner negatively, their love feelings fell, and several regulation strategies reduced the brain's attention response to the ex-partner's photo.

No study has given full IQ tests to people before and after they fell in love. The evidence consists of short attention tasks, brain scans of a few dozen people and self-report surveys. Those designs can show that new love captures attention. They cannot show that it changes intelligence.

There are good reasons to expect any effect to be small and short-lived. IQ in adults is highly stable across years, and the effects seen in the lab appeared in tasks measured in milliseconds, with one study failing to replicate them without a love induction. The hormonal differences in the Italian study faded within two years. If you converted the laboratory findings to IQ points, there would be nothing reliable to convert, because no study has reported a cognitive effect on an IQ-like scale.

The research on intelligence and love points in a different direction: intelligence shapes who people pair with. A 2023 meta-analysis by Tanya Horwitz and colleagues pooled partner correlations across 22 traits. For IQ, the average correlation between partners was r = .44 (95% confidence interval .23 to .61), among the strongest of any trait after political and religious values and education. In UK Biobank couples, scores on a brief 13-item fluid reasoning test correlated at r = .23. Part of this similarity reflects choosing partners at school, university and work, where people are already sorted by ability. Whether a high IQ or high emotional intelligence better predicts a happy relationship is a separate question, covered in our comparison of high IQ vs high EQ in long-term relationships.

Not in any lasting way. People in the early months of intense love were slightly worse at ignoring distractions on lab attention tasks in one study, but no study has shown a drop in IQ.

Early love draws attention toward the partner and is linked to higher cortisol, and studies suggest the effect is strongest while you are actively thinking about the person. These changes appear to fade as relationships settle.

Brain scans show that viewing a beloved partner quiets regions involved in critical social judgment and negative emotion. That may explain why people overlook a partner's faults, but it does not affect general reasoning ability.

A painful breakup can bring intrusive thoughts, poor sleep and low mood, which can depress test performance temporarily. Anyone with persistent low mood after a breakup should speak with a doctor or a licensed mental health professional.

Often, yes. Partners' IQ scores correlate at about .44 on average across studies, partly because people meet in schools and workplaces where others have similar abilities.

Love does not make you dumber. The best study found that intense new love was linked to slightly worse filtering of distractions, a follow-up without a love-song warm-up did not replicate it, and no study has measured an IQ change. Love redirects attention for a while, and a hard breakup can do the same with low mood and poor sleep. If you want an accurate reading of your reasoning ability, take a full-length online IQ test on a day when your mind is on the task.

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7. Marazziti, D., Akiskal, H. S., Rossi, A., & Cassano, G. B. (1999). Alteration of the platelet serotonin transporter in romantic love. Psychological Medicine, 29(3), 741-745. [doi.org/10.1017/S0033291798007946](. doi.org

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Hero image: Closeup of love padlocks on a bridge, Ljubljana, by domdomegg, CC BY 4.0. Via Wikimedia Commons.