Improve Cognitive Function with Oxytocin (OXTR)

When we think about cognitive function, most of us probably imagine the typical “intellectual” tasks we learned to do in school, such as doing math, writing essays, or memorizing new vocabulary words.

However, the truth is that these kinds of mental tasks are actually fairly unusual from an evolutionary perspective! In reality, the reason we humans evolved such large and sophisticated brains probably wasn’t to invent rocket science – but rather simply to keep up with our complex social environment.

The theory goes like this: as our ancestors began living in larger and more complex social groups, our brains had to grow in order to give us the ability to understand other peoples’ emotions and motivations so that we could use this information to maneuver through our social environment. Many biologists believe that it was precisely these kinds of “evolutionary pressures” that originally caused our brains to become so much larger and well-developed over time [R, R, R].

(In fact, humans aren’t the only animals whose brains seem to be built around navigating social relationships: similar correlations between social complexity and brain size are also seen in many other species, including not only many of our close primate relatives, but also dolphins, whales, and even ants [R, R, R]!)

In other words, all the complex and sophisticated things we can do with our minds today probably developed from brain mechanisms that were originally geared towards understanding and dealing with other human beings.

Why is all of this important for oxytocin? Well, oxytocin is most often studied for its influence over social behavior and emotional bonding – and because so much of our other cognitive abilities are rooted in these social mechanisms, this important neurotransmitter is also likely to have significant influences on many other cognitive functions as well [R, R, R, R, R, R].

The human brain originally evolved primarily to help us deal with complex social interactions. Because of this, the same biological mechanisms that regulate social behavior – such as oxytocin – probably also have a significant influence on many of our other cognitive abilities.

Although scientists are still mapping out exactly how oxytocin influences other cognitive skills, there’s already a wealth of evidence showing that it can have a significant effect on more general cognitive abilities such as overall intelligence (IQ) [R], cognitive flexibility (executive function and attention) [R, R, R], learning and memory [R, R, R, R, R], and decision-making [R].

For example, brain areas that are critical for higher cognitive functions – such as the prefrontal cortex and the hippocampus – contain significant numbers of oxytocin receptors. This suggests that oxytocin could have a relatively direct effect on cognitive processes that take place in these brain regions [R, R, R, R, R].

Other studies have found that the oxytocin system may also play a role in promoting synaptic plasticity, which would account for its influence on processes related to learning and memory [R, R, R].

These biological mechanisms do appear to play important roles in cognition, as many studies have indeed shown that changing levels of oxytocin has cognitive effects in both animals and humans.

In mice, for example, knocking out oxytocin-related genes or blocking oxytocin receptors produces significant deficits in learning and memory for both social and non-social forms of information [R, R, R].

Similarly, in humans, raising oxytocin levels (such as by having subjects take nasal sprays laced with oxytocin) improves memory for faces and other forms of social information [R, R].

Boosting oxytocin has also been shown to enhance many other forms of “social cognition” in humans. For example, giving healthy subjects oxytocin makes them better at identifying the emotions of others just from looking at pictures of their eyes [R].

These are just a few of the many studies showing that oxytocin plays a central role in “mind-reading” abilities, which form the cognitive foundations of empathy and other important aspects of social behavior [R, R, R].

But while most human studies have focused on these various forms of social cognition, there is also evidence that oxytocin affects general, “non-social” cognitive abilities as well.

For example, in one particularly interesting study, one group of subjects were asked to imagine being lonely and socially isolated – a kind of social stress that is known to cause changes in the brain’s oxytocin system.

Meanwhile, another group was asked to imagine different types of stress, such as physical injuries, living in poverty, or being in an accident.

Both groups were then given tests to measure their logic and reasoning skills. The people who experienced “social stress” group ended up performing significantly worse on logic and reasoning these cognitive tests, with both their accuracy and processing speed being reduced [R].

Studies like this one show how factors related to social behavior (in this case, imagining being lonely) can also have a major impact on seemingly-unrelated cognitive abilities – and hence why oxytocin-related genes might influence our intelligence!

Peoples’ oxytocin levels have a powerful influence on their “social cognition” abilities, and might also influence their performance in other, “non-social” types of mental tasks as well.

The SNP rs53576 is a part of the OXTR gene, which is the main gene responsible for creating oxytocin receptors throughout the brain [R].

This particular SNP has been associated with significant differences in cognitive ability in humans. You can see your genotype for this SNP in the table below:

For this SNP, the two possible alleles are ‘A’ and ‘G’. When it comes to cognitive function, it’s better to have the ‘G’ allele.

For example, one study on 206 adolescents found that people with the ‘AA’ genotype have significantly lower non-verbal intelligence compared to carriers of the ‘G’ allele [R].

While the effects of individual SNPs on overall intelligence are usually relatively small, in this case the effect is actually quite significant: the authors of this study found that this SNP alone could account for a difference of 8.5% in overall intellectual performance between the two genotype groups [R]!

Your genotype for rs53576 can potentially either increase or decrease your relative non-verbal cognitive abilities by nearly 9% according to one study.

Although scientists don’t yet fully understand the exact biological mechanisms involved in this SNP’s effects on cognitive ability, there are several lines of evidence to suggest that lowered oxytocin levels and reduced sensitivity to oxytocin (i.e. having fewer oxytocin receptors) are responsible for these effects.

Firstly, the same study that linked this SNP to non-verbal intelligence reported that the ‘A’ allele was also associated with reduced positive moods, increased negative moods, and greater feelings of loneliness – all effects that are consistent with lower oxytocin levels [R, R, R, R].

Secondly, a large number of other studies have also linked the ‘A’ allele of this SNP to a wide variety of behavioral and cognitive effects that are also consistent with lower oxytocin levels, including:

• Reduced emotion-reading ability [R]
• Less “pro-social” behavior [R]
• Less emotional bonding [R]
• Reduced interpersonal trust [R]
• Increased sensitivity to social stress [R, R]
• Lower optimism and self-esteem [R]
• Reduced maternal behavior (in mothers) [R]
• Increased risk of autism-spectrum disorders (ASDs), which typically involve deficits in many aspects of social cognition [R, R, R]

Importantly, many of the above effects of this SNP are also the same ones that have been shown to be improved by boosting oxytocin levels (in both healthy humans as well as autism patients) [R, R, R, R, R].

Therefore, it’s a safe bet to suppose that low oxytocin levels (or reduced sensitivity to oxytocin) is probably the main biological factor driving the effects of this SNP.

The potential negative cognitive effects of this OXTR SNP most likely stem from lower oxytocin levels and/or reduced sensitivity to oxytocin.