Source: NIH Image Gallery/Flickr
Sexual desire and love do not always co-exist, yet both are integral to satisfying romantic relationships. Although sexual attraction and emotional attachment may be independent processes, the brain responds to these feelings in remarkably similar ways.
In order to discover which areas of the brain are active when we feel love or sexual desire, researchers use functional magnetic resonance imaging (fMRI). This technique allows researchers to see which areas of the brain are active by detecting increases in blood flow to different areas of the brain while individuals perform specific tasks. In the studies assessing love, researchers typically ask participants to look at photographs or videos of loved ones, while in the studies assessing sexual desire, the participants usually view erotic stimuli as blood flow within the brain is recorded (Cacioppo et al., 2012).
After reviewing more than 20 different studies using fMRI technology to assess either love or sexual desire, Cacioppo et al. (2012) found that similar brain regions were associated with both feelings. The thalamus, hippocampus, and anterior cingulate cortex were active when individuals were feeling love or sexual desire. But the brain does not respond in exactly the same way to both sensations; the anterior portion of the insula was associated with love while the posterior portion was associated with desire. Furthermore, love more strongly activated the ventral tegemental area than sexual desire did (Cacioppo et al.).
Similar results were obtained by Stoessel and colleagues (2011). These researchers asked individuals who felt intensely in love with their partners to view erotic photographs of strangers as well as non-erotic photographs of their partners. These authors found that the anterior cingulate cortex, the insula, and the posterior cingulate cortex were active when individuals saw photographs of their loved ones as well as erotic photographs of strangers.
Other research suggests additional neural similarities between sexual desire and love. The neuropeptide oxytocin increases during sexual activity and orgasm for both men and women and is also associated with love and pair bonding (Birnbaum, 2017; Meston and Frohlich, 2000; Schneiderman et al., 2012). Elevated dopamine levels are also associated with feelings of love and sexual desire (Karup and Karup, 2003; Meston and Frohlich, 2000).
The common neural pathways to sexual desire and love lead researchers to suggest that love grows out of the pleasant feelings of sexual desire and fulfillment (Cacioppo et al., 2012). Evolutionary psychologists further propose that love has evolved to keep sexual partners together in order to increase children’s chances of survival (Birnbaum & Reis, 2018). Because the areas of the brain activated by both love and sexual desire are associated with the experience of reward, researchers also believe that both love and sexual desire may be better characterized as strong motivations rather than emotions per se, stating that the strong motivation to be with a partner (love) or the strong motivation to have sex with a partner (desire) can ultimately lead to feelings of euphoria (Aron et al., 2005).
Despite the similar neural activation evidenced when feeling love and sexual desire, the two states can differentially affect our cognitive performance. If you are interested in learning about how love makes you dumb and sex makes you smart, please read more on this subject here.
Portions of this post were derived from The Social Psychology of Attraction and Romantic Relationships. Copyright Madeleine A. Fugère (2015).