This month, ‘Fifty Shades of Grey,’ the highly anticipated movie adaptation of the best selling erotic romance novel, came out in theaters. Regardless of your view on its betrayal of bondage, domination, sadism, and masochism (BDSM), the franchise has captured the curiosity of audiences worldwide, bringing these erotic practices to the forefront of pop culture. Curious myself, I decided to look into the neural basis of these behaviors.
Why is it that some people derive pleasure from what appear to be very painful acts, while others do not? Pain is primarily known as a mechanism to prevent life-threatening harm. Common thought dictates that the sensation is aversive, likely due its association with negative experiences such as illness and injury. It is often coupled with nociception (when nerve fibers signal to the brain that there is tissue damage), but it is not solely a product of physical injury; non-physical insults such as social rejection can result in pain as well (Bastian et al., 2014). Whatever the cause, people make great efforts to avoid, reduce, and eradicate this unpleasant feeling. The global analgesics market was predicted to reach 34.6 billion USD by 2015, an indication that seeking pain as something desirable is still, very much, a non-normative behavior (Global Industry Analysts, 2010).
Upon further review, however, the consequences of pain are not always negative. Consider deep tissue massages, intense exercise, and the consumption of spicy foods – these pain-inducing practices are all behaviors that people deliberately seek out due to their rewarding properties. These painful experiences enhance subsequent pleasure, as the contrast following the pain cessation gives hedonic value to these acts (Bastian et al., 2014).
Common regions of the brain mediate both pain and pleasure: this includes the nucleus accumbens, pallidum, and amygdala, important areas for gauging reward and punishment (Leknes & Tracey, 2008). It is proposed that the hedonic value of pain specifically derives from activation of the brain’s reward circuit, eliciting the release of dopamine and opioids; these neurotransmitters are linked to learning, motivation, pain relief, and the experience of pleasure, and interact in a complex fashion (generally though, phasic [quick-responding] dopamine increases opioid levels, while tonic [slow-responding] dopamine decreases opioid levels) (Leknes & Tracey, 2008). Following pain, the release of opioids is thought to produce a shifting hedonic spectrum, where pain decreases and pleasure increases over time (Bastian et al., 2014). Even after the pain subsides, opioid release continues, possibly explaining why there is increased pleasure following the cessation of pain (Bastian et al., 2014). Therefore, there may be a neural case for the pleasure of painful, erotic practices.
If pain can be pleasurable, why aren’t all people participating in these acts? Well, it is important to note that pain, like all sensory modalities, is a matter of subjective perception. Therefore, individual differences in pain sensitivity may determine preferences for painful acts (Coghill, 2010). These variations are likely a product of how individuals’ opioid and dopamine systems function, but can also be the product of genetic, psychological, sociological, and even personality-based differences (Coghill, 2010). The jury is still out on what exactly the allure of behaviors like BDSM is; looking at it from a neuroscience perspective is just one of many ways to approach the phenomenon’s multifaceted etiology.
(refer to the following for more in-depth explorations of the neural basis of pain and pleasure)
Bastian, B., Jetten, J., Hornsey, M. J., & Leknes, S. (2014). The Positive Consequences of Pain A Biopsychosocial Approach. Personality and Social Psychology Review, 1088868314527831.
Coghill, R. C. (2010). Individual differences in the subjective experience of pain: new insights into mechanisms and models. Headache: The Journal of Head and Face Pain, 50(9), 1531-1535.
Leknes, S., & Tracey, I. (2008). A common neurobiology for pain and pleasure. Nature Reviews Neuroscience, 9(4), 314-320.