Scientific studies on sexual desire and the neurochemicals associated with this state have shown that the primary motivators driving individuals towards sexual activity are largely due to chemical reactions occurring in the brain.
Real-life experiences also demonstrate that sexual actions often do not stem from love or the desire to establish long-term relationships, but are simply driven by purely physical needs.
The Biological Origins of Sexual Behavior
The biological origins of sexual behavior are linked to the hypothalamus—an area of just a few square centimeters in the brain that plays a crucial and complex role in regulating instinctual behaviors such as eating and mating. The hypothalamus is present in many lower organisms and developed much earlier than other brain structures responsible for controlling complex cognitive processes in humans, such as memory and language. Together with other organs, the hypothalamus regulates testosterone levels—the hormone that triggers sexual arousal and activity. The sexual behavior of many animal species, including humans, is associated with testosterone levels. In both males and females, testosterone levels influence sexual desire and actions. However, unlike in the animal kingdom, there is not an absolute correlation between hormone levels and sexual behavior in humans, as consciousness also plays an intervening role.
Another chemical that has been discovered to relate to sexual behavior is neurotransmitters, which ensure communication between nerve cells in the brain. Psychiatrist Michael Liebowitz was one of the first to study neurochemistry in love and sexuality. He observed that some individuals readily engage in unsuitable romantic relationships but quickly become bored, changing partners as easily as changing clothes. He suggested that these individuals might lack phenylethylamine (PEA)—a brain chemical structurally similar to amphetamines, which governs feelings of euphoria and excitement. Due to a prolonged deficiency of this chemical, individuals seek “pleasure” in romantic or sexual encounters. Michael Liebowitz administered monoamine oxidase inhibitors (MAOIs)—a type of antidepressant that affects phenylethylamine levels as well as the levels of other neurotransmitters like dopamine, serotonin, and norepinephrine. After treatment, many patients lost their “flighty” tendencies and stopped seeking “love at all costs,” possibly because they no longer felt a heavy sense of loneliness or had become more confident and cautious in choosing partners. They no longer needed the excitement associated with fleeting relationships—a state reminiscent of using amphetamines.
In addition to phenylethylamine, new discoveries have identified two other hormones, oxytocin and vasopressin, which also play significant roles in sex and love. The levels of these two hormones increase in both males and females during sexual arousal and ejaculation. The secretion of oxytocin seems to be particularly important in developing emotional bonds, promoting pair bonding among partners. Larry Young and colleagues from the Department of Behavioral Sciences and Psychiatry at Emory University discovered that oxytocin is one of many other neurochemicals that regulate various social behaviors characteristic of monogamous relationships, including pairing between males and females and paternal involvement in child-rearing.
Helen Fischer, a female researcher and collaborator at the Department of Anthropology at Rutgers University, asserts that the system of neurochemicals in the human brain has evolved to encourage sexual attraction and mating, enabling couples to maintain the necessary duration for reproduction and child-rearing.
Differences in Human Sexual Behavior Compared to Animals
As mentioned, there is no absolute correlation between hormone levels and sexual behavior in humans due to the intervening role of consciousness. The development of consciousness (biologically based in the cerebral cortex) has led human sexual behavior to evolve in three positive directions, distinct from that of animals:
Ability to Exclude and Critique: Limiting metaphysical complexes, criticizing the denial of women’s roles in sexual life, selecting partners based on admirable standards (beyond appearance, considering intelligence, moral character, and soul), and not seeking sexual satisfaction at any cost. This characteristic forms the basis for fidelity in marital relationships, as well as the prevention of AIDS and other traps of debauchery.
Ability to Develop and Nurture Sexual Function: Enriching imagination through cultural products, facilitating sexual responses, and allowing sexuality to transcend the influence of consciousness (no physiological activity is as sensitive to cortical activity as sexual physiology…).
Ability to Refine and Elevate: Viewing deviant sexual behaviors as inferior, emphasizing the sexual lives of individuals (making sexual activity more meaningful and reassuring by inventing contraceptive methods, helping people master the harsh physiological rules of reproduction), and paying attention to factors that enrich and diversify life…
Dr. Đào Xuân Dũng (According to Health & Life)
