The Human Animal: The Biology of Love

Jolie and Pitt getting up close and personal.

Jolie and Pitt getting up close and personal.

What is love?

When humans have found an appropriate mate its clear that we somehow revert to childish behavior, which is referred to as ‘love’ in common culture. But is it love? What is love? Has it been merely manufactured by humans? Is it just a more romantic way of saying you are sexually attracted to someone? Morris says no and claims that it is so much more than that.  For Morris, ‘Love is a biological mechanism and it has a very specific function’.

The first time we encounter love is as a baby. This is the stage of total security, protection and trust. However, even at this early stage, humans have an urge to be independent and express themselves. The process of growing up is a process of this new urge gradually asserting itself, as the need for maternal protection grows weaker. When the infant becomes a teenager the urge for independence gets the upper hand and we experience our first true separation from our parents. On the horizon is the prospect of gaining new bounds and finding new partners.

It’s common for new couples to go on dates, to eat and drink at various bars and restaurants. These activities are often taken for granted but for Morris it evidences our natural biological tendencies in full view. Like many bird species humans indulge in courtship feeding. We now see a couple on a date in a restaurant, being recorded by a hidden camera. At first both individuals are quite formal in posture. As the night progresses however conversation and drinking ensue, relaxing both involved.

Their intimacy grows as we watch. Sexual signals as mentioned in earlier posts including blushing, smiling, strong eye contact and hair touching can be observed. We witness the first touch their hands meet which leads to a hand kiss. Then come the eating. Both mimic the behavior of infant and child as they each spoon feed one another. This behavior denotes our human need for security and protection. Then they share an intimate kiss. Finally like courting birds a gift is offered as the male buys flowers for the female. The date comes to an end. The date evidences not only pseudo parental feeding but also the reenactment of a prime evil exchange deeply embedded in our species after a million years of hunter-gatherers. Food sharing which in prime evil times was the very bases of human society. It could be argued that ever since humans developed from hunter-gatherers we have becomes ‘unnatural’ as humans. This idea I’ll explore again later.

As the sexual attachment of the couple increases we see them displaying publicly acts known as tie signs. These are forms of bodily contact, which tell other people that an exclusive couple is forming.  So whilst they reinforce the closeness of the couple they also exclude us from that relationship. Such signals include the arm around the shoulder or hand holding, whilst not particularly sexual or intimate it connect the two independent individuals and reinforce to others they are a pair.  Others are more intimate in nature, which evidence a growing trust and intimacy such as kissing and stroking near the face and lower regions.  The head is a highly protective area and so being able to touch such an area is exclusive to only their most trusted partner, the same applies to touching the knees, which is approaching our more intimate area. What separates us from our hairier relatives is our near naked skin, which allows us to explore more areas of our human bodies.

Another attribute, which separates humans from our animal relatives, is the male human penis.  Male mammals and male apes have a bone inside the penis.  The function of this bone is to produce an instant erection the moment a male approaches a female sexually.  The loss of this bone in the human male means that his female partner must sexually arouse him strongly before he can penetrate her. This means that human pre-sexual behavior becomes a lot more sensuous and longer. As a result sex in humans have evolved to be a lot more then pro-creative. Because it’s become more pleasurable and loving less automatic it’s become more complex. And in it’s final stages courtship becomes lengthened and more erotic. This is not a modern sophistication evolution has programmed us for this extended bodily intimacy using it as a mechanism to strengthen the courtship, the ‘pair-bond’ of the male and female for one another and the roles they are about to play: parents.

As with other monkeys and apes our offspring as we all know are nurtured inside the female body. However, unlike other animals human babies are utterly helpless at birth. The human baby has 10-15 years of being completely dependent on its parents, so preferably there must be two parents in order to raise the child sufficiently. A single parent may lack all the resources. So there has to be two and there has to be a biological mechanism to keep the couple together in the interests for the child. This mechanism is a strong pair bond, which in many cultures and societies is encouraged to be reinforced through the commitment of marriage. Whether traditional or modern, depending on the culture, it always carries the same public message: we are an official exclusive couple to the entire world.

The final stage in the biology of love is sexual intercourse. For those who have enjoyed the ‘natural’ process of falling in love it’s the end of the line. The mating act is sensuous and long in our species as the act itself is not just for the means of pro-creation its come with mutual sexual rewards.

The skin becomes super sensitive, one of many of the physical changes that take place during sexual arousal. The female’s lips becomes fuller, darker and sensitive, eyes glisten as a watery sheen films over them, pupils dilate and respiration increases dramatically as the body needs more oxygen for the vigorous activity which is about to take place. Nostrils flare, the heart pumps faster to increase blood supply and the internal arteries release natural body chemicals to create feelings of euphoria. Sweat glands open, creating copious amounts of perspiration, acting as a cooling agent and personal scent, which unconsciously stimulates the partner.  The whole body becomes a lot hotter to the touch specifically around the ear lobes and lips then eventually the entire head. The vagina progressively heats up also during sexual arousal. Females breast enlarge by up to 25% during sexual intercourse whilst the nipples become highly sensitive and increase in height by up to 1cm. The penis becomes swollen, heated and stiffly erect, normally doubling in size. The erection is caused by a rush of blood in up to nearly 60 times the normal level and a simultaneous rush off blood flow out which helps to maintain it.  At high intensities of arousal a sex flush appears on the female body and the mutual enjoyment of the partner is reinforced by orgasm. The male’s orgasm fulfills his biological function, to deliver a pool of ejaculate inside the vagina as close as possible to the cervical aperture.

Human sexual intercourse is intense, far more intense then that of any other species. However, this does not mean that every ‘pair-bond’ is concrete. Partnerships end and individuals find new ones. So what goes wrong? Wandering eyes? Travelling over seas? Temptation? Throughout history there has been adultery. For male humans, the advantages seem logical enough. He may be a good father and husband but he will also gain by scattering his genetic material over a wider range. Through his additional offspring guarantees his genes will live on.  However, the risk is if he gets caught out he will damage his ‘pair-bond’ and disrupt the rearing of his children. Adultery is frowned upon in our society. Of course, it’s not only the males that can commit adultery females can too and in some cultures it’s acceptable. Among the Wada be Nomads in Niger it is accepted if a married female is dissatisfied with her husband she can seek pleasure from somebody else’s. This behaviour is strongly frowned upon in most cultures and society’s, however, for Morris, it’s existence means there must be a biological advantage for an adulteress female as well as an adulteress male.

To understand the advantages of being an adulteress female, Morris returns to the human orgasm. When the male ejaculates a sperm pool is delivered in the cervix, the entrance of the womb. Females generally take longer to reach orgasm, however, they are just as intense. A females muscles contract through the genital region and as they do so, the contractions make the mouth of the uterus dip into the pool of ejaculate. This increases the chances of fertilization. It is thought that if a human female varies the times of her orgasms, she can increase or decrease her chances of getting pregnant by the sperm of her choosing.

For example, if the female were to be unfaithful and her body favored one sperm over the other, such as that of a young healthy lover, the sperm of the older husband will attack them and kill them. Some sperm are egg seekers whilst the others are there to protect the egg from being fertilized by any foreign sperm that may arrive. There are two types of this protective sperm: active, who seek out alien sperm and destroy them and blockers, who create barriers against invaders, allowing only sperm from the same male to pass towards the egg. These other functions to sperm could not have evolved and developed if there hadn’t existed promiscuity in the first place.  However, promiscuity is risky for the human animal and it is far better to be within a ‘pair-bond’. 99% of humans live in a partnership it’s a fundamental condition of the human species.

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