Naturally, through a series of observations, I discovered in my early years that there were anatomical differences between boys and girls. Towards my teens, I even conducted a few experiments to verify my hypothesis and by the time I was married, I also noted that females developed, behaved, thought about, valued and remembered things differently than I and my male counterparts did. And now, after 40-odd years of first hand experience with females, including my share of disappointment, confusion, rejection, arguments, and a divorce, I have finally invested some time studying the science of males and females, and more specifically the different way our brains are wired. This led to an interesting list of hormones that ebb and flow in all of our brains and a study of how they affect our emotions and perceptions of human conditions including anger, fear, jealousy, pain, pleasure, stress, threats, loneliness, aging, etc. On a personal note, my research opened doors to some of my own “secrets”, ones that I thought only existed in my most private thoughts and I also came to better understand females, their cycles, and how they perceive and respond to things differently than I. And I think back through the history of mankind and all of the misunderstandings, wars, murders, betrayals and scandals and I can`t help but think that if the cavemen had only known about estrogen, vasopressin, progesterone and oxytocin, we could have skipped a whack of catastrophes in our evolutionary development.
Recent advances in modern brain scanning equipment now allow scientists to scan people’s brains, not only when they are laying in an MRI machine in a hospital, but when they are arguing, eating chocolate, getting a massage, enjoying foreplay and yes, even while they are having sex. We now know where, how and why men and women process and react differently to stimuli.
Physical Differences between Males and Females
The obvious differences are that we men have exterior genitalia, are generally bigger and stronger with broader shoulders, expanded rib cages and higher lung capacity. We also have deeper voices, hairy backs and a sexy strip of pubic hair that runs right up past our navels to our chests, and in some cases, all the way back down the other side. We generally have more facial hair, prominent adam’s apples, and stronger facial features including our jaw bones, eye brows, chins, and noses. For whatever its worth, the average 20 year old man has 176,000 km of myelinated brain wiring while his 20 year old counterpart has about 149,000 km. What is less obvious is our larger brain structure, circuitry and the hormones that affect how we feel and behave.
The default for all human fetus brains is female and for the first several weeks of development, we can swing either way, or both! But for reasons not totally understood, male humans, that is the ones with both an X and a Y chromosome, suddenly get a massive infusion of testosterone at about 8 weeks, which causes the brain to suddenly make space in and around our hypothalamus for sexual pursuit, problem solving, spacial awareness, muscular coordination, pecking order hierarchy, aggression and in the core of the most primitive area of the brain, the amygdala, the alarm system for threats, fear and danger. The spike in testosterone causes the cells in the female reproductive organs to die, while cells for male reproduction split and divide.
Our testicles start manufacturing testosterone, vasopressin and a hormone called MIS (mullerian inhibiting substance) while in females, estrogen, progesterone and oxytocin take them on a journey of their own. All things considered, male and female brain circuits are similar, but men and women interpret, process and react using different hormones and brain circuits.
Testosterone is actually a steroid and it is primarily manufactured in the testicles of males and the ovaries of females. On average, an adult human male body produces about ten times more testosterone than a female, though females are more sensitive to the hormone. In males, testosterone is the primary indicator for sexual behaviour and it affects everything from penis size and enlargement, libido, frequencies of erections and masturbation as well as a hundred other things like how we feel, what we want to touch, taste, and eat, and feel. Testosterone is also credited with affecting our sense of pecking order, jealousy, dominance and the fight-or-flight response.
In females, much smaller dosages of testosterone secreted by their ovaries affect their need for sex, masturbation and also whether or not they have hair on their upper lips.
Following that body changing shot of fetal testosterone at about 8 weeks, we males develop two and a half times the brain space devoted to sexual drive in our hypothalamus than that of females. By the time we reach our later teens, we are hard wired to be on the look out for and to seize varied sexual opportunities at a moments notice. If testosterone were glasses of milk, a nine-year-old boy would get the equivalent of about a half a glass while fifteen year olds get the equivalent of two gallons a day and this generous daily dose of testosterone is served to us consistently well into our golden age.
Whether or not we intend to pursue females, we are hard-wired to check out the goods. Continuously running sexual thoughts flicker in the background of our visual cortex around the clock, day in and day out and when we see, smell or hear sexually capable females, our primitive brain reacts long before propriety gives us cause to behave ourselves. This includes the colour of human flesh, red lips, the feminine shape of feet, legs, bums, torsos, breasts, necks, faces, and also eye contact and if that isn’t enough, images of female nudity or suggestive scenes give us mind numbing jolts of testosterone and that neurotransmitter of ecstasy, dopamine. This chemical hormone stimulates ‘desire and reward’ by triggering an intense rush of pleasure and it accompanies food, sex, love and lust.
Sex is not the only thing on our mind. As testosterone surges through our perverted little brains, a companion hormone called vasopressin is also stimulated. Together, testosterone and vasopressin make our brains territorial and sensitive to peer pressure and perceived threats.
When these hormones get mixed up with the stress hormone cortisol, they supercharge our bodies and brain, and prepare us for the male fight-or-flight response in reaction to challenges to our status or turf. Our evolving caveman-like brains have been shaped for hundreds of thousands of years by living in status-conscious hierarchical groups. And while not all teen boys want to be king of the hill, they do want to be close to the top of the pecking order, staying as far from the bottom as possible. And that can mean taking risks that get them into trouble. Scientists say that testosterone levels play a major role in risk-taking during financial decisions such as buying homes and cars, investing, selling real estate etc. and also in recreational pursuits, especially in all of the extreme sports, which are generally dominated by fearless males bent on competing for the number one spot at the risk of self destruction.
Females and Oxytocin – “I want to have babies with you!”
It is very natural for females to fall in love following an episode or two of quality bonding with a healthy male, no matter how casual and no matter how pregnant she is or isn’t. Hundreds of thousands of years of having to raise cave babies by themselves has created a very natural hormonal response for a woman to want to attract and form a long term relationship with a healthy able-bodied hunter/gatherer. Females, directed by their primitive cave-woman brains along with healthy doses of oxytocin (The “love hormone”), adrenaline (also called epinephrine - sweaty palms, butterflies in your stomach), dopamine (Euphoria - “You make me feel so good!”), seratonin (“I can’t get you out of my mind!”) and vasopressin (“I want you for me!”) make women fall prey to feelings of attachment and they desire long term bonds.
Do you know why your cat purrs when it is petted and why your dog will run for miles for a pat on the head? Hormones. Years and years of breeding animals with high levels of oxytocin and vasopressin which are neuropeptides associated with the love of physical touch. We have it too.
Bonding/Love and Attachment
Recent studies in neuroscience have indicated that as people fall in love, the brain consistently releases a certain set of chemicals, including pheromones (“oh baby I love how you smell!”), dopamine (Euphoria - “You make me feel so good”), norepinephrine (“Oh you make my heart race!”), and serotonin (“I can’t get you out of my mind!”), which act in a manner similar to amphetamines, stimulating the brain's pleasure center and leading to side effects such as increased heart rate, loss of appetite and sleep, and an intense feeling of excitement. Research has shown that this stage generally lasts from one and a half to three years. Since the lust and attraction stages are both considered temporary, a third stage is needed to account for long-term relationships. Attachment is the bonding that promotes relationships lasting for many years and even decades. Attachment is generally based on commitments such as marriage and children, or on mutual friendship based on things like shared interests.
There is a brief moment in time, when males and females experience a hormonal break from all of their differences. A time when the world stands still for them and all that remains is the synchronized beating of their hearts free of anything but absolute unison. That’s right. Post copulation, the brief, yet intensely interpersonal moments after sex. Modern brain scans show that when testosterone and endorphins in ejaculated semen meet the women’s cervical wall, females receive a spike in testosterone, endorphins and oxytocin. Both men and women feel the effects of oxytocin but to varying degrees; a man is said to release oxytocin during and immediately after sexual climax, but a woman feels the release of oxytocin during the arousal phase, and then continued releases with each successive orgasm. Initially, oxytocin is released into the blood during hugging, cuddling, sensing of pheromones, touching, kissing and of course foreplay including arousal, oral sex, orgasms and good old fashioned copulation. The physical and emotional effects of this flood of oxytocin include increased sensitivity of nerve endings, involuntary muscle contractions, increased heart rate, a temporary feeling of bonding and attachment plus the desire to touch and be touched. This is one reason why a woman feels the need to cuddle after sex and feels more of an attachment to her partner, even following a casual sexual encounter.
While writing and researching this essay, I took a sentimental journey back to the 90’s when my marriage was wallowing in a complete lack of intimacy. I now understand the deterioration of those feelings of bonding and attachment given the lack of oxytocin and other hormones necessary to keep the bonds alive.