Let's Talk About Sex in Psychology.

 Biological Sex & Gender Identify

People have been having sex and writing songs about it carving statues of it and changing fashion for it since the dawn of humanity. But it wasn't until fairly recently, in the 1940s, that serious Western scientific study of sex began. And by most accounts, you can thank one guy for that, Alfred Kinsey. Kinsey was born in 1894 in New Jersey to poor, strict Methodist parents. He studied entomology in college, graduating with degrees in biology and psychology before heading to Harvard. His doctoral thesis was on the genealogy of gall wasps, a subject he tackled with intensity, meticulously collecting over five million samples, and measuring hundreds of thousands of specimens. Wasps are interesting and everything, but Kinsey's interest drifted toward human sexuality, and his research at Indiana University paved the way for decades of study into sex. 

He surveyed thousands of men and women about their sexual habits and histories and found all sorts of interesting things related to sexual preferences, masturbation, orgasms, and premarital sex. He established the Kinsey Scale, indicating degrees of sexual orientation, and went on to write seminal texts on sexual behavior in human males and females, respectively. Like many of the first researchers of human behavior, Kinsey and his colleagues were, and in some ways still are, pretty controversial. But he definitely succeeded in two very important tasks. One, he was an early adopter of a scientific approach to studying sex, and two, he showed that the popular perception of what people do and don't do sexually versus what people actually do and feel was often very different. 

Since then, we've seen innumerable sex-related studies examining the physiological, psychological, and social elements of sex. And there's a whole lot of lingering misinformation and judgy morality swirling around the subject of sex. It can be a tricky topic for sure, but we are here to clear some things up. It's the entire purpose of life, so there's no reason to blush. So, sex. That one little word has complicated so many lives. The desire for or lack of sex has spawned poetry and made babies and transmitted diseases and cost money driven people batty and kept late-night cable and business. Even the word itself can mean many different things. First, we got the verb kind of sex, the physical process of engaging in sexual acts and intercourse, which probably I don't need to describe to you. 

Then we've got the biological definition having to do with anatomical parts that go with the designations of male female or intersex. those who are born with reproductive parts that don't fall into predominant definitions of male or female. These are quite separate from gender, or an individual's sense of identifying as male or female or another gender identity, regardless of how that corresponds with their actual reproductive plumbing. For transgender people, for instance, gender identity typically doesn't match biological sex. And remember that gender identity is completely different from sexual orientation, which we'll talk about in a minute. So beyond definitions, we've got the physiological and the psychological aspects of sex. Let's start out with the physiological, and with that, Masters and Johnson. In the late 1950s and 60s, American gynecologist William Masters and his collaborator and future wife, sexologist Virginia Johnson, did something no researcher had ever done before. 

They invited nearly 700 male and female volunteers, many of whom were sex workers, to come into their lab and get it on, either alone or with their partners. Their aim? To record the body's physiological response to sex. This involved wearing a whole lot of wires and heart monitors and such, and it was probably about as sexy as it sounds. All the volunteers had to be willing and able to show arousal and capable of orgasm, and over the years, Masters and Johnson recorded more than 10,000 sexual cycles. The main thing they documented was that a complete sexual response cycle involved four distinct stages. Excitement, plateau, orgasm, and resolution. which Masters and Johnson maintained happened linearly, one after the other. In the excitement phase, things are getting going. 

Blood is rushing to all of the necessary places. Genital areas are becoming engorged and secreting lubricant. Next comes the plateau phase. Pulse blood pressure and breathing rates keep increasing and genitals are becoming fully engorged. The penis is often secreting pre-ejaculate as vaginal secretions increase until the big event, orgasm, during which muscles all over the body contract and breathing and pulse rates hit their peak. Of course, a biological male orgasm typically releases sperm that may lead to fertilization, depending on the situation. But female arousal and orgasm also help facilitate conception. Again, depending on the situation, those muscle contractions and lubrication help draw up and retain sperm in the uterus. Finally, the body comes back down to its normal state of affairs during the resolution phase. 

It's during this phase that biosex males enter a refractory period, during which they're unable to orgasm again for a few minutes, to a day or more, whereas a biological female's refractory period is very short in comparison. While the four-stage model of sexual response is still taught today, some have criticized both its rigid linear setup, arguing that things don't always work so tidily in the bedroom, and its insistence on including orgasm, which doesn't happen for everyone all the time. Others also question the model's clinical focus on only physiological factors, arguing that cultural attitudes, psychological and relationship factors, and other external details should also be considered when looking at sexual response. I'll get back to that in a minute, but before we move on to the psychology of sex, we've got to talk about hormones. 

You remember hormones, those chemical messengers brewed up by the endocrine system that travels through the bloodstream and regulates all sorts of physiological and behavioral activities from growth to digestion, to sleep, to sex. Our sex hormones serve two major purposes. One, they direct the physical development of biological sex characteristics, and two, they help activate sexual behavior. Estrogens, like estradiol, contribute to female sex characteristics and are secreted in greater amounts by females than males. And while all humans make testosterone, it's the predominant sex hormone for males, stimulating the growth and development of male sex characteristics. Now, most female mammals become sexually receptive when their estrogens peak during ovulation, but doesn't really work that way for humans. Our hormones are more loosely related to sexual behavior, although studies have found that, in general, female sexual desire spikes slightly around ovulation, when women are most fertile, and males can also be affected by this spike, responding with higher levels of testosterone when ovulating women are around. 

But these short-term changes hardly compare to the larger, more major hormonal shifts that occur throughout a lifetime. Puberty, for one, tends to get everyone a lot more hot and bothered and interested in dating and gazing at posters of their favorite celebrity crushes. Later in life, as sex hormone production naturally decreases, our amorous urges and endeavors tend to decrease as well. Age affects our libido. But in the end, you might think of sex hormones as fuel for your sexual engine. And while an engine can't run on a totally empty tank, it also won't run any better or worse on a full tank versus a half tank. We need our sex hormones, but we also need the right psychological stimuli to turn us on and keep us going sexually. 

So, finally, let's look at some of these psychological aspects of sex. First, there are the very important social and cultural influences Things like your families, your societies, your religions, and your personal values. Does your community view sex merely as the means for reproduction, or can it be fun too? What are the views on premarital sex and homosexuality? Showing some skin or kissing in public? Then there are the influences of external stimuli. In Western society, we're constantly bombarded with sexually charged content from movies and TV to advertisements, R&B slow jams, and Victoria's Secret catalogs, and constantly looking at images of things that you find extremely attractive can lead to folks viewing more average people, even their own partners, as being less attractive. But our sexual desire is also fueled by internal stimuli, our imagination memories, and fantasies. 

According to plenty of studies, at least 95% of people fantasize about sex at some point. The thing you gotta keep in mind is that none of these factors work independently of each other. How we respond to both external and internal stimuli can be really heavily influenced by social and cultural factors, and that is where a lot of the thinking and studying of sex has gotten really complicated. Human judgment and morality are often entangled with sex and desire, and sadly, a lot of people have been made to feel miserable for liking certain things or being attracted to certain people. There's also just been a lot of misinformation out there. For ages, a lot of folks believed that masturbation could make you go blind, become mentally ill, or kill the neighborhood kittens, it doesn't do that. And as I know you're thinking right now, one area of sexuality that's been needlessly associated with conflict, fear, and shame in many cultures is sexual orientation. 

For our purposes, sexual orientation can be defined as a relatively enduring physical or romantic attraction to another person. Heterosexual, homosexual, and bisexual are all types of sexual orientation, and although the field once stigmatized non-heterosexual orientations, we now know that homosexuality and bisexuality are in no way related to mental health. Psychologists are also beginning to look more in-depth at other sexual orientations. For instance, asexuality or nonsexuality, where no sexual attraction of any kind is experienced. In any case, whether a culture itself is friendly to or tyrannical against any of these orientations, all types prevail. 

Sexual orientation is neither chosen nor changed. So, what might cause these differences? Hopefully, you already know this, but it's worth repeating. There's no evidence that sexual orientation is determined by things like a dominating mother or a passive father, or sex hormone levels in your adult body, or your history of childhood abuse, or whether your parents were gay or straight. In other words, Decades of research have led most researchers to believe that once you're born, there are no clear environmental factors that influence your sexual orientation. And there's been a lot of research into possible biological components of sexual orientation, like genetics, brain anatomy, prenatal conditions or other things, it's also important to know that we're far from understanding sexual orientation on a purely biological level. 

If anything, the evidence we've got simply strengthens the idea that sexual orientation isn't a choice, but rather a naturally varying occurrence among human beings, like height. So, after all this talk about sex, perhaps you're wondering why we do it at all. I mean, It feels good, obviously, but the biggest function of sex goes beyond pure pleasure. In fact, sexual intimacy serves many of life's most basic purposes, sometimes procreation, but also stress reduction, maintaining healthy relationships, social bonding, and the expression of love and overall fulfillment. People say the brain is the most significant sex organ for a reason, and intimacy is often its own reward. Today, you learned about Alfred Kinsey's groundbreaking sex surveys, the differences between how we define biological sex and gender identity, 

and about Masters and Johnson's four-part sexual response cycle. We also looked at the role of sex hormones in our development and drive, how psychological and social factors play into sex, how we think about sexual orientation, and why we have sex in the first place.