3.4 billion years ago - Life appears. According to the fossil record, relatively complicated organisms like bacteria already existed when the earth was only one billion years old.
450 million years ago - the first Fishes. They posessed a very small brain, the first one that had existed on the earth up to that time.
300 million years ago - the first Reptiles. The brains of our reptile forebears were divided into three compartments: a front compartment for smell, a middle compartment for vision, and a rear compartment for balance and coordination. The basic instincts of survival - sexual desire, the search for food and the aggression responses of 'fight-or-flight' - were wired into the the diencephalon (a region between the smell brain and vision brain).
200 million years ago - the first Mammals
When the mammals evolved out of the reptiles, their brains began to change. First they developed a new package of instincts, related to the reptilian instincts for sex and procreation, but modified for the special needs of a mammalian lifestyle. Chief among these was the instincts for parental care of the young.
120 thousand years ago - Homo Sapiens appears. The growth
of the cerebral cortex reached explosive proportions in the last million
years of human history, culminating in the appearance of Homo Sapiens.
The primitive region in the brain, that held the circuits for the instinctive behavior of the reptile and the old mammal, was now completely enveloped by and buried within the human cerebral cortex. Yet this ancient command post is still active within us; it still vies with the cerebral cortex for control of the body, pitting the inherited programs of the old brain against the flexible responses of the new one.
From the book: 'The Enchanted Loom, Mind in the Universe' by Robert Jastrow
The hypothalamus is an exceedingly ancient structure and unlike most other
brain regions it has maintained a striking similarity in structure throughout
phylogeny and apparently over the course of evolution.
The hypothalamus is fully functional at birth and is highly involved in all aspects of endocrine, hormonal, visceral and autonomic functions and mediates or exerts controlling influences on eating, drinking, the experience of pleasure, rage, and aversion. The hypothalamus is the central core from which all emotions derive their motive force. The hypothalamus is also sexually differentiated. That is, structurally and functionally the hypothalamus of men and women are sexually dissimilar.
'The Limbic System. Foundations of Social, Sexual, Emotional Behavior, Love & Memory.' (Rnawn Joseph, Ph.D. The Brain Research Laboratory)
In recent years, neuroscientists have found that male and female brains are wired differently because of the role of testosterone and other male hormones during gestation. Brains growing under the influence of male hormones are slightly larger and have denser concentrations of neurons in some regions.
Male brains also contain a greater proportion of gray matter, the part of the brain responsible for computation, while women have relatively more white matter, which specializes in making connections between brain cells
Average IQ is the same among men and women.
Intelligence tests have found that men, on average, perform better on spatial tasks that require mentally manipulating objects. Men also do better on tests of mathematical reasoning. Women tend to do better on tasks requiring verbal memory and distinguishing whether objects are similar. The relative strengths tend to even out, studies indicate.
If men do have a slight advantage in math ability, is the difference really biological, or are exceptional girls and women intimidated by cultural stereotypes and discouraged from cultivating their talents from an early age?
The Boston Globe. Matt Crenson, Associated Press. February 28, 2005
vs Nurture: Male and Female Brains. Biology, Hormones, Culture
From the essay: "Scientists working at Johns Hopkins University, reporting in the 'Cerebral Cortex' scholarly journal, have discovered that there is a brain region in the cortex, called inferior-parietal lobule (IPL) which is significantly larger in men than in women. This area is bilateral and is located just above the level of the ears (parietal cortex).
Furthermore, the left side IPL is larger in men than the right side. In women, this asymmetry is reversed, although the difference between left and right sides is not so large as in men. This is the same area which was shown to be larger in the brain of Albert Einstein, as well as in other physicists and mathematicians. After allowing for the natural differences in overall brain volume which exist between the brains of men and women, there was still a difference of 5% between the IPL volumes (human male brains are, on average, approximately 10 % larger than female, but this is because of men's larger body size).
Another study by the same group has shown that two areas in the frontal and temporal lobes related to language (the areas of Broca and Wernicke, named after their discoverers) were significantly larger in women, thus providing a biological reason for women's notorious superiority in language-associated thoughts. Using magnetic resonance imaging, the scientists measured women had 23% (in Broca's area) and 13% (in Wernicke's area) more volume than men."
As most teenage boys know, it's not easy to keep hormones in check. While
humans can control their level of sexual excitation with some effort, a
new study suggests that this skill is a fairly recent gift from evolution.
By studying men watching pornographic videos, researchers in Canada have pinpointed areas of the brain that become active when the men tried to avoid being stimulated. In evolutionary terms, these regions of restraint are newer than the more primitive areas where the sexual urges arise in the first place.
Only primates have prefrontal cortexes. That region of the brain, located right behind the forehead, is most advanced in humans and is involved in analytical thinking, multitasking and problem solving.
The men's prefrontal cortexes turned on when they tried to control themselves. By contrast, erotic feelings prompted activity in older parts of the brain, including the region known as the limbic system, and the neocortex, which allows people to be aware of their feelings.
http://www.edwardtbabinski.us/male_brain/ - By Randy Dotinga November 29, 2006.
Scientists have concluded that women achieve most sexual satisfaction through
the stimulation of their brain and not any other organ. After eight years
of tests involving 3,000 women, Pfizer, the company behind Viagra,
the little blue pill that has transformed men's sex lives, has abandoned
efforts to prove that the drug works for females too.
Studies found that even though Viagra induced a greater pelvic blood flow in women. they did not feel substantially more aroused.
'The visual image is processed by the right side of the brain; print by the left. The latter is rational and analytical; the former holistic and pattern-recognising.
Left brain/right brain research is beyond the scope of analysis of this paper, but clearly questions need to be asked about the impact of the visual (whether photographic or film) image on the brain, particularly the male brain, which recent research indicates has much less connection between its left and right halves than the female brain, and therefore possibly much less opportunity for the rational left to control the impulses generated by the impressionistic right.'
'Sexual Offenders and Pornography: A Causal Connection?' by Marlene Goldsmith, Chairman, Legislative Council Standing Committee on Social Issues, Parliament of New South Wales
When your eyes are presented with erotic images in a way that keeps you from becoming aware of them, your brain can still detect and respond to the images according to your gender and sexual orientation, a team of University of Minnesota psychologists has found.
The purpose of the work was to uncover mechanisms by which the brain processes
visual information that is not consciously perceived by the subjects. The
researchers chose to generate brain activity by using erotic pictures because
they promised to elicit strong responses and clear patterns in the data.
But the researchers believe the mechanisms by which the brain processes
such images are universal.
'This definitely doesn't just work for erotic pictures,' said psychology professor Sheng He, 'But erotic images stand out in terms of potency to generate a response.'
http://www.sciencedaily.com/releases/2006/10/061026185636.htm - University of Minnesota
A new study suggests the brain is quickly turned on and 'tuned in' when a person views erotic images. Researchers at Washington University School of Medicine in St. Louis measured brainwave activity of 264 women as they viewed a series of 55 color slides that contained various scenes.
When study volunteers viewed erotic pictures, their brains produced electrical responses that were stronger than those elicited by other material that was viewed, no matter how pleasant or disturbing the other material may have been. This difference in brainwave response emerged very quickly, suggesting that different neural circuits may be involved in the processing of erotic images.
A great deal of past research has suggested that men are more visual creatures
than women and get more aroused by erotic images than women.
'Usually men subjectively rate erotic material much higher than women,' says Andrey P. Anokhin (Ph.D., Research Assistant Professor of Psychiatry). 'So based on those data we would expect lower responses in women, but that was not the case. Women have responses as strong as those seen in men.'
http://www.sciencedaily.com/releases/2006/06/060614000616.htm - Washington University School of Medicine
This book by David C. Geary attempts to explain human sex differences from
a single theoretical perspective, Darwin's principles of sexual selection.
Rather than study gender roles (cultural constructions), which is the norm of many social scientists, Geary explores evolutionary biology.
Page Title: 'Evolutionary Philosophy of Mind: Male Female Brain,
Sex Difference, Left Right Emotion Reason, Mental Health, Drugs'.
Want to be Involved? Join us in this research, which provides an excellent opportunity to present to the world the latest knowledge about the thing we all find most interesting - sex! The work will not just benefit humanity, it will profoundly enhance your own sexuality as you learn more about our complex and diverse sexual evolution.
We seek help in finding the latest scientific (evolutionary) research on our biological and cultural sexual evolution and distributing content (overviews / summaries) to relevant pages.
This site is well respected. We are listed as the Top Philosophy Website on the Internet with around 600,000 page views each week. So your contributions will be seen and read, and will be providing humanity with a great source of wisdom about a very important subject (that currently suffers due to cultural / religious myths).
If you would like to be involved (or have comments about this website) please write to us. Many thanks! Karene
Analyse any human emotion, no matter how far it may be removed from the sphere of sex, and you are sure to discover somewhere the primal impulse, to which life owes its perpetuation. ... The primitive stages can always be re-established; the primitive mind is, in the fullest meaning of the word, imperishable. ... Mans most disagreeable habits and idiosyncrasies, his deceit, his cowardice, his lack of reverence, are engendered by his incomplete adjustment to a complicated civilisation. It is the result of the conflict between our instincts and our culture. (Sigmund Freud)
We get a lot of people writing to us asking questions about sex. So we have added an 'Ask a Question' feature to our sexuality pages - to help share questions and answers as a way of helping one another.
Please use Facebook Connect (below) to add your questions / comments - the best questions and answers will be added to the page.
Karene (September, 2012)
Come and say hello to Karene - join a friendly (kind, sexually enlightened, moral) network.
Related PagesPhilosophy of Sexual Evolution: Beauty, Bonding, Health, Pleasure
|Anatomy: Pictures and Information on the Male and Female Human Body||Nudity: Public vs Private (Family). Evolution, Culture, Ethics, Law|
|Animal Copulation: Interesting Facts & Pictures of Animal Mating Behaviour||Philosophy of Love, Sex & Orgasm|
|Beauty & Natural Health: What we have Evolved to Find Beautiful||Pleasure: Erogenous Zones, Mind & Body|
|Beautiful Babes: Beauty of Body & Mind, Picture Gallery of Women||Primate Sexual Behaviour|
|Biology: Human Sexual Biology, Male & Female Genitals||Promiscuity: Male & Female Reproductive Strategies, Competition, Benefits|
|Brain: Sexual Arousal, Orgasm, Limbic System, Left Right Emotion Reason||Relationship Advice for Couples: Cultivation, Creativity, Love & Truth|
|Differences between Men & Women: Parental Care, Mating Strategies||Reproduction: Sexual vs Asexual, Male & Female Reproductive Systems|
|Hair & Clothing: Evolution of Body Hair, Sexuality, Beauty & Fashion||Sleep: Disorders, Sleeping with Family (Baby, Children, Dog)|
|Hormones: Function of Oxytocin, Estrogen, Testosterone||Testosterone: Androgens, Declining Levels, Emotions, Violence|
|Immune System: Function, Strengthen Immunity with Sex|
Support an open honest discussion of human sexuality by
sharing this knowledge.
Evolution of the Male Female Brain: Sexual Arousal, Orgasm, Hormones, Limbic System, Left Right Emotion Reason
Map - Academic
Sexology Studies & Good Quality Sexual / Erotic Sites - Banners
/ Reference Books - Contact
Email - About
Us & Site Statistics - Reasons
for this Sexuality Study - Legal
Truth & Reality
The Spherical Standing Wave Structure of Matter (WSM) in Space
Theory of Reality
Unity of Reality
Logic & Reality
Special & General
of Light & Matter
& Infinite Space
Truth & Reality