The Male Brain
twenty times more often than women do: Campbell 2006.
firing up his fighting circuits: Wirth 2007. and body for a fight: Becker 2009. For more on testosterone changes and power motivation in victory versus defeat, see Schultheiss 2005. For more on anger and driving, see Leal 2008.
changes prompting his aggressive behavior : Stanton 2007 and 2009b found that higher testosterone makes the male amygdala less responsive to fear and more ready to fight in the face of a dominance dominance, testosterone, and Mazur 1998, Archer 2006, Eme 2007, and Carre 2008. challenge. For more on physical aggression, see
emotional events better and longer : Cahill 2004. Canli 2002 found that women had more brain regions where emotions enhanced memory more powerfully, causing women to remember emotional events better than men.
for memory enhanced by emotion : Phelps 2004 found that the amygdala and hippocampal complex are linked to two independent memory systems and that in emotional situations, these two systems interact in subtle but important ways.
the emotion that they're feeling: Canli 2002 and Cahill 2004. and activate his territorial fight reaction : Stanton 2009b. Van Honk 2007 found that in humans a surge of testosterone reduces fear responses and stress-axis reactivity in the brain, altering the natural avoidance of threats by decreasing fear.
their anger harder to control : Wirth 2007 found that anger in faces was pleasurable and reinforcing to those with higher testosterone. They suggest that testosterone specifically encourages approaching and engaging with angry faces since it is a signal of dominance challenge. Carre 2009 found that changes in testosterone can ignite future aggressive behavior in men.
angry got him fired up : For more on testosterone fueling aggression, see Stanton 2009b, Wirth 2007, and Archer 2006.
if those feelings are unpleasant : Tamir 2008 found that individuals may choose to experience emotions that are instrumental (useful), despite short-term hedonic (unpleasant) costs.
us think more clearly, too: Tamir 2008. people more rational, not less: Tamir 2008. Anger has been claimed to trigger
information processing, but
superficial, nonanalytic
Moons 2007 found that induced anger promoted analytic processing. The study showed that angry people can have both the capacity and motivation to process and think more clearly.
acceptable to express their anger : For more on males' anger expression, see Dabbs 1996, Mazur 1998, and Archer 2006. Archer 2006 reports that the fear of males in females begins in the first or second grade. Archer 2009 found that sex differences in physical aggression increase with the degree of risk, occur early in life, peak in young adulthood, and are likely to be mediated by greater male impulsiveness and greater female fear of physical danger.
more dramatically to being challenged: Schultheiss 2003. For more on high-testosterone men, see Archer 2006. more aggressive than subordinate males : For more on dominance and subordination in primates, see Wrangham 2004, Sapolsky 1986 and 2005, and Archer 2006.
dominance, thus increasing his testosterone : For more on dominance challenges, fear, and testosterone, see Van Honk 2001, Hermans 2006, and Josephs 2006. Mehta 2009 found that high-testosterone winners chose to repeat the competitive task, whereas high-testosterone losers chose to avoid it.
by other men but also by women : Williams 2006 found that there is a perceptual system in both males and females that has evolved to rapidly detect aggression in males and that angry men get noticed more by both sexes. Cox 1999 found that angry men are also judged to be more competent; angry women are judged to be less competent. Roney 2006 found that women have a preference for male faces that indicate higher testosterone.
"you suppressed your anger altogether" : Harburg 2008 found that a good fight with your spouse may keep you and your marriage healthier.
tendency toward anger and aggression: Maner 2007 found that men behave differently when the dominance hierarchy is unstable and there is potential for losing their power.
dialed down by social conditions : Reber 2008 found that subordinate/dominant behavior in an unstable hierarchy influences the hypothalamic production of vasopressin and that subordinate males' exposure to dominants results in diminished body weight and increases anxiety-related behavior. They found that the hormones of aggression in the brains of subordinates decrease after only twenty days.
factors that dial it down: Burnham 2003 found that testosterone is lower in men who are in stable, committed relationships.
preparing them for turf wars : Ferris 2008a found that the neural circuitry of aggression and territorial defense can be dialed up with vasopressin.
in his hypothalamus and amygdala : Ferris 2008a found that the hypothalamus and amygdala help bridge the emotional, motor, and cognitive components of the brain's aggressive responses. The study found that drugs that block vasopressin neurotransmission suppress activity in circuits for aggression and motivation.
is wired into the male brain : Kozorovitskiy 2004 found that differences in social status correspond to structural differences in the male brain. They found that higher social status accounts for the effect that dominance has on growing new brain cells in the adult male brain.
to gain or maintain rank: Wrangham 2004. as they anticipate a confrontation : For more on rank, aggression, and confrontation in humans and primates, see Mazur 1998, Archer 2006, and Stanton 2009.
opponents within their own species: For more on male-male fighting and competition, see Motta 2009, Wrangham 2004, and Archer 2006.
circuitry for this instinctive one-upmanship : Motta 2009 found an area in the male brain's hypothalamus, called the DPN, is activated for instinctive one-upmanship in male rats for territory protection against higher-ranking males.
SEVEN: THE MATURE MALE BRAIN
he had in his thirties: McCrae 1996 found that personality is stable throughout life. suited to a luxury sedan : Mehta 2009 found that men with lower testosterone are more motivated to cooperate with others. Mykletun 2006 found that men in their fifties are more satisfied with their sex lives than men in their thirties and forties. And that men in their fifties recorded similar levels of satisfaction as twenty-to twenty-nine-year-old men.
make less testosterone and vasopressin : Rosario 2004 and 2009. Geenen 1988 found that young men make more vasopressin than oxytocin due to their high testosterone levels. Debiec 2005 found that oxytocin increases feelings of attachment and love, whereas vasopressin increases feelings of territoriality and defense. Huber 2005 found that vasopressin and oxytocin modulate the brain's circuits for love and fear via their different effects on the amygdala.
increases as men get older : Rosario 2009 found that in male brains, during normal aging, there was no decrease of estrogen but there was a decrease of testosterone. The ratio of estrogen to testosterone in men thus increased with age. Berchtold 2008 found that clear gender differences in brain aging are evident, indicating that the brain undergoes sex-specific aging changes in gene expression, not only in the developmental period but also in later life.
the cuddling and bonding hormone: Domes 2007b. Ditzen 2009 found that the effects of increased oxytocin on a couple's relationship could be measured during conflict oxytocin, communication behavior in relation to negative behavior during the couple's conflict discussion. Heinrichs 2008 says that vasopressin has been implicated as a primary factor in male-typical aggressive social behaviors, whereas oxytocin reduces conflict, anxiety, stress, and aggression. Thus relatively more oxytocin and less vasopressin may improve conflict resolution in close relationships.
resolution. When researchers gave more
it significantly increased positive to read subtle facial expressions : Domes 2007b found that oxytocin improved the men's performance on a test of the ability to "read the mind" of others from just looking at subtle facial expressions of the eyes and face. Unkelbach 2008 found that oxytocin increases the use of relationship words and language.
more dramatic effect on them : Juntti 2008 and Jo
rdan 2008. Kosfeld 2005 found that giving young men oxytocin increased their ability to trust others. Fliers 1985 found that with aging, the male brain changes in areas producing vasopressin, especially in brain areas where vasopressin innervation is dependent on higher testosterone levels. Thus as testosterone goes down and estrogen stays the same, the male brain may make not only less vasopressin but more oxytocin, becoming more like the female's.
she looked up to him: For more on the brain circuits involved in admiration, see Immordino-Yang 2009. listener, and be more affectionate : Burri 2008 found that when oxytocin was increased in men, the men's sexual arousal increased. And when the men in the study were asked about their subjective perception of whether oxytocin or placebo had been applied, eight out of ten subjects in the oxytocin group answered correctly, thus pointing to an altered perception of sexual arousal by oxytocin.
as his testosterone production declined : Johnson 2006 found that higher testosterone increases the drive to outdo other men.
no longer worth it to him : Winning and losing may not matter so much, and cooperation may matter more to men as their testosterone levels mellow out. Mehta 2009 found that high-testosterone men are motivated to gain status (good performance in individual competition), whereas low-testosterone men are motivated to cooperate with others (good performance in intergroup competition). So with age, a man's need for dominance may have biologically subsided.
group stability, and mediate conflict: Yamagiwa 2001.
up in trees for protection: Yamagiwa 2001. meant more than being lovers : For more on the hormones of pair bonding, see Young 2009 and Carter 1998. Kendrick 2000 found that after sexual intercourse, in the female the stimulation of the cervix and vagina, along with orgasm, causes a coordinated release of oxytocin in the brain that acts to increase maternal and pair-bonding behaviors lasting for up to one hour.
she is no longer fertile : Tuljapurkar 2007 found that female menopause, around age fifty, should theoretically be followed by a sharp increase in mortality for humans, a "wall of death." Their analysis showed that older men reproducing with younger women throughout evolution is what forms the basis for increasing human longevity in both sexes. For more on the genes of longevity, see Emery 2007.
in men who are social: Cacioppo 2009c.
the long run, as smoking: Cacioppo 2009b. engraved into their brain circuits : It turns out that for men, health and marriage are more connected than for women because men get most of their social interaction after retirement via their wives' social connections and social planning skills. For more on the brain and aging, see Decety 2009, Dedovic 2009, and Cacioppo 2009a.
circuits are weakened from disuse : Decety 2009 found that men need to use their social and emotional cognition and problem-solving circuits, or else their temporal-parietal junction (TPJ) will atrophy. The TPJ is associated with cognitively taking the perspective of another person, which happens only if other people are around to activate that part of the brain. Also see Cacioppo 2009b.
retained their reproductive abilities longer: Schmidt 2009. people who are socially isolated : Cacioppo 2009b found that the brain's TPJ is much less activated among the lonely than in the nonlonely. And the lonely also activate their brains' reward circuits less. So they begin to get less pleasure out of interacting with others, and their brains' social circuits may become less responsive if they stay lonely too long.
get married and stay married : Willcox 2006 found that before age eighty-five, the lack of a marital partner is associated with increased mortality. Schmitt 2007 found that marital satisfaction well-being and that a interaction is particularly important in predicting marital satisfaction and long marriages.
is important for health and
high quality of interpersonal men live 1.7 years longer: Smith 2009 found that marriage factors and health differ for men and women throughout the life span because being married shortens a woman's life by 1.4 years but lengthens a man's by 1.7 years. The study found that bad marriages, with lots of arguing and negative feelings, make both sexes stressed but cause physical illness only in wives. The men in bad marriages reported stress and reported being depressed, but their physical health didn't seem to be affected. For more on marriage and health, see Kiecolt-Glaser 1998, 2001, and 2005, Gabory 2009, Behar 2008, Willcox 2006, Felder 2006, and Levenson 1993.
make a man a man : Beach 1967 found that the male brain's sexual-pursuit and arousal circuits must be primed for action by testosterone in order for the man to function. For more on testosterone and sexual function, see Moffat 2007.
so-called andropause, or male menopause : Sharma 2009 found that the benefits of treating severely low testosterone are well established. Milder forms of low testosterone in the aging male, known as andropause, are common starting in the fifties and sixties. Researchers say that testosterone replacement therapy may produce a wide range of benefits for men, including improvement in libido, bone density, muscle mass, body composition, mood, and cognition. But they say there is no definitive verdict on the balance between risks and benefits of testosterone replacement therapy in aging males. For more on testosterone replacement in the aging male, see Lapauw 2008, Anawalt 2001, Qian 2000, Heaton 2001, Lincoln 2001, Hogervorst 2009, and Van Strien 2009. of life also includes sex: Smith 2007 found that desire for sexual activity remained high among men seventy and older. Colson 2006 found that almost 70 percent of men reported they would like to change some things about their sex life. Kontula 2002 found that, especially with the increased duration of the relationship, the frequency of masturbation actually increased in men who were in long-term partnerships, even if penile-vaginal sex was occurring regularly. Beaulieu-Prevost 2007 found that men after age forty continue to have reflexive erections while they're sleeping. Eight percent of older men's dreams were about intercourse and resulted in nocturnal erection. Laumann 1999 found that masturbation increased in older men because their current partner did not want sex; this was three times more often in men than in women.
at this stage in life : Siegel 2007 found that sexual changes that occur in men as they get older affect their self-perception and sexual identity. Janssen 2008 found that changes in the quality of older men's erections had a direct effect on their sexual encounters, including, for some, a shifting of focus to the partner and her sexual enjoyment. In this study, older men said that as they aged, they became more careful and particular in choosing sexual partners.
they produced in their twenties : Tanagho 2000 found that a man's testosterone peaks at about age seventeen; then it plateaus at a high level for a while and may slowly start to slide by the thirties and forties; then, by eighty, his testosterone may be less than half of what it was when he was young. Vermeulen 1999 says that as age increases, a man's body fat increases and his testosterone goes down. For more on testosterone and aging, see Qian 2000, Araujo 2007, and Laughlin 2008. For approaches to evaluating and treating men with low testosterone, see Snyder 2008.
quickly becoming a marital problem : For comprehensive research data on age, couples, and sex, see Laumann 1999. Erectile dysfunction (ED) is a common condition estimated to affect more than 150 million men worldwide. Doctors now believe ED should be regarded as a shared sexual problem because it has significant detrimental effects both on the men who experience it and on their partners. So the wives or partners should be included in treatment decisions for Viagra-like drugs or testosterone. Isidori 2005a found that in older men with sexual complaints, testosterone treatment moderately improved
thoughts
the number of nocturnal erections, sexual and motivation, number of successful
intercourses, scores
sexual satisfaction,
of erectile function, and overall but that in men with normal
testosterone levels at the beginning, the testosterone had no effect on erectile function compared to placebo. Mulhall 2008b found that 74 percent of men were willing to take erection-enhancing drugs if necessary. For more on treatment, see Wang P.
2009 and Sharma 2009.
organs working at full capacity : Redoute 2005 found that the brains of men with very low testosterone did not light up in the areas necessary for sexual arousal as they watched sex movie clips in the brain scanner. But after the males were injected with testosterone, these brain areas flashed back on again.
testosterone can kick-start abdominal weight loss: Gooren 2009. Srinivas-Shankar 2009b found that testosterone treatment in older men with low levels of testosterone composition function, and cognition. might have beneficial effects on body
(losing fat), muscle strength, sexual men, that's still not enough: For more on DHEA, androgens, and aging, see Rainey 2008, Baker 2006, Dharia 2004, Anawalt 2001, Parker 1999, and Sapolsky 1993.
results from androgen-replacement therapy: Cherrier 2007 studied the cognitive responses of older men in whom moderate or large increases in serum testosterone levels were induced by testosterone supplementation, and found that those with moderate testosterone replacement did better on cognitive tests.
and it's not for everyone : Wang P. 2009 says men must be monitored closely for prostate function and for prostate and breast cancer when considering or being prescribed testosterone replacement.
there may be other answers : Exercise, lowered stress, loving relationships, and healthy diet are well-proven aids to healthful aging in both men and women. Also see Roberts 2008.
men as the hormone DHEA : Unpublished data. Soma 2008 found that the adrenal androgen precursor dehydroepiandrosterone (DHEA) may be important for the expression of sexuality and aggression when gonadal testosterone synthesis is low. DHEA is metabolized into active sex steroids, both in the periphery and within the brain itself. For more on DHEA in development and aging, see Parker 1999.
marriage, even into old age: Laumann 1999a. "asked my doctor for Viagra" : Rosen 2006 found that for mature men, Viagra started a revolution, and this was true even for older men who did not have ED (erectile dysfunction). This is because older men now get the message: "Other guys are having a lot of sex as they get older. Why not me?" The researchers also found that the outcome in men with erectile dysfunction could be helped or hindered by their partners or wives.