Sex Sleep Eat Drink Dream (36 page)

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Some cases of prosopagnosia:
B. C. Duchaine and K. Nakayama, "Developmental prosopagnosia: a window to content-specific face processing,"
Current Opinion in Neurobiology
16, 166–73 (2006); Brad Duchaine, personal communication, August 2006.
Imaging studies show that neural activity:
D. Y. Tsao et al., "A cortical region consisting entirely of face-selective cells,"
Science
311, 670–74 (2006); G. Loffler, "fMRI evidence for the neural representation of faces,"
Nature Neuroscience
8:10, 1386–90 (2005).
In a recent experiment with monkeys:
D. Y. Tsao, "A dedicated system for processing faces,"
Science
314, 72–73 (2006).
Indeed, it appeared to be pretty far-fetched:
R. Quian Quiroga et al., "Invariant visual representation by single neurons in the human brain,"
Nature
435, 1102–7 (2005).

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 "
This neuron looks for all the world":
C. E. Connor, "Friends and grandmothers,"
Nature
435, 1036–37 (2005).
"
I suspect ... that if this patient":
Christof Koch, personal communication, September 2006.
Doris Tsao's work suggests:
Tsao, "A dedicated system for processing faces," 72–73.
The Tierra del Fuegans have an expression:
Howard Rheingold,
They Have a Word for It
(Louisville, Ky.: Sarabande Books, 2000), 80.
The whites of our eyes, which highlight:
H. Kobayashi and'S. Kohshima, "Unique morphology of the human eye and its adaptive meaning: comparative studies on external morphology of the primate eye,"
Journal of Human Evolution
40, 419–35 (2001).

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A team at University College London:
K. Kampe et al., "Reward value of attractiveness and gaze,"
Nature
413, 589 (2001).
Most of us prefer faces:
L. Mealey et al., "Symmetry and perceived facial attractiveness,"
Journal of Personality and Social Psychology
76, 151–58 (1999).
A team of Scottish and Japanese scientists:
D. Perrett et al., "Effects of sexual dimorphism on facial attractiveness,"
Nature
394, 884–87 (1998).
Craig Roberts and his team:
S. C. Roberts et al., "Female facial attractiveness increases during the fertile phase of the menstrual cycle,"
Proceedings of the Royal Society of London B
(Supp.), DOI: 10.1098/rsbl.2004.0174 (2004); I. S. Penton-Voak et al., "Menstrual cycle alters face preference,"
Nature
399, 741–42 (1999); Craig Roberts, personal communication, January 21, 2005.

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 "
In my lectures, I ask whether":
personal communication, Mel Rosenberg, September 2006.
To determine whether attractiveness:
R Thorne et al., "Effects of putative male pheromones on female ratings of male attractiveness: influence of oral contraceptives and the menstrual cycle,"
Neuroendocrinology Letters
23:4, 291–97 (2002).
our olfactory system is exquisitely sensitive:
R. W. Friedrich, "Odorant receptors make scents,"
Nature
430, 511–12 (2004).
Women are better at the task than men:
P. Dalton et al., "Gender-specific induction of enhanced sensitivity to odors,"
Nature Neuroscience
5, 199–200 (2002).

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According to D. Michael Stoddart:
D. M. Stoddart,
The Scented Ape
(New York: Cambridge University Press, 1991); personal communication, D. M. Stoddart, March 3, 2005.
wicked out into the world:
Charles Wysocki and George Preti, "Facts, fallacies, fears, and frustrations with human pheromones,"
Anatomical Record
281A, 1201–11 (2004); personal communication with Charles Wysocki, September 2006.
In his book
The Scented Ape: Stoddart,
The Scented Ape,
63.

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 "
If armpit odor is a turn-on":
Mel Rosenberg, personal communication, July 29, 2006.
The word "pheromone"...was coined:
P. Karlson and M. Luscher, "Pheromones: a new term for a class of biologically active substances,"
Nature
183, 55–56 (1959).
sex hormones secreted from the eyes:
H. Kimoto, "Sex-specific peptides from exocrine glands stimulate mouse vomeronasal sensory neurons,"
Nature
437, 898–901 (2005).
Among the first clues to the existence:
M. K. McClintock, "Menstrual synchrony and suppression,"
Nature
229, 244–45 (1971).
the same effect could be achieved:
M. McClintock et al., "Regulation of ovulation by human pheromones,"
Nature
392, 177–79 (1998).
Recently McClintock's team discovered:
S. Jacob et al., "Effects of breast-feeding chemosignals on the human menstrual cycle,"
Human Reproduction
19:2, 422–29 (2004); N. A. Spencer, "Social chemosignals from breastfeeding women increase sexual motivation,"
Hormones and Behavior
46, 362–70 (2004).

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exposed women to male underarm odors:
G. Preti et al., "Male axillary extracts contain pheromones that affect pulsatile secretion of luteinizing hormone and mood in women recipients,"
Biology of Reproduction
68, 2107–13 (2003).
Scientists asked women to wear a T-shirt:
D. Singh and P. M. Bronstad, "Female body odour is a potential cue to ovulation,"
Proceedings of the Royal Society of London B
268, 797–801 (2001).
Lawrence Katz ... overturned this view:
M. Luo et al., "Encoding pheromonal signals in the accessory olfactory bulb of behaving mice,"
Science
299, 1196–1201 (2003).
Since then, several studies have confirmed:
S. D. Liberies and L. B. Buck, "A second class of chemosensory receptors in the olfactory epithelium,"
Nature
442, 645–50 (2006); H. Yoon et al., "Olfactory inputs to hypothalamic neurons controlling reproduction and fertility,"
Cell
123, 669–82 (2005); Gordon M. Shepherd, "Smells, brains and hormones,"
Nature
439, 149–51 (2006).

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Women tend to prefer the odor:
C. Wedekind et al., "MHC-dependent mate preferences in humans,"
Proceedings of the Royal Society of London B
260, 245–49 (1995).
Martha McClintock and colleagues found:
S. Jacob et al., "Paternally inherited MHC alleles are associated with women's choice of male odor,"
Nature Genetics
30, 175–79 (2002).

10. BEWITCHED

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"
At night, every cat is a leopard":
Giovanni Torriano,
Piazza Universale di Proverbi Italiani; or, A Common Place of Italian Proverbs and Proverbial Phrases
(London, 1666), 171, quoted in A. Roger Ekirch,
At Day's Close: Night in Times Past
(New York: Norton, 2005), 42.

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When scientists studied the circadian:
R. Refinetti, "Time for sex: nyc-themeral distribution of human sexual behavior,"
Journal of Circadian Rhythms
3, 4 (2005).
Not surprisingly, research suggests:
J. Larson et al., "Morning and night couples: the effect of wake and sleep patterns on marital adjustment,"
Journal of Marital and Family Therapy
17, 53–65 (1991); reported in Michael Smolensky and Lynne Lamberg,
The Body Clock Guide to Better Health
(New York: Holt, 2000), 51.
Levels of testosterone ... are significantly lower:
R. Luboshitzky, "Relationship between rapid eye movement sleep and testosterone secretion in normal men,"
Journal of Andrology
20, 731–37 (1999); E W. Turek, "Biological rhythms in reproductive processes,"
Hormone Research
37 (supp. 3), 93–98 (1992).
Semen quality ... peaks in the afternoon:
A. Cagnacci et al., "Diurnal variation of semen quality in human males,"
Human Reproduction
14:1, 106–9 (1999).

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Our understanding of such positive states:
Over the past three decades, some ninety thousand studies have addressed anxiety, anger, and depression, and only five thousand have focused on happiness and joy. Figures from Paul Martin,
Making Happy People
(New York: Harper Perennial, 2006), cited in Maggie McDonald, "Cheer up children,"
New Scientist,
February 4, 2006, 56.
Touch is the sense least easily fooled:
F. Sachs, "The intimate sense,"
The Sciences,
January/February 1988, 28–34.

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The purported positive effects of massaging:
Touch Research Institutes, University of Miami School of Medicine,
www.miami.edu/touch-research/
, retrieved February 23, 2006.
Not long ago, the neurophysiologist Håkan Olausson:
H. Olausson, "Unmyelinated tactile afferents signal touch and project to insular cortex,"
Nature Neuroscience
5:9, 900–904 (2002); Olausson, personal communication, September 2006.

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Italian researchers probing the hormonal changes:
D. Marazziti and D. Canale, "Hormonal changes when falling in love,"
Psychoneuroendocrinology
29, 931–36 (2004).
Fisher ... has peered inside the head:
H. E. Fisher et al., "Defining the brain systems of lust, romantic attraction, and attachment,"
Archives of Sexual Behavior
31:5, 413–19 (2002); Helen Fisher, personal communication, February 18, 2005.

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This result confirmed earlier findings:
A. Bartels and'S. Zeki, "The neural basis of romantic love,"
Neuroreport
11:17, 3829–33 (2000).
One widely touted study ... of Swiss students:
M. Kosfeld et al., "Oxytocin increases trust in humans,"
Nature
435, 673–76 (2005).
"
A man falls in love through his eyes":
Woodrow Wyatt quoted in "Imaging gender differences in sexual arousal,"
Nature Neuroscience
7:4, 325–26 (2004).
studies of sex differences in the processing:
S. Hamann et al., "Men and women differ in amygdala response to visual sexual stimuli,"
Nature Neuroscience
7:4, 411–16 (2004).
Women are more sexually aroused:
Fisher et al., "Defining the brain systems of lust, romantic attraction, and attachment."

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When it comes to mental processing:
D. Kimura,"Sex differences in the brain,"
www.sciam.com/article.cfm?articleID=00018E9D-879D-1D06-8E49809EC588EEDF.
Functional MRI studies show:
B. A. Shaywitz et al., "Sex differences in the functional organization of the brain for language,"
Nature
373, 607–9 (1995).
In his classic studies on human sexuality:
The Kinsey Reports:
Sexual Behavior in the Human Male
(Bloomington: Indiana University Press, 1948, reprint 1998) and
Sexual Behavior in the Human Female
(Philadelphia: Saunders, 1953).

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As Leonardo da Vinci wrote:
Leonardo's essay "The Penis" quoted in Serge Bramly,
Leonardo: The Artist and the Man,
trans. Sian Reynolds (London: Edward Burlingame Books, 1991).
Contributing to the blood flow:
K. J. Hurt et al., "Akt-dependent phosphorylation of endothelial nitric-oxide synthase mediates penile erection,"
Proceedings of the National Academy of Sciences
99:6, 4061–66 (2002).
A study by Lique Coolen:
W. A. Truitt and L. M. Coolen, "Identification of a potential ejaculation generator in the spinal cord,"
Science
297, 1566–69 (2002).

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Work by Coolen:
L. M. Coolen et al., "Activation of mu opioid receptors in the medial preoptic area following copulation in male rats,"
Neuroscience
124:1, 11–21 (2003).
As for women:
A. M. Traish et al., "Biochemical and physiological mechanisms of female genital sexual arousal,"
Archives of Sexual Behavior
31:5, 393–400 (2002).
Yes, the G spot is real:
M. Giorgi et al., "Type 5 phosphodiesterase expression in the human vagina,"
Urology
60, 191–95 (2002).
Gentle pressure on the spot:
B. Whipple and B. R. Komisaruk, "Elevation of pain threshold by vaginal stimulation in women,"
Pain
21, 357—67 (1985); B. Whipple and B. R. Komisaruk, "Analgesia produced in women by genital self-stimulation,"
Journal of Sex Research
24:1, 130–40 (1988).
British researchers found that having sex:
S. Brody, "Blood pressure reactivity to stress is better for people who recently had penile-vaginal intercourse than for people who had other or no sexual activity,"
Biological Psychology
71, 214–22 (2006).
scientists at Rutgers University studying women:
B. R. Komisaruk et al., "Brain activation during vaginocervical self-stimulation and orgasm in women with complete spinal cord injury: fMRI evidence of mediation by the vagus nerves,"
Brain Research
1024, 77–88 (2004).
One new study points an intriguing finger:
K. Dunn et al., "Genetic influences on variation in female orgasmic function: a twin study,"
Biology Letters,
June 2005; online edition, DOI: 10.1098/rsbl.2005.0308.

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A case report in the
Lancet: R J. Reading and R. G. Will, "Unwelcome orgasms,"
Lancet
350, 1746 (1997).
Orgasm is ... a cerebral experience:
J. R Changeux,
Neuronal Man: The Biology of the Mind
(Princeton, N.J.: Princeton University Press, 1997), 112–14.
Dutch scientists shocked the neuroscience community:
G. Holstege et al., "Brain activation during human male ejaculation,"
Journal of Neuroscience
23, 9185–93 (2003); J. R. Georgiadis et al., "Brain activation during female sexual orgasm,"
Society of Neuroscience Abstracts
727:7, 31 (2003); J. R. Georgiadis et al., "Deactivation of the amygdala during human male sexual behavior," program no. 727.6, Society for Neuroscience meeting, November 8–12, 2003, New Orleans; B. R. Komisaruk and B. Whipple, "Functional MRI of the brain during orgasm in women,"
Annual Review of Sex Research
16, 62–86 (2005).