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Human Pheromones: Linking Neuroendocrinology and Ethology (revisited). International Society for Human Ethology, 2010 James V. Kohl Clinical Laboratory Scientist ASCP, ASCLS, AMT JVKohl@bellsouth.net www.pheromones.com.
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International Society for Human Ethology, 2010
James V. Kohl
Clinical Laboratory Scientist
ASCP, ASCLS, AMT
Kohl, Atzmueller, Fink, Grammer (2001)Human Pheromones: integrating neuroendocrinology and ethology.Neuroendocrinology Letters 22(5): 309-21.
Adapted for presentation from:
The Mind's Eyes: human pheromones, neuroscience, and male sexual preferences
Journal of Psychology & Human Sexuality, 18(4): 313-369.Concurrently published in the Handbook of the Evolution of Human SexualityGuest editor: Michael R. Kauth Editor: Eli Coleman. Taylor and Francis, Inc.
Kohl, Kelahan, Hoffmann (2009)
Human pheromones increase women's observed flirtatious behaviors and ratings of attraction
13th Annual Meeting of the Society for Behavioral Neuroendocrinology.
East Lansing, Michigan.
Neuroendocrinology: the study of the interactions between the nervous system and the endocrinesystem.
Ethology: the scientific study of animal behavior.
“The interaction between sensory input and hormonal levels appears to be a general rule in endocrine relationships underlying behavior.” (LeMagnen,1982)
In other words: Sensory input effects hormones that affect behavior.
Pheromones are species specific sensory input from the social environment that influence “…a definite behavior or a developmental process.”Karlson & Luscher (1959) Pheromones': a new term for a class of biologically active substances. Nature. 1959 Jan 3;183(4653):55-6.
[e.g., by causing changes in levels of hormones]
This gene-cell-tissue-organ-organ system pathway allows natural selection to proceed at a pace and in directions keyed to environmental cues, like food odors and pheromones.
The Gonads-Hormones-Behavior (G-H-B) model: A few genes cause gonadal differentiation and the gonadal hormones are responsible for the more widespread and contemporary aspects of structural development and function in the brain and body.
In the G-H-B model, mammalian pheromones activategeneexpression in gonadotropin releasing hormone (GnRH)-secreting nervecells oftissuein the medial preoptic area of the anterior hypothalamus, which is the area of the brain that modulates the hypothalamic GnRH pulse.
The brain is the most importantorganof anyorgan systeminvolved in behavior.
The effect of pheromones on reproductive hormone status is mediated by GnRH neurons.
GnRH plays an important role in the “control of sexual behaviors” via their link to reproductive hormone status [e.g., testosterone and estradiol] and sexual behavior that involves GnRH neurons.Boehm, U., Zou, Z., & Buck, L.B. (2005). Feedback loops link odor and pheromone signaling with reproduction. Cell, 123, 683-695.
Pheromones “control” definite behaviors by causing changes in levels of hormones.Shepherd, G. M. (2006). Behaviour: Smells, brains, and hormones. Nature,439, 149-151.
Complex and highly variable social factors in humans often obscure the exact mechanisms of events [that cause sex differences in behavior].
However, see Mak et al, (2007): Neurons in the olfactory bulb that express GnRH receive signals from pheromones and send projections to the hypothalamus, which results in the release of luteinizing hormone (LH) and follicular-stimulating hormone (FSH) by the anterior pituitary. Together, LH and FSH control the release of steroid hormones, such as estrogen, that influence sexual behavior…. (i.e., in the G-H-B model)
Pheromones alter GnRH-modulated:
neural circuitry, odor hedonics, mood,
memory, motivation, cognitive behavioral state,
and potentiating responses to other stimuli, and link
Nature to Nurture via affective reactions
The influence of pheromones from the same
sex or from the opposite sex on postnatal
PRE- and POSTNATAL
Learning and Memory
From the same sex
From the opposite sex
frequency and amplitude
LH / FSH
Medial preoptic area
of the anterior hypothalamus
One central neuronal (i.e., GnRH) pathway links:noradrenergic, dopaminergic, serotoninergic, and opiodergic pathways, as well as inhibitory neurotransmitters like gammaaminobutyric acid and excitatory amino acids like glutamic and aspartic acids and other brain peptides including pineal secretions like melatonin and corticotrophinreleasing hormone and the complex interactions among them (e.g., the effects of hormones)…
…to functional species-specific influences, which are linked to behavioral affect by the same hormone-secreting cells, that pheromones directly effect.
GnRH modulates the concurrent maturation of the neuroendocrine system, the reproductive system and the central nervous system.
GnRH is required for LH release
Increased GnRH pulse frequency favors LH release.
The opposite sex pheromones of other mammals cause LH release.
Axillary pheromones of men cause LH and mood change in women
"There is now ample evidence that GnRH is secreted episodically in the prepubertal child long before physical signs of puberty appear (Jakacki et al., 1982). The onset of puberty therefore appears to be associated with an amplification of pulsatile gonadotropin secretion.”
Hopwood, N.J., Kelch, R.P., Hale, P.M., Mendes, T.M., Foster, C.M., & Beitins. I.Z. (1990) The onset of puberty: biological and environmental factors. In: Bancroft, J, & Reinisch, J.M. (eds.) Adolescence and Puberty. (pages 29‑49) New York: Oxford University Press.
Unconditioned stimulus (UCS): Pheromones
Conditioned stimulus (CS): visual, auditory, tactile, gustatory—combined?
The CS (e.g., visual input), gains behavioral significance after being paired with a biologically active UCS (e.g., pheromones).
Odors/pheromones are the proximate cause
Hormone-driven preferences are their effect.
1.Positive and negative affective reactions can be evoked with minimal stimulus input and virtually no cognitive processing.
2.Affect dominates social interaction and it is the major currency in social interactions
3.Affective reactions can occur without extensive perceptual and cognitive encoding. They are made with greater confidence than cognitive judgments, and can be made sooner.
Olfactory input from the social environment fits the assertions of affective primacy.
For example, chemical cues allow humans to select for, and to mate for, traits of reproductive fitness that cannot be assessed simply from visual cues.
The affect of pheromones on our emotions
is linked to the effect of pheromones on the hormones of the hypothalamic-pituitary-gonadal axis – an unconscious affect.
Affect is conditioned in the presence of other sensory input.
Mammalian neuroanatomical pathways link vision and olfaction. Cooper et al. (1994)
Social-environmental odor cues, which males learn to visually associate with sexual activity, can be used to condition LH release.
After minimal conditioning, an arbitrary odor ultimately will elicit a male LH response, even in the absence of odor previously associated with a female.
Regardless of whatever other sensory input (e.g., visual input) is involved, the functional significance of the conditioned change in LH secretion lies principally in the unequivocal demonstration that olfactory cues can activate the male hypothalamic-pituitary-gonadal axis in a way that mimics, in every respect, the activation achieved by exposure to a female.Graham & Desjardins (1980)
Feminine features: small jaw, full lips, large breasts, narrow waist, shorter, higher vocal pitch, light complexion, etc.
…AND THE PHEROMONES OF WOMEN.
Masculine features: growth of the jaw, brow ridges, center of the face from the brow to the bottom of the nose, more facial hair, taller, darker, more muscular, etc.
…AND THE PHEROMONES OF MEN.
Used with permission from Victor Johnson
J.V. Kohl; L.C. Kelahan; H. Hoffmann
HUMAN PHEROMONES INCREASE WOMEN’S OBSERVED FLIRTATIOUS BEHAVIORS AND RATINGS OF ATTRACTION.
Conclusions: The known effect of androstenol on luteinizing hormone in women and what appears to be an associated behavioral affect of androsterone meet criteria that characterize human pheromones.
Kelahan-testing and results; Hoffmann-professorship; Kohl-study design
“[Cindy] ... had gone alone to a portable commode hidden in a thicket to change her tampon, unaware that a young stag was nearby... Smelling her [natural] secretions, [the male deer] became sexually aroused. He bounded through the trees and knocked Cindy to the ground. Then while prancing up and down with his forefoot on her shoulder, the sexually excited deer sprinkled her with semen."
Gibbons, D.L. (1989) Unusual case: Sex in the woods. Medical Aspects of Human Sexuality, 23, 10(Oct), 63.
“It is important to remember that the animal perceives erotic odors in a manner analogous to his perception of food odors.”
Bloch, I. (1933) Odoratus Sexualis: A Scientific and Literary Study of Sexual Scents and Erotic Perfumes. New York: American Anthropol. Soc.