Clinical Laboratory Scientist, ASCLS, NCA The Mind’s Eyes: Modeling the Development of Diverse Sexual Preferences Love looks not with the eyes, but with the mind, And therefore is winged Cupid painted blind. ~~William Shakespeare (1564–1616) The Reiss Plenary James V. Kohl Clinical Laboratory Scientist, ASCLS, NCA JVKohl@bellsouth.net www.pheromones.com

Adapted for presentation from: Kohl (2006) The Mind's Eyes: Human Pheromones, Neuroscience, and Male Sexual Preferences. Journal of Psychology & Human Sexuality, 18(4): 313-369. Guest editor: Michael R. Kauth Editor: Eli Coleman Concurrently published as a book chapter in Handbook of the Evolution of Human Sexuality The Haworth Press, Inc.

Luteinizing Hormone: The link between sex and the sense of smell Nature 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 SEXUAL DIFFERENTIATION Nurture PRENATAL The influence of pheromones from the same sex or from the opposite sex on postnatal sexual differentiation PRE- and POSTNATAL GnRH Nerve cell Migration Olfactory placode Olfactory Bulbs Limbic System Hypothalamic Pheromones Aging Sexual Expression Sexual Identity Sexual orientation Learning and Memory From the same sex From the opposite sex P H E R O M N S Extrahypothalamic GnRH Hypothalamus Positive Neuronal feedback Negative Male Female GnRH pulse frequency and amplitude Tonic Cyclic extrapituitary effects Pituitary LH / FSH HPA axis NEUROTRANSMISSION I’m not using this diagram, today--except once, as a reference point. I used an earlier version in my 1992 quad-S presentation, and this one for a continuing education session at the annual meeting last year. It’s a model for the development of sex differences in mammals. The article that won the Reiss theory award went beyond the neuroscience of sex differences to address issues that link this model to the development of human sexual preferences. Synaptogenesis Synaptolysis Apoptosis Synaptogenesis Synaptolysis Apoptosis HPG axis Gonads Adrenals LH FSH Testes (androgenic metabolites) Ovaries (estrogenic metabolites) Adrenal metabolites (androsterone) (etiocholanolone) Pheromones Luteinizing Hormone: The link between sex and the sense of smell

Dichotomies Nature vs Nurture (Genetics vs Social environment) Structure vs Function Organization vs Activation Effects of hormones vs Behavioral affects Conscious choice vs Unconscious affects Creation vs evolution (Normalcy vs Diversity) Most of these issues come in the form of dichotomies. In my model these dichotomies are eliminated: 1. Nature vs nurture becomes how genetic predispositions are influenced by the social environment. 2. Structure vs function becomes how structures function. 3. Organization vs activation becomes how structures are organized and what activates them 4. Activational Effects of hormones allow them to elicit their behavioral affects 5. The effects that hormones have on the development of behavior in any species are not due to conscious choice. But hormones do elicit unconscious affects on behavior as it develops. 6. Unconscious affects on the development of sexual preferences in other mammals, suggest that conscious choice either was a gift from our Creator, or it somehow evolved from single-celled organisms. And, whether or not we think the result of Creation or evolution is normal or diverse, sexual preferences are diverse.

Hormone-dependent facial features An example of this diversity is human sexual preferences for hormone-dependent physical features. Some women prefer the androgen-dependent features of the man on the left, and so do some men. But some men -- and some women -- prefer the estrogen-dependent features of the woman on the right--or something in between. Used with permission from Victor Johnson

Hormone-dependent WHR There’s also diversity in sexual preferences for the hormone-dependent Waist-to-Hip ratio, and other physical features. Most men prefer 0.7 women, as well as large-breasted women. Most women prefer men with androgen-dependent 1.0 waist-to-hip ratios and no breasts. But, some women prefer women and some men prefer men, which leads to the question: How do people develop diverse preferences for hormone-dependent physical features? Adapted from Marlowe et al. (2005)

High Estrogen/Androgen ratios, physical features… Feminine features: small jaw, full lips, large breasts, narrow waist, shorter, higher vocal pitch, light complexion, etc. …AND THE PHEROMONES OF WOMEN. My model details how sensory input from the social environment influences the development of hormone-dependent sexual preferences. For example: High estrogen/androgen ratios are associated with the attractive physical features and the pheromones of women.

Low Estrogen/Androgen ratios, physical features… 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. Low estrogen/androgen ratios, are associated with the attractive physical features and the pheromones of men.

Pheromones (traditional definition) Karlson and Luscher (1959): “… substances which are secreted to the outside by an individual and received by a second individual of the same species, in which they release a specific reaction, for example, a definite behaviour, or a developmental process.” (p. 55) The traditional definition of insect pheromones includes their effect on “a definite behaviour, or a developmental process.” This definition does not fit well in species that have relatively complex developmental processes, and a wider variety of behaviors. In mammals, species-specific reactions that release behavior or developmental processes are driven by hormones.

Pheromones are: Species-specific and hormone-dependent chemical signals that alter hormone levels and behavior in others. ---------------------------------------------------------- The only sensory input from our social environment that has a direct effect on hormones. Pheromones directly affect behavior. So, I reworded the definition of pheromones to make the role they play in the development of sexual preferences, more clear. Pheromones are species-specific--and hormone-dependent--chemical signals that alter hormone levels and behavior in others. Pheromones also are the only sensory input from our social environment that has a direct effect on hormones, which means that, unlike what we see or hear, pheromones directly affect behavior.

Olfactory/pheromonal input and pheromones are: No “sixth sense” No human vomeronasal organ (VNO) No “discoverer” of human pheromones Olfactory/pheromonal input and pheromones are: The role of pheromones in the development of human sexual preferences has been made less clear by misleading marketing ploys. No sixth sense or human VNO is required. And a woman who claims to have discovered human pheromones in 1986 won’t tell us what pheromones she discovered, or how they affect behavior. Ten years after her “discovery,” I discovered the domain pheromones.com was still available and have used it as an information source about pheromones and about how they affect behavior ever since. Pheromones are processed by olfactory pathways, which makes “olfactory/pheromonal input” synonymous with the term pheromones, which are body odors with properties that are similar to food odors. Food odors influence the development of our food preferences. But body odors, like pheromones, influence the development of our sexual preferences, whether or not we can smell them. Most people don’t think about things they can’t see or smell, so they aren’t likely to think about how pheromones, body odors from other people, or whatever you call them, influence hormones and the development of sexual preferences -- even when we cannot smell them. Body odors that, whether or not we smell them, alter hormone levels and behavior in others. See: www.pheromones.com

The Mind’s Eyes and Diverse Food Preferences Before I say more about The Mind’s Eyes, and how body odors influence the development of sexual preferences, I’d like you to keep in mind that odors from food, or from other people, enter the body through the nose. As the body reacts to their entry, odors are associated with what we see. But, unlike odors from food, we are only exposed to species-specific pheromones during social circumstances that involve the body odors of other people. Fortunately, we are not usually aware of their body odor. By the time we have developed our response to body odor, we’ve already been conditioned to respond to any concentrated odor by avoiding it. Even a rose - by any other name - does not smell as sweet, when it is one of 1000 flowers in a small room. It is their unconscious association with other sensory input that allows the odors of other people to determine who or what we prefer to see, hear, touch, or taste, without ever knowing for sure if, in the long run, someone is going to come up smelling like a rose, or make us sick, because in some aspect of our unconscious, they stink. MED_071C Image Club Royalty Free Photograph

The Mind’s Eyes and Diverse Sexual Preferences Unconditioned stimulus (UCS): Body odor 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. In The Mind’s Eyes, body odor is an unconditioned stimulus. It has biologically relevant effects, just like food odor. Throughout life, other sensory input from our social environment that does not have biologically relevant effects is repeatedly paired with food odors or odors from other people. At an unconscious level, biologically active odors condition the hormone responses associated with who or what we prefer to see, hear, touch, or taste. Food odors condition our food preferences. People produce odors that condition our sexual preferences. Beginning at birth, odor associations are the proximate cause that effects what we prefer to allow into our body, whether it’s associated with food, whispers in our ear, or any other sensory input from another person.

Brain Imagery 1: Body odors vs Common odors Johan N. Lundstrom, Julie A. Boyle, Robert J. Zatorre, and Marilyn Jones-Gotman (2007) Functional Neuronal Processing of Body Odors Differs from that of Similar Common Odors. Cereb Cortex. published online 12 October 2007 Most preferences for sensory input can be found in relatively equal distribution in males and females. Males and females develop similar food preferences, and men and women usually agree on whether other people look good. But there are sex differences in preferences for body odors. More females than males develop preferences for male pheromones, and vice versa. This explains why men and women are not likely to agree on whether other men and women smell good. One reason for the sex differences in preferences for body odors is that they are processed in different neuronal circuitry of the brain compared to other odors, as brain imagery from last month’s publication in Cerebral Cortex shows.

Brain Imagery 2: Male vs Female response Savic, I., Berglund, H., Gulyas, B., & Roland, P. (2001). Smelling of odorous sex hormone-like compounds causes sex-differentiated hypothalamic activations in humans. Neuron., 31(4), 661-668. Another reason for sex differences in preferences for body odor is that there are sex differences in the effect of pheromones on the human hypothalamus, as the brain imagery from this study shows.

Brain Imagery 3: Male / Female sexual preferences Martins, Y., Preti, G., Crabtree, C. R., Runyan, T., Vainius, A. A., & Wysocki, C. J. (2005). Preference for human body odors is influenced by gender and sexual orientation. Psychol Sci., 16(9), 694-701. Savic, I., Berglund, H., & Lindstrom, P. (2005). Brain response to putative pheromones in homosexual men. Proc Natl Acad Sci U S A., 102(20), 7356-7361. Epub 2005 May 7359. Berglund, H., Lindstrom, P., & Savic, I. (2006). Brain response to putative pheromones in lesbian women. Proc Natl Acad Sci U S A, 103(21), 8269-8274. A study of preferences for body odors, and the imagery from two other studies of brain activation also show variations that link pheromones to the sexual preferences of men, and the sexual preferences of women.

Savic, I. Brain response to putative pheromones in humans Savic, I. Brain response to putative pheromones in humans. AChemS 29th Annual Meeting, April 25-29, 2007 Sarasota, Florida Smelling male and female pheromones, activates the human brain in a sex differentiated manner. The pattern of activation in homosexual subjects raises the question of whether this pattern could be effect of sexual behavior or reflect a variant organization of the hypothalamic circuits. (embargoed) “These issues will be discussed in relation to new data from male–to-female transsexuals…” Forthcoming brain imagery will add data that may link pheromones to the sexual preferences of male-to-female transsexuals. The bottom line is that brain imagery links pheromones to diverse sexual preferences. We also know that biologically active food odors and body odors can condition hormone responses from the mammalian hypothalamus that are associated with visual input, and with other sensory input. This brings me to the concept of “the mind’s eyes,” and how it applies to the development of sexual preferences.

The Mind’s Eyes: A distributed network of nerve cells that collectively integrates hormone responses to pheromones with visual input, and with other associated sensory input from our social environment. The mind’s eyes consist of a distributed network of nerve cells that collectively integrates hormone responses to pheromones with visual input, and with other associated sensory input from our social environment.

The Mind’s Eyes Nature + Nurture (Genetics + Social environment) Nature: Genetically determined mechanisms for the identification of others of the same species and for the development of sexual preferences. Nurture: A direct effect on genes by sensory input from the social environment Pheromones directly link nurture (the social environment) to gene activation (nature). Genetically predisposed mechanisms for the identification of others of the same species and for the development of sexual preferences are included. Nature and nurture are linked through a direct effect of pheromones on genes.

The Mind’s Eyes Structure + Function Gene activation occurs in hormone-secreting nerve cells of brain tissue that is located in a structure: the hypothalamus. The function of these hormone-secreting cells is to direct the concurrent maturation of the brain, the neuroendocrine system, and the reproductive system—all of which are directly effected by pheromones, which affect the development of sexual preferences. This gene activation occurs in hormone-secreting nerve cells of the hypothalamus, which is the brain structure that links pheromones to the function of these hormone-secreting cells. These cells direct the concurrent maturation of the brain, the neuroendocrine system, and the reproductive system—all of which are directly effected by pheromones and all of which affect the development of sexual preferences starting on the day we are born.

The Mind’s Eyes Organization + Activation Before birth, genetically determined sexually dimorphic hormones organize the number and density of these cells in the hypothalamus. At birth, these cells are activated differently by the pheromones of other males compared to other females. Pheromones from other people cause hormone levels to change: re-organization. The reproductive system begins to organize the number and density of these cells in the hypothalamus before we are born. Prenatal organization also partially establishes a genetically determined sex difference in the processing of pheromones. At birth, pheromones from other males have a different effect on hormone-secreting cells in the male hypothalamus than do the pheromones of females. The sex difference in the production of pheromones and the sex difference in their effect on hormones helps to further organize sex differences in nerve cells, as we develop our sexual preferences.

The Mind’s Eyes Effect of hormones + Behavioral affect The direct effect of pheromones on these hormone-secreting cells in the hypothalamus controls levels of many other hormones. In mammals, the effect of pheromones on levels of hormones conditions behavioral affects. People are mammals. Visual input from our social environment is not likely to have direct effects on hormones or on behavior. When it comes to the social environment of mammals, only pheromones are capable of directly effecting hormones. Other sensory input associated with pheromones, like visual input, can then elicit the hormone changes that were conditioned by pheromones. With minimal conditioning of hormone responses by pheromones, other associated sensory input can elicit changes in hormones—without exposure to the pheromones that initially conditioned the hormone response. That’s how pheromones condition unconscious behavioral affects. This also explains why hormone changes occur when we see images of what we prefer, or see someone from across a crowded room that “looks” good to us -- just as a picture of a preferred food might look “good” to us. But what looks good to us must determined by either the odors of food, or body odors, because what we see does not directly effect any hormone that is associated with the development of our preferences.

The Mind’s Eyes Effect of hormones + Behavioral affect One central neuronal 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. One central neuronal pathway links many different hormones to their effect on behavior, and it’s the same pathway that is directly effected by pheromones. I’d tell you more about the different hormones and pathways if I could sequentially pronounce the ones that are listed here: Some of you are aware of changes in behavior that are associated with levels of these peptide hormones, their receptors, or the pathways that link them to behavior. You may also be aware of their side effects on sexual behavior. Pheromones directly effect these hormones, receptors, pathways -- and their species-specific influences on the development of sexual preferences.

The Mind’s Eyes Conscious choice + Unconscious affects A hormone conserved in species as diverse as yeast and primates is the biological core of mammalian reproductive sexual behavior, and it is activated by human pheromones. Similar hormone pathways are conserved in mammals that do not consciously choose their mates. Conscious choice is probably less important than the direct effect of pheromones on hormones and their unconscious affects on the behavior of most species. Pheromones first effect a hormone that is conserved in species as diverse as yeast and primates. This hormone, the biological core of properly timed mammalian reproductive sexual behavior, effects levels of many other hormones and pathways that are intricately linked to the sexual preferences, and the sexual behavior, of all mammals. The same hormone and similar pathways are conserved across all species that sexually reproduce and pheromones are required for sexual reproduction in these species, regardless of what they might think, if they could think at all. This strongly suggests that pheromones are the driving force behind the development of human sexual preferences—regardless of what people think.

The Mind’s Eyes Creation + Evolution (Normalcy + Diversity) The Creation or Evolution of lock and key (hormone and receptor) proteins enable communication of sex differences and immune system differences in all species that sexually reproduce. One hormone is a “key” that is conserved across all species that sexually reproduce. Diversification of the different “locks” that this key opens enables speciation -- and predates the genetic origin of vision. Genetically coded hormone and receptor proteins are like locks and keys that are involved in the communication of sex differences and immune system differences. The same mechanisms for the communication of these differences, are found in species from single-celled yeasts to primates, and, as I indicated before, one genetically coded hormone is conserved across species. What diversifies is this hormone’s receptor, and its diversification enables the species-wide ability to distinguish the genetically determined similarities and differences that allow sexual preferences for other members of the same species to develop. Yet when we think about our sexual preferences, we assume that beauty is in the eyes of the beholder instead of in The Mind’s Eyes, which get their input from our nose.

The Mind’s Eyes: No Dichotomies Nature + Nurture (Genetics + Social environment) Structure + Function Organization + Activation Effects of hormones + Behavioral affects Conscious choice + Unconscious affect Creation + Evolution (Normalcy + Diversity) The lack of sex differences in the development of diverse food preferences attests to the likelihood that something other than visual input is essential to the development of diverse sexual preferences. The diversity of food preferences and of sexual preferences attests to the likelihood that they depend on every aspect of development that is included in this model. There are sex differences in every aspect of this model, and in the production of pheromones and in the way they are processed. Since there is no question that sexual preferences are diverse across species -- and among humans -- one question that remains is whether the diversity of human sexual preferences is part of Creation or if it evolved. We already know that males and females develop diverse preferences without thought. We also know that visual and auditory stimuli have relatively no direct impact in any mammalian model. And we know that by the time we think about our sexual preferences, pheromones have conditioned the hormone responses that are typically associated with affects on behavior.

The Mind’s Eyes: No Dichotomies Nature + Nurture (Genetics + Social environment) Structure + Function Organization + Activation Effects of hormones + Behavioral affects Conscious choice + Unconscious affect Creation + Evolution (Normalcy + Diversity) What’s clear is that by the time you think about sexual preferences, pheromones –from birth--have already conditioned the hormones involved in your sexual response cycle. After they have conditioned your sexual response cycle, physical features that once were associated with pheromones may also activate changes in hormones, even without additional exposure to the pheromones. With additional exposure to pheromones, the sexual response cycle can change as it develops. People are unique since they may choose whether to respond with behaviors that are prompted by unconscious affects. I think that’s why people sometimes wonder “What was I thinking!” –after the fact. Most of us have wondered about choices we have made, but some people tend to focus on the choices made by others. When we learn more about the biological basis of unconscious affects on the development of sexual preferences, we might also learn to focus on our own sexual preferences, rather than on the diverse sexual preferences of others. And if we’re going to focus on the sexual behavior of others-- for God’s sake, and perhaps for our own, let’s not judge them as an ill-defined group and think that our thoughts should make sense to everyone else.

Reality check: Individuals vs. groups I think it’s time for a reality check! After odors condition changes in hormones, preferred physical features elicit odor-associated changes in hormones. So, even when we think we are responding to visual or other sensory input from our social environment, we are responding to the association of these cues with odors; olfactory-pheromonal input; or pheromones. Magic tricks capitalize on the ability to make things appear to be what they are not. The magic of these images is that they come from a computer program. They are not real people. The biological facts of my model are real. If the facts and model fit, we should be able to use pheromones to make people appear to be more like their idealized imagery. Almost like magic, we might be able to help some men and women smell like they look good. We already use make-up and other techniques to help men and women look like they smell good. Change a male’s physical features to indicate higher androgen levels (taller, darker), and he becomes more appealing. Change a female’s physical features to indicate higher estrogen levels (larger lips and breasts), and she becomes more appealing. Add male or female pheromones to people, and they should also become more appealing. Used with permission from Victor Johnson

Clinical Laboratory Scientist, ASCLS, NCA The Mind’s Eyes: Modeling the Development of Diverse Sexual Preferences Love looks not with the eyes, but with the mind, And therefore is winged Cupid painted blind. ~~William Shakespeare (1564–1616) The Reiss Plenary James V. Kohl Clinical Laboratory Scientist, ASCLS, NCA JVKohl@bellsouth.net www.pheromones.com For many years, perfumers have used the pheromones of other species in attempts to make us more appealing. But pheromones are species-specific chemicals. A clinical laboratory scientist with a mammalian model is more likely than a perfumer to discover human pheromones that make people more appealing. Unfortunately, peer-reviewed articles to date don’t tell us three things we we need to know to evaluate work with human pheromones: the name of the pheromone, the hormones it changed, and the behavior that changed. For more than 15 years, that left me with only cross-species comparisons, and no proof that my model extends to human sexual preferences.

Sexual preference difference (1) Hypothalamus But during the past few years, I’ve added a few more details to the model. The sex difference in the response to pheromones is in the hypothalamus. So is area that Simon LeVay suggested was intermediate in size in homosexual men -- compared to heterosexual men and women. This is the area that Dean Hamer suggested might be influenced by a “gay” gene. It’s also where William Byne found that that men have more nerve cells than women, a difference that he said may be effected by the environment. Pheromones from our social environment cause changes in hormones that are controlled by this area of the hypothalamus. The immune system also contributes to changes in this area of the hypothalamus, which means that my model incorporates several existing theories of psychosexual differentiation that translate well to how human pheromones effect hormones and human sexual preferences. Medial preoptic area of the anterior hypothalamus MPOA/AH MP-AHN

Male Pheromone/Female Response Female Pheromone/Male Response I recently read that the use of brain imagery helps to convince people that neuroscience is applicable to behavior. It also helps to pinpoint the most likely location of the Mind’s Eyes. The Mind’s Eyes are probably in the area of the hypothalamus that brain imagery shows lights up differently when men and women are exposed either to a male pheromone or to a female pheromone. This area controls sexual differentiation. The Mind’s Eyes are in the area of the brain that lights up differently when exposed to male or female pheromones. Adapted from Savic et al., 2001

Sexual preference difference (M) HeW HoM HeM Male pheromone Female pheromone The way the Mind’s Eyes light up varies with sexual preferences. For example: a male pheromone causes similar changes in the hypothalamus of women and in men who have developed a sexual preference for men. Adapted from Savic et al., 2005

Sexual preference difference (F) HeW Lesbian HeM Male pheromone Female pheromone A female pheromone causes similar changes in the hypothalamus of men and in women who have developed a sexual preference for women. Adapted from Berglund et al., 2006

Poster session: Saturday 330-530 Kelahan, L.C, Hoffmann H., and Kohl, JV Putative Human Pheromones May Condition a Human Female Hormonal Effect / Behavioral Affect The point I hope to convey is that brain imagery and biological facts may be helpful to our understanding of the diversity of sexual preferences, no matter what we think about how they develop. Anyone who is interested in learning more about neuroscience, conditioned responses, or about the mixture and species-specificity of the pheromones we tested, their effect on hormones, and their affect on behavior may want to attend our poster session tomorrow.

How to Smell Like You Look Good Love looks not with the eyes, but with the mind, And therefore is winged Cupid painted blind. ~~William Shakespeare (1564–1616) The Reiss Plenary James V. Kohl Clinical Laboratory Scientist, ASCLS, NCA JVKohl@bellsouth.net www.pheromones.com Throughout the rest of the conference I’ll be distributing samples you can privately test to see if they make you look as good as you smell when wearing the samples.

And now, I’ll answer the first question, before it’s asked: What about birds? Until recently, my typical answer was that people are mammals, not birds. Evidence from birds now suggests that visual input, like the peacock’s tail; the size of his willy and his pheromones are all connected. And, as my friend Julie Hagelin has said: “The chemosensory abilities of birds stand as a promising means of understanding avian biology, because it challenges traditional views that birds respond to their world primarily through visual and auditory signals.” So my answer to the question What about birds, is that they will probably turn out to be as dependent on pheromones as we are in the development of our sexual preferences.   What about birds? Hagelin, J. (2007). Odors and chemical signaling. In B. G. M. Jamieson (Ed.), Reproductive Behavior and Phylogeny of Aves. Vol. 6B. (pp. 76-119). Enfield, NH: Science Publishers.

Ira L. Reiss: 12/02/1999. We need to know why something is the way we find it, not just describe what is found. Theory gives us the ability to derive hypotheses about what else might be true and check them out. Explanation (theory) is how science progresses and finds ways of helping society contain its many problems. To me explanation is the heart of science. Unfortunately we in social science do not have as much explanation in our published journal articles as we should. But few would dismiss explanation as unimportant or unnecessary. My model explains a lot. So, I encourage those of you who have questions after the presentation to read the article, or talk with me if you think that something I’ve said doesn’t fit the model. It’s difficult to explain everything that does fit the model, but -- as Ira Reiss once wrote: “explanation is how science progresses”.

You can't just keep explaining things by your model. Jay Feierman: 7/29/2007 You can't just keep explaining things by your model. You need to predict that which has not yet occurred by the model and be able to show that a primary visual mechanism is not able to predict the same thing. Others may disagree, especially if they think that visual input is most important to the development of sexual preferences—despite the fact that no mammalian model details any aspect of a primary visual mechanism. In reality, I can’t find biologically based evidence for a primary visual mechanism in any other species. That means I can predict that no one will ever show that a primary visual mechanism explains anything about the development of human sexual preferences; especially not a man’s sexual preference for the hormone-dependent physical features of another man. There will be no direct link to hormones, not enough variation in receptors, no sex differences in input, no evolutionary basis, no discussion of structure or function or of anything else that might explain how a either visual mechanism, or an auditory mechanism, could direct the development of sexual preferences that depends on pheromones in all other species that sexually reproduce.

Pheromones effect hormones and control sexual behaviors 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 and sexual behavior that involves GnRH neurons. A 2005 article co-authored by olfactory researcher and Nobel Laureate, Linda Buck, further clarifies that pheromones, and their effect on the hormone, GnRH, control sexual behavior. “Control” was the word they used. Since it may be politically incorrect to say, or even imply, that hormones control sexual behaviors, I’m glad I didn’t say it. Even a media interpretation can get you in trouble for saying such things, and even when what you say is the truth. Boehm, U., Zou, Z., & Buck, L.B. (2005). Feedback loops link odor and pheromone signaling with reproduction. Cell, 123, 683-695.