Barely touched a computer for days. She told me bout an aunt that has no sense of smell and consequently can’t taste anything. I remember learning that apples and onions taste pretty much the same without your sense of smell. This made me think about sex. To quote a recent NYTimes article on gaydar – ‘Using a brain imaging technique, researchers have shown that homosexual and heterosexual men respond differently to two odors that may be involved in sexual arousal, and that the gay men respond in the same way as women.’ This study, like every study on pheromones, is qualified with the usual ‘but smell isn’t important to humans’. Which would seem true. However, if you if you consider taste to be part of smell, then it makes a lot more sense. Foreplay – from kissing to Condoleezza – is all about taste. If you taste a person then you’re mainlining pheromones.
from a paper I did on Web Design and the Brain. Can’t find original source.
People have brains like the ones above. It’s a bunch of stuff piled onto your spine, and that _very_ loosely approximates the climb of human evolution. The spine we share with fish, snakes and any vertebrates. Over time evolution stacked more and more stuff on top of the spine. We have a ‘lower brain’ that we share with mice, and cortex that we share with monkeys and higher mammals. What most people think of as the brain is the cortex, but the lower brain is the vital plumbing. It keeps you standing and eating and mating, etc.
The part that’s most associated with Sex is _not_ your reasonable cortex. You can perform the home experiment of soaking your cortex in alcohol to see the results. The parts most closely associated with Sex are in the lower brain, which we share with hamsters and mice and all.
There are better pictures online, but none quite as suggestive as my old Biopsychology text (Pinel).
At the top of the lower brain you have the Thalamus and Hypothalumus. The Thalamus is the thing that looks like the tip of a penis, and the Hypothalamus is the little clitoris thing under it. I have not met God, but he is definitely a parsimonious designer. The Thalamus is a relay for just about every sensation you get. It basically patches your cortex into the other parts of your brain. The hypothalamus (loosely) governs the release of the hormones which, in turn, govern motivation. The brain is pretty big and interesting, but these are the only parts in question. Pheromomes usually have their arousing effects through the hypothalamus.
Smell and taste are so old in an evolutionary sense that they’re qualitatively different from every other sense. They are both called *chemical senses*. They were also really weird and we skipped over them to spend most of the semester on Vision. Things like vision and audition are sorta *digital* in that they sample a continuous phenomenon into discrete bits – be they dots on your retina or hairs inside your cochlea. Your retina could care less if you’re looking at a dog or a rock, it’s just another pattern of light. Smell and taste, however, are almost *analog*. Thousands of smells each have their own special binding sites. When you smell a fart, airborne poo particles are literally entering your nose and binding to specific receptors. That’s gross, but easy to understand.
*Smell*: Scent particles enter your nose and go up to enter the olfactory bulbs. That does some basic processing and passes the information _directly_ to your temporal lobe (piriform cortex). This is odd cause every other sense has to go thru the Thalamus. Smell is the only sense that can mainline into the cortex. Smell data eventually goes to the Thalamus, but only after. Axel and Buck got the Nobel in 2004 for their more interesting work on the genetic and physiological nature or smell,
All living organisms can detect and identify chemical substances in their environment. It is obviously of great survival value to be able to identify suitable food and to avoid putrid or unfit foodstuff. Whereas fish has a relatively small number of odorant receptors, about one hundred, mice – the species Axel and Buck studied – have about one thousand. Humans have a somewhat smaller number than mice; some of the genes have been lost during evolution.
Smell is absolutely essential for a newborn mammalian pup to find the teats of its mother and obtain milk – without olfaction the pup does not survive unaided. Olfaction is also of paramount importance for many adult animals, since they observe and interpret their environment largely by sensing smell. For example, the area of the olfactory epithelium in dogs is some forty times larger than in humans.
*Taste*: The tongue alone can only really taste sweet, sour, bitter, salty and MSG (seriously, called unami). It passes the data to the thalamus which maps it near the facial sensory cortex. What we call ‘taste’ is really mostly a function of smell. “If you lick a pink ice cream cone,” says Donald Leopold, an otolaryngologist at Hopkins’s Bayview Medical Center, “your tongue tells you it’s cold and sweet and smooth, but your sense of smell tells you it’s strawberry. Probably 80 percent of what you eat, you appreciate through your sense of smell.”
No textbook really sees fit to seperate these senses, and I don’t think it’s useful to do so experimentally. One can safely refer to both as the chemical sense. As such, any experiments on pheromomes should include taste as well as smell. It’s a chemical process. There’s no point ignoring the other chemical sense.
Pheromones are ‘chemicals emitted by one individual to evoke some behavior in another of the same species, are known to govern sexual activity in animals, but experts differ as to what role, if any, they play in making humans sexually attractive to one another’ (NYTimes). Normal odors will go to thru the olfactory bulb to the temporal lobe, but pheromones are different. They go to the hypothalamus, which releases hormones, which can change your behavior. Specifically, turn you on or off. The process is pretty obvious in other mammals,
‘Arguably, the single most interesting aspect of the chemical senses is their role in the social lives of many species (Catanzaro 2000). The members of many species release pheromones – chemicals that influence the behavior of conspecifics (members of the same species). For example, Murphy and Schneider (1970) showed that the sexual and aggressive behavior of hamsters is under pheremonal control. Normal male hamsters attack and kill unfamiliar males that are placed in their colonies, whereas they mount and impregnate unfamiliar sexually receptive females. However, male hamsters that are unable to smell the intruders engage in neither aggressive nor sexual behavior. Murphy and Schneider confirmed the olfactory basis of hamsters’ aggressive and sexual behavior in a particularily devios fashion. They swabbed a male intruder with the vaginal secretions of a a sexually receptive female before placing it in an unfamiliar colony; in so doing, they converted it from an object of hamster assassination to an object of hamster lust.’ (Pinel textbook, pg 186)
The latest Swedish study from the Times shows that the process is at work in humans as well. This seems pretty obvious. Anything that’s coded that low is almost statically impossible for the cortext to override.
The estrogen-like compound, though it activated the usual smell-related regions in women, lighted up the hypothalamus in men. This is a region in the central base of the brain that governs sexual behavior and, through its control of the pituitary gland lying just beneath it, the hormonal state of the body.
The male sweat chemical, on the other hand, did just the opposite; it activated mostly the hypothalamus in women and the smell-related regions in men. The two chemicals seemed to be leading a double life, playing the role of odor with one sex and of pheromone with another.
The Swedish researchers have now repeated the experiment but with the addition of gay men as a third group. The gay men responded to the two chemicals in the same way as did women, Dr. Savic reports, as if the hypothalamus’s response is determined not by biological sex but by the owner’s sexual orientation.
Pheromone Delivery Mechanism
… Is as yet undefined. Most researchers agree that it’s probably not smell alone. Modern humans find overt smell to be noxious. We wear deodorant and perfumes to cover up the very sweat that releases pheromones. The more you sweat the less attractive you’ll be, which almost seems to argue for an exact opposite reaction to pheromones. All the experiments basically consist of having people sweat into T-Shirts and then having other people smell the T-Shirts. This artificial setup leads to the criticism that
‘There is no direct evidence that human odors can serve as sex attractants (Doty, 1986). To put it
mildly most subjects do not find the aforementioned body odors to be particularily attractive.’
Mice are known to influence each other’s sexual behavior through emission of chemicals that act like hormones on the recipient’s brain and so are known as pheromones. Hopes by the fragrance industry, among others, of finding human pheromones were dashed several years ago when it emerged that a tiny structure in the nose through which mice detect many pheromones, the vomeronasal organ, is largely inactive in humans, having lost its nervous connection with the brain.
Researchers interpreted that to mean that humans, as they evolved to rely on sight more than smell, had no need of the primitive cues that pass for sexual attractiveness in mice. But a role for human pheromones could not be ruled out, especially in light of findings that women living or working together tend to synchronize their menstrual cycles. (NYTimes)
The broad consensus today is that pheromones *do not* govern human behavior because smell is not an adequate delivery mechanism. I would venture to say that this is because they’re got the delivery mechanism wrong. The delivery mechanism for pheromones is the chemical sense in general, specifically taste. There isn’t that much research on it, but it looks like pheromones can be carried by taste,
The general principles that Axel and Buck discovered for the olfactory system appears to apply also to other sensory systems. Pheromones are molecules that can influence different social behaviours, especially in animals. Axel and Buck, independent of each other, discovered that pheromones are detected by two other families of GPCR [G protein-coupled receptors], localized to a different part of the nasal epithelium. The taste buds of the tongue have yet another family of GPCR, which is associated with the sense of taste. (Axel and Buck)
Not an expert, but 90% of sex (should be) foreplay. Most foreplay basically consists of tasting the other person. Kissing, necking, licking, biting, nibbling, sucking etc. At the furthest level, of course, there’s oral sex. The only kind of contact foreplay that isn’t taste-related would be whatever you’re doing with your hands. However, it’s rare to do that without some concurrent kissing or nibbling.
At one level, mouthplay is tactile, but you’re also getting an awful lot of information from sweat and taste in general. That information is not sweet, salt, sour, or bitter so it must be processed as smell. That’s going through the hypothalamus, which directly influences your mood and arousal. Foreplay could be seen as a massive ingestion of pheromones.