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jvkohl
03-22-2004, 08:28 PM
Some

forum members may be interested in the following post sent today to listservers for evolutionary psychology;

sexuality; and chemical senses. Though the focus on the post
is on recent neuroscientific reports, the question

remains:
How does mammalian biology allow for males and females to find visual appeal in other males and

females?
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Whether or not there is a functional human

vomeronasal organ (VNO), human pheromones appear to elicit a typical mammalian luteinizing hormone (LH) response.

This biological fact might antagonize those with the anthropocentric view that trichomatic vision differentiates us

from other primates, at least when it comes to our olfactory prowess (as indicated and subsequently contraindicated

below).

--------------indicated--------------------
Unlike other New World Monkeys, these [howler monkeys]

have a full set of visual proteins, so can distinguish all colors in their environment. To achieve this full color

vision, the howler, like humans and apes, increased their proportion of olfactory pseudogenes and lost part of their

keen sense of

smell.

http://dsc.discovery.com/news/afp/20040

119/primate.html (\"http://dsc.discovery.com/news/afp/20040119/primate.html\")

--------contraindicated--------------------
This and other observations indicate that

howler monkeys have maintained both their systems of pheromone communication and full trichromatic vision,

suggesting that the presence of full trichromacy alone does not lead to the loss of pheromone communication. We

suggest that the ecological differences between OW and NW primates, particularly in habitat selection, may have also

affected the evolution of pheromone perception.

Genetic Evidence for the Coexistence of Pheromone Perception and

Full Trichromatic Vision in Howler Monkeys David M. Webb, Liliana Cortes-Ortiz, and Jianzhi Zhang
Mol. Biol. Evol.

2004 21(4): p.

697-704
http://mbe.oupjournals.org/cgi/conte

nt/abstract/21/4/697?ct (\"http://mbe.oupjournals.org/cgi/content/abstract/21/4/697?ct\")

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Even as

comparisons are made and remade, it is more interesting to ask whether anyone might attempt to explain sexual

differentiation of the amygdala, which is indicated in the following

abstract:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&amp

;list_uids=15004563 (\"http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&

list_uids=15004563\")

In my opinion, there is no evidence that a sexually dimorphic response to visual input

could develop unless it developed in accord with the logical link from mammalian pheromones to LH, sex steroid

hormone production, and neuroanatomical sexual differentiation (e.g., olfactory conditioning of the visual

response).


\"...the functional significance of the conditioned change in LH secretion lies principally in the

unequivocal demonstration that olfactory cues can activate the male pituitary-gonadal axis in a way that mimics, in

every respect, the activation achieved by exposure to a

female.\"

http://www.nel.edu/22_5/NEL220501R01_Review

.htm (\"http://www.nel.edu/22_5/NEL220501R01_Review.htm\")

The development of food preferences is more likely to be based upon olfactory input (conditioning)

than on visual input alone. If sexual differentiation of the visual response (e.g., mate preferences) is not due to

pheromonal conditioning, how might it occur, biologically?