Nostril-Specific Olfactory Modulation of Visual Perception in Binocular Rivalry The Journal of Neuroscience, 28 November 2012, 32(48): 17225-17229 Wen Zhou, Xiaomeng Zhang,Jennifer Chen, Li Wang, and Denise Chen
The article [subscription required] links the epigenetic effects of nutrient chemical-dependent calibration and pheromone-controlled perception of visual cues to movement required for food acquisition, socialization, and mate choice in organisms that sexually reproduce.
My comment: Cognition is not required at the macro level of environmental affect. The affect is driven by epigenetic effects of olfactory/pheromonal input on hormones that affect behavior via the life-long link between in utero conditioning and postnatal responses to visual input via chemical exchanges in placental mammals.
The molecular mechanisms that enable the epigenetic effects, however, are the same in species from microbes to man. Cause and effect can now be addressed at the level of the microRNA / messenger RNA balance required for cellular homeostasis in different cell types of different tissues including our adaptively evolved glucose-dependent brain tissue. It is the epigenetic effects of nutrient chemicals and pheromones that cause changes in intracellular signaling changes that cause intermolecular changes in DNA that result in the finely tuned (e.g., bottom up / top-down) stochastic gene expression of olfactory receptor genes that enable adaptation to an ever-changing environment across the lifetime of organisms, which are primarily dependent on chemical ecology — not visual or auditory input — for species survival.
This does not discount the role of other sensory input in human interactions or the interaction of other species with eyes and ears; it merely addresses incentive salience from a perspective on adaptive evolution. Wen’s work with Denise and others has been fast-forwarding us in that context, but the systems biology involved may be obscuring the insight others have provided. Also, there’s the fact that many people still think that human pheromones don’t exist. If not, there would be no direct link from the eye to the mind and behavior.
Without food odors we would not survive long enough to develop hormone-controlled food preferences for the visual appeal of food. Similarly, and via the same molecular mechanisms, without human pheromones we would not survive long enough to develop genetically predisposed hormonally controlled preferences for the visual appeal of other people, as detailed in The Mind’s Eyes: Human pheromones, neuroscience, and male sexual preferences and in my other published works.