(Medical Xpress) — Our senses aren’t just delivering a strict view of what’s going on in the world; they’re affected by what’s going on in our heads. A new study finds that hungry people see food-related words more clearly than people who’ve just eaten.
What’s inside each organism from microbes to man are intracellular signaling pathways. These pathways are activated by nutrient chemicals that cause gene expression linked to the metabolism of nutrients. Nutrient metabolism is required for the organism’s ongoing proper selection of chemicals that ensure its survival. Proper selection for metabolites expressed as chemical signals of self and non-self recognition enable speciation. No other sensory input and no brain is required, only genetic predisposition, the epigenetic influence of chemicals, and the ligand-receptor binding common to the chemical senses across all species.
Biologists are becoming more familiar with these processes, which many psychologists seem to think require a brain and perception. But the processes involved exemplify a “no-brainer” approach to understanding the biology of evolved human behaviors, which also require ligand-receptor binding for activation. Food odors and pheromones are ligand that activate odor receptors. The transduction of a chemical signal to electrical signals, which are the common language of the brain, allows odors to directly effect hormones that affect behavior. But the same transduction occurs and alters behavior even in organisms with no brain.