In all mammals, a life-long developmental process that begins before birth is responsible both for physical attractiveness, and for our personal preferences. For example, our food preferences for different types of food depend on odor associations with different foods we have tasted. It’s the chemistry of the food that is most important.
Our preferences for the physical characteristics of other people depend on human pheromones. It’s the chemistry between people that is most important.
Like food odors, we can sometimes detect human pheromones with our sense of smell. Unlike food odors, the production of human pheromones and our response to them depends on the differences between men and women.
Typically, women respond to increased male pheromone production with increased attention. Men respond to increased female pheromone production with increased attention.