A female dog in heat releases pheromones that will attract all male dogs living within a radius of several miles. Ants leave behind pheromones to mark a fast trail to an unsuspecting group of picnickers. In our species, pheromones may be responsible for that 'physical chemistry' we experience with certain people. Pheromones are biochemicals that are secreted in our sweat and unconsciously perceived by tiny receptors in our nasal passages. These pheromones often 'carry' certain messages that elicit an unconscious response from others.
Pheromones also deliver messages about a person's sexual state and general health.
Studies have shown that pheromones play a role in helping us choose a mate whose genetic resistance to disease complements our own. This serves the evolutionary purpose of ensuring healthy children. Though this research has exciting implications about the power of our unconscious primitive minds, pheromones represent only the very tip of the human attraction iceberg.