Final answer:
Pheromones are chemical signals influencing behavior or physiology within a species, and studies like the Sweaty T-Shirt Study indicate they may play a role in human attraction. Unlike other odors, pheromones evoke more instinctual responses, but in humans, their influence is less clear and still under research.
Step-by-step explanation:
Pheromones are chemical signals secreted by individuals which affect the behavior or physiology of other individuals of the same species. Oftentimes, these pheromonal signals are not consciously perceived, unlike other odors. In humans, while the evidence for pheromones' role in behavior is more ambiguous than in other species, there are studies suggesting they play a part in communication and attraction.
One well-known study, often referred to as the Sweaty T-Shirt Study, investigated the role of pheromones in human attraction. Women were asked to smell t-shirts worn by different men and rate them based on attractiveness. The results indicated that women preferred the scent of men whose immune system genes were different from their own, suggesting a possible role for pheromones in mate choice and sexual selection.
Different from other odorants, pheromones trigger more instinctive and specific responses. They can influence a wide range of behaviors, from mating and feeding to marking territory. However, in humans, the influence of pheromones is less pronounced and the focus of ongoing research.