Love is an emotion of a strong affection and personal attachment. Love is also said to be a virtue representing all of human kindness, compassion, and affection —"the unselfish loyal and benevolent concern for the good of another". Love may describe compassionate and affectionate actions towards other humans, one's self or animals.
In English, love refers to a variety of different feelings, states, and attitudes, ranging from pleasure "I loved that meal" to interpersonal attraction "I love my partner". "Love" may refer specifically to the passionate desire and intimacy of romantic love, to the sexual love of eros, to the emotional closeness of familial love, to the platonic love that defines friendship, or to the profound oneness or devotion of religious love, or to a concept of love that encompasses all of those feelings.
This diversity of uses and meanings, combined with the complexity of the feelings involved, makes love unusually difficult to consistently define, compared to other emotional states.
Love in its various forms acts as a major facilitator of interpersonal relationships and, owing to its central psychological importance, is one of the most common themes in the creative arts.
Love may be understood as part of the survival instinct, a function to keep human beings together against menaces and to facilitate the continuation of the species
Romantic love both exhilarates and motivates us. It is also critical to the continuation of our species. Without the attachment of romantic love, we would live in an entirely different society that more closely resembled some (but not all) of those social circles in the animal world. The chemicals that race around in our brain when we're in love serve several purposes, and the primary goal is the continuation of our species. Those chemicals are what make us want to form families and have children. Once we have children, those chemicals change to encourage us to stay together to raise those children. So in a sense, love really is a chemical addiction that occurs to keep us reproducing.
The debated topic of human pheromones still carries some weight in the field of love research. The word "pheromone" comes from the Greek words pherein and hormone, meaning "excitement carrier".
In the animal world, pheromones are individual scent "prints" found in urine or sweat that dictate sexual behavior and attract the opposite sex. They help animals identify each other and choose a mate with an immune system different enough from their own to ensure healthy offspring. They have a special organ in their noses called the vomeronasal organ (VNO) that detects this odorless chemical.
The existence of human pheromones was discovered in 1986 by scientists at the Chemical Senses Center in Philadelphia and its counterpart in France. They found these chemicals in human sweat. A human VNO has also been found in some, but not all, people. Even if the VNO isn't present in all of us -- and may not be working in those who do have it -- there is still evidence that smell is an important aspect of love (note the booming perfume industry). An experiment was conducted where a group of females smelled the unwashed tee shirts of a group of sweaty males, and each had to select the one to whom she was most "attracted." Just like in the animal world, the majority of the females chose a shirt from the male whose immune system was the most different from their own.