Young Kissing Girls

In modern times, scientists have done brain scans on people when a romantic relationship progresses. Some studies found that after that "first magical meeting or perfect first date," a complex system in the brain is activated that is essentially "the same thing that happens when a person takes cocaine." In studies of affection between lovers, when participants viewed images of their partners, their brains' ventral tegmental area, which houses the reward and motivation systems, was flooded with dopamine, an internal chemical that is "released when you're doing something highly pleasurable ..."
Within the natural world of animals there are numerous analogies, notes Crawley, such as "the billing of birds, the cataglottism of pigeons and the antennal play of some insects." Even among higher animals such as the dog, cat and bear, similar behavior is noted.