However, one particularity of the human species is that pair bonds are often formed without necessarily having the intention of reproduction.
In modern times, emphasis on the institution of marriage, generally described as a male-female bond, has obscured pair bonds formed by same-sex and transsexual couples, and that many heterosexual couples also bond for life without offspring, or that often pairs that do have offspring separate.
Cars extended the range of dating as well as enabled back-seat sexual exploration.
In the mid-twentieth century, the advent of birth control as well as safer procedures for abortion changed the equation considerably, and there was less pressure to marry as a means for satisfying sexual urges.
Neurobiologist Robert Sapolsky constructed a reproductive spectrum with opposite poles being tournament species, in which males compete fiercely for reproductive privileges with females, and pair bond arrangements, in which a male and female will bond for life.
Although in many countries, movies, meals, and meeting in coffeehouses and other places is now popular, as are advice books suggesting various strategies for men and women, in other parts of the world, such as in South Asia and many parts of the Middle East, being alone in public as a couple with another person is not only frowned upon but can even lead to either person being socially ostracized.
In the twentieth century, dating was sometimes seen as a precursor to marriage but it could also be considered as an end-in-itself, that is, an informal social activity akin to friendship.
It generally happened in that portion of a person's life before the age of marriage, enabled dates to be arranged without face-to-face contact.
As humans societies have evolved from hunter-gatherers into civilized societies, there have been substantial changes in relations between people, with perhaps one of a few remaining biological constants being that both adult women and men must have sexual intercourse for human procreation to happen.
Humans have been compared to other species in terms of sexual behavior.