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.
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.
These species-particular behavior patterns provide a context for aspects of human reproduction, including dating.
Today, the institution of dating continues to evolve at a rapid rate with new possibilities and choices opening up particularly through online dating.
Social rules regarding dating vary considerably according to variables such as country, social class, race, religion, age, sexual orientation and gender.
As humans societies have evolved from hunter-gatherers into civilized societies, there have been substantial changes in relations between men and women, 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.
Historically, marriages in most societies were arranged by parents and older relatives with the goal not being love but legacy and "economic stability and political alliances", according to anthropologists.
New types of relationships formed; it was possible for people to live together without marrying and without children.
Information about human sexuality grew, and with it an acceptance of all types of sexual orientations is becoming more common.
Still, dating varies considerably by nation, custom, religious upbringing, technology, and social class, and important exceptions with regards to individual freedoms remain as many countries today still practice arranged marriages, request dowries, and forbid same-sex pairings.
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.