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.From about 1700 a worldwide movement perhaps described as the "empowerment of the individual" took hold, leading towards greater emancipation of women and equality of individuals.Men and women became more equal politically, financially, and socially in many nations.Behavior patterns are generally unwritten and constantly changing.
While the term has several meanings, the most frequent usage refers to two people exploring whether they are romantically or sexually compatible by participating in dates with the other.
Accordingly, there was little need for a temporary trial period such as dating before a permanent community-recognized union was formed between a man and a woman.
While pair-bonds of varying forms were recognized by most societies as acceptable social arrangements, marriage was reserved for heterosexual pairings and had a transactional nature, where wives were in many cases a form of property being exchanged between father and husband, and who would have to serve the function of reproduction.
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.
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.