Behavior patterns are generally unwritten and constantly changing.There are considerable differences between social and personal values.
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.
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.
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.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.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.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.