Dating as an institution is a relatively recent phenomenon which has mainly emerged in the last few centuries. From the standpoint of anthropology and sociology, dating is linked with other institutions such as marriage and the family which have also been changing rapidly and which have been subject to many forces, including advances in technology and medicine. As humans have evolved from the hunter-gatherers into civilized societies and more recently into modern societies, there have been substantial changes in the relationship between men and women, with perhaps the only biological constant being that both adult women and men must have sexual intercourse for human procreation to happen. Dating is a part of human mating process whereby two people meet socially for companionship, beyond the level of friendship, or with the aim of each assessing the other's suitability as a partner in an intimate relationship or marriage. It can be a form of courtship consisting of social activities done by the couple. While the term has several meanings, it usually refers to the act of meeting and engaging in some mutually agreed upon social activity in public, together, as a couple.