become the key motivations to continue. A 2009 study of first smoking experiences of seventh-grade students found out that the most common factor leading students to smoke is cigarette advertisements. Smoking by parents, siblings and friends also encourages students to smoke. History Use in ancient cultures Smoking's history dates back to as early as 5000–3000 BC, when the agricultural product began to be cultivated in Mesoamerica and South America; consumption later evolved into burning the plant substance either by accident or with intent of exploring other means of consumption. The practice worked its way into shamanistic rituals. Many ancient civilizations – such as the Babylonians, the Indians, and the Chinese – burnt incense during religious rituals. Smoking in the Americas probably had its origins in the incense-burning ceremonies of shamans but was later adopted for pleasure or as a social tool. The smoking of tobacco and various hallucinogenic drugs was used to achieve trances and to come into contact with the spirit world. Also, to stimulate respiration, tobacco smoke enemas were used. Eastern North American tribes would carry large amounts of tobacco in pouches as a readily accepted trade item and would often smoke it in ceremonial pipes, either in sacred ceremonies or to seal bargains. Adults as well as children enjoyed the practice. It was believed that tobacco was a gift from the Creator and that the exhaled tobacco smoke was capable of carrying one's thoughts and prayers to heaven. Apart from smoking, tobacco had uses as medicine. As a pain killer it was used for earache and toothache and occasionally as a poultice. Smoking was said by the desert Indians to be a cure for colds, especially if the tobacco was mixed with the leaves of the small Desert sage, Salvia dorrii, or the root of Indian balsam or cough root, Leptotaenia multifida, the addition of which was thought to be particularly good for asthma and tuberculosis. Popularization In 1612, six years after the settlement of Jamestown, Virginia, John Rolfe was credited as the first settler to successfully raise tobacco as a cash crop. The demand quickly grew as tobacco, referred to as "brown gold", revived the Virginia joint stock company from its failed gold expeditions. In order to meet demands from the Old World, tobacco was grown in succession, quickly depleting the soil. This became a motivator to settle west into the unknown continent, and likewise an