Unlike the opiates, which are a rather homogeneous group, the drugs we call stimulants come in a variety of forms. In this chapter, we will devote most of our time to the classical stimulants, cocaine and the amphetamines, but will consider as well caffeine, nicotine, ephedrine, and modafinil. All are capable of enhancing mental and physical performance, and some produce distinctly pleasurable effects that sometimes lead to addiction. About the time that humans living in what is now South America started to draw on the walls of their caves, one among them discovered the unusual properties of the coca shrub. When the leaves were chewed, wondrous things happened to the chewer: Hunger and fatigue were replaced by feelings of strength and power; the world seemed not such a bad place to live. By the time Francisco Pizarro led his conquistadors into Peru early in the 16th century, coca leaf had found an exalted place in the Incan Empire. One legend has it that coca was brought from heaven to earth by Manco Capac, son of the Sun god and the Inca from whom the ruling class traced its lineage. (Interesting how often royalty has claimed divine origins.) The Spaniards developed no great respect for coca, regarding it as but another facet of a pagan people who had no claim on civilization. But the new rulers were nothing if not practical. Coca allowed native workers to be pushed beyond the normal bounds of physical endurance. More tin and silver could be brought from the mines with fewer workers fed less food. Coca leaf lost its status as a sacrament and a pleasure of the ruling class. It became a part of the internal economy of Spanish Peru, a means of enhancing productivity, and a contributor to the destruction of the Incan people and their civilization. It was inevitable that Europeans would become familiar with the effects of coca leaf both by their observation of native use and by personal experience. In 1859, an Italian physician named Paolo Mantegazza who had spent some time among the Peruvian natives put it this way.
Does the impact of plant closure on labour market attachment differ between immigrants and native workers across the business cycle?
