What are the key factors and developments that have led to the transition of psychology into the contemporary era?

Also influential on the emerging discipline of psychology were debates surrounding the efficacy of Mesmerism (a precursor to hypnosis) and the value of phrenology. The former was developed in the 1770s by Austrian physician Anton Mesmer (1734–1815) who claimed to use the power of gravity, and later of “animal magnetism”, to cure various physical and mental ills. As Mesmer and his treatment became increasingly fashionable in both Vienna and Paris, it also began to come under the scrutiny of suspicious officials. In 1784, an investigation was commissioned in Paris by King Louis XVI which included American ambassador Benjamin Franklin, chemist Antoine Lavoisier and physician Joseph-Ignace Guillotin (later the popularizer of the guillotine). They concluded that Mesmer’s method was useless. Abbé Faria, an Indo-Portuguese priest, revived public attention in animal magnetism. Unlike Mesmer, Faria claimed that the effect was ‘generated from within the mind’ by the power of expectancy and cooperation of the patient. Although disputed, the “magnetic” tradition continued among Mesmer’s students and others, resurfacing in England in the 19th century in the work of the physician John Elliotson (1791–1868), and the surgeons James Esdaile (1808–1859), and James Braid (1795–1860) (who reconceptualized it as property of the subject’s mind rather than a “power” of the Mesmerist’s, and relabeled it “hypnotism”). Mesmerism also continued to have a strong social (if not medical) following in England through the 19th century (see Winter, 1998). Faria’s approach was significantly extended by the clinical and theoretical work of Ambroise-Auguste Liébeault and Hippolyte Bernheim of the Nancy School. Faria’s theoretical position, and the subsequent experiences of those in the Nancy School made significant contributions to the later autosuggestion techniques of Émile Coué. It was adopted for the treatment of hysteria by the director of Paris’s Salpêtrière Hospital, Jean-Martin Charcot (1825–1893).

Phrenology began as “organology”, a theory of brain structure developed by the German physician, Franz Joseph Gall (1758–1828). Gall argued that the brain is divided into a large number of functional “organs”, each responsible for particular human mental abilities and dispositions – hope, love, spirituality, greed, language, the abilities to detect the size, form, and color of objects, etc. He argued that the larger each of these organs are, the greater the power of the corresponding mental trait. Further, he argued that one could detect the sizes of the organs in a given individual by feeling the surface of that person’s skull. Gall’s ultra-localizationist position with respect to the brain was soon attacked, most notably by French anatomist Pierre Flourens (1794–1867), who conducted ablation studies (on chickens) which purported to demonstrate little or no cerebral localization of function. Although Gall had been a serious (if misguided) researcher, his theory was taken by his assistant, Johann Gaspar Spurzheim (1776–1832), and developed into the profitable, popular enterprise of phrenology, which soon spawned, especially in Britain, a thriving industry of independent practitioners. In the hands of Scottish religious leader George Combe (1788–1858) (whose book The Constitution of Man was one of the best-sellers of the century), phrenology became strongly associated with political reform movements and egalitarian principles (see, e.g., Shapin, 1975; but also see van Wyhe, 2004). Phrenology soon spread to America as well, where itinerant practical phrenologists assessed the mental well-being of willing customers (see Sokal, 2001).