ABSTRACT
Psychology studies the mind and its operations, including sense perception, action, imagination, attention, and thought. Philosophers and scientists have studied such psychological phenomena since the time of the ancient Greeks. The nineteenth century was an important period in the development of psychology. As the century opened, psychology was mainly studied either within medical physiology or as a part of philosophy. By the end of the century, psychology was on the way to establishing itself in university departments as an experimental natural science. The new experimental psychology appropriated the experimental techniques of sensory physiology and the empirical observations and theoretical constructs of philosophical psychology. In order to understand the development of psychology during the nineteenth century, we must consider psychology during the eighteenth century, when it separated itself from the study of living things in general and became a specialized discipline of its own. In the mid-eighteenth century, several thinkers, both philosophers and medical physiologists, proposed that psychology should be a natural science. They meant that psychology should use careful observations, including some quantitative observations, to study the phenomena of mind and chart the laws of such phenomena. At this time, most authors classi…ed psychological phenomena as products of various mental faculties or mental powers, including sensory capacities, imagination, and memory. Over the course of the century, theorists came more and more to emphasize the laws of association as explanatory factors within psychology. According to such laws, the contents of mental states become “associated” so that, subsequently, when one occurs (in thought or sensation) the other comes forth through association. The law of contiguity says that sensations or ideas that are constantly conjoined (spatially or temporally) in experience become associated; the law of similarity says that sensations or ideas with resembling content become associated. At the start of the nineteenth century, some theorists proposed resolving all psychological phenomena into the laws of association and foregoing any talk of faculties. During the nineteenth century, psychological thought developed in several distinct contexts. Within the universities, psychology was taught as a distinct subject matter in the faculty (or school) of philosophy. German philosophical psychology often
situated itself in relation to the thought of Immanuel Kant, although alternative viewpoints soon arose. Also at universities, but within the medical faculty, physiologists continued to work on the physiology and psychology of sensorimotor and mental functions. Sensory physiologists, together with some physicists, invented sophisticated laboratory techniques for measuring sensory phenomena (especially visual phenomena) and for testing theories. Initially in Germany, this work was synthesized into a new, self-avowedly “scienti…c” and ultimately “experimental” psychology. Outside the universities, the work of Herbert Spencer and Charles Darwin provided a new impetus for allying psychological thought with biology. Spencer’s Principles of Psychology offered a view of the mind as a faculty for adapting the organism to its environment. Darwin applied evolutionary thinking especially to the emotions. The work of these “gentleman scholars” soon had an impact within the universities. In Germany, the sensory physiologist Ewald Hering immediately applied Darwinian thinking to the senses. In Britain and America, Darwin’s evolutionary psychology was taken up and developed into a comprehensive outlook toward psychological phenomena. In the latter part of the nineteenth century, the new experimental psychology gained recognition as a distinct subject matter in German and American universities. The new discipline found especially fertile soil in North America, where by the beginning of the twentieth century forty-two universities and colleges had founded psychological laboratories in the arts and sciences faculty. The discipline continued to grow in North American universities, but it took longer to establish itself in Germany, Britain, and France. Indeed, in the early decades of the twentieth century some German authors were proclaiming a “crisis” in psychology concerning its ability to become a natural science while also addressing central aspects of human thought (Ash 1991). In institutional terms, European psychology gained a similar status to American psychology only after the Second World War. In subsequent sections, this chapter …rst enlarges on psychology in the eighteenth century. It then recounts developments within German psychology, British psychology, evolutionary psychology, and American psychology, followed by a discussion of introspective methods in the laboratory. The …nal three sections discuss con¶icting opinions on the existence of unconscious mental states, review relations between philosophy and psychology, and survey the state of psychology in the early twentieth century.
