Wilhelm Wundt (1832–1920) was a German scientist who was the first person to be referred to as a psychologist. His famous book entitled Principles of Physiological Psychology was published in 1873. Wundt viewed psychology as a scientific study of conscious experience, and he believed that the goal of psychology was to identify components of consciousness and how those components combined to result in our conscious experience. Wundt used introspection (he called it “internal perception”), a process by which someone examines their own conscious experience as objectively as possible, making the human mind like any other aspect of nature that a scientist observed. He believed in the notion of voluntarism—that people have free will and should know the intentions of a psychological experiment if they were participating (Danziger, 1980). Wundt considered his version experimental introspection; he used instruments such as those that measured reaction time. He also wrote Volker psychologie in 1904 in which he suggested that psychology should include the study of culture, as it involves the study of people.

Wundt’s version of introspection used only very specific experimental conditions in which an external stimulus was designed to produce a scientifically observable (repeatable) experience of the mind (Danziger, 1980). The first stringent requirement was the use of “trained” or practiced observers, who could immediately observe and report a reaction. The second requirement was the use of repeatable stimuli that always produced the same experience in the subject and allowed the subject to expect and thus be fully attentive to the inner reaction. These experimental requirements were put in place to eliminate “interpretation” in the reporting of internal experiences and to counter the argument that there is no way to know that an individual is observing their mind or consciousness accurately, since it cannot be seen by any other person.

The Birth of Experimental Psychology

Wundt's work was preceded by an important breakthrough by E.H. Weber in the study of human physiology. Weber discovered that if you hold a pile of rocks in your hand, there is a specific ratio by which the weight of that pile would need to be increased before you would notice the change in weight. Weber discovered this by noticing that weight-lifters were able to discriminate between weights better when picking them straight off the floor, but when they were already holding the weights in their hands, the weight had to increase by a specific ratio before the weight-lifters noticed the increased heaviness. What was most important about Weber's breakthrough was that it was discovered not through introspection but through experimentation.

Wundt believed that this approach could be applied to experimental psychology. Experimental psychology is the branch of psychology that seeks to study the mind through empirical experiments. Wundt was one of the first people to believe that consciousness could be studied through experimentation and that consciousness and other mental phenomena should be the object of study in psychology. While these assumptions may seem obvious to us, they were a complete departure from what many philosophers believed at the time.

Methods of Experimental Psychology

These days, we have MRIs, computed tomography and other methods of neuroimaging that allow us to see physiological reactions in the brain. Of course, Wundt did not have these technologies at his disposal. Therefore, he had to rely on a combination of control of external stimuli and reports of internal observations by the research subject. He believed that there were two sides to any explanation of a phenomena - the external side, measured in the laboratory, and the psychological side, measured by self-report of internal observations.

Many of Wundt's experiments, especially his earlier ones, built on Weber's work by concentrating on sensation and perception. Sensation is the physiological response to an external stimuli (for example, the mechanisms of the eye registering a round, small, red object), and perception is the psychological interpretation of sensation (for example, stating that you see an apple). Wundt's experiments consisted of varying external stimuli in a laboratory setting and then asking research subjects to report their relative internal changes. The difference between Weber's and Wundt's work was that, while Weber's experiments were only concerned with physiological reactions, Wundt's experiments were concerned with psychological reactions. Even though Wundt had strict rules about self-observation, it was because of his reliance on internal observation that critics were originally skeptical of Wundt's methods.