In this chapter, I shall first give a short description of psychology as an empirical science as it appears at the beginning of the twenty-first century. Then, I shall discuss how a study of the history of psychology can contribute to our understanding of present-day psychology. Further, I shall account for the way (I believe) psychology as an empirical science originated. Finally, before I present the plan for the book, I shall discuss reasons why empirical psychology over time has undergone changes. In this discussion, I shall be particularly concerned with the problem of assessing progress in psychology as an empirical science.

A Short Characterization of Present-Day Psychology

Here at the beginning of the twenty-first century, psychology as an empirical science has grown into a broad, diversified field of study. We can gain an impression of its breadth by noting that it borders on the biological sciences on the one hand and the social sciences on the other.

Psychology is a theoretical as well as an applied science, and also a profession incorporating a number of specialties. In a wide variety of areas it has produced knowledge useful for the solution of theoretical problems as well as problems of practical and social life. However, so far, psychology has hardly produced comprehensive theories or scientifically acceptable principles of a general nature. Thus, the discipline appears highly fragmented.

The Present Approach to the Study of the History of Psychology

The attempt to establish psychology as an empirical science raised several questions that were not easily answered and that soon became controversial. Questions such as what is the relationship between mind and brain, between human and animal behavior, and between genetic endowment and environmental influence (nature and nurture) emerged at the inception of the discipline and have remained controversial to this day. At an early stage, disagreement arose about whether we should conceive of psychology as the study of mental experiences or the study of behavior. In what sense should we regard as mental experiences various types of nonconscious processes, such as the subconscious and the unconscious? How do society and culture influence human thinking and behavior? This last question emerged later in psychology's history and is of central importance for the advancement of psychology as an empirical science.

When controversial questions such as these have been satisfactorily answered, psychology will be considerably advanced.

The question you ask me in your letter of 15 September, Sir, is important and weighty; knowing whether there is a demonstrable morality or not hinges on how it is resolved.

Three Influential European Cognitive Psychologists: Piaget, Vygotsky, and Bartlett

Extensive research in cognition took place in the United States and Europe throughout the first half of the twentieth century. In Europe, where American behaviorism had little influence, some of the most creative and influential cognitive psychologists did most of their work.

Jean Piaget, a dominant figure not only in child psychology but also in cognitive psychology, began his research in the 1920s. His early work was known in Europe and the United States, but it was not until the 1950s that he was recognized as a central figure in psychology. His Russian contemporary, Lev Vygotsky, exerted a profound influence on Soviet psychology from the 1930s, but his work first became influential in Western psychology in the 1960s. The Gestalt psychologists carried out extensive studies in cognition throughout the period 1920–60. The British psychologist Frederick Bartlett of Cambridge University began to have an impact on US cognitive psychology only in the 1960s, but his main work was already published in 1932, and so he belongs in this chapter.

The study of animal learning attracted the greatest interest among US experimental psychologists, but a number of researchers also pursued the study of memory in the Ebbinghaus–Müller tradition. Their work, as well as that of other US cognitive psychologists outside this tradition, has a place in the history of psychology and shall be reviewed in this chapter.

Jean Piaget (1896–1980)

Jean Piaget was interested and active in research in biology, logic, philosophy, and psychology. A book on language and egocentricity in children made him famous as early as 1924. His reputation as a central figure in child psychology rests mainly on his idea that philosophical problems, particularly logical problems, can be elucidated by a study of ontogenetic development. When his book La psychologie de l'intelligence (The Psychology of Intelligence) was translated into English in 1950, it aroused enormous interest, and in the 1950s and 1960s, this interest spread like wildfire. I shall concentrate on Piaget's ideas of language and egocentricity, and the development of intelligence and logical thinking.

So long as a number of men united consider themselves as a single body, they have but a single will regarding the common preservation and the general welfare. Then all the springs of the State are vigorous and simple, its maxims are clear and luminous, it has no confused, contradictory interests, the common good is everywhere fully evident and requires only good sense to be perceived. Peace, unity, equality are enemies of political subtleties. Upright and simple men are difficult to deceive because of their simplicity, they are not taken in by sham and special pleading; they are not even clever enough to be dupes. When, among the happiest people in the world, troops of peasants are seen attending to affairs of State beneath an oak and always acting wisely, can one help feeling contempt for the refinements of the other nations that make themselves illustrious and miserable with so much art and mysteries?

Here it is, Sir, this wretched chatter for which my humbled amour propre made you wait such a long time, because I failed to sense that a much nobler amour propre should have taught me to overcome the first. It does not much matter that my rambling might strike you as wretched, so long as I am satisfied with the sentiment which dictated it to me. As soon as my improved state restored some of my strength, I took the occasion to re-read and send it to you. If you have the courage to go on to the end, I ask you to be so kind and return it to me, without telling me anything of what you may have thought about it, and which I understand in any event. I greet you, Sir, and embrace you wholeheartedly.