This chapter presents the most salient psychological theories of personality. Personality is a core determinant of individual differences in everyday behaviors. The chapter discusses the difference between what psychologists broadly refer to as normal and what they regard as abnormal or clinical/mental illness. If one looks for an Elvis among personality psychologists, Sigmund Freud would be the one. During the mid-20th century, behaviorism emerged as a dominant paradigm for understanding human behavior, including personality. Although the social cognitive theory of personality has its origins in the radical behaviorist tradition, it emerged in clear opposition to it. According to the lexical hypothesis, historically, the most important and socially relevant behaviors that people display will eventually become encoded into language. Indeed, personality disorders are defined as long-standing, pervasive, and inflexible patterns of behavior and inner experience that deviate from the expectations of a person’s culture.

Psycholinguist is someone who studies phenomena in the intersection of linguistics and psychology. The whole endeavor of psycholinguistics often finds a home in the broader research field of cognitive science—an interdisciplinary field that addresses the difficult question of how animals, people, and even computers think. The centrality of language in the daily lives means that any disruption to the ability to use it may be keenly felt—the worse the disruption, the more devastating the impact. From the beginning of psychology, there has been an interest in language. In psychology, behaviorism was a movement in which the study of mental states was more or less rejected, and the idea that one could account for human behavior in terms of mental states or representation was discounted. This book covers a number of topics that are very much relevant in current psycholinguistics, including child language acquisition, sign language, language perception, and grammatical structure.

In 1920, in America, psychology was dominated by two main currents. The first was a tendency to reduce life to habit, and the second was to establish differences between humans by test. The second tendency, toward testing, had burst suddenly on the scene with the coming of the Binet tests to America in 1905. The idea of contextualized relationships determined by perceptual interpretation challenged the notions that had sprung up around behaviorism that the brain was empty, functioning only as a router between environmental stimulus and motor response. The idea, still vivid in American psychology during the 1920s, that psychology was “the science of mental life” was reinforced and extended by the diffusion of Gestalt psychology through American psychology over the coming decades, as the rest of these reviews of theory and practice will show.

This chapter starts with a global definition of motivation: an internal state that arouses people to action, moves them in particular directions, and keeps people engaged in certain activities. Motivation is not a learning theory, but it affects what people learn. Classical conditioning, think Pavlov’s dogs is a learning theory and motivation has essentially no role in it. The chapter provides an overview of early theories of motivation, starting with Aristotle. Compulsion occurs when people feel that they must act, even though they may not wish to act in a particular way. For ancient Greek philosophers, hedonism meant pleasure is to exceed pain over the long haul, thereby acknowledging life will not always be pleasurable. The James–Lange theory involves motivation from an emotional perspective. Behaviorism is hard to describe mainly because most people have a misunderstanding of two of its elements: punishment and reinforcement.