10 Most Influential Psychologists
A study that appeared in the July 2002 issue of the Review of General Psychology created a ranking of the 99 most influential psychologists. The rankings were mostly based on three factors: the frequency of journal citations, introductory textbook citations, and the survey responses of 1,725 members of the American Psychological Association.1. B. F. Skinner
In the 2002 study ranking the 99 most eminent psychologists of the 20th century, B.F. Skinner topped the list. Skinner’s staunch behaviorism made him a dominating force in psychology and therapy techniques based on his theories are still used extensively today, including behavior modification and token economies.2. Sigmund Freud
When people think of psychology, many tend to think of Freud. His work supported the belief that not all mental illnesses have physiological causes and he also offered evidence that cultural differences have an impact on psychology and behavior. His work and writings contributed to our understanding of personality, clinical psychology, human development, and abnormal psychology.3. Albert Bandura
Bandura’s work is considered part of the cognitive revolution in psychology that began in the late 1960s. His social learning theory stressed the importance of observational learning, imitation, and modeling. “Learning would be exceedingly laborious, not to mention hazardous, if people had to rely solely on the effects of their own actions to inform them what to do,” Bandura explained in his 1977 book Social Learning Theory.4. Jean Piaget
Jean Piaget’s work had a profound influence on psychology, especially our understanding children’s intellectual development. His research contributed to the growth of developmental psychology, cognitive psychology, genetic epistemology, and education reform. Albert Einstein once described Piaget’s observations on children’s intellectual growth and thought processes as a discovery “so simple that only a genius could have thought of it.”5. Carl Rogers
Carl Rogers placed emphasis on human potential, which had an enormous influence on both psychology and education. He became one of the major humanist thinkers and an eponymous influence in therapy with his “Rogerian therapy.” As described by his daughter Natalie Rogers, he was “a model for compassion and democratic ideals in his own life, and in his work as an educator, writer, and therapist.”6. William James
Psychologist and philosopher William James is often referred to as the father of American psychology. His 1200-page text, The Principles of Psychology, became a classic on the subject and his teachings and writings helped establish psychology as a science. In addition, James contributed to functionalism, pragmatism, and influenced many students of psychology during his 35-year teaching career.7. Erik Erikson
Erik Erikson’s stage theory of psychosocial development helped create interest and research on human development through the lifespan. An ego psychologist who studied with Anna Freud, Erikson expanded psychoanalytic theory by exploring development throughout the life, including events of childhood, adulthood, and old age.
8. Ivan Pavlov
Ivan Pavlov was a Russian physiologist whose research on conditioned reflexes influenced the rise of behaviorism in psychology. Pavlov’s experimental methods helped move psychology away from introspection and subjective assessments to objective measurement of behavior.9. Kurt Lewin
Lewin is known as the father of modern social psychology because of his pioneering work that utilized scientific methods and experimentation to look as social behavior. Lewin was a seminal theorist whose enduring impact on psychology makes him one of the preeminent psychologists of the 20th-century.10. Reader’s Choice
Following the examples of Eugene Garfield’s 1977 ranking list and Haggbloom’s 2002 ranking, the final position on this list has been left blank in order to allow “the reader’s best case for a psychologist who should have made the list” (Haggbloom, 2002).
Jean Piaget's Theory of Cognitive Development
Jean Piaget was one of the first developmental psychologists to examine how children think and reason. He asked whether children perceive and make sense of the world the way adults do and created a theory that explores how children’s thought processes change with development.
Piaget argued that children’s thought processes progress through several distinct, predictable stages. At each stage, the way in which we look at the world changes. We progress through each in order, with no skipping or regression under normal circumstances.
Sensorimotor stage (Infancy)
During the sensorimotor stage, from birth to around 18-24 months, infants are not yet able to use symbols or images to represent objects in the external world. To think about an object they must act on it with their senses and motor abilities. The major advance of this stage is object permanence, the understanding that objects continue to exist outside of sensory awareness.
If an infant reaches for a toy and you cover it with a cloth, he or she will stop reaching and look at something else. If you secretly remove the toy and then lift the cloth, the baby will look at the empty spot without surprise or disappointment. According to Piaget, the baby does not yet have object permanence; out of sight is out of mind. By a year of age, children develop object permanence and can use mental representation and think about objects that are not physically present.
Pre-operational stage (Toddler and Early Childhood)
From 2 to about 7, the child is in the preoperational stage of development. Now they can use mental representation to think. They begin to use pretend play. Children are now capable of symbolic representation - using a symbol to represent an object. Because of this, children learn language, a system of symbols.
Piaget emphasized that during this period, children’s abilities are limited. One pervasive limitation of children’s reasoning during the preoperational period is egocentrism, the inability to take the perspective of another person. A child may assume that everyone has the same knowledge, experiences, and perspective that he or she has. Egocentric thinking predominates.
Concrete operational stage (Elementary and early adolescence)
The concrete operational stage lasts from about age 7 to 11. Now children can engage in mental representation and think logically about the world around them. Specifically, children are able to manipulate their mental representations to think and solve problems. Thought becomes logical, overcoming the limitations of the preoperational stage of reasoning. Now children are capable of understanding conservation, that a change in the size of shape of a substance (like clay) does not change its mass. Operational thinking develops (mental actions that are reversible). Egocentric thought diminishes.
Formal operational stage (Adolescence and adulthood)
During early adolescence, individuals enter Piaget’s period of formal operations. Now cognitive development reaches its peak. Teenagers become capable of using and manipulating their symbolic representations in abstract thought. They can create and logically think through hypothetical situations. Scientific and deductive reasoning become possible. The individual is cognitively mature. Early in the period there is a return to egocentric thought. Only 35% of high school graduates in industrialized countries obtain formal operations; many people do not think formally during adulthood.