Developmental psychology is the scientific study of how and why the human mind grows, changes, and adapts over the course of a human lifetime. Originally concerned with infants and children, the field has expanded to include adolescence, adult development, aging, and the entire lifespan. Developmental psychologists aim to explain how thinking, feeling, and behaviors change throughout life. This field examines change across three major dimensions, which are physical development, cognitive development, and social emotional development. Within these three dimensions are a broad range of topics including motor skills, executive functions, moral understanding, language acquisition, social change, personality, emotional development, self-concept, and identity formation.
Developmental psychology explores the influence of both nature and nurture on human development, as well as the processes of change that occur across different contexts over time. Many researchers are interested in the interactions among personal characteristics, the individual's behavior, and environmental factors, including the social context and the built environment. Ongoing debates regarding developmental psychology include biological essentialism vs. neuroplasticity, and stages of development vs. dynamic systems of development. While research in developmental psychology has certain limitations, ongoing studies aim to understand how life stage transitions and biological factors influence human behavior and development.
Developmental psychology is related to a range of fields, such as educational psychology, child psychopathology, forensic developmental psychology, child development, cognitive psychology, ecological psychology, and cultural psychology. Influential developmental psychologists from the 20th century include Urie Bronfenbrenner, Erik Erikson, Sigmund Freud, Jean Piaget, Mary Ainsworth, John H. Flavell, and Lev Vygotsky.
Historical antecedents Jean-Jacques Rousseau and John B. Watson are typically cited as providing the foundation for modern developmental psychology. In the mid-18th century, Jean Jacques Rousseau described three stages of development: infants (infancy), puer (childhood) and adolescence in Emile: Or, On Education. Rousseau's ideas were adopted and supported by educators at the time.
Developmental psychology generally focuses on how and why certain changes (cognitive, social, intellectual, personality) occur over time in the course of a human life. Many theorists have made a profound contribution to this area of psychology. One of them is the psychologist Erik Erikson, who created a model of eight phases of psychosocial development. According to his theory, people go through different phases in their lives, each of which has its own developmental crisis that shapes a person's personality and behavior.
In the late 19th century, psychologists familiar with the evolutionary theory of Darwin began seeking an evolutionary description of psychological development; prominent here was the pioneering psychologist G. Stanley Hall, who attempted to correlate ages of childhood with previous ages of humanity. James Mark Baldwin, who wrote essays on topics that included Imitation: A Chapter in the Natural History of Consciousness and Mental Development in the Child and the Race: Methods and Processes, was significantly involved in the theory of developmental psychology. Sigmund Freud, whose concepts were developmental, significantly affected public perceptions.
Theories Psychosexual development
Sigmund Freud developed a theory that suggested that humans behave as they do because they are constantly seeking pleasure. This process of seeking pleasure changes through stages because people evolve. Each period of seeking pleasure that a person experiences is represented by a stage of psychosexual development. These stages symbolize the process of becoming a mature adult.
The first is the oral stage, which begins at birth and ends around a year and a half of age. During the oral stage, the child finds pleasure in behaviors like sucking and other mouth-related activities. The second is the anal stage, from about a year or a year and a half to three years of age. During the anal stage, the child defecates from the anus and is often fascinated with defecation. This period of development often occurs during toilet training. The child becomes interested in feces and urine. Children begin to see themselves as independent from their parents. They begin to desire assertiveness and autonomy.
The third is the phallic stage, which occurs from ages 3 to 5 (most of a person's personality forms by this age). During the phallic stage, the child becomes aware of its sexual organs. Pleasure comes from finding acceptance and love from the opposite sex. The fourth is the latency stage, which occurs from age five until puberty. During the latency stage, the child's sexual interests are repressed.
Stage five is the genital stage, which occurs from puberty through adulthood. During the genital stage, puberty begins. Children have now matured and begin to think about other people instead of just themselves. Pleasure comes from feelings of affection from other people.
Freud believed there is tension between the conscious and the unconscious because the conscious resists what the unconscious seeks to express. To explain this, he developed three personality structures: id, ego, and superego. The id, the most primitive of the three, functions according to the pleasure principle: seek pleasure and avoid pain. The superego plays the critical and moralizing role, while the ego is the organized, realistic part that mediates between the desires of the id and the superego.
Theories of cognitive development
Jean Piaget, a Swiss theorist, posited that children learn by actively constructing knowledge through their interactions with their physical and social environments. He suggested that the adult's role in helping the child learn was to provide appropriate materials. In his interviews with children, which formed an empirical basis for his theories, he used a form of Socratic questioning to elicit their thinking. He argued that a principal source of development was through the child's inevitable generation of contradictions through their interactions with their physical and social worlds. The child's resolution of these contradictions led to more integrated and advanced forms of interaction, a developmental process that he called "equilibration."
Piaget argued that intellectual development occurs through a series of stages generated by the process of equilibration. Each stage consists of steps that the child must master before moving on to the next. He believed that these stages are not separate from one another, but rather that each stage builds on the previous one in a continuous learning process. He proposed four stages: sensorimotor, pre-operational, concrete operational, and formal operational. Though he did not believe these stages occurred at any given age, many studies have determined when these cognitive abilities should take place.
Stages of moral development
Piaget claimed that logic and morality develop through constructive stages. Expanding on Piaget's work, Lawrence Kohlberg determined that the process of moral development was principally concerned with justice, and that it continued throughout the individual's lifetime.
He proposed three levels of moral reasoning: pre-conventional, conventional, and post-conventional. Pre-conventional moral reasoning is typical of children and is characterized by reasoning based on the rewards and punishments associated with different courses of action. Conventional moral reasoning occurs during late childhood and early adolescence and is characterized by rule-based reasoning grounded in societal conventions. Lastly, post-conventional moral reasoning is a stage during which the individual sees society's rules and conventions as relative and subjective, rather than as authoritative.
Kohlberg used the Heinz Dilemma to apply to his stages of moral development. The Heinz Dilemma involves Heinz's wife dying from cancer and Heinz having the dilemma of saving his wife by stealing a drug. Preconventional morality, conventional morality, and post-conventional morality apply to Heinz's situation.
Stages of psychosocial development
German-American psychologist Erik Erikson and his collaborator and wife, Joan Erikson, posit eight stages of human development, influenced by biological, psychological, and social factors, throughout the lifespan. At each stage, the person must resolve a challenge or an existential dilemma. Successful resolution of the dilemma results in the person ingraining a positive virtue, but failure to resolve the fundamental challenge of that stage reinforces negative perceptions of the person or the world around them, preventing the person's personal development.
The first stage, "Trust vs. Mistrust", takes place in infancy. The positive virtue for the first stage is hope, in the infant learning who to trust and having hope for a supportive group of people to be there for them. The second stage is "Autonomy vs. Shame and Doubt" with the positive virtue being will. This takes place in early childhood, when the child learns to become more independent by discovering what they can do. If the child is overly controlled, feelings of inadequacy are reinforced, which can lead to low self-esteem and doubt.
The third stage is "Initiative vs. Guilt". The virtue gained is a sense of purpose. This takes place primarily via play. This is the stage when the child will be curious and engage in many interactions with other kids. They will ask many questions as their curiosity grows. If too much guilt is present, the child may have a slower, harder time interacting with their world and the other children in it.
The fourth stage is "Industry (competence) vs. Inferiority". The virtue of this stage is competence and results from the child's early experiences in school. This stage is when the child will try to win others' approval and understand the value of their accomplishments.
The fifth stage is "Identity vs. Role Confusion". The virtue gained is fidelity, and it takes place in adolescence. This is when the child ideally begins to identify their place in society, particularly regarding their gender role.
The sixth stage is "Intimacy vs. Isolation", which happens in young adults, and the virtue gained is love. This is when a person starts to share their life intimately and emotionally with someone else. Not doing so can reinforce feelings of isolation.
The seventh stage is "Generativity vs. Stagnation". This happens in adulthood, and the virtue gained is care. A person becomes stable and starts to give back by raising a family and becoming involved in the community.
The eighth stage is "Ego Integrity vs. Despair". When one grows old, they look back on their life and contemplate their successes and failures. If they resolve this positively, the virtue of wisdom is gained. This is also the stage when one can gain a sense of closure and accept death without regret or fear.
Stages based on the model of hierarchical complexity
Michael Commons enhanced and simplified Bärbel Inhelder and Piaget's developmental theory, and offers a standard method of examining the universal pattern of development. The Model of Hierarchical Complexity (MHC) is not based on the assessment of domain-specific information. It divides the Order of Hierarchical Complexity of tasks to be addressed from the Stage performance on those tasks. A stage is the order of hierarchical complexity of the tasks the participant successfully addresses. He expanded Piaget's original eight stages (counting the half-stages) to seventeen stages. The stages are:
Calculatory Automatic Sensory & Motor Circular sensory-motor Sensory-motor Nominal Sentential Preoperational Primary Concrete Abstract Formal