- Describe the three major issues debated in development
- Describe many of the common theories of development
- Describe the developmental tasks for each of Erikson’s stages
Developmental psychologists study how humans change and grow from conception through childhood, adolescence, adulthood, and death. This area of research began in the 1890s by a psychologist named G. Stanley Hall, who established the first institute that was solely dedicated to child development research. Gerontology, the scientific study of aging, another core aspect of lifespan development, emerged after World War II.
Development is a lifelong process that is researched scientifically across three developmental domains:
- Physical development involves growth and changes in the body and brain, the senses, motor skills, and health and wellness.
- Cognitive development involves learning, attention, memory, language, thinking, reasoning, and creativity.
- Psychosocial development involves emotions, personality, and social relationships.
Early developmental psychologists used a normative approach, aiming to establish the concept of “normal development” across the three domains. In the early decades of the 20th century, normative psychologists studied large numbers of children at various ages to determine norms (i.e., average ages) of when most children reach specific developmental milestones in each of the three domains, including crawling, speaking in sentences, and starting puberty (Gesell, 1933, 1939, 1940; Gesell & Ilg, 1946; Hall, 1904).
Not all normative events are universal, meaning they are not experienced by all individuals across all cultures. Biological milestones, such as puberty, tend to be universal, but social milestones, such as the age when children begin formal schooling, are not necessarily universal; instead, they affect most individuals in a particular culture (Gesell & Ilg, 1946). Because of this, the normative approach has been heavily critiqued due to its limited scope and applicability, as it largely uses samples from Western, educated, industrialized, rich, and democratic countries (WEIRD populations). This raises concerns about the generalizability of findings to diverse populations. Relying solely on normative data overlooks the experiences and developmental paths of individuals from various cultural backgrounds, socioeconomic statuses, or regions, resulting in an incomplete understanding of “normal” development across diverse populations.
Throughout this module, we will explore the impact of culture, age, cohort, gender, and socioeconomic status on development, recognizing that these factors contribute to individual differences and shape developmental outcomes.
Research Methods in Developmental Psychology
Developmental psychologists use research approaches in order to better understand how individuals change mentally and physically over time. These methods include naturalistic observations, case studies, surveys, and experiments, among others.
Naturalistic observations involve observing behavior in its natural context. A developmental psychologist might observe how children behave on a playground, at a daycare center, or in the child’s own home. While this research approach provides a glimpse into how children behave in their natural settings, researchers have very little control over the types and/or frequencies of displayed behavior.
In a case study, developmental psychologists collect a great deal of information from one individual in order to better understand physical and psychological changes over the lifespan. This particular approach is an excellent way to better understand individuals, who are exceptional in some way, but it is especially prone to researcher bias in interpretation, and it is difficult to generalize conclusions to the larger population.
In one classic example of this research method being applied to a study of lifespan development, Sigmund Freud analyzed the development of a child known as “Little Hans” (Freud, 1909/1949). Freud’s findings helped inform his theories of psychosexual development in children, which you will learn about later in this module. Little Genie, the subject of a case study discussed in the module on thinking and intelligence, provides another example of how psychologists examine developmental milestones through detailed research on a single individual. In Genie’s case, her neglectful and abusive upbringing led to her being unable to speak until, at age 13, she was removed from that harmful environment. As she learned to use language, psychologists were able to compare how her language acquisition abilities differed when occurring in her late-stage development compared to the typical acquisition of those skills during the ages of infancy through early childhood (Fromkin, Krashen, Curtiss, Rigler, & Rigler, 1974; Curtiss, 1981).
Experiments involve significant control over extraneous variables and manipulation of the independent variable. As such, experimental research allows developmental psychologists to make causal statements about certain variables that are important for the developmental process. Because experimental research must occur in a controlled environment, researchers must be cautious about whether behaviors observed in the laboratory translate to an individual’s natural environment.