Cognitive development researchers study how people acquire, organize, and learn to use knowledge. They are interested in both quantitative changes, like the width of a pine tree each year, and qualitative changes such as the ability to remember that a hidden object still exists.
To understand these changes, psychologists conduct experiments. The results, such as 3- to 6-year-olds recognizing a cat named Maynard when he is wearing a dog mask, help lifespan cognition developmental researchers answer important questions.
What is Cognitive Development?
Cognitive development is the process of acquiring and using mental skills to understand and make sense of the world around us. As people, we are born with an innate curiosity and a desire to learn. We acquire our cognitive skills over time as we interact with the world – touching, hearing, seeing, tasting, smelling – and through our own experience.
The field of cognitive development is a vast one, covering such topics as how infants’ brains develop, how they acquire language, and how they build logical thinking skills. Seminal theories in this area, like Piaget’s stage theory, suggest that children move through a series of stages – moving from concrete and dichotomous thinking to more abstract, integrative thinking.
Other researchers, however, have suggested that these stages may not be the best way to think about cognitive development. Rather, they suggest that we consider the complexities of developmental trajectories, a concept known as “the web of learning,” which depicts an individual’s growth along different skill domains concurrently and interactively with each other. The web model suggests that a child’s abilities can move up or down strands at different times, that links between strands exert bidirectional influence on each other, and that there is the possibility of going backward along a strand in order to solidify a new skill.
Stages of Cognitive Development
The famous cognitive scientist Jean Piaget developed a theory of cognitive development based on the idea that children gain thinking skills in four stages. He argued that these stages occur in a fixed order and that every child goes through them regardless of their social or cultural background. Piaget also believed that children acquire knowledge through interacting with their environment, a notion known as constructivism.

The sensorimotor stage lasts from birth to about 18 months, during which infants learn about their surroundings through a variety of sensory experiences and motor activities. For example, they may play with toys, listen to their parents talk, watch tv or anything else that attracts their attention. They cannot consolidate information into unified concepts at this time, and their thoughts are mostly reflexive (based on instinct).
During the preoperational stage (2 – 7 years), children begin to think more logically as they realise that one object can stand for another. They also develop a general symbolic function and start to use words to represent objects and feelings. Their thoughts are still egocentric, which means that they believe others see the world the same way they do.
The concrete operational stage (7 – 12 years) is characterised by a greater ability to use logic and understand the concept of conservation (that although an object may change in appearance, its properties remain the same). At this point, children can also solve problems involving a sequence of events and show awareness of their own actions. They also start using metacognition and displaying complex moral reasoning.
The Role of Nature and Nurture
The debate about whether people’s personalities and cognitive abilities are the result of nature or nurture has raged for centuries. Nature refers to a person’s genetic predispositions, while nurture describes the impact of their environment (including relationships and experiences) on those traits.
The idea that human behavior is a combination of both nature and nurture has become the prevailing view within psychology. However, untangling the way these two factors interact to produce certain behaviors is complex. For example, some genetic mutations make an individual more likely to develop a certain mental illness, but the degree of that illness can be mitigated by positive (nurturing) behavioral interventions.
Thinking is a higher level of mental activity that involves manipulating information in ways that allow for making decisions, solving problems, and creating new ideas (Piaget, 1936). Children’s cognitive development activities begin with building knowledge, which makes them capable of learning more and being able to solve problems.
Other mental activities that involve thinking are perceiving objects and events in the environment, acting skillfully on them, storing and retrieving memory, and creating conceptualizations (Kashyap & Minda, 2016). These are often seen as precursors to more advanced forms of thinking. In fact, thinking is only one component of a broad domain of human mental activity that includes personality and temperament. These other activities include emotional regulation, problem-solving, coping with stress, and forming relationships.
Continuity and Discontinuity in Cognitive Development
One of the central debates in cognitive developmental research is whether or not growth and development occurs in gradual, continuous steps. Some researchers, like Piaget, believe that the development process is largely linear and step-like, while others, such as Sternberg and Okagaki, argue for discontinuous development.
Discontinuous development proposes that individuals move from one stage to the next with sudden shifts, often without warning or signs of progressive change. For example, a child who was once struggling with language acquisition might suddenly seem to have a breakthrough and be able to form complex sentences.
A key part of this concept is that development can occur in qualitative as well as quantitative changes. This means that a change from one level of skills to another is not simply progressing up a ladder, but also reshaping or even discarding earlier levels in the process.
In this way, a discontinuous approach to cognitive development can be useful in understanding certain milestones, such as the ability of infants to recognize their own reflection in a mirror, or the fact that children from low-income families often seem to lag behind their peers when it comes to math, even as they progress through school. However, there are some drawbacks to this type of thinking. It can be easy to get caught up on highlighting these big, dramatic changes in an individual’s life, and miss the more subtle and incremental ways that their understanding or abilities may have grown.