Cognition refers to the mental processes related to acquiring knowledge and comprehension, including thinking, knowing, remembering and perception. In the past infants were thought to be able to think or create complex ideas only after they learned a language. Scientists have, however, found that even babies have awareness of their surroundings and begin to learn from the day of their birth.
The cognitive development of children has been subject to a variety of studies. Older studies are based on intelligence tests. One of the widely used tests is the Stanford Binet Intelligence Quotient (IQ) introduced in the United States by psychologist Lewis Terman (1877 to 1956) in 1916. IQ suggests that children of average intelligence have similar scores, while scores of a gifted child match the scores of an older child. Children with slower cognition abilities have performance comparable to that of younger children. Such IQ tests have drawn sharp criticism because of the narrow definition of intelligence.
Unlike IQ tests which focus on a child's native abilities, behaviorist researchers John Watson (1878 to 1958) and B. F. Skinner (1904 to 1990) created the learning theory arguing that children are completely malleable. Learning theory takes into account the effect of environmental factors on a child's intelligence.
Jean Piaget (1896 to 1980), one of the most influential researchers in developmental psychology in the 20th century, is the author of the most well-known cognition theory. Piaget's theory was published in 1952 as a result of his long observation of children in their natural environment while behaviorists based their theories on laboratory experiments. While working in Binet's IQ test lab in Paris, Piaget's attention was drawn by the way children think. He noticed that young children answer questions in a quite different way than older children which led him to the conclusion that the younger children are not less intelligent but they just answered the questions in a different manner than older ones because they thought in a different way. Piaget suggested that a child's knowledge consists of schemes - units of knowledge which help structure past experiences and help understand new ones.
Piaget suggested that babies are born with schemes called reflexes which are replaced with constructed schemes in the process of the infant's adaptation to the environment. According to Piaget, people use two processes for adaptation - assimilation and accommodation. An individual uses these processes throughout life as the person adapts to the environment. Assimilation refers to the process of transforming the environment so that it can be incorporated into existing schemes. This means that the person relates new experiences to already known ones in order to assimilate them. Accommodation is the process of changing existing cognitive schemes in order to assimilate something from the environment.
According to Piaget, there are four stages of cognitive development. The first stage is the sensorimotor stage, or infancy, when intelligence is expressed through motor activity without the use of symbols. Newborn babies are able to focus on moving objects, see colors and distinguish voices. At the age of nine months, infants can understand simple words. By twelve months, babies can speak several words and imitate sounds, they develop a sense of attachment to certain objects. The second stage is the pre-operational stage, or early childhood, when children demonstrate their intelligence using symbols and language. The stage covers the age between 18 months and three years. The memory and imagination are more developed. However, at that age children still think in a non-logical way as infants are predominantly egocentric. Children of this age have to know between 100 and 150 words and should add several new words every day. Toddlers begin to understand emotions like love, fear. At this age children are curious, ask questions and use primitive reasoning. They are able to focus their attention on one characteristic. Children at this stage have no awareness of conservation. The third stage is the concrete operational stage, or elementary and early adolescence. This stage includes younger children aged between six and 12 years who can use logical and coherent skills in solving problems. Children in this stage are less egocentric. They are able to name and identify groups of objects according to their characteristics. Children see logical relationships between elements in a serial order. The fourth stage is the formal operational stage, or adolescence and adulthood. People at this stage demonstrate their intelligence using symbols related to abstract concepts. Young adults return to egocentric thinking. An alternative approach to Piaget's theory is the information-processing approach, which uses the computer as a way to understand cognitive development. The approach focuses on the gradual improvement in children's ability to assimilate new information.