Cognitive Development

Piaget’s Cognitive Development Theory

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The Swiss psychologist Jean Piaget (1896 – 1980) has long been regarded as the ‘giant of developmental psychology’ (Hunt, 1969), and was ‘a towering figure internationally’ (Bliss, 2010). Piaget’s contribution to our understanding of children’s development has been quite extraordinary. By the early 1960s Jean Piaget’s theory of cognitive development dominated the study of child development.

In Piaget’s theory we have a comprehensive and detailed account of cognitive development from birth to adulthood. Cognitive development proceeds through a series of stages, each more complex than the last, and each building on the achievements of the previous one.

Underlying Structures and Processes

1.   Schemes

Piaget proposed that the basic unit of understanding was a scheme.

Schemes make up our frames of reference through which we filter new information. Therefore, everything we know starts with the schemes we are born with. Three of the basic schemes we are born with are reflexive actions that can be performed on objects: sucking, looking and grasping. As children grow older they begin to use schemes based on internal mental representations rather than using schemes based on physical activity (Lamb et al., 2002). Piaget called these mental schemes operations.

2.   Processes: Organisation and Adaptation

In order to explain how children modify their schemes Piaget proposed two innate processes: organisation and adaptation.

For example, initially young infants have separate looking, grasping and sucking schemes. Over time these schemes become organised into a more complex multisensory cognitive system that allows the infant to look at an object, pick it up and suck it.

This organisation enables the child to learn about the nature of these objects (e.g. their shape, texture and taste). However, in order to adapt to environmental demands we also need to incorporate new ideas.

When faced with a new experience, infants/children try to assimilate this new information by incorporating the information into their existing schemes. For example, if a child believes all furry four legged animals are ‘dogs’ and then they encounter a breed of dog they have not seen before, they will probably apply a ‘dog’ label to the dog. The child will assimilate information about this ‘new’ breed of dog into their existing scheme. If the child then encounters a cat for the very first time they may apply a ‘dog’ label to the cat.

As you can see from this example, assimilation allows us to generalize and apply what we know to many individual instances, although it may distort reality and not adapt to it. However, if the child is told that the cat is not a dog, or notices that the animal is considerably smaller than a dog and doesn’t bark like a dog then the child needs to adjust their existing concept of four-legged animals (not all furry four-legged animals are dogs, some are cats) or generate a new scheme (accommodation). Thus, through the processes of accommodation and assimilation we adjust to reality rather than distort it.

Piaget’s Stages of Cognitive Development

Piaget’s complementary processes of assimilation and accommodation comprise the equilibration process.

According to Piaget we are, by nature, constantly motivated to be able to fully assimilate and accommodate to objects and situations in our environment; to reach a state of cognitive equilibrium.

At times, however, so many new levels of understanding converge that we reach a major reorganization in the structure of our thinking. Piaget called these shifts to new levels of thinking stages. Stages aren’t simply quantitative additions to a child’s knowledge and skills; rather they are defined as qualitative shifts in a child’s way of thinking.

Although Piaget provided typical ages for the four main stages and various substages, the ages at which they are achieved will vary from one child to another. However, the order of progressing through stages is invariant, with each stage based on development in the previous stage.

Piaget believed his stages were universal in two senses. First, he thought all people would develop through the same sequences of stages. Second, he thought that for any given stage children would be in that stage for all of their thinking and problem-solving strategies, whether in mathematical understanding, problem-solving skills, social skills or other areas, although he recognised that there were transitional periods as children moved from one stage to the next, higher stage.

1.   The sensorimotor stage: Birth to 2 years

The sensorimotor stage spans the first two years of life, and is divided into six substages.

During this period all that infants know is derived from information that comes in through the senses and the motoric actions that they can perform; hence the name ‘sensorimotor’.

It is important to note that for most of this stage young children are pre-verbal and therefore have no symbol use. Hence, young children must live in the present dependent upon sensorimotor input and the overt actions they can perform.

The first substage, the reflexive schemes substage, covers the period from birth to one month of age. During this substage infants use their innate reflexes (e.g. sucking, grasping) to explore their world. For example, if a nipple is placed near a newborn’s mouth they will automatically open their mouth, seek to latch onto the breast and begin to suck. Whilst many of these innate reflexive schemes are designated to keep the infant alive, they also act as the building blocks for sensorimotor intelligence.

In the second substage, termed primary circular reactions (1 – 4 months), there is a shift in the infant’s voluntary control of behaviour. The infant starts to show a degree of coordination between the senses and their motor behaviour through the primary circular reactions. To illustrate, the infant accidentally discovers a new experience as a result of their own motor activity (e.g. thumb sucking) and then repeats the event over and over again.

The term primary is used because such repetitive behaviours are focused almost exclusively around the infant’s body and not the external world, while the term circular refers to the fact that the behaviour is repetitive. During this substage there is also some anticipation of events, although it is fairly limited. For example, a hungry infant may stop crying when approached by their mother because the infant anticipates being fed.

In the third substage, secondary circular reactions, which lasts from 4 to 10 months, there is a shift in the infant’s voluntary control of behaviour as they become more aware of the external world. Infants now direct their behaviour to reaching and grasping objects (behaviours become secondary). Although the actions are still circular as the infant engages in repetitive behaviour (e.g., banging a cup on a table over and over again), the infant has begun to intentionally act on his environment.

During substage 4 (coordination of secondary schemes), which lasts from 10 to 12 months, the infant begins to deliberately combine schemes to achieve specific goals. In other words, they begin to engage in goal-directed behaviours. Perhaps the best example of this behaviour is demonstrated in the fact that infants in this substage solve object performance tasks in which the infant has to co-ordinate two schemes (e.g. lifting a cover and grasping an object).

In Substage 5, which lasts from 12 to 18 months, the child engages in tertiary circular reactions. The child has now begun to walk and begins to search for novelty. As children consolidate their understanding of causal relations between events (e.g. if a bowl is pushed off a table, it will crash onto the floor) they begin to systematically experiment with varying the means to test the end results. For example, they may see what happens if they push another object off a table. Such activities enable children to discover more about their world and new ways of solving problems.

During the final substage (18 – 24 months), the beginning of thought, children become able to form enduring mental representations. This capacity is clearly demonstrated in toddlers’ ability to engage in deferred imitation.

Enduring mental representations also mean that children no longer have to go through the trial and error method; rather they can mentally experiment by performing the actions in their minds.

Further evidence for symbol use is shown in toddlers’ ability to engage in simple pretend play (Bosco et al., 2006; Piaget, 1962), which develops further in the next substage.

2.   The preoperational stage: 2 to 7 years

The preoperational stage is a stage that is characterised by an impressive increase in mental representation and accompanied by equally impressive limitations! This stage subdivides into the symbolic function substage (2 – 4 years) and the intuitive substage (4 – 7 years).

Symbolic function substage: 2 to 4 years

This ability to engage in symbolic thought expands the child’s mental world as they are no longer tied to the here and now and they no longer require sensory input to think of things.

Evidence of symbolic function can be seen in pretend play.

Early on the child requires a high level of similarity between external prop and referent in order to symbolize the referent. For example, children younger than 2 years will pretend to drink from a cup but refuse to pretend that a cup is a hat (Tomasello et al., 1999). However, over time, children can use external props that are dissimilar to the referent (e.g. a banana to stand for a telephone, Leslie, 1987). Eventually, children can just imagine the referent and event (Rakoczy et al., 2002; Striano et al., 2001).

Other examples of children engaging in symbolic thought can be seen in their use of language and their production of drawings. One of the most impressive examples of the symbolic function is in our use of language.

At 16 months of age the average child comprehends over 150 words but in their early language they are restricted to producing one word at a time, and between 18 and 24 months their productions are typically restricted to two-word utterances.

However, from around 2 years this word-length restriction becomes lifted and children learn an impressive nine words a day on average, so that they have a vocabulary of approximately 14,000 words by the time they are 6 years old (Hollich & Houston, 2007). Likewise, research shows that children understand the symbolic nature of drawings. For example, Preissler & Bloom (2008) found that 2-year-old children understand that a picture of a banana only represents a banana. They don’t try to eat it!

Egocentrism/Animism

Other than the notable acquisition of symbolic representation, Piaget also discussed what the preoperational child cannot do. According to Piaget the most important limitations shown by children in the symbolic function substage are egocentrism and animism

Egocentrism

Thus, children often assume that other people will perceive and think about the world in the same way they do.

Piaget and Inhelder (1956) investigated young children’s egocentrism by devising the three mountains task, a task used by Piaget where the child is shown a model of three mountains and asked to choose the view that would be seen by someone in a different location from themselves, and the preoperational child typically chooses the view from their own location.

The child is asked to walk around the model and view it from different perspectives. The child is then seated on one side of the table and the experimenter places the doll in different locations around the model. At each location the child is asked to draw or choose, from a set of different views of the model, the view the doll would be able to see.

Indeed, Piaget found that children could not correctly identify the doll’s view from the different locations or viewpoints until 9 or 10 years of age. This inability to take into account that another person can view the world differently can also be seen in young children’s assumption that if they know something other people will too (Ruffman & Olsen, 1989).

Animism

Another limitation of preoperational thought is animistic thinking — the belief that inanimate objects have lifelike qualities (such as thoughts, feelings, wishes) and are capable of independent action.

A young girl might show animism by thinking that dropping her teddy down the stairs will cause her teddy pain, stating that it is raining because the clouds are feeling sad, or stating that the stating that the stairs made her fall down.

Piaget discovered animistic thinking through interviewing children and asking questions such as, ‘If you pricked a stone would it feel it?’; ‘Why does the sun move?’ (Piaget, 1960). Piaget suggested that young children’s egocentric thinking prevents them from accommodating. As such they cannot adjust their schemes to accommodate the real-world state of affairs.

Intuitive thought substage: 4 to 7 years

The intuitive thought substage roughly spans from age 4 to 7, and is characterised by a shift in children’s reasoning. Children begin to classify, order and quantify in a more systematic manner.

Piaget called this substage intuitive because although a child can carry out such mental operations they remain largely unaware of the underlying principles and what they know. Hence a child’s reasoning is largely based on perception and intuition, rather than rational thinking, and this leads to some striking limitations in reasoning ability.

For example, when preoperational children are asked to arrange 10 sticks in order of length (a seriation task), some children sort the short sticks into a pile and the longer ones into another pile, while others arrange one or two sticks according to length but are unable to correctly order all 10 sticks.

Researchers have challenged Piaget’s account that children’s successful solutions to seriation tasks are based on underlying change to mental operations that develop during the next major stage of development (the concrete operations stage).

Some researchers have suggested that the difficulty the preoperational child faces in verbal inference tests results from a lack of memory capacity. When researchers have employed procedures to ensure that children remember the information that they are given then young children can grasp transitive inference (e.g. Bryant & Trabasso, 1971).

Transitive inferences

Transitive inference is the ability to seriate mentally between entities that can be organised into an ordinal series. For example, in a family of five people, the father may be the tallest, followed by the mother, then their three sons (Jasper, Scott and Ronan, respectively).

Bryant & Trabasso (1971) conducted an experiment that showed that 4-year-old children could make transitive inferences as long as they were trained to remember the premises. Four-to-six-year-olds were trained to remember the lengths of variously coloured rods presented in descending order of size.

The rods were kept in a wooden block with holes drilled in it, with the rods reducing in size from the left- to the right-hand side of the block. Regardless of the length of the rod, the wooden block was designed so that each rod protruded the same amount above the surface of the block.

During the training session children were presented with four different pairs made up from five different coloured rods (A > B, B > C, C > D, D > E). These pairs created a logical five-term series (A > B > C > D > E).

Children were tested on their knowledge regarding the relative length of adjacent pairs (A > B, B > C, and so forth – note that they were asked about the relationship between the different colours, e.g. ‘is the red one longer than the green one?’ and not the relationship between the letters!) when the pairs of rods had been returned to the block.

Following training children were asked questions about the relative length of non-adjacent pairs. Children were asked, ‘Which is longer, A or C and C or E?’ Children gave the correct answers to both of these questions showing that they had deducted that A > C and C > E.

By using a five-term series (A > B > C > D > E), rather than a three-term series (A > B > C), the researchers were able to ask the critical question, ‘Which rod is longer, B or D?’.

This question provides a true test of inferential ability because in a five-term series two components (B and D) have both been verbally labelled, during training, as ‘longer than’ and ‘shorter than’ adjacent rods A, C and E. Hence, a transitive inference is required to work out the relationship between B and D.

Remember, this is the critical pair in determining whether the children could infer the correct relation between these two rods from their experience with the other pairs. The results showed that 4-, 5- and 6-year-olds were able to make this transitive inference.

Hence, researchers have argued that children’s failure during the preoperational stage resulted from their failure to remember all of the relevant information rather than not possessing the necessary logic needed to make the correct inference.

However, an alternative hypothesis is that children correctly answered the inferential test question by simply remembering the presentation order of the colured rods, as rods were presented in descending order of size.

By manipulating Piaget’s methodology in this manner, the procedure might have yielded false positives. In this case, children may simply pass the B-D test question by remembering that B is bigger than D because it was mentioned before D.

In this case, children may simply pass the B – D test question by remembering that B is bigger than D because it wsa mentioned before D.

Pears & Bryant (1990) tested this interpretation by presenting 4-year-olds with a transitive inference task where the order of premises was varied. The results showed that children’s performance was still above chance level and numerous studies have replicated Bryant and Trabasso’s (1971) findings.

3.   The Concrete Operations Stage: 7 to 11 Years

During this stage children’s thought processes change yet again. They develop a new set of strategies called concrete operations.

Piaget called these operations concrete because although children’s thought is more logical and flexible, their reasoning is tied to concrete situations. They have attained the processes of decentration, compensation and reversibility and, thus, can solve conservation problems.

To illustrate, children not only begin to pass liquid conservation tasks but are aware that a change in one aspect (e.g., height) is compensated by a change in another aspect (e.g. width). Moreover, children often state that if the water is puoured back into the original glass then the liquid in both glasses will be the same height (reversibility).

This understanding of reversibility underlies many of the gains reported during this stage of development. Subsequent research has confirmed that children appear to acquire conservation of number, liquid, mass, length, weight and volume in that order, which is the order Piaget proposed (e.g. Tomlinson-Keasey, 1978). They can laso seriate mentally, an ability named transitive inference. For example, children may be presented with two pairings of three children of differeing heights.

In pair 1, the child sees that Jane is taller than Amanda, and in pair 2 the child sees that Amanda is taller than Claire. The child can then reason, without seeing the actual pairing, that Jane is taller than Claire. However, if the same problem is presented verbally, in an abstract form, simply by being told that ‘Jane is taller than Amanda’ and ‘Amanda is taller than Claire’, the child encounters difficulty in solving the problem.

So whilst the concrete operational child can seriate mentally, it appears that the objects necessary for problem solution need to be physically present.

Between the ages of 7 and 10, children gain in their ability to classify objects and begin to pass Piaget’s class inclusion problem. They can attend to relations between a general and two specific categories at the same time (e.g., Fischer & Roberts, 1986; Ni, 1998).

For example, children can sort flowers into a major class and a subclass: yellow tulips, yellow daisies, yellow roses, red tulips, red daisies and red roses while ignoring irrelevant properties such as the number of petals (Fischer & Roberts, 1986).

Whilst subsequent research has confirmed many of Piaget’s observeations about the concrete operations stage, other research has also shown that children’s performance on tasks may be influenced by the context of the task.

It has been demonstrated that culture and schooling affects children’s performance on a number of Piagetian tasks. For example, children of the Hausa, a village society in Nigeria who rarely send their children to school, do not understand conservation tasks until around age 11 (Fahrmeier, 1978). Likewise, underprivileged children in Brazil receive hardly any formal schooling. Mostly, these children work as street vendors selling books to passers-by.

Ceci and Roazzi (1994) showed that 6-to 9-year-old Brazilian street vendors demonstrate poor performace on formal class inclusion tasks, yet when the contest of the task is changed so that it is relevant to street vending their performance improves. For example, the researchers presented these young street vendors with a problem in which the street vendors had four pieces of mint chewing gum and two pieces of grape chewing gum for sale, and simply asked the children whether it would be better to sell the mint chewing gum or all of the gum. Under such conditions the Brazilain street vendors outperformed children attending school.

Other researchers have examined the effect of how long children have been attending school. When children of the same age are tested on transitive inference problems, those that have been in school the longest perform best (Artman & Cahan, 1993). Such findings suggest that culture and context play an important role in children acquiring the forms of logic required to pass classical Piagetian tasks.