Describe and evaluate Piaget’s theory of cognitive development.

Piaget believed that children are not able to undertake certain tasks until they are psychologically mature enough to do so. These developments don’t happen entirely smoothly and there are stages where children move into new capabilities, him seeing those transitions taking place at about 18 months, 7 years and 11 or 12 years. Piaget believed that schemas (an evolving unit of knowledge which we use to understand situations) are key to cognitive development. Adults have complex schemas developed while babies have simple ones like the sucking reflex. Assimilation is where new elements are added to existing schemas by applying a schema to a new situation, such as applying the pull along schema to a wooden dog on wheels with pull rope or by adding new information to an existing schema. Accommodation is where a schema has been changed in order to deal with a new situation, for example the pull along schema can’t be used for a wind up tractor, so the wind up schema needs to be developed to understand how the wind up tractor.

The first stage of Piaget’s theory is the sensorimotor stage, which is between 0-2 years. Piaget believes that each stage is invariant, where each child passes through the stages in the same order, also believing that the stages are universal, Piaget proposing that these sequential stages apply to all children regardless of their culture. At this stage, knowledge consists of simple motor reflexes such as grasping and sucking. The child’s cognition is limited to sensations and motor movements. At the ages of 8 months, the child begins to understand object permanence, which is the understanding that objects exist independently even if they are not being observed. In order to have object permanence, a child needs the ability to hold simple mental representations of objects.

One of Piaget’s key studies that investigates object permanence tested infants individually where Piaget waited until the child was playing with an object and then removed the toy from its grasp and hid it beneath a blanket when the child looked on. If the child searched for it, this would suggest that the child could understand that the object continued to exist even when out of sight, indicating object permanence. Infants less than 8 months didn’t search for the toy, apparently forgetting that the toy existed out of sight. Children at approximately 8 months searched for the hidden toy however when Piaget moved it from the blanket to another place, the child looked for it where they last found it not where they last saw it. This is the type A not B error, which indicates simple object permanence. At around 12 months the infant then begins to look for the toy where they last saw it being hidden, showing a more complex object permanence.

The weaknesses of this study is that infants under 8 months didn’t search for the toy for other reasons, for example they lacked the necessary motor skills to look for it, they simply weren’t interested or that the deliberate covering of the toy led them to believe that it was forbidden. The tests that Piaget conducted were accused as lacking ‘human sense’, where critics have suggested that he underestimates the age at which children develop object permanence. Other studies such as the Bower and Wishart demonstrate that even children as young as 3 months may have object permanence. They turned out the lights and then observed the child with infrared camera. They found that infants continued reaching for objects in the dark, suggesting that they realise they’re there.

Within the next stage, the pre- operational stage (2-7 years), children can use symbols, images and can recognise that one thing can stand for another however there are certain cognitive tasks that they are unable to do, these include animism, centration and egocentrism. Animism is the belief that inanimate objects have emotions nevertheless this is still questionable because it could be argued that they are making the best use of their limited powers of expression. Centration is where children in the pre-operational stage can only deal with one factor at a time, Piaget suggesting that children can only begin to de-centre at the age of 7.

Egocentrism is the inability for a child to take another point of view into consideration. The study that Piaget conducted for this idea is the 3 mountain experiment. Children were shown a 3D display of 3 mountains and then a doll was placed in various positions around the mountain. Ten images of the model were shown to the child and they were asked to select the perspective that the doll could see. Children at the middle of the stage tended to pick their own view, demonstrating egocentrism however by 7-8 years, when they were coming out of this stage; children were beginning to lose this egocentric trait and began selecting the dolls perspective.

Some weaknesses in this study is that the children may have found it difficult to analyse the pictures and may indeed recognise that the doll is viewing the mountain from a different angle but struggled to identify which view it was from the pictures given. The children that didn’t correctly complete the task may have felt a lack of interest in it because it was so irrelevant and unfamiliar to them compared to their daily lives. Other evidence provided from other studies, such as Hughes and Donaldson have suggested that children are able to de-centre from a much younger age, given a familiar situation. 90% of children aged between 3 and a half- 5 years were able to hide the boy from the two policemen in a hide and seek (cross model) situation successfully. This could be because the task was clearly understood and the child could understand the motives behind each of the characters because to them it was a game of hide and seek.

Conservation is the understanding that even though the physical appearance of an object has changed, the volume, density and mass of the object remains the same. Piaget studied the age at which children could conserve volume by showing them 2 identical beakers with equal amounts of water within them before asking which one contained more water. The water from one beaker was poured into a third, taller beaker, with the children being asked the same question. Most children under 7 stated that the 3rd beaker contained the most water, showing that the ability to conserve develops at the age of 7 as children older than this knew that the amounts were equal. One limitation of this study is that the children may have assumed that the experimenter was expecting a different answer as they saw them pour the water into a different beaker, so they may have just gone with the beaker that changed and not necessarily believed it. Also the language that is used in the experiment may have made it more difficult for the younger children to conserve. When the experimenter used the word more, they wouldn’t have been taking it in the adult sense of volume but instead would have interpreted it as ‘higher’ or ‘fuller,’ thus affecting the results. A study that was conducted by McGarrigle and Donaldson shows that children can conserve numbers earlier than Piaget suggested because alterations in terms of counters were made both by the experimenter and the other condition was made to look accidental with the intervention from a ‘naughty teddy.’ 16% showed conservation when the experimenter made the alterations however 62% of the 4-6 years olds conserved with the ‘accidental’ mistake.

From the age of 7, Piaget suggested that there is a cognitive shift where the child is now able to perform mental operations- an internal schema that enables logic such as ordering, multiplication, division, subtraction and addition. This is within the concrete- operational stage. Another cognitive ability that children acquire at this stage is class inclusion, where they become aware of categories and the classification of objects. They are able to recognise the difference between general categories and sub categories. Piaget’s study that supports this idea is the experiment with the wooden beads- 20 of which 18 are brown and 2 are white. The children are then asked 3 questions- 1) Are the beads all wooden? 2) Are there more brown or white beads? 3) Are there more brown beads or wooden beads? Children under the age of 7 usually answered the first 2 questions correctly because even though they are being asked about two separate categories, the two classes are separate, they do not overlap, unlike the third question where the subclass of the brown beads overlaps with the superordinate class of all the wooden beads. One limitation of this study is that the wording of the questions may have affected the answers that were given by the children, which is demonstrated in the study from McGarrigle and Donaldson.

Children about 6 years old were shown 3 black cows and a white cow that were laid on their side in a sleeping position, with the children being asked- 1) Are there more black or white cows? And 2) Are there more black cows or sleeping cows? The first questions was answered correctly 25% of the time and the second 48% of the time. This shows how the wording of the question affects the responses because by giving more emphasis to the whole group through the adjective ‘sleeping’, this helped them give the right answer.

When a child reaches the age of 12 they enter the formal- operational stage, where they are now able to understand abstract concepts. This is where they can refer to things that are not tangible, examples are boredom and calm. Children at this stage know what these concepts mean despite not being able to see or touch them as they don’t physically exist.

One study that Piaget used in order to show systematic reasoning is with the pendulum problem. Children were asked to change variables such as the weight, length of string etc. in order to observe which affected the rate of the swing of the pendulum, thus creating a cause and effect relationship. Children who were not in the final stage changed more than one variable at a time and couldn’t come to any conclusion however those that were in the stage changed one variable at a time and could correctly identify the factors that were affecting the rate of the swing.

Another cognitive ability that is present in formal operational thinkers is hypothetical thinking- this is where thinking can be speculative and they are able to imagine situations. One example that can be sed is the third eye problem. Children were asked where they’d put a 3rd eye if they had one. Schaffer conducted this test and found that 9 year olds made conventional suggestions such as the forehead however 11 year olds were capable of hypothetical thinking and made more initive suggestions such as on the hand.

 There are many criticisms that can be used of the methods that Piaget used in order to carry out his work. The sample that he used was small and unrepresentative of the whole population because he used his own children and the children of his friends who all came from Switzerland. This is biased in the sense that it is a small sample and they all came from one cultural background instead of investigating the cognitive development of several cultures around the world. The reporting methods that Piaget used could also be greatly criticised because he often failed to record the number and ages of many of his participants, meaning that many participants from his studies may have not been included and if they were, then their results may have turned the conclusion out very differently.

Piaget also used the clinical interview technique, where he did not stick to normal scientific procedures of standards and control. His interactions with the children were usually conversational in an informal sense, with each participant being treated slightly differently. He based all of his theory on the qualitative work that he collected, he never took data or correlations that could make his work in any way scientific. It has also been argued that because the reported answers were of a conversational tone rather than statistical evidence, Piaget may have selected particular examples to support his theory.

Strengths of his work is that it allowed for further research and he was a key cognitive psychology pioneer. He made cognitive development an important sector of cognitive psychology. There have also been a large amount of others that have conducted studies based around Piaget’s work to see whether they are able to support his findings. However it was found that many studies actually refuted his work.

Another strength is that Piaget did conduct many experiments that did support his idea of there being a sequential set of stages that all children universally pass through at set ages and despite of what cultural background. His cross cultural studies used samples of children from the USA, Britain, Africa and China, which supported Piaget’s idea behind universality. However other research on other cultures doesn’t completely support Piaget’s age related stages. Dasen found that children from societies that aren’t as industrialised, where they have less state education, reached the stages that Piaget proposed at a much later date, suggesting that environmental factors play a part in child cognitive development. This idea has been supported through cross cultural research and Piaget can also be praised on the fact that his experiments were innovative and creative that may be deemed as entertaining for the children nevertheless his experiments could be said to be out of context and unfamiliar to the children, which may have affected their responses greatly if they became confused.

One limitation of Piaget’s theory is the criticism that the formal- operational stage has received. Few adults demonstrate the thinking required for scientific reasoning even in industrialised societies. Martorano tested 12- 18 females on ten Piaget tests to do with formal operational science problems, including the pendulum problem. Only 2 of the 20 women succeeded on all the problems and the success rate for 18 year olds varied from 15% to 95%.

Further limitations is that Piaget’s beliefs were that children went through a sequential set of cognitive development stages one at a time and were unable to recognise that sometimes these stages can overlap in which is called horizontal decalage. A child could show signs of more than one stage at a time, for example a child may be able to conserve correctly depending on the task, they might be able to conserve numbers but not volume as it is a harder conservation task. Nevertheless Piaget’s argument about an actual difference in qualitative thinking amongst these stages has appeared to have been supported.

Moreover, another strength of Piaget’s work is that the finding that Piaget has had, as well as the entire theory itself, has had an enormous impact on modern day educational systems and the school curriculum. His theory of children not being able to perform certain cognitive tasks until they hit a certain age has been applied to classroom situations where teachers are now basing the complexity of their teaching around Piaget’s theory.


Suzanne W. A Level Psychology tutor, GCSE Psychology tutor

1 year ago

Answered by Suzanne, an A Level Psychology tutor with MyTutor

Still stuck? Get one-to-one help from a personally interviewed subject specialist


Holly K. Mentoring -Personal Statements- tutor, GCSE English Language...
View profile
£20 /hr

Holly K.

Degree: English literature (Bachelors) - Durham University

Subjects offered: Psychology, Extended Project Qualification+ 5 more

Extended Project Qualification
English Literature
English Language
-Personal Statements-

“About me: I am an English Literature student at Durham University, having sat English at GCSE and A-Level, as well as doing an Extended Project Qualification on literature. I am a firm believer that the beauty of English lies in the f...”

PremiumKarolina K. Mentoring -Medical School Preparation- tutor, GCSE Biolog...
View profile
£24 /hr

Karolina K.

Degree: Dentistry (Bachelors) - Kings, London University

Subjects offered: Psychology, Science+ 5 more

-Personal Statements-
-Medical School Preparation-

“Hi, my name is Karolina and I am a Dentistry Student from King's College London.  I understand that many students find certain aspects of the A-level syllabus challenging and having recently completed mine I believe that I know how to...”

Joshua F. A Level Law tutor, GCSE Law tutor, A Level Psychology tutor...
View profile
£22 /hr

Joshua F.

Degree: Law (Bachelors) - York University

Subjects offered: Psychology, Law+ 2 more

-Personal Statements-

“About me:  I am currently a law student at the University of York and am proceeding ito my second year of study. During my first year I managed to achieve a first class grade whilst balancing my studies with extra-curricular activitie...”

MyTutor guarantee

About the author

Suzanne W. A Level Psychology tutor, GCSE Psychology tutor
View profile

Suzanne W.

Currently unavailable: no new students

Degree: Psychology (Applied) (Bachelors) - Durham University

Subjects offered: Psychology


“Hello! I am an Applied Psychology student that is in the first year of studing an undergraguate degree at Durham University. I completed Psychology, History and English Combined to A2 level and Mathematics to AS. I understand that many...”

MyTutor guarantee

You may also like...

Posts by Suzanne

Describe and discuss factors that effect obedience in Psychology

Describe and Discuss the methods that are used in the UK for measuring crime

Describe and Discuss the Multi Store Model for memory

Describe and evaluate Piaget’s theory of cognitive development.

Other A Level Psychology questions

What is the reductionism vs holism debate in psychology?

How can I write a good essay in such a limited time?

What is meant by the terms nominal, ordinal, interval and ratio data and why is it important to know the difference between the four terms?

What is the difference between correlations and experiments?

View A Level Psychology tutors


We use cookies to improve our service. By continuing to use this website, we'll assume that you're OK with this. Dismiss