Theories of Developmental Psychology
Developmental psychology is a branch of psychology that studies the growth and maturation of a person over time. This includes things such as physical, cognitive and social changes, and how each of these affects us during the different stages of our life.
Child psychology is a subset of developmental psychology, and focuses on the stages of life from birth to the beginning of adolescence (around age 12-13). Adolescent psychology is also a subset of developmental psychology, and is concerned with development during early adolescence to our late teenage years of life (13-19).
The reason why theories of developmental psychology are an important area of study, is because all adults are products of their childhood and the things they experienced during that childhood. Therefore, by studying infants, children, and teenagers, developmental psychology theories can help us to gain a better understanding of the adult mind.
In addition to this, developmental psychology also studies the changes that occur during adulthood, which subsequently, allows to us understand the various factors that affect our behavior from birth to death.
Whilst much of our behavior comes as a result of the things we learn and experience in life, what underlines the type of behavior that we display is our biology, or more specifically, our genetics.
For example, if a fertilized egg contains two X chromosomes (XX), then the resulting individual will be born a female. Should however, that egg contain an X and a Y chromosome (XY), then that individual will be born a male. So right from the very start of life our biology plays a hugely significant role in the type of behavior that we will display throughout our entire life.
For example, if you are born a female, then you may like the color the pink and enjoy playing with dolls. If you are born a male, then you may like the color blue and enjoy playing with toy cars or action men.
Of course, I am stereotyping the sexes here, but this is only done to demonstrate how a small difference in our biology (our chromosomal patterns) can result in us behaving in one way or another.
Another example of how biology can affect our behavior at the chromosomal level, can be found with people who suffer from Down’s syndrome.
These individuals are born with a chromosomal abnormality called trisomy 21, which results in three chromosomes instead of the usual pair. The effect of this is mental retardation, poor health and a shortened lifespan.
This view of biology playing a significant role in development was something which was held by Sigmund Freud, who is quoted as saying “Biology is destiny“.
Whether or not biology is our ultimate destiny is open to debate, because as is shown with feral children, even though our genetics may give us the potential to achieve something, it is the environment which ultimately determines whether or not we will realize that potential.
Sperm, Ovum & Chromosomes
Life begins when a sperm (spermatozoon) provided by the father unites with an egg (ovum) provided by the mother. Both the sperm and egg contain twenty-three single chromosomes, and when the ovum is fertilized, these chromosomes combine to form twenty-three pairs of chromosomes.
Through the process of mitosis, these chromosomal pairs in the fertilized egg are replicated into daughter cells which each contain the same number of chromosomes as the original egg. These daughter cells then continue to divide, eventually producing billions of cells.
Each chromosome contains a series of genes, which are ultimately responsible for the various characteristics that we develop when we are born and then display throughout our life. For example, one person may have a gene that gives them blonde hair, whilst another person may have a gene that gives them brown hair.
These genes, and their resulting characteristics, are inherited from both the mother and father. They are therefore, passed on from generation to generation through the process of sexual reproduction.
Conception & Birth
There are four stages associated with conception and birth:
A zygote is a fertilized egg which is formed when the sperm and ovum unite. This stage lasts for about one week, and is characterized by the division of one single cell into a large group of cells.
After the zygote has been formed, its cells continue to divide and replicate forming a structure known as the embryo. This occurs from weeks one to seven. During this stage, the cells begin to differentiate (become specialized) and form three distinct embryonic layers.
Ectoderm means outside skin, and will eventually become the sense organs, skin and nervous system.
Mesoderm means middle skin, and will eventually become the heart, bones, connective tissue and muscles.
Endoderm means inside skin, and will eventually become the inner lining of the stomach, intestines and lungs.
From weeks seven to birth the embryo becomes the foetus, during which time the cells of the foetus continue to divide and become more specialized.
During this period, cells such as brain cells, skin cells and hair cells are formed, and later, the body will start to form as the head and limbs begin to appear.
The foetal stage typically lasts for around seven months, which makes the time from conception to birth around nine months.
Neo means “new” and nate means “birth”. A neonate is therefore a newborn, something that most people simply refer to as a baby. Technically, a baby is an infant, which is a neonate that has gained weight after birth and can neither walk nor talk.
Freud’s Psychosexual Development Theory
Sigmund Freud’s theory of development attempts to explain how we form our sexual identity, our attitudes towards sexual behavior and our emotional reactions to sex. He called this theory “Psychosexual Development”, because Freud believed that sexual development was more psychological in nature than it was biological.
So psychosexual development could be rephrased as “the psychology of sexual development“, which studies the mental and emotional aspects of sexual development.
Stages of Psychosexual Development
According to Freud, our sex drive causes us to seek pleasure in different parts of our body during the various stages of psychosexual development.
Freud called this sex drive our psychosexual energy or libido, which we use to experience pleasure in our erogenous zones (i.e. areas of the body associated with sexual pleasure) during the five different stages of psychosexual development. The main erogenous zones are the mouth, anus and genitals.
Below are the five stages of psychosexual development.
Oral (birth to 18 months)
The oral stage lasts for about two years, during which time the infant obtains pleasure via their mouth by sucking, biting and chewing on things.
Anal (18 months to three years)
The anal stage lasts for about one to two years, during which time toddlers obtain pleasure from withholding fecal matter or expelling it.
Note : This stage coincides with when children are toilet trained.
Phallic (ages three to six)
The phallic stage lasts for about three years, during which time the preschool child obtains pleasure from self stimulation of the phallus. In males, the phallus is the penis, and in females, it is the clitoris. This stage ends at around six years of age.
Latency (age six to puberty)
The latency stage lasts for about six years, beginning at age six or seven and ending at age twelve to thirteen or as puberty begins. During this stage, the child’s sexual desire is focused on their parent of the opposite sex.
However, because this type of sexual desire is considered to be socially unacceptable, the child feels guilty and so represses these desires at an unconscious level. This subsequently causes their libido to become dormant (hidden away).
This unconscious sexual desire for the parent is what Freud called the Oedipus complex, which was inspired from an ancient Greek tragedy called “Oedipus The King”. In this play, Oedipus inadvertently kills his own father and then unknowingly marries his own mother.
Freud used the term Oedipus complex to refer to both males and females, although some people use that term only when referring to males, and the term “Electra Complex” to refer to females, which was a play that had a similar storyline to Oedipus The King.
Genital (puberty onwards)
The genital stage begins at age twelve or thirteen and continues throughout adulthood. As puberty begins, the repression previously exerted on the libido begins to lift, and the individual starts to become conscious of sex and their sexual desires towards members of the opposite sex.
This sexual desire shifts from a focus on the phallus, to a more general interest in sex with the opposite sex.
Note: The liberation of sexual desire from the unconscious level to the conscious level, manifests itself as an interest in members of the opposite sex and away from the parent or other family members. This is something Freud considered to be normal sexual development.
Fixation of Libido
Freud believed that sexual development could be negatively affected if there was too much excitement or inhibition associated with a particular psychosexual stage.
The result of either too much excitement or inhibition would result in a “fixation of libido”, which would cause the libido to become “stuck” in one particular erogenous zone.
This could cause a person to develop various problems later in life, such as overeating, constipation, pedophilia, alcoholism, fetishism, erectile dysfunction and an inability to enjoy sex or a lack of sexual desire.
Criticisms of Freud’s Psychosexual Theory
It is important to see Freud’s views on sexual development not as a series of facts, but rather as a series of concepts which may help to explain the process of sexual development. Many people do not agree with Freud’s theory, and suggest that his views on sexual development were a result of the era in which he was brought up in.
Freud lived during the Victorian era, a time in which the display of sexual desires and sexuality was generally discouraged. As a result, this may have heavily influenced Freud’s views and the theory on sexual development he ultimately came up with.
Many people today may view Freud’s theory with disgust, especially his belief that the child possessed a sexual desire for their parent. It could be the case, as some people would say, that the child did not have a sexual interest in their parent but rather was jealous of the power they had within that family. As a result the child wishes to take the place of their parent, but despite their desire to do so, they cannot.
It is also important to remember that for any theory there is a tendency for the theorist to project their own views, and possibly, also their own experiences in life onto that theory. So what may be true and therefore apply to one person, may not be true and apply to another.
Erikson’s Psychosocial Development Theory
Unlike Freud’s theory of psychosexual development which places great emphasis on sex, Erik Erikson’s theory of psychosocial development focuses more on the choices that people make and the conflicts they face during the different stages of their life.
Erikson’s theory of psychosocial development has eight stages. Within each stage, there are different types of conflicts that an individual must resolve, and if they are unable to do so, they will struggle with those conflicts later in life.
The eight stages of psychosocial development are :
• Trust Vs Mistrust
• Autonomy Vs Shame & Guilt
• Initiative Vs Guilt
• Industry Vs Inferiority
• Identity Vs Role Confusion
• Intimacy Vs Isolation
• Generativity Vs Self-Absorption
• Integrity Vs Despair
For each of these stages, the first attribute is considered to be a positive or desirable personality trait. For example, autonomy is a positive trait. The second attribute is considered to be a negative or undesirable trait. For example, isolation is a negative trait.
Throughout a person’s life, as they move from stage to stage, they must overcome the various challenges they face so that they can form the positive trait. If they are unable to do this, it will cause them problems later in life.
So basically, Erikson’s theory is about the challenges we face in life, and whether or not we are able to overcome those challenges to form certain desirable (positive) traits.
Let’s explore each of these eight stages of psychosocial development in more detail.
Trust vs Mistrust (birth – 2 years old)
Trust vs. mistrust is a stage associated with infancy, and lasts until we are two years of age. If an infant develops a sense of trust as a result of being looked after, attended to and loved by its parents, then that infant will be happy and in good health.
However, if the infant develops a sense of mistrust as a result of being neglected or treated poorly by its parents, they will display a lack of interest in their surroundings and have poor health. These are characteristics associated with infantile depression, which may then result in adult depression later in life.
So overall, this stage can be summarized by saying that if the infant is looked after well (develops trust) it will be happy and healthy. But if the infant is looked after poorly (develops mistrust) it will be depressed and unhealthy.
Autonomy vs Shame and doubt (2-3 years old)
The stage of autonomy vs. shame and doubt occurs during year’s two to three (toddlerhood).
A toddler with a sense of autonomy will be interested in exploring their surroundings, and will constantly be looking for new things to stimulate (mentally) themselves with. They will tend to perform this exploration by themselves, and as a result, may appear to wander off randomly or try to escape from their parents somehow to explore new surroundings.
A toddler with a sense of shame and doubt will tend to do the opposite. They will be more withdrawn, appear to lack confidence and not venture too far into areas that they have not been before.
So this stage can be summarized by saying that a child with autonomy likes to explore new things, whereas a child with shame and doubt does not. One is confident, the other isn’t.
Initiative vs Guilt (3-6 years old)
The initiative vs. guilt stage occurs during years three to six (preschool children).
A preschooler with a sense of initiative will tend to complete tasks that they start. For example, if they start to draw a picture they will keep drawing until they finish it. A preschooler with a sense of guilt will tend not to seek challenges, and tends to hold back expressing who they are and what they would like to do.
This stage can be summarized by saying that a preschooler with initiative expresses who they are, whereas a preschooler with guilt does not.
Industry vs Inferiority (6-12 years old)
Industry vs. inferiority is associated with children aged six to twelve years old. Children with a sense of industry show an interest in school work, tasks they are given at home and display a responsible attitude.
Children with a sense of inferiority will tend to display the opposite type of behavior, such as being uninterested in school work or tasks they are given, because they feel that they are not good enough to complete those tasks successfully. This sense of inferiority can become further entrenched if that child is criticized by their parents or other people.
So we can summarize this stage by saying that a child with a sense of industry is one who is interested in challenges and enjoys responsibility, being somewhat confident in their abilities to complete the tasks that they are given.
Children with a sense of inferiority however, do not like responsibility or being given tasks to complete. They feel that if they are given these tasks, or given responsibility, that they won’t be able to complete them very well and so will be criticized as a result.
Identity vs Role confusion (12-18 years old)
The identity vs. role confusion stage is associated with adolescence, with includes years twelve to eighteen.
An adolescent with a sense of identity will feel as though they know where they are going in life, or at least what they would like to be when they are older. As a result, they go throughout adolescence with that goal in mind, and tend to have a high level of self-esteem because their life has direction and a sense of purpose.
Adolescents with a sense of role confusion feel as though they have no direction or purpose in life, and feel unsure as to what the future holds for them. They are unlikely to have any long-term goals, and their behavior could best be described as drifting aimlessly through life. They are also likely to have low self-esteem.
So in summary, an adolescent with a sense of identity knows what they want to be when they are older. Whereas an adolescent with a sense of role confusion, is uncertain as to what they will be or do when they are older.
Intimacy vs Isolation (18 onwards)
The intimacy vs. isolation stage is associated with early adulthood, and tends to begin at age eighteen when adolescence ends. However, it is important to note that the stage of adulthood may be delayed somewhat, until the adolescent is able to form a sense of identity (i.e. they know what they want to do with their life).
As a result, an “adult” (someone aged over 18) may not technically enter adulthood even if they are in their twenties, thirties or older. Unless they are able to form a sense of identity, they will feel as though they are somewhat trapped in adolescence (like they have never really matured fully from school).
An adult who is capable of intimacy will tend to form close bonds with people, such as by forming friends and having romantic relationships with members of the opposite sex, eventually, leading to marriage.
An adult with a sense of isolation finds it difficult to form relationships with people, and is unable to understand what other people are thinking or feeling. As a result they spend most of the time by themselves, with little or no friends.
This stage can be summarized by saying that an adult with intimacy can form close relationships with people, whereas an adult with isolation cannot.
Generativity vs Self-absorption (adult)
An adult with the trait of generativity is capable of productive work, which they usually undertake for several years. This trait is also linked to helping others in some way, for example, a mother who looks after her children. An adult with a trait of self-absorption is more concerned with themselves rather than other people.
This stage can be summarized by saying that a person with generativity likes to give something to others, whereas a person with the trait of self-absorption likes to take things from others.
Integrity vs Despair (old age)
The stage of integrity vs. despair is associated with old age.
A person with a trait of integrity can face death with peace of mind, because they know that their life has been lived to the fullest and that they have achieved the things they wanted to do in life.
A person with a trait of despair feels a sense of desperation as their life draws to a close, because they feel that they have wasted it and not been able to do the things they hoped to do.
In summary, a person with integrity can accept death, but a person with despair wishes for a second chance and for more time before they die.
Piaget’s Cognitive Development Theory
Jean Piaget was a child psychologist who studied how children think and how this ability develops as they grow older.
His interest into the child mind came as a result of his interest in epistemology, which is a branch of philosophy that studies knowledge and how we acquire that knowledge. As a result, Piaget wanted to know how we know what we know, and he did this by focusing his study on children.
To study the child mind, Piaget used a method known as the phenomenological method. This method of investigation involves asking a child a series of carefully worded questions about something in their immediate environment.
The answer the child gives would then reveal how they see and interrupt the world around them. As a result of Piaget’s investigations, he came to the conclusion that there are four stages of cognitive development (the development of we think):
• The sensorimotor stage
• The preoperational stage
• The concrete operations stage
• The formal operations stage
According to Piaget’s cognitive development theory, a child is faced with an increasingly difficult set of challenges which they must overcome before they are able to move on to the next stage.
Let us look at each of these four stages now.
The Sensorimotor Stage (birth – 2 years old)
The sensorimotor stage occurs in infancy from birth to two years of age. The infant is aware (conscious) of their surrounding environment, but has not yet developed the ability to become self-conscious (aware of themselves).
The infant also possesses reflexes, and will react to a stimulus with a predictable motor response. For example, touching the soles of the infant’s feet will cause them move or twitch.
This is why Piaget called this stage the “sensorimotor” stage, because the infant is able to sense the world and react to it, but does not necessarily think about it or reflect upon the experiences which they have in it.
As the infant grows older, their actions start to become more intentional, although they still lack the ability to realize that they exist in the same way that you or I do. However, it is important to point out that there is no way to verify this, as infants cannot speak and therefore we cannot question them to ascertain a definitive answer.
We can only infer from the actions that the infant makes as to the degree in which they are or are not self-conscious. For example, if an infant is shown their reflection in a mirror, they may reach out to touch their reflection but do not seem to realize that they are seeing themselves.
If a mark is placed on the child’s face, again they may become interested, but make no effort to remove that mark from their face.
When this test is performed on children over two years of age, they are able to recognize their reflection and will attempt to remove the mark from their face. We can therefore conclude that infants in the sensorimotor stage lack the ability of self-awareness (self-consciousness).
However, it could be argued that the reason the infant does not recognize their reflection in the mirror is because they have never seen a mirror before, and do not know what it does, and so have never seen themselves before or learned to associate what the mirror reflects with themselves.
Interestingly, the same thing happens when animals are shown their reflection in a mirror. They may look at it briefly, but altogether seem uninterested in it and do not appear to “understand” that they are seeing themselves.
Overall, we can summarize the sensorimotor stage by saying that children under two years of age are able to experience and react to the world they live in, but have not yet the developed the ability of self consciousness.
The Preoperational Stage (ages 2-7)
The preoperational stage is associated with children aged two to seven years old (toddlers & preschoolers). This stage is characterized by the child’s inability to grasp the concept of cause and effect, and instead, tends to think in “magical terms”.
Magical thinking is a phrase used to describe thought that does not take into consideration the laws of nature. For example, a child in the preoperational stage who is shown a picture of a person flying, would not consider it to be unusual or unreal.
Two other characteristics of the preoperational stage are anthropomorphic thinking and egocentrism.
Anthropomorphic thinking simply means giving non human things human characteristics.
A good example of this can be found with speaking animals in children’s cartoons, who are given human characteristics such as emotions and the ability to talk.
The second characteristic of egocentrism describes how the child tends to see themselves as the centre of the universe.
For example, a child walking outside with their parent at night, may think that the moon is following them. Or, if they are shown a globe, they may think that people in Australia walk upside down.
The preoperational stage can be summarized by saying that the child is able to analyze the world they see, but do so in a way that does not accurately reflect reality.
The Concrete Operations Stage (ages 7-12)
The concrete operations stage, or concrete operational stage, occurs at age’s seven to twelve and marks the beginning of the child’s ability to think in terms of cause and effect.
The term “concrete” is used to describe the fact that the child is able to understand what they see and experience, but cannot yet understand abstractions (i.e. form ideas from examples that are given).
For example, a child in the concrete operations stage can understand that 5 + 5 = 10 because they can add these two values together on their fingers. However, if the child is asked what X represents in X + 6 = 11, they are unable to determine that the answer is 5.
In these examples, the child is able to understand arithmetic but cannot understand algebra, because their thinking cannot yet deal with abstractions. Children in this stage tend to be interested in how things work and what causes things to happen. They also like to build things, such as Lego or models.
The concrete operations stage can be summarized by saying that children can understand what they see, but do not fully understand what they don’t see.
The Formal Operations Stage (ages 12 onwards)
The formal operations stage is associated with adolescence (12-13+) and adulthood, and it is during this stage that abstract thinking begins to develop. They are able to understand algebra and form complex ideas based on information they are given.
As a result, the formal operations stage allows the adolescent to use both inductive and deductive logic for the first time, which lets them form conclusions based on facts rather than speculation.
Overall, the formal operations stage can be summarized by saying that adolescents develop a higher level thought which subsequently allows them to see the world for how it really is.
Kohlberg’s Moral Development Theory
Lawrence Kohlberg was a developmental psychologist who drew inspiration from Piaget’s theory of cognitive development to create a theory of moral development.
The term “moral development” simply describes an individual’s ability to tell right from wrong, and this development occurs as a result of the things that we learn and experience in life.
One of the major influences in our moral development are the role models who we have in life and the values that are instilled upon us by society.
Therefore, a high level of moral development could be said to come as a result of our cognitive development, because the things we learn in life ultimately affect the things we believe in and the things we do.
Note: Kohlberg’s view of moral development differs from past theories such as those by Plato and Immanuel Kant, because they speculated that our “moral sense” is largely inborn.
There are three main levels of moral development as proposed by Kohlberg :
• The Premoral Level
• The Conventional Level
• The Principled Level
Each of these levels contains a variety of stages that must be worked through before moving on to a higher stage and then to a higher level.
The Premoral Stage (ages 2-7)
The premoral stage occurs during early childhood between the ages of two to seven. The central theme of this stage is “might is right”, something which is referred to as power orientation.
To the child, its parents are seen as “right” because they are bigger and stronger. As a result, the way the child behaves towards their parents is influenced more by fear than it is through a sense of right or wrong.
For example, if a child wants some pocket-money for sweets at school, but is not given any money, the child may then consider stealing that money from their mother or father. Whether or not the child chooses to steal the money will be based upon the likelihood and consequences of getting caught.
If they feel that their parents will find out and then punish them for stealing, the child will most likely choose not to steal the money. If however, they think that they can get away with it, then they probably will steal the money. Therefore, the child’s actions are not based on a sense of right or wrong (morals), but instead are based on fear.
Interestingly, a similar thing happens with pets. If for example, a cat is trained by one member of the family not to jump on the sofa or bed, it will avoid doing so whenever that family member is nearby (i.e. when there is a risk that the cat will get caught).
But as soon as the cat feels it is safe to do so, it will quickly jump on the sofa or bed where it will proceed to spend the rest of the day in a deep slumber. Again, the cat’s actions are influenced by fear, rather than by what is right or wrong.
What I have just described is something that many pet owners should be able to relate to, and it certainly does make you question whether morals are developed through experience as Kohlberg proposes, or are inborn as Plato suggested.
Note : A person who has not yet developed a sense of morals is said to be “amoral”, which means without morals or without a sense of right or wrong. An amoral person does not feel guilt for doing things which are considered to be “wrong” or “bad”.
The Conventional Level (age 7-18)
The conventional level occurs during late childhood (around age 7) and adolescence (to around age 18). Although it should be pointed out that most adults will tend to stay in this level, never progressing to the next level.
The basic idea of the conventional level is of law and order. Something is “right” because there are laws which tell us that it is right. These “laws” can come from society, religion, social groups (e.g. clubs) and our family. If we break these laws, then we know that we will (or expect to) receive some sort of punishment as a result of our actions.
So basically, what we believe to be right is what we are told to be right, and very rarely will we question these values that have been imposed upon us.
For example, if from an early age your religion has taught you to behave in a certain way or to live a certain lifestyle, then you will consider that behavior or lifestyle to be “right” because your religion tells you it is right. Very rarely will these people question why it is right, or try to challenge it.
The Principled Level
The principled level represents only a small percentage of adults, and is characterized by an independent ability to decide upon what is right and wrong. In other words, people who can think for themselves rather than having other people think for them.
Adults who have reached the principled level are able to think logically about something, before deciding whether it is right or wrong. For example, if there is a law which you are told that you must obey, then most people (who are in the conventional level) would obey it without much analysis because they have been told that obeying that law is right.
However, people in the principled level would first decide upon whether that law is just or unjust. If obeying that law is unjust, then they may choose to rebel against it by not obeying it. This is how revolutions start in many countries, because people choose to rebel against laws which they consider to be unjust.
Reviewed – 27th March 2016