Lifespan Development | ISC Class 12 Psychology Notes

This note covers the meaning of development, growth and maturation; why lifespan development is studied; the heredity-environment interaction and twin studies;

Bronfenbrenner's Ecological Systems Theory; infancy (motor, cognitive and socio-emotional development, reflexes, Piaget's sensorimotor stage and attachment, including the strange situation and attachment styles); childhood (gross and fine motor skills, Piaget's preoperational and concrete operational stages, the emergence of self and gender concepts, and Kohlberg's moral development); and adolescence (physical changes at puberty, Piaget's formal operational stage, identity formation through Erikson and Marcia, and the concerns of delinquency, substance abuse and eating disorders).

What do development, growth and maturation mean?

Development is the pattern of progressive, orderly and predictable changes that begin at conception and continue throughout life.

It is influenced by an interplay of biological, cognitive and socio-emotional processes which are interwoven throughout the life-span, and it mostly involves changes that include both growth and decline, as seen in old age.

Development is not confined to one area of life; changes occur in the person in an integrated manner.

Growth refers to an increase in the size of body parts or of the organism as a whole; it can be measured or quantified, for example growth in height or weight. Growth is only one aspect included within development.

A temporary change caused by a brief illness is not considered part of development, because development has a direction and a definite relationship with what precedes and follows it.

Definition: Maturation. Maturation refers to changes that follow an orderly sequence and are largely dictated by the genetic blueprint, "unfolding from within" according to an inner, genetically determined timetable characteristic of the species.

Most children sit without support by about 7 months, stand with support by about 8 months and walk by about one year; special efforts to accelerate these behaviours do not help if the infant is maturationally not ready.

The Life-Span Perspective makes several assumptions: development is lifelong, involving both gains and losses that interact dynamically; it is multi-directional (some dimensions increase while others decrease, for example wisdom may grow while speed of performance declines); it is highly plastic, meaning skills can be improved throughout life though plasticity varies between individuals; it is influenced by historical conditions; it concerns many disciplines such as psychology, anthropology, sociology and neuro-sciences; and the individual responds to contexts that include what was inherited and the physical, social, historical and cultural environment.

Why is the study of lifespan development important, and what determines it?

Studying lifespan development helps us understand the changes that occur in different domains across the human life-span, from the prenatal period through infancy, childhood, adolescence, adulthood and old age.

It is a journey of personal understanding that also helps in dealing with others better, since it explains why people of the same age can differ while still sharing many commonalities, such as most infants learning to walk by the first year and talk by the second year.

Heredity and environment

Human differences and similarities arise from the interaction of heredity and environment. We inherit a genetic code from our parents, present in every cell, which makes a fertilised human egg grow into a human baby rather than any other species.

The genotype is a person's actual genetic material or genetic heritage; the phenotype is the way a genotype is expressed in observable and measurable characteristics, such as height, weight, eye and skin colour, and psychological traits like intelligence, creativity and personality.

Genes set limits within which the environment then influences development: an individual with "short height" genes will never grow taller than average even in a very good nutritional environment, but within that limit the environment shapes the outcome.

Parents also influence the type of environment a child encounters, and children themselves choose environments on the basis of their own genotype, for example a musically gifted child seeking out music-related settings.

Twin studies

Comparing identical twins (who share the same genetic make-up), fraternal twins (who share genes to the same degree as ordinary siblings) and twins who have been separated and reared apart lets researchers estimate how far a characteristic is shaped by heredity as against environment: traits on which identical twins resemble each other more closely than fraternal twins, even when the identical pair has been reared in different environments, are judged to have a stronger genetic basis.

For example, identical twins reach menarche closer in time to each other than do fraternal twins, pointing to a genetic influence on the timing of puberty.

How does Bronfenbrenner's Ecological Systems Theory explain the context of development?

Development never takes place in a vacuum; it is always embedded in a particular socio-cultural context, and transitions such as entering school, becoming an adolescent, finding a job, marrying or retiring are joint functions of biological change and environmental change.

Urie Bronfenbrenner's contextual view of development emphasises the role of environmental factors and sets out five nested levels.

Draw the individual at the centre, surrounded by four concentric rings labelled, from innermost to outermost, microsystem, mesosystem, exosystem and macrosystem, with the chronosystem shown as a separate dimension of time running alongside all the rings.

• The microsystem is the immediate environment in which the individual lives, where the child directly interacts with social agents: the family, peers, teachers and neighbourhood.
• The mesosystem consists of the relations between these microsystem contexts, for instance how a child's parents relate to the teachers, or how parents view the adolescent's friends.
• The exosystem includes events in social settings where the child does not participate directly but which still influence the child's experience, for example a parent's job transfer causing tension that affects interactions with the child, or the quality of schooling and medical care available.
• The macrosystem includes the culture in which the individual lives, with its attitudes, ideologies, beliefs and traditions.
• The chronosystem involves events in the individual's life course and the socio-historical circumstances of the time, such as parents' divorce or economic setback, and their effect on the child.

In short, a child's development is significantly affected by the complex world that envelops her or him, from the minutiae of everyday conversations to the broader social and economic circumstances of birth.

Children in impoverished environments, lacking stimulating resources such as books and toys and with less effective role models, are shown to be at a disadvantage in learning.

What happens in infancy: motor, cognitive and socio-emotional development?

Motor development and reflexes

A motor milestone is an age-related marker of physical skill, such as grasping and reaching for objects, sitting, crawling, walking and running, which typically follows a universal sequence with minor exceptions.

The newborn's movements are initially governed by reflexes, which are automatic, built-in responses to stimuli that are genetically-carried survival mechanisms and act as the building blocks for later voluntary motor development.

Cognitive development: Piaget's sensorimotor stage

According to Jean Piaget, the infant, during roughly the first two years of life, experiences the world through the senses and through interaction with objects, that is, by looking, hearing, touching, mouthing and grasping. This is the sensorimotor stage.

The newborn largely lives in the present and, at first, lacks object permanence, the awareness that objects continue to exist even when they are not perceived; if a toy is hidden in front of a young infant, the infant will not search for it, acting as if it has ceased to exist.

Gradually, by around 8 months, the child begins to pursue an object that is only partially covered in its presence, showing object permanence slowly emerging.

Babbling, the basis of later verbal communication, usually begins between 3 and 6 months of age.

How does attachment develop in infancy, and how do secure and insecure attachment differ?

The close emotional bond of affection that develops between infants and their parents or caregivers is called attachment.

By 6 to 8 months of age, as infants become more mobile, they show a preference for their mother's company, and they cry or show distress when frightened by a new face or separated from the mother, reciprocating with smiles or hugs on reunion.

Note: the Harlow and Harlow surrogate-mother study (1962). Baby monkeys separated from their mothers about 8 hours after birth were reared for 6 months by a wire "mother" or a cloth "mother"; regardless of which surrogate fed them, the baby monkeys preferred and spent far more time with the cloth mother, showing that contact-comfort, not feeding alone, is crucial for attachment.

According to Erik Erikson, the first year of life is the key period for developing trust or mistrust, built on the infant's sense of physical comfort.

Responsive, sensitive and accepting parenting gives the infant a strong base to explore the environment, leading to secure attachment; insensitive or dissatisfied parenting can instead create feelings of self-doubt in the child.

Mary Ainsworth and Lamb's strange situation test is a laboratory procedure used to assess the type of attachment an infant has formed with its caregiver, by observing the infant's reactions to brief separations from and reunions with the caregiver in an unfamiliar room with a stranger present.

1. The infant and the mother are brought into an unfamiliar room containing toys, and the infant is allowed to explore while the mother is present.
2. A stranger enters the room, interacts briefly with the mother, and then approaches the infant.
3. The mother quietly leaves the room, so that the infant is alone with the stranger.
4. The mother returns and the stranger leaves, allowing the infant's reunion behaviour to be observed.
5. The mother leaves again, so the infant is briefly alone in the room.
6. The stranger re-enters to comfort the infant if needed.
7. The mother returns for the final reunion, and the infant's response to her return is recorded.

Draw a sequence of boxes in a row, each labelled with one episode above (infant with mother, stranger enters, mother leaves, mother returns, mother leaves again, stranger returns, mother returns), with arrows joining them to show the order of the episodes.

Secure versus insecure attachment styles: how do they differ?

Securely attached infants respond positively when picked up, move freely and play, whereas insecurely attached infants feel anxious when separated, cry from fear and get upset. A close, warm and affectionate relationship with caregivers is a child's first step towards healthy development.

What happens in childhood: motor and cognitive development?

Motor development

Gross motor skills are physical skills that use the large muscles of the arms and legs, involved in moving around with confidence and purpose in the environment, such as hopping, jumping and running.

Fine motor skills involve finger dexterity and eye-hand coordination, such as picking up objects with the forefinger and thumb or fitting a jigsaw puzzle; these improve substantially during early childhood, and the child's preference for the left or right hand also develops during this period.

Cognitive development: preoperational and concrete operational stages

In Piaget's preoperational stage (roughly 2 to 7 years), the child gains the ability to mentally represent an object that is not physically present, through symbolic thought, but still lacks the ability to do mentally what could earlier only be done physically.

A salient feature of this stage is egocentrism, seeing the world only in terms of one's own self and being unable to appreciate another's point of view; connected to this is animism, the tendency to attribute life-like qualities to inanimate objects, for example a child saying "road hurt me" after slipping.

Another feature is centration, focusing on a single characteristic of a situation while ignoring others, for example insisting that a tall narrow glass holds more juice than a short broad one even when both hold the same amount.

In the concrete operational stage (roughly 7 to 11 years), intuitive thought is replaced by logical thought built on operations, mental actions that are reversible and that let the child do mentally what was earlier done physically.

In the classic clay-ball test, a child of this stage correctly judges that a ball of clay rolled into a long thin strip still contains the same amount of clay as the untouched ball, because the action can be mentally reversed.

This decline in egocentrism lets the child appreciate that there are different ways of looking at the same thing, though abstract thinking, such as manipulating ideas with no concrete objects present, is still not possible.

How does the self, including gender, emerge in childhood?

During early childhood, self-understanding is limited to physical characteristics, such as "I am tall" or "I am a girl"; during middle and late childhood, children define themselves increasingly through internal, psychological characteristics and through social comparison with others.

According to Erikson, how parents respond to a child's self-initiated activities, such as play and questions, leads to a sense of initiative if encouraged, or a sense of guilt if the activities are belittled.

Definition: sex versus gender. Sex refers to the biological dimension of being male or female; gender refers to the social dimension of being male or female, including the roles, behaviours and expectations a culture attaches to each sex.

• Gender identity is the sense of being male or female, which most children begin to acquire and can accurately label themselves by about 3 years of age.
• Gender role is a set of expectations that prescribes how females and males should think, act and feel, and specifies the range of behaviours considered appropriate for each sex.
• Gender stereotype is a generalised, often inaccurate belief about what behaviours, traits or interests are typical of males or females; media, including cartoons and commercials, are known to perpetuate such stereotypes.
• Gender stability is the understanding that one's own gender remains the same over time, for instance that a boy will grow up to be a man.
• Gender consistency (also called gender constancy) is the understanding that one's gender stays the same despite superficial changes in appearance, clothing or activity.

"Gender typing" occurs when individuals are ready to encode and organise information along the lines of what is considered appropriate or typical for males and females in a society.

Parents influence gender socialisation through rewards and punishments from early childhood, restricting school-aged girls more than boys and assigning different chores, while peer influence is also a major contributor.

How does moral reasoning develop according to Kohlberg?

Lawrence Kohlberg presented children with stories describing moral dilemmas and asked what the characters should do and why; from their answers he described age-related stages of moral development, organised into three levels.

The young child, before about 9 years of age, thinks mainly in terms of external authority (the pre-conventional level).

As the child grows, by early adolescence, moral reasoning develops through internalised rules accepted as one's own (the conventional level), and as logical thought matures during adolescence, moral thinking gains flexibility, allowing the individual to explore options and decide on a personal moral code (the post-conventional level).

What physical and cognitive changes mark adolescence?

Adolescence is the transitional period in a person's life between childhood and adulthood, beginning at the onset of puberty, when sexual maturity, or the ability to reproduce, is attained. The physical changes of this stage are universal, though the social and psychological experience of adolescence depends on the cultural context.

Physical changes at puberty

Primary sex characteristics are those directly related to reproduction. Secondary sex characteristics are features or signs of achieving sexual maturity that are not themselves part of the reproductive organs, such as facial hair and voice change in boys.

Pubertal changes in boys include an acceleration in growth, facial hair and changes in voice; in girls, rapid growth in height usually begins about two years before menarche, the onset of menstruation.

The growth spurt generally begins at age 12 or 13 for boys and at age 10 or 11 for girls, though there is normal variation in this sequence, and historical trends show the age of menarche declining in industrialised nations, reflecting better nutrition and medical care.

Cognitive development: formal operational thought

Piaget believed that formal operational thought appears between the ages of 11 and 15. During this stage, adolescent thinking expands beyond actual concrete experience into abstract terms, and the adolescent becomes capable of examining their own thoughts and others' thoughts.

Adolescent thought is also idealistic: adolescents compare themselves and others against ideal standards. Piaget called the systematic, logical approach to problem solving at this stage hypothetical deductive reasoning, in contrast with the trial-and-error approach used earlier in childhood.

How does identity develop in adolescence?

The primary task of adolescence is to establish an identity, which is who a person is and what their values, commitments and beliefs are, separate from the parents.

According to Erik Erikson, adolescence is the stage of ego-identity versus role diffusion: those who cope with the conflicting identities available to them develop a new, coherent sense of self, while those unable to resolve this "identity confusion" may isolate themselves from peers and family or lose their identity in the crowd.

Adolescents may at once desire independence and fear it, showing rapid swings between self-confidence and insecurity.

Definition: personal identity. Personal identity is a person's own sense of who they are and what their values, commitments and beliefs are, built through the detachment process of adolescence as a set of beliefs that are uniquely their own.

James Marcia categorised adolescents' identity status along two dimensions, exploration of options and commitment to a choice, giving four categories:

• Identity achievement: the adolescent has explored the available options and has made a firm commitment.
• Identity moratorium: the adolescent is actively exploring options but has not yet committed to one.
• Identity foreclosure: the adolescent has committed to an identity, often adopted from parents, without having explored alternatives.
• Identity diffusion: the adolescent has neither explored options nor made any commitment.

Cultural background, societal values, ethnic background and socio-economic status all influence identity formation; family relationships become less important as adolescents spend more time outside the home and develop a strong need for peer support and acceptance, though parents and peers generally serve complementary roles.

Vocational commitment, the ability to think about the future and set achievable career goals, is another major factor shaping identity.

What are the major concerns of adolescence?

Delinquency

Delinquency refers to a variety of behaviours ranging from socially unacceptable conduct and legal offences to criminal acts, such as truancy, running away from home, stealing or vandalism.

It is often associated with a negative self-identity, decreased trust, low achievement, low parental support, inappropriate discipline and family discord; adolescents from communities marked by poverty, unemployment and feelings of alienation may commit antisocial acts to gain attention and popularity among peers.

Most delinquent adolescents, however, do not remain delinquent; change of peer group, growing social responsibility, better self-worth and positive role models help reduce delinquent behaviour.

Substance abuse

Substance abuse refers to the harmful use of drugs, in general, and alcohol, usually arising from peer pressure, the need to be accepted by the group, the desire to act more grown up, or the need to escape the pressure of schoolwork or social activities.

Continued use can lead to dependence, a physiological state in which the body has adapted to the substance and needs it to function normally;

tolerance, needing increasing amounts of the substance to achieve the same effect; and withdrawal symptoms, the physical and psychological distress that follows when the substance is stopped.

Adolescents who are more vulnerable to drug, alcohol and nicotine use tend to be impulsive, aggressive, anxious, depressive and unpredictable, with low self-esteem and low expectations of achievement.

Positive relationships with parents, siblings and other adults play an important role in preventing substance abuse.

Eating disorders

Anorexia nervosa is an eating disorder that involves the relentless pursuit of thinness through starvation; adolescents with this disorder commonly eliminate certain foods from their diets or eat only "slimming" foods, often influenced by the media's projection of thinness as a desirable image.

Bulimia is an eating disorder in which the individual follows a binge-and-purge pattern: an eating binge is followed by purging through self-induced vomiting or laxative use, at times alternated with fasting. Both disorders are primarily female disorders, more common in urban families.

Glossary

• Development — the pattern of progressive, orderly and predictable changes that begin at conception and continue throughout life.
• Growth — an increase in the size of body parts or of the organism as a whole, measurable in units such as height or weight.
• Maturation — changes that follow an orderly, genetically determined sequence, unfolding from within regardless of special practice.
• Genotype — a person's actual genetic material or genetic heritage inherited from the parents.
• Phenotype — the way an individual's genotype is expressed in observable and measurable characteristics.
• Microsystem — the immediate environment in which an individual directly interacts with family, peers, teachers and neighbourhood.
• Chronosystem — the dimension of time, covering events in the individual's life course and the socio-historical circumstances of the time.
• Reflex — an automatic, built-in response to a stimulus, present before the newborn has had any opportunity to learn.
• Object permanence — the awareness that objects continue to exist even when they are not being seen or touched.
• Attachment — the close emotional bond of affection that develops between infants and their parents or caregivers.
• Egocentrism — seeing the world only in terms of one's own self and being unable to appreciate another's point of view.
• Gender identity — a child's own sense of being male or female, usually acquired by about 3 years of age.
• Gender stability — the understanding that one's own gender remains the same over time.
• Menarche — the onset of menstruation, marking the attainment of reproductive maturity in girls.
• Delinquency — socially unacceptable behaviour, legal offences or criminal acts committed by an adolescent.

Common errors and misconceptions

• Misconception: Growth and development mean the same thing. Correct: Growth is only the measurable increase in size; development includes growth along with changes in thinking, language and social relationships.
• Misconception: Reflexes such as rooting or grasping are learned behaviours. Correct: Reflexes are automatic, built-in responses present before the newborn has had any chance to learn.
• Misconception: Object permanence appears suddenly at a fixed age. Correct: Object permanence develops gradually; by about 8 months the infant begins pursuing a partially hidden object, a partial step towards full object permanence.
• Misconception: Secure and insecure attachment styles are told apart only by how much the infant cries. Correct: Styles differ in the whole pattern of behaviour across separation and reunion, such as whether the infant is easily soothed, avoids the caregiver, or shows ambivalent or disorganised behaviour.
• Misconception: Gender identity, gender stability and gender consistency are the same idea. Correct: Gender identity is simply labelling oneself as male or female; gender stability is knowing one's gender stays the same over time; gender consistency is knowing gender stays the same despite changes in appearance.
• Misconception: Kohlberg's conventional level reasoning is driven only by fear of punishment. Correct: Conventional-level rules are internalised to be virtuous and to win approval from others, not merely to avoid punishment.
• Misconception: Identity moratorium is a failure of identity development. Correct: Moratorium describes an adolescent who is actively exploring options without yet committing; it is a normal, exploratory status, not a failure.
• Misconception: Anorexia and bulimia are the same disorder. Correct: Anorexia nervosa is relentless pursuit of thinness through starvation, while bulimia involves a binge-and-purge eating pattern.

Exam-style questions with model answers

Q1. Define maturation. [2 marks]

1. Maturation refers to changes that follow an orderly sequence and are largely dictated by the genetic blueprint, unfolding from within according to an inner, genetically determined timetable characteristic of the species.

Q2. State two reflexes present in the newborn and when each usually disappears. [2 marks]

1. The rooting reflex, turning the head and opening the mouth when touched on the cheek, usually disappears between 3 and 6 months.
2. The grasping reflex, in which the baby's fingers close around an object pressed into the palm, usually disappears in 3 to 4 months and is replaced by voluntary grasping.

Q3. Nine-year-old Reema is shown two balls of clay, one rolled into a long thin strip, and correctly says both contain the same amount of clay. Which Piagetian stage does this illustrate, and why? [4 marks]

1. This illustrates the concrete operational stage of cognitive development, which spans roughly 7 to 11 years of age.
2. At this stage the child possesses operations, which are mental actions that are reversible, so Reema can mentally reverse the rolling of the clay back into a ball.
3. This ability to perform reversible mental operations on concrete objects is what allows her to judge correctly that the amount of clay has not changed despite its new shape.
4. A younger, preoperational child would instead focus on only one feature, such as the length of the strip, and wrongly conclude that the amount of clay has changed, because preoperational thought shows centration.

Q4. Distinguish between gender role and gender stereotype. [4 marks]

1. A gender role is a set of expectations that prescribes how females and males should think, act and feel, specifying the range of behaviours considered appropriate for each sex.
2. A gender stereotype is a generalised, often inaccurate belief about what traits, behaviours or interests are typical of males or females.
3. Gender roles are broader social expectations about appropriate conduct, whereas gender stereotypes are specific beliefs that may oversimplify or exaggerate differences, for example assuming only men are suited to certain sports and only women to domestic tasks.
4. Both are learned through socialisation by parents, peers and media, but a gender stereotype can act as a rigid belief that reinforces a gender role even when individual behaviour does not fit it.

Q5. An infant, when separated from the mother in an unfamiliar room, shows little distress, and on her return actively avoids and ignores her. Identify the attachment style shown, and describe one other attachment style for comparison. [4 marks]

1. This infant shows the avoidant attachment style, marked by little obvious distress on separation and active avoidance or ignoring of the caregiver at reunion.
2. By comparison, a securely attached infant explores freely using the caregiver as a secure base, shows some distress when the caregiver leaves, but greets the caregiver positively and is easily comforted on reunion.
3. The avoidant infant's lack of visible distress does not mean the bond is absent; it reflects a particular style of managing separation that differs from a secure infant's open display of distress and easy comfort-seeking.
4. Recognising such differences helps explain why some infants settle quickly after separation while others continue to appear withdrawn even once the caregiver has returned.

Q6. Explain Bronfenbrenner's Ecological Systems Theory of the context of development. [7 marks]

1. Bronfenbrenner's contextual view holds that development never takes place in a vacuum but is always embedded within a particular socio-cultural context, shaped jointly by biological change and the environment.
2. The microsystem is the immediate environment in which the individual directly interacts with social agents such as the family, peers, teachers and neighbourhood.
3. The mesosystem consists of the relations between these microsystem settings, for example how parents relate to teachers or view an adolescent's friends.
4. The exosystem includes events in settings the child does not participate in directly but which still affect the child's experience, such as a parent's job transfer or the general quality of schooling and medical care available.
5. The macrosystem is the broader culture in which the individual lives, including its attitudes, ideologies, beliefs and traditions.
6. The chronosystem involves events across the individual's life course and the socio-historical circumstances of the time, such as a parental divorce or economic setback.
7. Together these five nested systems show that a child's development is shaped by everything from immediate daily interactions to the wider historical and cultural moment into which the child is born.

Q7. Sixteen-year-old Rohan says his parents "don't understand" him, yet he still turns to them at times, and he is confused about which career to choose. Using the ideas of Erikson and Marcia, explain what Rohan is going through. [7 marks]

1. This illustrates the central task of adolescence: forming an identity, which is the adolescent's own sense of who they are and what their values, commitments and beliefs are, separate from the parents.
2. According to Erik Erikson, adolescence is the stage of ego-identity versus role diffusion; adolescents who cannot resolve the conflicting identities available to them experience "identity confusion", which can lead to isolating themselves from peers and family.
3. Rohan's statement that his parents "don't understand" him, alongside his occasional dependence on them, reflects the rapid fluctuation between self-confidence and insecurity that is typical of this stage, as adolescents simultaneously desire independence and fear it.
4. James Marcia's framework helps describe Rohan's status more precisely along two dimensions, exploration and commitment: his confusion about a career without having committed to one suggests either identity moratorium, if he is actively exploring options, or identity diffusion, if he has not yet begun to explore.
5. Family relationships, cultural background, societal values and vocational commitment, including the ability to set realistic future goals, all influence how this identity search is resolved.
6. As peer support becomes more important during adolescence, parents and peers generally serve complementary roles, so Rohan's search for identity is likely to be shaped by both sets of relationships rather than by either alone.

Q8. Discuss delinquency, substance abuse and eating disorders as major concerns of adolescence. [7 marks]

1. Delinquency refers to a range of behaviours from socially unacceptable conduct and legal offences to criminal acts, such as truancy, running away from home, stealing or vandalism.
2. It is often linked to a negative self-identity, decreased trust, low achievement, low parental support, inappropriate discipline and family discord, with communities marked by poverty and unemployment contributing further.
3. Substance abuse, the harmful use of drugs in general and alcohol, commonly arises from peer pressure, the desire to be accepted by the group or to act more grown up, or the need to escape pressure from schoolwork.
4. Continued substance use can create dependence, where the body adapts and needs the substance to function; tolerance, needing more of the substance for the same effect; and withdrawal symptoms when use is stopped.
5. Anorexia nervosa is the relentless pursuit of thinness through starvation, often involving the elimination of certain foods, influenced by media images that project thinness as desirable.
6. Bulimia is a binge-and-purge eating pattern in which an eating binge is followed by self-induced vomiting or laxative use, sometimes alternated with fasting; both eating disorders are primarily female disorders, more common in urban families.
7. Across all three concerns, positive relationships with parents, siblings and peers, along with growing social responsibility and self-worth, play an important role in prevention and recovery.

Key takeaways

• Development includes growth and maturation but also qualitative changes in thinking, language and social relationships across the whole life-span.
• Heredity sets limits within which the environment shapes outcomes; twin studies compare identical, fraternal and separated twins to judge heritability.
• Bronfenbrenner's theory places the developing individual within nested microsystem, mesosystem, exosystem, macrosystem and chronosystem influences.
• Newborn reflexes such as rooting, Moro, grasping and Babinski are automatic responses that disappear as voluntary motor control matures.
• Piaget's sensorimotor stage in infancy gives way to the preoperational and concrete operational stages of childhood and the formal operational stage of adolescence.
• Attachment, studied through the strange situation, can be secure, avoidant, ambivalent or disorganised/disoriented, each with its own pattern across separation and reunion.
• The self in childhood develops through gender identity, gender role, gender stereotype, gender stability and gender consistency.
• Kohlberg's pre-conventional, conventional and post-conventional levels of moral reasoning move from obedience to internalised rules to a personal ethical code.
• Adolescent identity formation, as described by Erikson and categorised by Marcia into achievement, moratorium, foreclosure and diffusion, is shaped by family, peers and vocational goals.
• Delinquency, substance abuse and eating disorders are major concerns of adolescence, each linked to particular family, peer and psychological pressures.

Test yourself

What is the difference between growth and development?

Growth is a measurable increase in size, such as height or weight; development is the wider, progressive and orderly pattern of change including growth, cognition, language and social relationships across life.

Name the five systems in Bronfenbrenner's theory.

Microsystem, mesosystem, exosystem, macrosystem and chronosystem, moving from the immediate environment outward to the broader culture and the dimension of time.

What did the Harlow and Harlow surrogate-mother study show about attachment?

Baby monkeys preferred the cloth "mother" over the wire "mother" regardless of which one fed them, showing contact-comfort, not feeding alone, is crucial for attachment.

What is object permanence, and roughly when does it begin to emerge?

Object permanence is the awareness that objects continue to exist when not perceived; it begins emerging by about 8 months, when infants start pursuing partially hidden objects.

Give the four attachment styles identified through the strange situation.

Secure, avoidant, ambivalent (resistant) and disorganised/disoriented attachment, each showing a different pattern of behaviour across separation from and reunion with the caregiver.

What is centration, and give the example used for it?

Centration is focusing on a single feature of a situation; the example is a child insisting a tall narrow glass holds more juice than a short broad one holding the same amount.

Name Kohlberg's three levels of moral development.

Pre-conventional, conventional and post-conventional levels, moving from obedience and reward-seeking to internalised rules and finally to a personal ethical code.

What distinguishes identity foreclosure from identity moratorium in Marcia's categories?

Foreclosure is committing to an identity, often adopted from parents, without exploring alternatives; moratorium is actively exploring options without yet having committed to any.