Developmental psychology focuses on examining how individuals transform physically, mentally, and socially from conception through old age.

This field investigates changes that are part of typical growth trajectories, contrasting with temporary fluctuations like illnesses or sudden growth spurts.

A fundamental question arises: At what point does human development cease? If change is continuous, how can a standard or typical representation of a human at different ages be defined? Given that individuals are constantly changing, establishing a consistent baseline for psychological study presents a challenge, as age acts as an inherent confounding variable in research.

Two primary perspectives exist regarding the nature of development:

• Continuity View: This perspective sees development as a gradual, smooth process.
• Discontinuity View / Stage Theories: This perspective posits that development occurs in distinct, disconnected stages.

Related concepts include:

• Heritability: The extent to which genetic factors contribute to variations in a particular behavior or trait within a population.
• Environmentability: The degree to which environmental or cultural influences impact a specific trait or behavior within a population.

Genetics and Environment

An individual’s genotype represents their underlying genetic makeup, composed of DNA organized into genes and chromosomes. Epigenetics studies how gene expression can be altered by environmental factors without changes to the DNA sequence itself; possessing a gene does not guarantee it is active.

Maturationism is a viewpoint suggesting that children’s growth primarily follows genetic instructions, with the environment playing a secondary role.

Variations in chromosome numbers can lead to specific syndromes:

• Down Syndrome: Characterized by an extra 21st chromosome.
• Turner’s Syndrome: Involves a missing X chromosome (in females).
• Klinefelter’s Syndrome: Occurs in males with an extra X chromosome (XXY).

It is crucial to remember that concepts like heritability and environmentability describe influences within a population, not a single individual. It is impossible to attribute a specific person’s trait, such as shyness, solely to one gene or one environmental factor.

The phenotype refers to the observable characteristics or traits an individual actually displays. This includes traits influenced by dominant and recessive genes (like hair color, e.g., blond or red hair). Genetic diseases can also be linked to specific genes. Many traits are polygenic, meaning they are controlled by multiple genes. Some genes are frequently inherited together.

The relationship between genes and behavior is complex and bidirectional. Environmental input and even mental habits can influence gene activity (epigenetics). Methylation, a process where gene expression is turned off by protein interactions, is one mechanism by which the environment affects genes. For example, maternal stress hormones have been shown to influence which genes are activated or deactivated in offspring.

Development Before Birth (Prenatal)

Just as we examine the postnatal environment’s influence on behavior, understanding the prenatal environment is essential for discussing a baby’s well-being and mental health.

The placenta serves as a crucial filter during pregnancy, allowing essential oxygen and nutrients to reach the fetus while blocking some harmful substances.

Amniocentesis is a medical procedure typically performed between 14 and 20 weeks of pregnancy to test for genetic abnormalities. Ethical considerations surround the use of this test.

Prenatal development proceeds through distinct periods:

• Germinal (Zygotic) Period: The initial two weeks. The fertilized egg (zygote) undergoes rapid cell division and implants in the uterine wall.
• Embryonic Stage: From the 3rd to the 8th week. This is a time of rapid growth and differentiation, where the body’s major organs and systems form. Genes on the sex chromosomes, along with hormonal influences, guide the initial development of the sex organs. This stage is highly fragile and, along with the germinal period, is the most likely time for a miscarriage. Development follows specific patterns:
  
  • Cephalocaudal: Development proceeds from head to tail (e.g., the central nervous system develops from top down).
  • Proximodistal: Development occurs from the center outward (e.g., internal organs develop before limbs).
• Fetal Stage: The longest stage, lasting for the remaining seven months. Body systems continue to grow and mature in preparation for life outside the womb. Myelination (the formation of a fatty sheath around nerve fibers, improving transmission) also occurs during this period.

Risks During Prenatal Development

Teratogens are agents or substances that can harm the developing fetus, potentially causing abnormal development or birth defects. The embryonic stage represents the period of greatest vulnerability to these harmful influences. Examples include:

• Maternal hormones: Stress and testosterone levels can influence development. Intriguingly, early in development, all babies are biologically female; exposure to testosterone at the appropriate time triggers male sex organ development. Questions remain about the timing and level of such exposure.
• Radiation: Can lead to high rates of cancers and physical deformities.
• Industrial chemicals: Linked to potential cognitive deficits.
• Diseases: Certain maternal infections like AIDS, syphilis, or rubella can have severe effects on the fetus.
• Marijuana: Associated with anxious and irritable infants.
• Alcohol: Heavy maternal alcohol consumption, particularly in the first 12 weeks, is the cause of Fetal Alcohol Syndrome (FAS). FAS can result in a combination of physical characteristics and cognitive and behavioral issues, including intellectual disability and hyperactivity. It’s worth noting how medical advice has evolved; attitudes towards alcohol consumption during pregnancy were different decades ago.

Infancy

Modern understanding reveals that babies are capable of more complex behaviors than previously thought, even exhibiting behaviors like feigning crying.

Key aspects of infant development:

1. While the cerebral cortex is still immature, some brain regions are genetically predisposed for basic functioning.
2. Brain areas involved in learning demonstrate greater plasticity (adaptability) than those associated with basic sensation.
3. Newborns have an excess of neurons and synapses.
4. Synaptic pruning, the process of eliminating unused neurons and synapses, occurs and continues until approximately age 25.
5. Infants are born with various reflex actions, such as sucking, rooting (turning the head towards a touch on the cheek), facial mimicry, swimming, and stepping.
6. Infant bodies are initially disproportionate, with relatively large heads, but limbs grow to catch up.
7. Newborns spend about 70% of their time asleep, though often not during typical nighttime hours! REM sleep is believed to be crucial for synapse formation and pruning. Entrainment refers to the process of synchronizing biological rhythms with external cues.Maturationism, as mentioned earlier, suggests that genetic instructions primarily guide child development, with the environment playing a secondary role.

Physical Development in Infancy and Childhood

Vision:

1. Infants lack a fully developed fovea (the central part of the retina with high cone density).
2. Eye movements are initially slow and jerky.
3. Infants gradually increase their looking time at stimuli, possibly indicating developing attention spans and muscle control.
4. Newborn vision is estimated to be around 20/600 (meaning they see at 20 feet what a person with normal vision sees at 600 feet).
5. Infants tend to prefer looking at large patterns.

Hearing: Hearing is already quite developed at birth; one-day-old infants can distinguish between tones one musical note apart, suggesting an evolutionary basis.

1. Full hearing development takes years.
2. This developmental timeline might contribute to young children’s listening challenges.
3. Newborns show a preference for female, high-pitched, rising intonational sounds, characteristic of “baby talk.”

The Visual Cliff experiment demonstrates depth perception development:

1. Very young babies may not perceive the apparent drop-off.
2. By around 9 months, infants develop depth perception and will often look to their caregiver for cues before deciding whether to cross the visual cliff.

Oral Signals:

1. Infants show a preference for sweet tastes and smells.
2. They can differentiate their mother’s milk from others, a behavior linked to evolutionary advantages as breast milk provides immune support.

Motor Skills: The development of motor skills involves both genetic predisposition (Nature) and environmental influences (Nurture). While humans are genetically programmed with the potential to stand and walk, recent research indicates that environmental factors play a role, but only when development reaches a certain readiness or critical stage.

Approximate ages for acquiring physical abilities:

• 1 month: Can hold chin up
• 3 months: Can reach for an object
• 4 months: Can sit up with support
• 7 months: Can sit alone
• 8 months: Can stand with help
• 11 months: Can walk when led
• 14 months: Can stand alone
• 15 months: Can walk alone

Preschool Age:

• Physical: Walking progresses from the awkward toddle to a more coordinated gait with feet closer together.
• Mental: Grasping and drawing abilities improve. This reinforces the idea that readiness is key to learning; a child must be developmentally prepared before they can acquire certain skills. This concept contrasts with purely behaviorist views (like those of Watson, Skinner, Thorndike, and Pavlov) that emphasize environmental shaping alone.

Middle Childhood: During this period, the body grows rapidly, and motor skills continue to refine. Girls’ growth often matches or exceeds boys’ by age 10. Generally, boys tend to excel in gross motor skills, while girls often show better fine motor skills.

Moral Development

Increasing evidence suggests a basic human tendency towards prosocial behavior. The “Yale baby study,” for instance, showed that infants prefer puppets who help others over those who hinder.

Lawrence Kohlberg proposed a stage theory of moral development, emphasizing the reasoning behind a moral decision rather than the decision itself, often illustrated by the Heinz Dilemma:

1. Preconventional Level: Morality is based on external consequences.
   
   • Stage A: Obedience and punishment orientation.
   • Stage B: Individualism and exchange (favors are exchanged).
2. Conventional Level: Morality is based on social rules and expectations.
   
   • Stage A: Interpersonal relationships (good boy/girl orientation).
   • Stage B: Maintaining social order (law and order orientation).
3. Postconventional Level: Morality is based on abstract principles and values.
   
   • Stage A: Social contract and individual rights.
   • Stage B: Universal ethical principles.

Language Development

Early theories, like Skinner’s, viewed language learning as based on reinforcement. However, Noam Chomsky argued against this, proposing an innate Language Acquisition Device (LAD) in the brain. Research shows that babies comprehend language before they can produce it.

Language development milestones include:

• Cooing: Around 2 months, infants produce vowel-like sounds.
• Babbling: Around 6 months, consonants are added to sounds.
• Holophrases: Single words are used to convey meaning (e.g., “juice” for “I want juice”).
• Telegraphic Speech: Around 18-24 months, children use two-word phrases with essential words (e.g., “juice spill”).
• Whole Sentences: Gradually, children begin to form complete sentences.

Studies indicate that the brains of bilingual individuals have structural differences and potentially more synaptic connections.

Memory in Children

Sigmund Freud proposed that we repress disturbing childhood memories, but it’s debated whether few early memories are actually troubling. Some cognitive psychologists suggest that young children’s limited sense of self or underdeveloped schemas prevent them from forming strong, retrievable memories. Earlier memories may be more implicit (unconscious) than explicit (conscious). It’s also possible that the lack of sophisticated language skills hinders the encoding of specific memories. Biological psychologists point to the immaturity of brain structures like the hippocampus, which is crucial for memory formation, as a reason for limited early explicit memories.

Cognitive Development

Cognitive development is significantly influenced by an enriched environment. Socioeconomic status (SES) is a major environmental factor impacting a child’s cognitive growth; factors like parental reading, exposure to multiple languages, interactions with siblings, access to educational games, books, computers, internet, and family expectations all play a role. Some research controversially suggests that poverty can have detrimental effects on brain development.

The concept of a critical period proposes that certain skills or abilities must be acquired during specific developmental windows; if stimulation or instruction is absent during this time, development may not occur correctly or fully. Famous experiments involving kittens’ visual cortex by Hubel and Wiesel demonstrated a critical period for visual development, highlighting the lack of plasticity in that specific case after the window closed.

In contrast, a sensitive period is a time when learning is optimal, but still possible, though perhaps more challenging, afterward. Language acquisition is often considered to occur during a sensitive period; while easier during early childhood, learning a language later is still possible. This concept emphasizes plasticity, the brain’s ability to adapt.

Lev Vygotsky emphasized the importance of social interaction in cognitive development, particularly with more knowledgeable peers and adults. He introduced scaffolding, where a “teacher” (adult or more skilled peer) supports the learner, gradually withdrawing support as the learner becomes more competent. The Zone of Proximal Development (ZPD) is the gap between what a child can do independently and what they can achieve with assistance. Vygotsky’s ideas support cooperative learning (children working together) and reciprocal teaching (students taking on teaching roles).

Jean Piaget proposed distinct stages of cognitive development, arguing that adult minds do not simply possess more information but think in qualitatively different ways than children. Piaget introduced the concept of a schema, a mental structure or framework that represents how the world works. Learning occurs through:

1. Assimilation: Fitting new information into existing schemas.
2. Accommodation: Modifying or creating new schemas to incorporate new information (e.g., a child’s schema for “doggie” changes after seeing a horse).

Piaget’s Stages:

• STAGE 1: Sensorimotor Period (Birth to ~2 years): Thinking is primarily limited to sensory experiences and motor actions. True abstract cognition is absent. Thinking is doing. This stage ends when infants develop the ability to think about things not immediately present. A key achievement is object permanence, the understanding that objects continue to exist even when not visible. Piaget’s early observations suggested that very young infants would not search for partially hidden objects and that searching for missing objects was random and brief. The understanding of object permanence fully develops around 18-24 months. There is debate about whether the age of achieving object permanence correlates with future intelligence.
• Critiques of Piaget’s Sensorimotor Stage: Piaget’s experimental methods were sometimes seen as too difficult for infants. For example, requiring a child to physically remove a blanket might have masked earlier understanding. More recent research using advanced techniques (like measuring looking time) by researchers like Renee Baillargeon has shown that infants appear to grasp basic physical principles and object permanence earlier than Piaget estimated, demonstrated by longer stares at “impossible” events that violate physical laws. This suggests infants form early mental models of the world.
• STAGE 2: Pre-operational Period (~2 to 7 years): Children develop symbolic thought but lack logical reasoning in many situations. A key limitation is difficulty with conservation, the understanding that certain properties (like volume or quantity) remain the same despite changes in appearance. For example, in Piaget’s famous task, children shown equal amounts of liquid in different shaped glasses will often say the taller, narrower glass contains more liquid, focusing only on height.
• STAGE 3: Concrete Operational Period (~7 to 11 years): Children gain the ability to think logically about concrete events and objects. They can perform mental operations like addition and subtraction but only on things they know exist. They still struggle with abstract concepts like justice or freedom.
• STAGE 4: Formal Operational Period (~12 years and up): Adolescents develop the capacity for abstract, hypothetical, and philosophical thought. They can reason about possibilities and ideals. This stage often brings idealism, where individuals contemplate ideal worlds and may become critical of reality. They also become adept at identifying inconsistencies, such as questioning societal rules (e.g., drafting people who cannot legally purchase alcohol).

Social and Emotional Development

Konrad Lorenz’s work demonstrated imprinting in waterfowl, where newly hatched birds form a strong bond with the first moving object they see, typically their mother. While sometimes compared to the early bond between human infants and caregivers, adoptive parents form equally strong bonds, suggesting human attachment is more flexible than rigid imprinting.

Emotional Development:

• Babies have a rich emotional life, evident in the “Still Face” experiment where infants react negatively to a caregiver’s unresponsive expression.
• Prolonged emotional neglect has been linked to detrimental effects on brain development.
• The Visual Cliff experiment also highlights the role of emotional cues; older infants (around 9 months) rely on their mother’s facial expression (fear or encouragement) to decide whether to cross. Younger infants (before 9 months) typically lack the depth perception or understanding to show fear or rely on cues.
• Babies practice emotions by mimicking facial expressions.
• Studies show infants prefer looking at human faces and smiling faces and are sensitive to their mother’s moods, often looking away if she appears distressed.
• From their first months, children are drawn to other people and elicit positive responses from others.
• Psychologists study how children learn through play, develop morality, acquire societal rules, and learn language.

Temperament: Refers to an individual’s innate behavioral style and emotional reactivity, often seen as the foundation of personality. Temperaments are relatively stable, but the environment can influence their expression. Common categories include:

1. Easy Babies: The most common type, characterized by predictable routines for hunger and sleep and generally positive moods.
2. Difficult Babies: Tend to be irritable, irregular in routines, and react negatively to new situations.
3. Slow-to-Warm-Up Babies: Initially withdrawn or hesitant in new situations but gradually adapt over time.

Self-concept: A person’s understanding and evaluation of themselves, developing partly through identification with parents. Factors influencing this include parental status, competence, similarity to the child, warmth, affection, and positive regard.

Egocentrism: The inability to see the world from another person’s perspective. This is characteristic of young children and can also manifest in adolescents in their interactions with parents.

Mary Ainsworth’s Strange Situation Study is a research method used to assess the quality of attachment between an infant and caregiver. Unlike temperament, this focuses on the specific bond with a particular caregiver. Based on the infant’s behavior when the caregiver returns after a brief absence, different attachment styles are identified:

1. Secure Attachment: Infants are distressed when the caregiver leaves but are quickly comforted upon their return. They tend to show greater resilience, self-control, and curiosity later in childhood.
2. Anxious-Avoidant Attachment: Infants show little distress when the caregiver leaves and actively avoid or ignore the caregiver upon return.
3. Anxious-Resistant (or Ambivalent) Attachment: Infants are distressed when the caregiver leaves and are both clingy and resistant (angry) upon return, difficult to comfort.
4. Disorganized Attachment: Infants display confused and contradictory behaviors upon the caregiver’s return, seemingly unable to respond in a consistent way.

The predictability of these attachment styles for later development is an area of ongoing research. Reflecting on one’s own childhood attachment style based on parental descriptions can be insightful.

Harry Harlow’s experiments with rhesus monkeys highlighted the importance of contact comfort, demonstrating that infant monkeys preferred the soft, cloth “mother” figure over a wire figure that provided food. This suggested that comfort and physical closeness are primary reinforcers and a biological need, potentially relating to Maslow’s hierarchy of needs. These studies shed light on why some infants are active, sleepy, fearful, or enthusiastic, indicating the interplay of innate predispositions and early experiences.

Adolescence

Adolescence is a multidimensional period of transition encompassing physical, intellectual, emotional, social, and financial changes. This period has become more protracted (lengthened) across generations. It typically begins with the onset of puberty, which appears to be starting earlier in recent times, possibly due to factors like improved healthcare or hormones in the food supply. The end of adolescence is less clearly defined, often marked by achieving self-sufficiency. The term “teenager” only gained common usage in the mid-20th century.

G. Stanley Hall famously characterized adolescence as a time of “storm and stress,” though research suggests this is not universally true. Hall also proposed Recapitulation Theory, suggesting individual development parallels the evolutionary history of the species, implying children pass through all earlier stages of human existence before adulthood. This theory is not widely accepted in modern psychology.

Erik Erikson described adolescence as the stage of Identity vs. Role Confusion, where individuals grapple with forming a coherent sense of self.

Sigmund Freud viewed adolescence as the Genital Stage, focusing on the maturation of sexual interests.

Jean Piaget described the cognitive stage of adolescence as Formal Operations, where individuals develop the ability to think abstractly, hypothetically, and consider possibilities they haven’t directly experienced. This leads to Idealism, as adolescents contemplate ideal worlds and may become critical of reality. They also become skilled at identifying inconsistencies, questioning authority and societal rules based on their developing abstract reasoning.

James Marcia expanded on Erikson’s identity concept, identifying different identity statuses based on exploration and commitment:

1. Foreclosure: Committing to a role or identity without exploring alternatives.
2. Identity Diffusion: Failing to commit to a role or actively explore options, remaining in a state of uncertainty.
3. Moratorium: Actively exploring different roles and identities but not yet having made a firm commitment.
4. Identity Achievement: Having explored alternatives and made a firm commitment to a sense of self.

David Elkind described adolescent egocentrism, characterized by heightened self-consciousness and two related concepts:

• Personal Fable: The belief in one’s own uniqueness and invincibility (“It won’t happen to me”).
• Imaginary Audience: The belief that everyone else is constantly observing and evaluating them, creating a sense of being on stage (the spotlight effect).

Erikson’s Stages of Psychosocial Development: A summary of Erikson’s eight stages across the lifespan, each marked by a core conflict and resulting outcome based on resolution:

• Infancy (Birth-18 months): Trust vs. Mistrust (Feeding) -> Hope
• Toddlerhood (2-3 years): Autonomy vs. Shame and Doubt (Toilet Training) -> Will
• Preschooler (3-5 years): Initiative vs. Guilt (Exploration) -> Purpose
• Elementary School (6-11 years): Industry vs. Inferiority (School) -> Competence
• Adolescence (12-18 years): Identity vs. Role Confusion (Social Relationships) -> Fidelity
• Young Adulthood (19-40 years): Intimacy vs. Isolation (Relationships) -> Love
• Middle Adulthood (40-65 years): Generativity vs. Stagnation (Work and Parenthood) -> Care
• Late Adulthood (65+ years): Ego Integrity vs. Despair (Reflection on Life) -> Wisdom

Physical Development in Adolescence

Puberty is the process leading to reproductive maturity, typically starting around age 12 for girls and 14 for boys.

• Menarche: The onset of menstruation, marking the start of puberty for girls.
• Spermarche: The first ejaculation, marking the start of puberty for boys.
• Primary Sexual Characteristics: Traits directly involved in reproduction, such as the development of the sex organs.
• Secondary Sex Characteristics: Traits not directly involved in reproduction but that differentiate sexes, such as voice changes, body hair growth, and breast development.

Klinefelter’s Syndrome, as mentioned earlier, involves an extra X chromosome in males (XXY) and can be associated with certain physical characteristics.

The timing of pubertal onset can impact self-esteem.

• Early Maturing Girls: May experience shyness, introversion, lower social skills, and earlier engagement in risky behaviors.
• Early Maturing Boys: Often show more confidence, relaxation, social responsibility, and are well-regarded by peers.

Developmental differences between genders exist; girls tend to develop faster physically, speak more fluently earlier, and have fewer speech issues. Boys may exhibit more aggressive behavior and find it more challenging to achieve autonomy from parents compared to girls, who may demand less independence. Girls also tend to face more internalizing emotional challenges like depression and self-esteem issues.

Sex and Gender

Sex refers to the biological distinctions between males and females, including external and internal genitalia, chromosomes, and hormones. Sex roles are behaviors traditionally associated with biological sex, such as breastfeeding.

Gender refers to the behavioral patterns, roles, and expectations deemed appropriate for men (masculine) and women (feminine) by a particular culture.

Sexual orientation describes a person’s pattern of emotional, romantic, and/or sexual attraction to others.

Gender Identity is an individual’s internal sense of being male, female, both, or neither, regardless of their biological sex assigned at birth.

Gender expression is how a person outwardly presents their gender, often based on traditional gender roles..

Gender Development: The understanding and expression of gender are shaped by complex factors, including brain structure, gestational hormonal exposure, later-life hormonal interactions, upbringing, self-identification, sexual orientation, and external/internal biological sex.

Gender role refers to the set of expected behaviors for males and females within a society. Gender schema or acculturation describes how a child learns and internalizes these gender roles from their culture.

Debate exists regarding the origins of differences between males and females. While some historical viewpoints, like John Money’s (associated with the controversial John/Joan experiment), suggested that gender was primarily shaped by upbringing, a wealth of studies on individuals across the lifespan indicates significant differences that cannot be solely attributed to nurture. Simon LeVay’s research, for example, identified structural differences in the hypothalamus potentially related to sexual orientation.

However, it is crucial to acknowledge that the commonalities between males and females significantly outweigh the differences, although discussions often focus disproportionately on the distinctions. Observations of young female chimps engaging in behaviors resembling doll-cradling suggest some potential biological predispositions influencing play preferences. By age 3, children typically recognize their gender identity, and their subsequent development involves understanding the societal meaning of that identity. While a 1970s perspective emphasized the sameness of males and females, ongoing research continues to explore the interplay of nature and nurture. Anecdotal evidence from parents and teachers of young children often points to observable differences in thinking, acting, and interests between boys and girls, suggesting these are not solely products of upbringing.

Even brain scans, which appear to offer objective biological data, are analyzing brains that have developed within social and cultural contexts, meaning observed differences can reflect the influence of these factors as well as biology.

Adolescence and Sexual Behavior

Early sexual activity in adolescence is associated with a range of potential challenges:

1. Adolescents engaging in early sexual activity may hold less conventional views on morality and behavior. It is important to note that “conventional views” are defined by dominant societal groups.
2. They are more likely to engage in smoking, drinking, and substance use.
3. Their parents may have lower levels of education and less parental supervision.
4. They may have less strong relationships with their parents.
5. There is a correlation between early sexual activity and childhood abuse.
6. It can be linked to declining academic performance.
7. It carries the risk of pregnancy.
8. A significant proportion (approximately one-quarter) of new AIDS cases occur in adolescence.

Based on available research, there is no evidence to suggest that early sexual activity is healthy, acceptable, or beneficial for either boys or girls across various indicators, including financial, emotional, academic, social, physical, and spiritual well-being.

Daryl Bem’s Gender Role Theory proposes that adolescence is a time when gender-stereotypical behaviors may become exaggerated.

1. Adolescent boys may exhibit preoccupation with physical power and competition (e.g., strength, fighting ability, car speed).
2. Adolescent girls may focus on understanding and managing social relationships and emotions (e.g., expressing affection, reacting to perceived meanness).

Adulthood tends to see a general decline in these exaggerated gender-specific behaviors. In later life, women may become less concerned with social agreement, and men may become less focused on appearing tough.

Social Development in Adolescence

Social skills gain increasing importance during adolescence, and there is a growing interest in relationships with the opposite sex. Adolescents typically become less reliant on their parents and spend more time and become more involved with their peers.

Adolescent egocentrism continues to influence social thinking, marked by the personal fable (belief in uniqueness and invincibility) and the imaginary audience (belief that everyone is constantly watching and judging them).

A key question in adolescent development is the relative influence of parents versus peers.

• Friends: Peer relationships become increasingly vital, and the adolescent’s social network, context, and community shape their values, norms, and expectations. Peer groups often reinforce traits and goals fostered by parents. Adolescents tend to form friendships with peers similar in age, social class, race, and attitudes towards behaviors like drinking, dating, and education.
• Parents: Parent-adolescent relationships are generally positive, building upon existing patterns from childhood. Less than 10% of adolescents report a dramatic deterioration in parent-child relationships. Common areas of conflict often involve choices like friends or the final authority on certain decisions. The stereotype of rebellious teenagers and overbearing parents doesn’t reflect the reality for most families.

Emotional Development

Developing the ability to regulate emotions is a critical aspect of development throughout the lifespan. Key aspects of emotional health include:

1. Ability to self-soothe.
2. Ability to delay gratification and exercise impulse control.
3. Ability to understand the feelings of others.
4. Ability to manage anger constructively.
5. Ability to respond appropriately within a group context.

Cognitive Development

Contrary to stereotypes, research suggests that adolescents are often as capable as adults at assessing risks. The difference lies not simply in increased risk-taking but in how they evaluate potential gains versus risks. Adolescents may minimize the likelihood of negative consequences and focus more on the potential rewards of a behavior, while adults tend to prioritize the risks.

Parenting Styles

Diana Baumrind’s research identified different parenting styles based on levels of demandingness and responsiveness. A common question arises regarding approaches to infant crying, such as whether to let the baby “cry it out.”

Conflicts with parents, within reasonable limits, are considered normal and beneficial during adolescence, as they allow teens to test their developing abilities in reasoning, moral judgment, physical skills, and social interactions. Highly educated parents, in particular, tend to encourage independent thought in their children.

Baumrind’s Parenting Styles:

• Permissive: Parents are low in demandingness and high in responsiveness. They tend to be lenient, set few rules, and are inconsistent in enforcing them.
• Authoritarian (Dictatorial): Parents are high in demandingness and low in responsiveness. They are rigid, demand obedience, and often use harsh punishments. This style is sometimes associated with lower socioeconomic status. The term “tiger moms” describes a highly strict, demanding approach focused on achievement, sometimes to the exclusion of social activities, which can have negative consequences.
• Authoritative: (Note: The original text lists “UNINVOLVED” under this heading, which is incorrect based on Baumrind’s model. Authoritative parents are high in both demandingness and responsiveness. They set clear rules and expectations but are also warm, supportive, and responsive to their children’s needs, explaining reasons for rules and involving children in decision-making where appropriate).
• Uninvolved (or Neglectful): (This style, not correctly placed in the original text, describes parents who are low in both demandingness and responsiveness, providing little guidance, warmth, or support).

Emerging Adulthood

Emerging adulthood is a relatively new concept describing young adults in developed countries who are not yet fully independent in their early to late 20s. They may not have children, live independently, or have sufficient income to support themselves. The term “boomerang generation” describes those who return to live with their parents, reflecting the protracted nature of achieving full self-sufficiency.

Adult Development

Intimate Relationships: Forming intimate relationships, including marriage and starting a family, becomes increasingly important in adulthood. People tend to marry partners who are similar to them in physical attractiveness, social and educational background, ethnicity, attitudes, values, and beliefs (homogamy).

Parenthood: The arrival of children often leads to a decline in marital satisfaction, alters a person’s identity and lifestyle. Adjustment is smoother in warm, positive marital relationships where household and childcare responsibilities are shared. Marital satisfaction often increases again when children leave home (the “empty nest”).

Development vs. Decline in Adulthood: Adulthood involves both continued development and gradual decline in certain areas.

• Positive aspects of aging: Verbal skills, emotional intelligence, and crystalized intelligence (accumulated knowledge and skills) tend to remain stable or even improve.
• Negative aspects of aging: May include reduced brain size, deterioration of vision and hearing, slower reaction times, reduced motor control. Genetics and environmental factors contribute. Lack of continued practice of skills and the body’s wear and tear play a role (“use it or lose it!”). Engagement in physical and mental exercise is important.

Aging can involve visible changes like hair loss, graying hair, and wrinkles, as well as internal changes like menopause (in women), reduced efficiency of body organs, and declines in physical strength, endurance, and sensory capabilities.

Social Development of Adults

As adults age, they often become more selective in their social interactions, focusing on a smaller number of rewarding relationships and friendships. This contrasts with younger people who may actively seek out new friends. Older adults may have a clearer understanding of what they value in friendships.

Friendships:

• Females: Tend to confide in friends about feelings, problems, and interpersonal relationships.
• Males: May minimize discussions about relationships or personal feelings, preferring to engage in mutually interesting activities together.

Work: Career changes are increasingly common, and dual-career families are on the rise.

Activity Theory of Aging: This theory proposes that maintaining a similar level of activity as in earlier life is associated with higher life satisfaction in late adulthood. Having at least one confidant is linked to higher morale, better mental health, and greater psychological well-being.

Late Adulthood and Aging

The average life expectancy is approximately 72 years for males and 79 years for females (these numbers can vary significantly by region and other factors).

Aging-related issues can include damage to the inner ear leading to dizziness and falls. Cognitive changes involve the interplay of crystalized intelligence (stable or increasing with age) and fluid intelligence (ability to solve new problems, which may show a slight decline). Sleep patterns change; older adults may take longer to fall asleep. Research suggests that engaging in activities like video games can improve cognitive abilities in older adults. There is a small but reliable decline in working memory and retrieval accuracy from long-term memory, associated with a small deterioration (around 5%) of the hippocampus.

Dementia is a broad term for cognitive decline, and while earlier experiences can increase risk, the chance of developing dementia may actually decrease after age 80. A phenomenon known as “sundowners syndrome” involves increased confusion in the late afternoon or evening. Alzheimer’s disease is the most common cause of dementia; interestingly, musical memories often persist longer than other types of memories. Stroke is another cause of cognitive impairment.

Stereotypes vs. Reality of Aging: Common stereotypes portray older adults as being in poor health, inactive, socially isolated, and mentally/physically incompetent. The reality is that most older people are healthy, active, and self-sufficient. Only a small percentage of those over 65 (around 5%) live in nursing homes, although this number increases for those over 85 (around 25%).

K. Warner Schaie’s research on intellectual abilities across the lifespan suggests that general abilities tend to increase until the early 40s, remain stable until around 60, and show a small but steady decline thereafter. Higher levels of education and a stimulating lifestyle are associated with less cognitive decline. The importance of keeping the mind active is emphasized.

Dying and Death

Anxiety about death tends to peak in middle adulthood and then decreases. People experience a wide range of emotions in response to dying and death.

Elisabeth Kubler-Ross proposed a model of five stages of grief, though it’s important to note these stages are not always experienced linearly and not by everyone:

1. Denial: Refusing to accept the reality of the situation.
2. Anger: Expressing frustration and resentment.
3. Bargaining: Attempting to negotiate with a higher power or medical professionals.
4. Depression: Experiencing sadness, withdrawal, and despair.
5. Acceptance: Coming to terms with the reality of death.