Module 1: Introduction and Basic Concepts

1a. The Study of Human Development

The study of human development is the study of constancy and change throughout the lifespan. As a field, it is simultaneously scientific, applied, and interdisciplinary.

It is scientific in that it employs theories, hypotheses, and empirical evidence to draw conclusions. It is applied insofar as it helps to inform a wide variety of individual, family, and community interventions and policies, such as those practiced and advocated for by social workers and others in similar professions. It is interdisciplinary because researchers in human development work within and across many disciplines, including philosophy, biology, psychology, sociology, anthropology, and beyond.

*Kimberly Noble — How does income affect childhood brain development? (TED, 2019)*

Kimberly Noble’s work illustrates all three dimensions of the field: her research on the relationship between socioeconomic status and children’s brain development is scientifically rigorous, it draws from multiple disciplines including neuroscience and economics, and it has clear applied implications for social policy and early childhood intervention programs.

1b. Key Debates in Human Development

There are four core debates that shape the study of human development. The position one adopts on each debate influences nearly every question one asks about development.

The Role of the Child

The degree to which children themselves have an impact on their own development has been debated for centuries. Two broad camps exist.

Children as Active thinkers have generally argued that children are willful agents whose own choices matter for their development. Swiss philosopher Jean-Jacques Rousseau (1712–1778) and Chinese philosopher 孟子 Mèng Zǐ (372–287 BC) framed children as essentially good by nature — if allowed to express their natural impulses, they will develop into generous and moral individuals. Conversely, English philosopher Thomas Hobbes (1588–1679) and Chinese philosopher 荀子 Xún Zǐ (313–238 BC) saw children as active, but essentially bad by nature and in need of external civilizing forces.

Children as Passive thinkers view children as entities whose personality is shaped over time by experience. English philosopher John Locke (1632–1704) drew on empiricism and framed the child as a tabula rasa — a blank slate waiting to be shaped by experience. For Locke, social approval and disapproval are powerful shapers of behavior, and inborn predispositions toward good or evil play little role.

Stability vs. Plasticity

Researchers often debate the degree to which human beings are stable or plastic (changeable) during their development.

Theories that emphasize stability tend to assert that lifelong patterns of behaviour are established early in childhood and remain relatively static. Pioneering psychologist Melanie Klein, for instance, emphasized the profound importance of early childhood experience on later behaviour and development.

Theories that emphasize plasticity argue that different aspects of human development may be open to lifelong change, and that the degree and nature of such change is itself a key subject of inquiry. The concept of neuroplasticity — the brain’s capacity to reorganize itself — is central to this perspective.

Nature vs. Nurture

The “nature vs nurture” debate is perhaps the most publicly recognized debate in developmental science. Are key traits predetermined by biology and genetic makeup? Or do experiences and social circumstances determine how we develop?

Nature theorists emphasize that physical and psychological features inherited from parents are the strongest determinants of development. Modern evolutionary and behavioral genetics perspectives belong here.

Nurture theorists focus on the impact of physical and social forces, arguing that they can significantly influence both biological and psychological development.

Research often relies on twin studies, in which identical twins (sharing identical genetic material) raised in separate environments are studied to observe similarities and differences in development. Nancy Segal’s work using such research makes a compelling argument for the influence of genetics on human development.

*Nancy Segal — Twins: A Window into Human Nature (TEDxManhattanBeach, 2017)*

Helen Pearson’s long-running British cohort studies, by contrast, emphasize the enormous importance of upbringing, parenting decisions, and socioeconomic circumstances in shaping children’s outcomes over the lifespan.

In spite of differences in emphasis, contemporary developmental science most commonly employs interactionist models which acknowledge the complex, bidirectional interplay of nature and nurture.

Continuous vs. Discontinuous Development

A final debate concerns whether human beings develop gradually and continuously throughout life, or whether development comes in discrete, qualitatively distinct stages.

Continuous development theorists frame human development as a gradual process in which the effects of learning increase steadily throughout life without sudden major qualitative changes.

Discontinuous (or stage) theorists view human development as happening in stages dependent on maturation. Changes within each developmental stage are described as qualitatively different from one stage to another — certain developments happen within certain stages rather than across all of life. Piaget’s theory of cognitive development and Erikson’s psychosocial stages are classic examples of discontinuous models.

1c. Factors Influencing Human Development

Multiple, interacting forces influence human development. Such factors can be:

• Age-related (considered universal to the species)
• History and context related (sometimes called the cohort effect — where the specific era and cultural circumstances in which one grows up shape development)
• Individual-specific or nonnormative (unusual circumstances affecting specific individuals)

Individual-specific factors include:

Sensitive periods refer to limited time windows in development during which the effects of experience on the brain are unusually strong. During a sensitive period the developing organism is particularly responsive to certain kinds of stimulation.

Critical periods are a special class of sensitive periods in which behaviors and their neural substrates do not develop normally if appropriate stimulation is not received during a restricted period of time. For example, research by Hubel and Wiesel (1970) demonstrated that if normal binocular input is not achieved by three months of age in kittens, no cells will ever respond to input from the occluded eye, even if visual input is restored after the critical period. In adult cats, very long periods of monocular deprivation produce little physiological effect — demonstrating that the critical period is a time of heightened vulnerability specific to early development.

Atypical development can include other unusual circumstances and specific situations affecting individuals in their development.

The English Romanian Adoptee Study (ERA)

One of the most significant examples of research exploring factors in human development is the English Romanian Adoptee Study (ERA), initiated in 1992. This landmark longitudinal study followed 165 adopted children who had experienced early deprivation in Romanian institutions for varying periods (ranging from a few months to 42 months of age), along with a comparison group of 52 non-deprived adopted Romanian children.

All children were assessed comprehensively at ages 4, 6, 11, 15, and 22 on measures of cognitive, social, emotional, behavioral, and health outcomes. Key findings include:

• Children transferred from Romanian orphanages to British adoptive homes in the first six months of life attained average scores and fared as well as British early-adopted children, suggesting full recovery from extreme early deprivation.
• Romanian children adopted after 6 months of age performed well below average.
• Children adopted after age 2 improved between ages 6 and 11, but continued to show serious intellectual deficits.
• One third of the Romanian children placed for adoption after six months experienced problems requiring professional educational, psychological, or psychiatric services.
• Follow-ups at age 15 and into young adulthood revealed unusual patterns of persisting, deprivation-specific deficits, including emotional, conduct, and peer relationship problems.

The ERA study powerfully demonstrates the long-term consequences of early deprivation and the importance of sensitive and critical periods in human development, while also showing the remarkable capacity for recovery when supportive environments are provided early enough.

1d. Periods and Domains of Human Development

Human development is studied across three primary domains:

• Physical development: changes in body size, brain, motor abilities, and health
• Cognitive development: changes in thought, memory, reasoning, language, and problem-solving
• Social-emotional development: changes in emotional communication, self-understanding, morality, and relationships

These domains are active throughout the entire lifespan and can be examined at any stage.

Development is also studied through the lens of developmental periods or stages. The course (and the HDEV textbook) identifies eight basic stages:

Stage	Age Range
Prenatal	Conception to birth
Infancy and Toddlerhood	Birth to 2 years
Early Childhood	2–6 years
Middle Childhood	6–11 years
Adolescence	11–18 years
Early Adulthood	18–40 years
Middle Adulthood	40–65 years
Late Adulthood	65 years to death

This course takes a mixed approach: examining key themes and domains in the early modules before shifting into a stage-based examination in later modules. The first four modules address foundational conceptual frameworks; Modules 5–12 follow lifespan stages from infancy through the end of life.

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Module 2: Theories and Methods

2a. Theories of Human Development

Scientific Inquiry

The study of human development is founded in scientific inquiry, which involves the interplay of inductive and deductive thinking in a continuous cycle. From observations, theories are formed through inductive reasoning. From theories, hypotheses are generated through deductive reasoning. Research then collects empirical evidence to test hypotheses, and these new observations refine existing theories or generate new ones.

A theory is an integrated set of statements that describes, explains, and predicts behavior. With different perspectives on human development, different theories emerge. Many researchers blend more than one theoretical approach.

Major Theoretical Perspectives

Psychoanalytic Perspectives trace to the work of Sigmund Freud (1856–1939), whose psychosexual theory proposed that personality develops through a series of stages — oral, anal, phallic, latency, and genital — each centered on a different erogenous zone. Unresolved conflicts at any stage produce lasting effects on personality. Erik Erikson (1902–1994) reformulated Freud’s approach in his psychosocial theory, proposing eight stages of psychosocial development that span the entire lifespan, each defined by a central crisis whose resolution (or failure) shapes personality. Erikson placed greater emphasis on social and cultural forces and on the entire lifespan than Freud had.

Behavioral Perspectives focus on observable behavior rather than inner states. Ivan Pavlov’s classical conditioning demonstrated that organisms can learn to associate a neutral stimulus with a reflex-eliciting stimulus. John B. Watson extended this to human behavior. B. F. Skinner’s operant conditioning emphasized that behavior is shaped by its consequences — reinforcement increases behavior; punishment decreases it.

Cognitive Perspectives emphasize the role of thinking and reasoning. Jean Piaget’s (1896–1980) theory of cognitive development proposed that children progress through four qualitatively distinct stages: sensorimotor, preoperational, concrete operational, and formal operational. The child actively constructs understanding through the processes of assimilation (fitting new information into existing schemas) and accommodation (modifying schemas to fit new information). Information-processing theory views the mind as analogous to a computer, focusing on how information is encoded, stored, and retrieved.

Social-Cognitive and Sociocultural Perspectives include Albert Bandura’s social-cognitive theory, which emphasizes observational learning and the concept of self-efficacy — one’s belief in one’s ability to perform behaviors successfully. Lev Vygotsky’s (1896–1934) sociocultural theory emphasizes that cognitive development is fundamentally shaped by social interaction and cultural context. Vygotsky introduced the zone of proximal development (ZPD) — the gap between what a learner can do independently and what they can do with guidance — and scaffolding as the support provided by a more capable partner.

Ethological and Evolutionary Perspectives draw on the study of behavior in its evolutionary context. Konrad Lorenz’s work on imprinting in animals, and John Bowlby’s application of ethology to human attachment theory, fall within this tradition. Bowlby argued that the need to form close attachment bonds is a biologically innate characteristic of humans and other species, shaped by natural selection because it promotes survival.

Systems Perspectives view development as the outcome of interacting systems across multiple levels. Urie Bronfenbrenner’s bioecological theory proposes that development is influenced by nested environmental systems:

• Microsystem: the immediate settings in which the child participates (family, school, peers)
• Mesosystem: the connections between microsystems (e.g., the relationship between home and school)
• Exosystem: settings the child does not directly participate in but which affect development (e.g., a parent’s workplace)
• Macrosystem: the broader cultural, social, and ideological context
• Chronosystem: the dimension of time and historical change

Jack Shonkoff’s ecobiodevelopmental theory extends this by integrating biological research on the impact of early experience on brain development, emphasizing that adversity in early life can have lasting effects through “toxic stress.”

Lifespan Perspectives (associated with Paul Baltes and others) argue that development is a lifelong process that cannot be understood by studying only childhood or adolescence. Key principles include the ideas that development is multidirectional (involving both growth and decline), multidimensional (spanning biological, cognitive, and social-emotional domains), plastic (capable of change), and embedded in historical and cultural context.

Humanistic Perspectives include Abraham Maslow’s hierarchy of needs and Edward Deci and Richard Ryan’s self-determination theory (SDT), which emphasizes three innate psychological needs — competence, autonomy, and relatedness — as the foundations of intrinsic motivation and well-being.

The Scientific Community

Scientific inquiry is a community process in which scientists share empirical findings, and new studies verify and build on each other’s work. For research to be evaluated, the methods used to gather evidence must be clearly described so others can replicate and verify findings. This is why understanding research methodology is a core competency for students in social and developmental sciences.

2b. Research Methods

Quantitative and Qualitative Methods

Studies in the social sciences can be distinguished on the basis of whether they use quantitative methods, qualitative methods, or a combination.

Quantitative methods involve the collection and analysis of numerical data. Studies that explore statistics, standardized test scores, or numerical survey data are quantitative.

Qualitative methods involve considering non-numerical data, such as in-depth interviews, observations described as “thick description,” or other interpretive assessments of people and contexts.

Many studies incorporate both approaches.

Correlational and Experimental Methods

Correlational methods involve observation only — data may be collected in real-world settings and assessed to draw conclusions about relationships between variables. A correlation coefficient (ranging from −1.00 to +1.00) expresses the direction and strength of the relationship between two variables. Critically, correlational studies cannot establish cause and effect; they can only show that two variables are related.

Experimental methods involve deliberate manipulation of one or more independent variables, measurement of dependent variables, and control for extraneous variables through random assignment. By randomly assigning participants to experimental and control groups, researchers can establish causal links with greater confidence. Experiments may be conducted in laboratory settings (allowing high control) or in field settings (maximizing ecological validity).

Key Designs for Development Studies

Because human development researchers are centrally concerned with age and change over time, two major design strategies are used:

Cross-sectional studies examine different age groups at the same point in time. For example, a study comparing cognitive performance in children aged 5, 8, and 11 in the same year uses a cross-sectional design. This approach is efficient but is subject to the cohort effect — differences between age groups may reflect generational differences rather than developmental change per se.

Longitudinal studies follow the same group of participants repeatedly over an extended period, recording changes as they develop. The Terman Studies of Genius, begun in the 1920s, tracked high-intelligence children for over 50 years. Longitudinal designs can trace true developmental change within individuals, but are time-consuming, expensive, and subject to participant attrition.

Cross-sequential research (also called cohort-sequential design) combines both approaches: multiple age cohorts are followed longitudinally over a shorter period. This allows both cross-sectional and longitudinal comparisons while controlling for cohort effects.

When interpreting findings, students should identify which type of evidence they are working with, since this shapes the significance and generalizability of conclusions.

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Module 3: Viewing the Lifespan from an Attachment Lens

3a. Attachment Theory

Attachment is an integral part of human nature from the cradle to the grave.

— Bowlby, 1969

Attachment is a deep and enduring emotional bond that connects one person to another across time and space (Ainsworth, 1973; Bowlby, 1969). For John Bowlby and Mary Ainsworth — the two most important figures in the early development of attachment theory — attachment constitutes the emotional tie to a parent that is experienced by an infant, and from which the child derives a sense of security.

Attachment theory is an approach to human psychology and well-being that places the quality of early attachment bonds at the centre of our understanding of human development. Attachment theorists maintain that the ability and need to form an attachment relationship early in life are genetic characteristics of all human beings. This biologically innate view of attachment is sometimes called the ethological perspective, reflecting Bowlby’s integration of ethology (the biological study of behavior in its natural setting) with psychoanalytic and developmental thinking.

While the term “attachment” refers specifically to the infant’s emotional bond to a caregiver, the sense of connection a parent feels toward an infant is called the affectional bond.

*John Bowlby: Attachment Theory Across Generations (Davidson Films, 2010)*

Attachment as a Theory of Love

While attachment is rooted in the infant–caregiver relationship, Bowlby argued that the need for close relationship bonds follows us “from the cradle to the grave.” These bonds provide:

• An emotional safe haven in times of distress
• A secure emotional base from which to encounter the world
• The proximity to others that we all seek
• Comfort when experiencing separation distress

Bowlby thus conceptualized attachment not merely as a feature of infancy but as a fundamental organizing principle of human emotional life across the entire lifespan.

3b. Attachment Research

Parent-Child Attachment and Synchrony

Because attachment impacts development throughout life, helping a baby develop a secure attachment is one of the most important things a parent can do. Both parent and child contribute to the way their attachment connection develops. The term used to describe the mutual, interlocking pattern of attachment behaviors shared by a parent and child is synchrony.

One of the most important experiments demonstrating the role of synchrony is the still-face experiment, developed by Edward Tronick. In this procedure, a caregiver and infant engage in normal interactive play, then the caregiver suddenly adopts a neutral, expressionless “still face.” Infants respond with distress, attempts to re-engage, and ultimately withdrawal — powerfully demonstrating how dependent infants are on the responsiveness of their caregiver.

*Still Face Experiment: Edward Tronick (UMass Boston, 2009)**Still Face with Dads (Children's Institute, 2016)*

While mothers are often the focus of attachment research, fathers’ bonds with infants are equally dependent on the development of synchrony. Fathers and mothers tend to interact somewhat differently with infants — fathers are often less consistent than mothers in responding to infant cues — but babies benefit from interactions with both parents and from the somewhat different forms of synchrony developed in each relationship.

Mary Ainsworth’s Strange Situation Experiment

In the 1970s, psychologist Mary Ainsworth developed a method for observing various types of attachment relationships between mothers and babies. The Strange Situation experiment exposed mother–infant dyads to mildly stressful conditions (separation, the presence of a stranger, and reunion) to observe the nature of their attachment bond. Ainsworth’s original procedure followed this protocol:

1. Observer brings mother and baby into experimental room and leaves.
2. Mother sits while baby explores.
3. Stranger enters, is silent for a minute, talks to mother for a minute, then approaches baby. Mother leaves.
4. Stranger and baby are alone.
5. First reunion: Mother returns, greets, and comforts baby. After engaging baby in play, mother says “bye-bye” and leaves.
6. Second separation: Baby is alone.
7. Stranger enters and is alone with baby.
8. Second reunion: Mother enters, greets, and picks up baby. Stranger leaves.

*Mary Ainsworth's Strange Situation: Attachment and the Growth of Love (Davidson Films, 2010)*

Variations in Attachment Quality

On the basis of Ainsworth’s experiments and subsequent research, psychologists today categorize variations in attachment quality into several attachment styles. Attachment is broadly characterized as either secure or insecure, with insecure attachment subdivided into three types:

• Secure attachment: The infant uses the caregiver as a safe haven during stress and a secure base for exploration. In the Strange Situation, the child is distressed when the caregiver leaves and is quickly comforted upon reunion. Secure infants tend to have caregivers who are emotionally responsive and sensitive to their needs.

• Avoidant attachment (insecure): The infant appears indifferent to the caregiver’s departure and avoids or ignores the caregiver upon reunion. This often develops when caregivers are consistently unresponsive or rejecting.

• Ambivalent attachment (insecure): The infant is highly distressed by the caregiver’s departure but is not easily comforted upon reunion, often showing anger or clinging. This typically develops when caregivers are inconsistently available.

• Disorganized/disoriented attachment (insecure): The infant shows confused or contradictory behavior in the Strange Situation — for example, approaching the caregiver while looking away, or displaying fear. This is most associated with caregivers who are themselves a source of fear (due to abuse, severe neglect, or unresolved trauma).

Caregiver characteristics that influence attachment quality include the caregiver’s emotional responsiveness, marital status, socioeconomic status, and mental health.

Long-Term Outcomes of Secure Attachment

Children rated as securely attached to their mothers in infancy are later:

• More sociable and more positive in their behavior toward friends and siblings
• Less clinging and dependent on teachers, and less aggressive and disruptive
• More empathetic and more emotionally mature
• More socially skilled in early years and more likely to be leaders
• Higher in self-esteem
• More sociable throughout early, middle, and late adulthood

These characteristics continue into adolescence and adulthood and affect the eventual parenting behaviors of those children once they become parents themselves — illustrating the intergenerational transmission of attachment.

Circle of Security is one therapeutic approach rooted in attachment theory that helps parents develop greater emotional availability and sensitivity to their children’s needs.

*Circle of Security Parenting — DVD Excerpt (CircleOfSecurity, 2010)*

3c. Attachment in Adults

Intergenerational Transmission of Attachment

Attachment styles tend to be transmitted from parent to child across generations. Research has shown that parents’ attachment organizations tend to correspond to their children’s attachment organizations. Remarkably, a parent’s state of mind with respect to attachment — as assessed by the Adult Attachment Interview (AAI) — predicts the infant’s pattern of attachment behavior at 12 months, even when the AAI is administered before the infant’s birth (Main, Hesse, & Kaplan, 2005). This finding holds for both fathers and mothers.

The AAI is a tool that psychologists use to assess attachment in adults by evaluating the coherence and quality of the narrative a person tells about their own childhood experiences. The following table shows the correspondence between child and adult attachment categories:

Child Attachment	Adult Attachment (AAI)
Secure: Trusts caregiver; child perceives self as lovable and has positive expectations of others	Secure/Autonomous: Describes coherent narrative about childhood; values relationships; self-reflective and adaptable
Avoidant: Denies needs; appears independent; believes must care for self	Dismissing: Denies importance of early rejection or neglect; prefers independence; suppresses feelings; distances from others
Ambivalent: Clingy or impulsively angry; longs for closeness; difficulty with autonomy	Preoccupied: Depends heavily on others; high emotional intensity; fears being devalued; views self as unworthy
Disorganized: Hypervigilant; conflicted; fight/flight/freeze responses	Unresolved/Disorganized: Has not resolved early trauma or loss; perceives relationships as dangerous; may dissociate

(Wang & Stalker, 2016)

Mirror Neurons and Adult Attachment

As children, we mirror and respond to what we see in the people closest to us: our parents. As adults, we mirror and respond to what we see in the person closest to us: our partner. This mirroring has a profound impact on the brain. When we respond to those close to us, the brain triggers a variety of mirror neurons that help us to better understand what the other person is feeling, and to engage in affect regulation — regulating our emotions appropriately.

Adult attachment, in the work of psychologist Sue Johnson (developer of Emotionally Focused Therapy, or EFT), functions analogously to parent-child attachment: both involve healthy interdependency. The quality of our relationship bond shapes how we see ourselves, engage with others, and deal with stress. To be emotionally connected is to be stronger — more resilient and more autonomous.

The greatest gift a parent has to give a child — and a lover has to give a lover — is emotionally attuned attention and timely responsiveness.

— Sue Johnson, 2013

*Love Sense: from Infant to Adult — Sue Johnson and Ed Tronick (Sue Johnson, 2016)*

Emotional presence is key to healthy attachment in adult relationships. Johnson uses the acronym A.R.E. to describe what partners need to know about each other:

• Accessible
• Responsive
• Emotionally Engaged

A secure, loving relationship is the cornerstone of human happiness and general well-being. Crucially, it is never too late to form a secure adult attachment, even without early models of this kind of relationship.

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Module 4: Resilience from a Developmental Perspective

4a. Resilience from a Developmental Point of View

The word resilience comes from the Latin resilire, meaning to rebound, recoil, or spring back. Ann Masten and colleagues offer this definition:

[Resilience is] the capacity of a dynamic system to withstand or recover from significant challenges that threaten its stability, viability, or development.

— Masten, Gewirtz, & Sapienza, 2013

Resilience is a concept used widely in humanitarian work, child protection, community recovery, and the prevention of long-term negative outcomes. Research has made clear that resilience is not simply an individual character trait — it is better understood as a process that changes systems. Just as physical health depends on systems like families, government policies, the economy, and the natural environment to provide what we need to sustain wellbeing during difficult times, resilience too emerges from the interaction of individual characteristics and multiple social and environmental systems.

Any definition of resilience must take two things into account: good adaptation or recovery in the context of risk or adversity. If no risk or adversity has been present, we might describe a person as doing well — but we would not describe them as showing resilience.

*Resilience Processes in Development — Ann Masten (University of California Television, 2019)*

Resilience and Developmental Tasks

When evaluating how well a child’s or adult’s life is going, we must first consider developmental tasks — the expectations we have for individuals at various points in development in order to be considered as “doing well” in life.

Some developmental tasks are universal: all over the world, different cultures expect the same things from children at similar ages. For example, infants and toddlers everywhere are expected to learn to sit up, walk, and form attachment bonds with caregivers. These are universal human developmental tasks.

There are also culturally specific developmental tasks that vary between communities. These include rites of passage marking the transition from childhood to adult status, religious rituals, and the learning of traditional skills and crafts specific to a given culture or environment.

Studying resilience from a developmental perspective means asking: why do certain children and adults meet or exceed expectations with respect to key developmental tasks in spite of adverse circumstances, while others do not? For example, many children succeed academically despite growing up in poverty. What factors have helped to offset their socioeconomic disadvantage? Answering such questions informs both future research and the design of effective interventions and policies.

Resilience is as much about what we have (our individual and collective resources) as what we think (our mindset).

— Ungar, n.d.

4b. Factors in Resilience

Resilience is not simply a character trait on the part of an individual — many social and environmental factors contribute substantially to it.

*What resilience is and isn't — 9 things children need by Michael Ungar (Roots of Empathy, 2020)*

Masten’s Short List of Resilience Factors

Ann Masten (Director of Project Competence Research on Risk and Resilience at the University of Minnesota) identifies the following key resilience factors and their associated human adaptive systems:

• Positive attachment bonds with caregivers (attachment; family)
• Positive relationships with other nurturing and competent adults (attachment)
• Intellectual skills (integrated cognitive systems of a human brain in good working order)
• Self-regulation skills (self-control systems and related executive functions of the human brain)
• Positive self-perceptions and self-efficacy (mastery motivation system)
• Faith, hope, and a sense of meaning in life (meaning-making systems of belief)
• Friends or romantic partners who are supportive and prosocial (attachment)
• Bonds to effective schools and other prosocial organizations (sociocultural systems)
• Communities with positive services and supports for families and children (sociocultural)
• Cultures that provide positive standards, rituals, relationships, and supports (sociocultural)

(Masten, 2009)

Ungar’s Resilience-Promoting Program Ingredients

Michael Ungar (Canada Research Chair in Child, Family and Community Resilience; Director of the Resilience Research Centre at Dalhousie University) identifies key ingredients of successful resilience-promoting programs. Such programs focus far more on increasing capacity than decreasing disorder. Their essential experiences include:

• Building relationships
• Encouraging powerful identities
• Providing participants with opportunities for power and control
• Promoting social justice
• Improving access to basic material needs (food, housing, safety)
• Developing a sense of belonging, responsibility for others, spirituality, and life purpose
• Encouraging a sense of culture and historical roots

(Ungar, n.d.)

*Michael Ungar — Assessing Your Resilience Resources (Roots of Empathy, 2018)*

The concept of Adverse Childhood Experiences (ACEs) — a research framework stemming from a landmark CDC-Kaiser study — has become central to understanding risk factors for poor long-term outcomes. ACE scores quantify exposure to various forms of childhood adversity (abuse, neglect, household dysfunction). Higher ACE scores are associated with elevated risks for a broad range of poor health and social outcomes in adulthood. Resilience research complements this by asking: given exposure to adversity, what protective factors allow individuals to do well anyway?

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Module 5: Infancy

Textbook: Rathus, HDEV (6th ed.), Chapters 5 & 6

Physical Development in Infancy (Chapter 4)

The period from birth through approximately age two is one of the most dramatic in all of human development for physical change. At birth, the average neonate weighs approximately 7.5 pounds and is about 20 inches long. By the end of the first year, most infants have tripled their birth weight.

Growth patterns in infancy follow the cephalocaudal (head-to-foot) and proximodistal (center-to-periphery) trends. That is, the head and trunk develop before the legs, and the inner parts of the body develop before the extremities.

Brain development is particularly rapid and significant during infancy. At birth, the brain has already undergone two major growth spurts (the first during the fourth and fifth prenatal months when neurons proliferate; the second between the 25th week of prenatal development and the second year after birth). The process of myelination — the coating of neural axons with a fatty myelin sheath that greatly speeds neural transmission — continues throughout childhood and into early adulthood. Synaptic pruning, in which unused neural connections are eliminated to increase efficiency, is also an important feature of early brain development.

Motor development follows a predictable sequence: infants gain head control before trunk control, roll before sitting, sit before standing, and pull to stand before walking. The average infant takes first steps around 12 months, though there is substantial normal variation. Both maturation and experience contribute to motor development.

Sensory and perceptual development shows that newborns are far more capable than once thought. Neonates can distinguish their mother’s voice from strangers’ voices (having heard it in utero), show preferences for faces, and can detect odors. Visual acuity improves rapidly in the first months. The phenomenon of intermodal perception — the coordination of information across sensory modalities — appears early in infancy.

Cognitive Development in Infancy (Chapter 5)

Piaget’s Sensorimotor Stage

According to Jean Piaget, infants are in the sensorimotor stage of cognitive development (birth to approximately 2 years). During this stage, infants learn about the world through their senses and physical actions. The stage is divided into six sub-stages, during which infants gradually develop object permanence — the understanding that objects continue to exist even when out of sight. Object permanence emerges gradually between approximately 8 and 12 months of age.

Information Processing in Infancy

Information-processing approaches to infant cognition focus on how infants encode, store, and retrieve information. Research using habituation paradigms — in which infants are shown stimuli repeatedly until they lose interest, and then shown novel stimuli — reveals surprisingly sophisticated cognitive capacities in early infancy. Infants can form memories, detect patterns, and update expectations about physical events.

Imitation is another important cognitive capacity. Research by Andrew Meltzoff demonstrated that newborns only a few hours old can imitate facial gestures such as tongue protrusion — a feat made possible by mirror neurons, which fire both when an action is performed and when it is observed.

Language Development in Infancy

Language development in infancy proceeds through a predictable sequence: cooing (vowel sounds) around 2 months, babbling (consonant-vowel combinations) around 6 months, and first words typically around 12 months. By 18 months, most children have a vocabulary of 50+ words and begin to combine two words. The vocabulary explosion typically occurs around 18–24 months.

Joint attention — in which an infant and caregiver focus together on the same object or event — is a critical social-cognitive mechanism for language development. Children learn the meanings of words in large part through joint attention and communicative context.

Infant-directed speech (also known as “motherese” or child-directed speech) — the high-pitched, slow, simplified, and repetitive speech that adults naturally use with infants — appears to facilitate language learning by making sounds more discriminable and highlighting important features of language.

Social and Emotional Development in Infancy (Chapter 6)

Attachment in Infancy

The development of secure attachment (as discussed in Module 3) is the central social-emotional task of infancy. The quality of early attachment is associated with a wide range of developmental outcomes across the lifespan, including social competence, emotional regulation, and cognitive development.

When Attachment Fails

Harry Harlow’s classic experiments with infant rhesus monkeys demonstrated that contact comfort (the warmth and texture of a cloth mother figure), rather than feeding, is the primary basis of attachment. Monkeys raised with wire “mothers” that provided food but no contact comfort showed severe social and emotional disturbances — they were socially withdrawn, unable to interact normally with peers, and showed aberrant parenting behaviors if they later had offspring. These studies, though conducted with animals, helped illuminate the critical importance of warm physical contact and emotional responsiveness for healthy development.

The ERA study findings (from Module 1) and Harlow’s monkey experiments together underscore how devastating early social deprivation can be.

Day Care

Whether and how day care affects infant development has been widely studied. Research from the NICHD Study of Early Child Care (the largest longitudinal study of child care in the US) indicates that the quality of caregiving — both at home and in child care settings — is the most important predictor of child outcomes. High-quality child care characterized by low child-to-caregiver ratios, caregiver responsiveness, and stimulating activities does not harm and may benefit child development.

Emotional Development

Infants display a range of emotions from birth. Primary emotions (happiness, sadness, anger, fear, surprise, and disgust) appear in the first months of life. Social referencing — the tendency of infants to look to caregivers for emotional cues in ambiguous situations — appears around 8–10 months, demonstrating the social regulation of emotion even in early infancy.

Temperament — the relatively stable, biologically based individual differences in reactivity and self-regulation — shapes how infants respond to their environment and interact with caregivers. Stella Chess and Alexander Thomas identified three broad temperament types: easy, difficult, and slow-to-warm-up. Goodness of fit between a child’s temperament and the demands and expectations of the environment is an important predictor of developmental outcomes.

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Module 6: Early Childhood

Textbook: Rathus, HDEV (6th ed.), Chapters 7 & 8

Physical and Cognitive Development in Early Childhood (Chapter 7)

Physical Growth

During early childhood (ages 2–6), physical growth slows compared to infancy. Children grow about 2–3 inches and gain approximately 5 pounds per year. By age 6, the average child is approximately 45 inches tall and weighs about 45 pounds. Growth follows the cephalocaudal and proximodistal trends established in infancy.

Motor development advances rapidly. By the end of early childhood, children have developed both fine motor skills (using crayons, scissors, building with blocks, beginning to write) and gross motor skills (running, jumping, throwing, climbing). Preschool-age children show impressive increases in motor coordination and physical activity. However, left-right differences in skill (handedness) become more established during this period.

Sleep is important for health and brain development in early childhood. Most preschoolers need 11–13 hours of sleep per day. Sleep problems, including nighttime waking and nightmares, are common.

Piaget’s Preoperational Stage

According to Piaget, children aged approximately 2–7 years are in the preoperational stage. Hallmarks of preoperational thinking include:

• Symbolic/representational thought: children use words, images, and drawings to represent objects and events, enabling language and make-believe play
• Egocentrism: the child’s tendency to see the world only from their own perspective (demonstrated by Piaget’s “three mountains” task, in which children assumed others would see a model landscape the same way they did)
• Animism: attributing life or mental properties to inanimate objects
• Centration: focusing on only one aspect of a problem at a time
• Irreversibility: inability to mentally reverse a sequence of events
• Lack of conservation: the child does not understand that quantity remains the same despite changes in appearance (e.g., the same amount of water looks different in a tall, thin glass vs. a short, wide glass)

Theory of Mind

Theory of mind — the ability to attribute mental states (beliefs, desires, intentions) to oneself and others and to understand that others can have beliefs different from one’s own — typically develops around age 3–5. The classic false belief task (Sally-Anne task) assesses this: a child must understand that another person will act on a false belief (that an object is in its original location) rather than on the child’s own knowledge (that the object has been moved). Children typically pass false belief tasks around age 4.

Vygotsky and Social Learning

Lev Vygotsky emphasized that cognitive development in early childhood is fundamentally shaped by social interaction and language. The zone of proximal development (ZPD) describes the range of tasks a child can accomplish with guidance but not yet independently. Through scaffolding — supportive guidance from a more knowledgeable partner — children are helped to perform at the edge of their current abilities, gradually internalizing these skills.

Private speech (talking aloud to oneself) is common in early childhood and, for Vygotsky, serves an important cognitive function — it is a form of self-guidance. Children who use more private speech tend to show better problem-solving performance.

Language Development in Early Childhood

Language development is explosive during early childhood. Vocabulary grows at the rate of approximately 5–10 new words per day during this period. Children develop increasingly complex grammar, moving from two-word utterances to complex sentences. Characteristic features of early language include overregularization (applying grammatical rules too broadly, as in “I goed” or “two mouses”), which actually indicates that the child has learned the rule and is applying it systematically.

Social and Emotional Development in Early Childhood (Chapter 8)

Parenting Styles

Diana Baumrind’s research identified four major parenting styles based on two dimensions — warmth/responsiveness and demandingness/control:

• Authoritative: high warmth + high demandingness. These parents are warm and responsive while also setting clear standards and reasoning with their children. Associated with the most positive outcomes across cultures.
• Authoritarian: low warmth + high demandingness. These parents demand obedience without explanation (“because I said so”). Associated with higher compliance but lower self-esteem and social competence in some cultural contexts.
• Permissive: high warmth + low demandingness. These parents are nurturing and responsive but set few limits. Associated with impulsivity and low self-reliance in some contexts.
• Uninvolved/Neglecting: low warmth + low demandingness. These parents are minimally involved. Associated with the poorest developmental outcomes.

Erikson’s Initiative vs. Guilt

During early childhood, the central psychosocial crisis in Erikson’s framework is Initiative vs. Guilt. The child is increasingly capable of undertaking purposeful activities and experiencing a sense of purpose and accomplishment. If attempts at initiative are met with excessive criticism or punishment, the child may develop an exaggerated sense of guilt about their own motives and actions.

Moral Development

Piaget observed that young children in the heteronomous morality stage judge the wrongness of an action primarily by the amount of damage done (consequences) rather than the intention behind it. For instance, a child who broke 15 cups while trying to help is judged “naughtier” than one who broke 1 cup while doing something forbidden. Older children develop autonomous morality, in which intentions matter more than consequences.

Gender Role Development

Children develop an understanding of gender identity early in life. By age 2–3, most children can correctly label themselves as boys or girls. Gender constancy — the understanding that one’s gender is stable and consistent regardless of changes in appearance or behavior — is typically achieved around age 5–7. Children’s understanding of gender is shaped by biological factors, cognitive development, social learning (observation of and reinforcement for gender-typed behavior), and cultural norms.

Play and Social Development

Play is the central activity of early childhood and serves crucial developmental functions. Mildred Parten’s early research on social play identified a developmental progression: from solitary play (playing alone) and parallel play (playing near others without interaction) to associative and cooperative play (genuinely interactive, with shared goals and roles). Sociodramatic play (pretend play involving roles) is particularly important for social-emotional and cognitive development.

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Module 7: Middle Childhood

Textbook: Rathus, HDEV (6th ed.), Chapters 9 & 10

Physical and Cognitive Development in Middle Childhood (Chapter 9)

Physical Growth

Middle childhood (ages 6–11) is a period of steady, gradual physical growth. Children grow about 2–3 inches and gain 5–7 pounds per year. The brain continues to mature, with myelination and pruning of neural connections ongoing. Executive functions — cognitive processes including working memory, cognitive flexibility, and inhibitory control — show substantial development during middle childhood.

Motor development continues to refine. Children become more skilled at complex motor activities, sports, and crafts. Sex differences in motor development become more pronounced: boys tend to show greater strength and speed, while girls often show better fine motor coordination.

Approximately 15–20% of children in North America are classified as overweight or obese, with rates having increased substantially since the 1970s. Sedentary lifestyles, screen time, and food environments all contribute to this trend. Overweight and obesity in childhood are associated with increased risks for cardiovascular disease, type 2 diabetes, and psychological difficulties.

Piaget’s Concrete Operational Stage

During middle childhood, children enter Piaget’s concrete operational stage (approximately ages 7–11). Key achievements include:

• Conservation: understanding that quantity remains constant despite changes in appearance
• Decentration: considering multiple aspects of a problem simultaneously
• Reversibility: mentally undoing or reversing a sequence
• Classification: sorting objects into hierarchical categories
• Seriation: arranging objects in a logical series (by size, weight, etc.)
• Transitivity: using logic to infer relationships among objects
• Understanding of number and mathematical operations

Concrete operational thinking remains tied to concrete, tangible objects and events. Abstract, hypothetical reasoning requires the formal operations stage that emerges in adolescence.

Moral Development

Lawrence Kohlberg proposed a stage theory of moral development with three levels:

1. Preconventional morality (characteristic of children before age 9): moral judgments are made on the basis of consequences for the self — avoiding punishment and pursuing rewards.
2. Conventional morality (characteristic of most older children, adolescents, and adults): moral judgments are based on conforming to social norms and authority.
3. Postconventional morality (achieved by some adults): moral judgments are based on abstract principles of justice and individual rights that may transcend specific laws or social norms.

Carol Gilligan criticized Kohlberg’s framework as gender-biased, arguing that women’s moral reasoning is more likely to be based on an ethic of care (responsiveness to context and relationships) rather than the ethic of justice that structures Kohlberg’s hierarchy.

Intelligence and Achievement

Alfred Binet’s original intelligence test was designed to predict school achievement. The concept of IQ (intelligence quotient) was originally defined as (mental age / chronological age) × 100. Modern IQ tests (such as the WISC-IV) yield scores relative to age norms.

Howard Gardner’s theory of multiple intelligences proposes eight or more distinct types of intelligence (linguistic, logical-mathematical, spatial, musical, bodily-kinesthetic, interpersonal, intrapersonal, naturalist), challenging the notion of intelligence as a single entity. Robert Sternberg’s triarchic theory identifies three aspects of intelligence: analytic, creative, and practical.

Reading development during middle childhood involves the mastery of phonological awareness, phonics (letter-sound correspondences), and increasingly fluent reading comprehension. Children who struggle with reading often have difficulties in phonological processing.

Social and Emotional Development in Middle Childhood (Chapter 10)

Erikson’s Industry vs. Inferiority

Erikson identified the central psychosocial crisis of middle childhood as Industry vs. Inferiority. Children are increasingly expected to produce things — to master skills and accomplish tasks — in contexts like school, sports, and arts. Success builds a sense of industry (competence, pride in accomplishment); repeated failure or criticism builds a sense of inferiority.

The Family

Parental divorce has complex effects on children’s development. Research suggests that many children show adjustment problems in the first one to two years following divorce, with most improving thereafter. The most important predictor of child adjustment post-divorce is not divorce itself but the level of ongoing parental conflict — exposure to parental conflict is more harmful than divorce per se.

Blended families (stepfamilies) are increasingly common. Adjustment in blended families can be challenging, particularly for children in early adolescence.

Peer Relationships

Peer relationships become increasingly important in middle childhood. Children develop friendships based on shared interests, trust, and loyalty. Social status in the peer group — as measured by sociometric methods — can be classified as popular, average, rejected, or neglected. Rejected children (especially those rejected due to aggression) are at elevated risk for later social and emotional problems.

Bullying — systematic, repeated aggressive behavior in which there is an imbalance of power — is prevalent in middle childhood schools. Both bullies and victims are at elevated risk for long-term difficulties. Bystander behavior is increasingly recognized as central to bullying dynamics.

The School Environment

Schools are a major developmental context in middle childhood. Factors associated with positive school outcomes include a school climate characterized by warmth and clarity of expectations, the quality of teaching, and the fit between teaching approaches and children’s individual characteristics.

Stereotype threat — the risk of confirming a negative stereotype about one’s group — can undermine academic performance among children from stigmatized groups. Research by Claude Steele and others has shown that subtle reminders of stereotypes can impair performance on academic tasks.

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Module 8: Adolescence

Textbook: Rathus, HDEV (6th ed.), Chapters 11 & 12

Physical and Cognitive Development in Adolescence (Chapter 11)

Puberty

Puberty is the period of biological maturation that transforms a child’s body into an adult’s body capable of sexual reproduction. It is triggered by the hypothalamic-pituitary-gonadal axis: the hypothalamus signals the pituitary gland, which in turn stimulates the gonads (ovaries or testes) to produce sex hormones.

In females, puberty typically begins between ages 8 and 13, with the growth spurt preceding menarche (first menstruation) by about 2 years. Average age of menarche in North America is approximately 12.5 years.

In males, puberty typically begins between ages 9 and 14, with the growth spurt occurring later than in females. The first ejaculation (spermarche) typically occurs around age 13.

Early maturation has different implications for males and females. Early-maturing boys tend to be seen as more mature and capable, often gaining social status. Early-maturing girls are more likely to experience difficulties including body dissatisfaction, depression, risky behavior, and peer pressure from older adolescents.

Adolescent Brain Development

A critical finding from neuroscience is that the prefrontal cortex — the part of the brain responsible for executive functions including planning, impulse control, and risk assessment — does not fully mature until the mid-20s. The limbic system (associated with emotion and reward) matures earlier. This developmental mismatch helps explain adolescents’ heightened emotional reactivity, risk-taking, and sensation-seeking, particularly in the presence of peers (the “social brain” during adolescence).

Health and Risk Behavior in Adolescence

Adolescence is a period of generally good physical health but also elevated risk behavior. Common concerns include:

• Substance use (alcohol, tobacco, cannabis): experimentation is common; early initiation is associated with greater risk for dependence and negative health outcomes
• Eating disorders (anorexia nervosa, bulimia nervosa): peak onset in adolescence, more common in females; sociocultural pressures around body image are significant contributing factors
• Sexually transmitted infections (STIs): adolescents have higher rates of STIs than any other age group
• Accidents and injuries: the leading cause of death in adolescence in developed countries, with motor vehicle accidents prominent among them

Cognitive Development: Formal Operations

According to Piaget, adolescents who have developed formal operational thinking are capable of:

• Abstract reasoning: thinking about hypothetical and abstract concepts
• Hypothetico-deductive reasoning: systematically generating and testing hypotheses
• Propositional thought: evaluating the logic of verbal propositions independent of their content

Not all adolescents — or adults — achieve formal operational thinking, and performance can vary across domains. David Elkind described two common errors in adolescent thinking related to egocentrism:

• Imaginary audience: the belief that others are as focused on oneself as one is (leading to self-consciousness)
• Personal fable: the belief that one’s experiences are unique and that one is somehow invulnerable to the risks that affect others

Moral Development

Adolescence is typically when individuals move from preconventional to conventional morality in Kohlberg’s framework, and some begin to develop postconventional moral reasoning. Adolescence is also characterized by the development of moral identity — the degree to which moral commitments are central to one’s sense of self.

Social and Emotional Development in Adolescence (Chapter 12)

Identity Development

Erik Erikson identified the central psychosocial challenge of adolescence as Identity vs. Role Confusion. Adolescents must integrate various aspects of themselves — physical changes, cognitive developments, social roles, values — into a coherent sense of who they are. Failure to achieve a stable identity results in role confusion — a diffuse, uncertain sense of self.

James Marcia elaborated Erikson’s framework into four identity statuses based on two dimensions — exploration and commitment:

• Identity diffusion: no exploration, no commitment
• Identity foreclosure: commitment without exploration (adopted parental or authority-given identity without questioning)
• Identity moratorium: active exploration without yet reaching commitment
• Identity achievement: exploration followed by firm commitment

Relationships with Parents and Peers

Adolescence is characterized by a gradual shift in the relative importance of parents and peers. While parents remain highly influential in matters of values, education, and life decisions, peers become increasingly important for day-to-day social life and identity exploration. The process of individuation — developing a sense of self as distinct from the family — is a central developmental task of adolescence.

Peer groups in adolescence are characterized by cliques (small, intimate groups) and crowds (larger, reputation-based categories such as “athletes” or “nerds”). Peer conformity peaks in early to mid-adolescence and declines thereafter.

Adolescent Sexuality

Adolescence brings the development of sexual attraction and the beginning of romantic relationships. In Canada and the United States, the majority of young people have had sexual intercourse by the end of adolescence. Comprehensive sex education (including information about contraception and STI prevention) is associated with better sexual health outcomes than abstinence-only approaches.

Sexual minority youth (LGBTQ+ adolescents) face elevated risks for depression, anxiety, and victimization compared to their heterosexual peers, largely due to stigma, discrimination, and lack of social support. Supportive adults and safe school environments are protective factors.

Juvenile Delinquency

Antisocial and delinquent behavior peaks in adolescence. Most adolescents who engage in minor delinquency do not continue into adult criminality. However, a smaller group shows persistent antisocial behavior across the lifespan, often with roots in early childhood.

Risk factors for delinquency include low socioeconomic status, poor parental monitoring, peer deviance, and neighborhood disadvantage. Protective factors include school engagement, positive peer relationships, and strong family bonds.

Adolescent Suicide

Suicide is a leading cause of death among adolescents. Risk factors include depression, substance abuse, previous attempts, family history of suicide, and access to lethal means. Protective factors include strong social support, engagement with school, and access to mental health services. Warning signs should be taken seriously and help sought promptly.

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Module 9: Early Adulthood

Textbook: Rathus, HDEV (6th ed.), Chapters 13 & 14

Physical and Cognitive Development in Early Adulthood (Chapter 13)

Emerging Adulthood

Psychologist Jeffrey Arnett proposed the concept of emerging adulthood to describe the period from approximately age 18 to 25 in industrialized societies. This is a distinct developmental phase characterized by:

• Identity exploration in love and work
• Instability (frequent changes in residence, work, relationships)
• Self-focus (relatively free of adult responsibilities)
• Feeling in-between (neither adolescent nor fully adult)
• A sense of possibilities and optimism

This period has become recognized as a distinct developmental phase in societies where higher education and delayed entry into permanent adult roles are common.

Physical Development

Early adulthood (roughly 18–40) represents the peak of physical functioning for most systems. Muscular strength peaks in the mid-20s; cardiovascular fitness is at its highest; immune function is strong. Reaction time peaks in the mid-20s and begins a slow decline thereafter.

Health behaviors established in early adulthood — exercise, nutrition, sleep, substance use — have profound implications for health in middle and late adulthood. Young adults engage in a disproportionate share of risk behaviors including hazardous drinking, drug use, reckless driving, and sexual risk-taking.

Cognitive Development

Some cognitive abilities — particularly fluid intelligence (processing speed, working memory, novel problem-solving) — peak in the mid-20s and begin to decline. Crystallized intelligence (accumulated knowledge and verbal ability) continues to increase through middle adulthood.

William Perry’s research on cognitive development in college students identified a progression from dualism (knowledge as either right or wrong) to multiplicity (acknowledging multiple perspectives without a clear way of evaluating them) to relativism (understanding that knowledge is contextual and must be evaluated by specific criteria). This kind of postformal thinking involves an ability to tolerate ambiguity, consider multiple perspectives, and understand that knowledge is context-dependent.

Career development begins in earnest in early adulthood. Donald Super’s stage theory proposes that young adults are in the exploration and establishment stages, during which they explore possible careers and begin to settle into a chosen occupational path.

Social and Emotional Development in Early Adulthood (Chapter 14)

Erikson’s Intimacy vs. Isolation

The central psychosocial challenge of early adulthood in Erikson’s theory is Intimacy vs. Isolation. Successfully achieving intimacy involves forming deep, committed relationships while maintaining one’s individual identity. Failure results in isolation — a sense of distance from others and an inability to form meaningful intimate connections.

Theories of Adult Love

Robert Sternberg’s triangular theory of love proposes that love consists of three components:

• Intimacy: feelings of closeness, connectedness, and bondedness
• Passion: the drives that lead to romance, physical attraction, and sexual consummation
• Commitment: the decision to love someone and maintain that love

Different combinations of these three components yield different forms of love: romantic love (intimacy + passion), companionate love (intimacy + commitment), fatuous love (passion + commitment), and consummate love (all three).

John Lee’s styles of love (or “colors of love”) include eros (erotic, passionate love), ludus (playful love), storge (affectionate, friendship-based love), pragma (practical love), mania (obsessive love), and agape (selfless, altruistic love).

Marriage and Partnerships

Marriage (and cohabitation) is the central relationship structure of early adulthood for most people. Cohabitation rates have increased dramatically since the 1970s, particularly in North America and Europe. Research on the relationship between cohabitation and subsequent marital stability has been mixed.

Factors associated with marital satisfaction include effective communication and conflict resolution, emotional expressiveness, shared interests, sexual satisfaction, and the absence of contempt and defensiveness. John Gottman’s research identified contempt as particularly destructive to relationships — more predictive of divorce than any other behavior.

Divorce rates in North America peaked in the 1970s-80s and have declined somewhat since, but approximately 40–50% of first marriages still end in divorce. Divorce has significant effects on both adults and children, though effects are highly variable.

Parenthood

The transition to parenthood is a major life event that typically decreases marital satisfaction (at least in the short term), increases division of labor along traditional gender lines, and fundamentally reorganizes adult identity and daily life. However, parenthood is also associated with meaning, purpose, and joy.

Decisions about how to balance career and family are shaped by both individual preferences and structural factors including workplace policies, childcare availability and cost, and cultural gender norms.

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Module 10: Middle Adulthood

Textbook: Rathus, HDEV (6th ed.), Chapters 15 & 16

Physical and Cognitive Development in Middle Adulthood (Chapter 15)

Physical Changes

Middle adulthood (approximately ages 40–65) brings gradual but noticeable physical changes. These include:

• Vision: presbyopia (farsightedness due to loss of lens flexibility) becomes common in the 40s; sensitivity to glare increases
• Hearing: presbycusis (age-related hearing loss, especially of high frequencies) typically begins in the 40s-50s
• Cardiovascular system: cardiac output gradually declines; arteries become somewhat less elastic
• Metabolism: basal metabolic rate declines gradually, contributing to weight gain if activity and caloric intake remain constant
• Skin and hair: skin loses elasticity; hair becomes gray as melanin production declines

Menopause — the cessation of menstruation — typically occurs between ages 45 and 55 (average age approximately 51) in women. The transition (perimenopause) can take several years and involves declining estrogen levels. Symptoms vary widely and may include hot flashes, sleep disturbances, and mood changes. Hormone Replacement Therapy (HRT) can relieve symptoms but carries increased risks for certain conditions.

Men do not experience an equivalent abrupt hormonal change, though testosterone levels decline gradually (sometimes called andropause or “male menopause”), with gradual declines in energy, libido, and muscle mass.

Health

The leading causes of death in middle adulthood in North America are cardiovascular disease and cancer. Lifestyle factors — diet, exercise, smoking, alcohol use, stress management — are major determinants of health in this period.

Stress is a significant health concern. The general adaptation syndrome (Selye) describes the body’s response to prolonged stress through stages of alarm, resistance, and exhaustion. Chronic stress is associated with elevated cardiovascular risk, immune suppression, and mental health difficulties.

Cognitive Development

K. Warner Schaie’s Seattle Longitudinal Study provided some of the most comprehensive data on cognitive change across adulthood. Key findings include: most cognitive abilities remain largely stable through the 50s; significant individual variation exists; decline is not universal in middle adulthood; and cohort effects are substantial (more recent generations perform better on many cognitive tasks than earlier generations at the same age).

Fluid intelligence tends to show some decline starting in the 40s-50s, while crystallized intelligence continues to grow. Practical intelligence and domain-specific expertise often peak in middle adulthood.

Creativity need not decline with age. Many artists and scientists make major contributions well into middle and late adulthood. Research suggests different creative peaks in different domains — mathematicians and poets may peak earlier than novelists and philosophers.

Social and Emotional Development in Middle Adulthood (Chapter 16)

Theories of Midlife Development

Erikson’s central challenge of middle adulthood is Generativity vs. Stagnation. Generativity refers to the concern for establishing and guiding the next generation — through parenting, mentoring, teaching, creative work, or civic engagement. Stagnation occurs when the individual becomes self-absorbed and fails to invest in others’ well-being.

Daniel Levinson’s research on the seasons of life proposed that adult development proceeds through alternating periods of stable structure-building and transitional structure-changing. The mid-life transition (around age 40–45) involves re-evaluation of one’s life structure and choices. The popular concept of a mid-life crisis overstates the drama of this transition for most people; research suggests most people navigate midlife with equanimity, and genuine mid-life crises (characterized by dramatic change) are experienced by a minority.

Stability and Change in Personality

Research on adult personality development using the Big Five personality traits (Openness, Conscientiousness, Extraversion, Agreeableness, Neuroticism) generally shows:

• Conscientiousness tends to increase through early and middle adulthood
• Neuroticism tends to decrease
• Agreeableness may increase with age
• Openness is relatively stable or shows modest decline in later life
• There is both cross-cultural consistency and substantial individual variation

Work and Career in Middle Adulthood

Middle adulthood is often the peak period of career achievement and earning power. It may also be a time of career reassessment — some adults experience dissatisfaction and consider career change.

Occupational burnout — a syndrome of emotional exhaustion, depersonalization, and reduced personal accomplishment — is a significant concern in helping professions. Factors contributing to burnout include excessive workload, lack of autonomy, poor social support, and value conflicts.

Relationships in Middle Adulthood

The “empty nest” transition (when children leave home) is often experienced positively by parents, particularly mothers, contrary to the popular assumption that it is primarily a source of loss. Marital satisfaction often shows a U-shaped pattern over the lifespan — higher in early marriage, declining during the child-rearing years, and rising again after children leave home.

Middle adults are increasingly part of the “sandwich generation” — simultaneously caring for aging parents and raising or supporting children. This dual caregiving role can be a source of significant stress, particularly for women who are disproportionately expected to provide care.

Grandparenthood, which typically begins in middle adulthood, is a source of considerable meaning and satisfaction for many people.

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Module 11: Late Adulthood

Textbook: Rathus, HDEV (6th ed.), Chapters 17 & 18

Physical and Cognitive Development in Late Adulthood (Chapter 17)

Physical Development

Late adulthood (age 65 and beyond) brings continued physical change. Primary aging refers to the universal, gradual biological changes that accompany aging; secondary aging refers to the decline caused by disease, disuse, and environmental factors that is not inevitable.

Key physical changes in late adulthood include:

• Cardiovascular: cardiac output continues to decline; blood pressure tends to rise
• Respiratory: lung capacity decreases
• Musculoskeletal: loss of muscle mass (sarcopenia) and bone density (osteoporosis), particularly in women after menopause
• Neurological: loss of some neurons; slowing of neural transmission; sleep changes (more frequent waking, less deep sleep)
• Sensory: continued decline in vision (cataracts, macular degeneration, glaucoma become more common) and hearing; reduced taste and smell sensitivity

Life expectancy has increased dramatically over the 20th century in developed countries. Gender differences in life expectancy persist (women live on average 5–7 years longer than men in North America), with both biological and behavioral explanations proposed.

The distinction between the “young-old” (65–74), “old-old” (75–84), and “oldest-old” (85+) is important — these groups differ substantially in health, cognition, and social circumstances.

Theories of Aging

Why do organisms age and die? Several biological theories attempt to explain this:

• Cellular clock/telomere theory: each cell has a limited number of times it can divide (the Hayflick limit); telomeres (protective caps on chromosomes) shorten with each division, eventually triggering cell senescence
• Free radical theory: reactive oxygen species (free radicals) produced in metabolism accumulate and damage cellular structures over time
• Wear and tear theory: the body simply wears out from accumulated damage
• Hormonal/immune theories: changes in hormone levels and immune function with aging contribute to decline

Cognitive Development in Late Adulthood

Episodic memory (memory for specific events and experiences) shows the most pronounced age-related decline. Semantic memory (general knowledge) is better preserved. Procedural memory (how to do things) is most resistant to age-related decline.

Processing speed (the speed at which cognitive operations are performed) declines consistently with age and underlies many other age-related cognitive changes.

Dementia — significant cognitive decline interfering with daily functioning — is not a normal consequence of aging, though its prevalence increases with age. Alzheimer’s disease is the most common form of dementia, characterized by accumulation of amyloid plaques and neurofibrillary tangles in the brain, progressive memory loss, and eventual impairment of all cognitive functions. Vascular dementia (due to strokes or other vascular problems) is the second most common form.

Health Concerns

The leading health concerns of late adulthood include cardiovascular disease, cancer, stroke, Alzheimer’s disease, osteoporosis, and arthritis. Falls are a major cause of injury and death among older adults, with multifactorial prevention strategies including exercise (especially balance and strength training), medication review, and environmental modification.

Social and Emotional Development in Late Adulthood (Chapter 18)

Erikson’s Integrity vs. Despair

The central psychosocial challenge of late adulthood in Erikson’s framework is Ego Integrity vs. Despair. Integrity involves a sense of acceptance and meaning in one’s life as it has been lived — the ability to look back without regret and to accept one’s life as one’s own responsibility. Despair results from feeling that one’s life has been wasted or misdirected, and from a fearful preoccupation with death.

Activity vs. Disengagement Theory

Two contrasting theories have shaped debate about optimal aging:

Disengagement theory (Cumming & Henry, 1961) proposed that aging involves a natural, mutual withdrawal between older adults and society — a process that is functional for both the individual and society. This theory has been largely disconfirmed by subsequent research.

Activity theory proposes that the most satisfied and well-adapted older adults are those who remain engaged with life — maintaining activities, roles, and relationships as much as possible. Research generally supports the idea that social engagement and activity are associated with better outcomes in late adulthood, though the relationship is complex.

Selective optimization with compensation (Baltes & Baltes) provides a more nuanced model: successful aging involves selecting those domains that matter most, optimizing performance in them, and compensating for losses in other areas.

Social Contexts of Aging

Social relationships remain a critical determinant of well-being in late adulthood. Social convoy theory (Kahn & Antonucci) proposes that individuals move through life with a changing network of close social relationships that provide support and protection.

Social selectivity theory (Carstensen) proposes that as people age and time horizons shorten, they become more selective in their social relationships, preferring emotionally close relationships over large social networks. Emotional regulation improves in late adulthood — older adults show a positivity effect (tendency to attend to and remember positive stimuli more than negative ones), which contributes to well-being.

Retirement

Retirement is a major life transition that has become normative in developed countries. Research shows that adjustment to retirement depends on:

• Whether retirement was voluntary or involuntary
• Financial security in retirement
• Continuity of social relationships and activities
• Health
• Whether retirement was gradual or abrupt

Contrary to the stereotype that retirement is a time of sharp decline, many people adapt well to retirement and report high levels of life satisfaction.

Successful Aging

Research from several major longitudinal studies (e.g., the Harvard Study of Adult Development, the Nun Study) has identified key factors associated with successful aging:

• Absence of disease and disability
• High cognitive and physical function
• Active engagement with life (including social relationships and productive activities)
• Personal resilience and acceptance

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Module 12: Death and Dying

Textbook: Rathus, HDEV (6th ed.), Chapter 19

Understanding Death and Dying

Death can be defined in multiple ways: clinical death is the cessation of heartbeat and breathing; brain death is the irreversible loss of all brain functions (the legal and medical standard in most jurisdictions). The definition of death has become increasingly complex with the development of life-sustaining technologies.

The dying process has been described by Elisabeth Kübler-Ross in her landmark 1969 book On Death and Dying, in which she proposed five stages that dying patients often experience:

1. Denial: “This can’t be happening to me.”
2. Anger: “Why me? This isn’t fair.”
3. Bargaining: “If I can just live until…”
4. Depression: grief and sadness over impending losses
5. Acceptance: a quiet acknowledgment of the reality of death

Kübler-Ross’s model has been widely influential but also criticized. Not all dying people experience all five stages, not everyone moves through them in order, and the model has sometimes been used prescriptively in ways that pathologize individual variation in coping with dying.

Where People Die

The setting in which death occurs has changed dramatically in the 20th century. In earlier eras, most people died at home. Today, the majority of deaths in developed countries occur in hospitals or long-term care facilities. This medicalization of death has raised questions about the quality of dying experience.

Hospice care is a philosophy and system of care focused on comfort, quality of life, and dignity at the end of life rather than curative treatment. Hospice emphasizes:

• Palliative care: managing pain and symptoms
• Family-centered care and support for caregivers
• Support for the emotional, spiritual, and psychosocial needs of the dying person
• Bereavement support for family members after death

Hospice is associated with better quality of dying and often with comparable or longer survival compared to aggressive curative treatment in advanced illness.

Euthanasia

Euthanasia (from the Greek for “good death”) refers to actions taken to end a person’s life in order to relieve suffering. A distinction is drawn between:

• Active euthanasia: directly causing death (e.g., administering a lethal drug)
• Passive euthanasia: withdrawing or withholding life-sustaining treatment
• Physician-assisted death (PAD, also called medical assistance in dying, MAID): a physician providing a prescription for lethal medication that the patient self-administers

In Canada, MAID was legalized under specific conditions following the Carter v. Canada Supreme Court decision in 2015 and subsequent legislation (Bill C-14 in 2016, expanded under Bill C-7 in 2021). Eligibility criteria and procedures vary by jurisdiction and have been the subject of ongoing ethical debate.

Key ethical arguments in this debate include:

• For: respect for individual autonomy; the right to die with dignity; compassionate relief of suffering
• Against: concerns about slippery slope; pressure on vulnerable populations; the primacy of life; alternative approaches (palliative care) should be prioritized

Lifespan Perspectives on Death

Children’s understanding of death develops gradually:

• Preschool-age children typically do not understand death as permanent, universal, or inevitable
• By ages 5–7, most children understand that death is permanent and universal
• By later childhood and adolescence, understanding of death becomes more sophisticated and personal

Adolescents and young adults often have a sense of personal invulnerability — the personal fable (discussed in Module 8) — that can interfere with realistic risk assessment around death.

Older adults, as noted in Laura Carstensen’s socioemotional selectivity theory, tend to have a more accepting orientation toward death when the end of life is perceived as near. Older adults who have successfully achieved Erikson’s integrity are better prepared to face death with equanimity.

Terror management theory (Greenberg, Pyszczynski, & Solomon) proposes that awareness of mortality generates existential terror that humans manage primarily through cultural worldviews that promise symbolic or literal immortality. This theory has generated extensive research showing that reminders of death (mortality salience) increase the strength of cultural identification and defensiveness toward those with different worldviews.

Coping with Death and Bereavement

Bereavement is the state of having lost someone significant. Grief is the emotional response to loss. Mourning refers to the culturally prescribed ways of expressing grief.

Normal grief may include sadness, crying, difficulty concentrating, sleep disturbances, and preoccupation with the deceased. George Bonanno’s research has shown that the most common response to bereavement in adults is resilience — the maintenance of relatively stable, healthy levels of psychological functioning — contrary to the earlier assumption that failure to experience intense grief indicates pathology.

Complicated grief (or prolonged grief disorder) refers to grief that is unusually intense, prolonged, or impairing. Risk factors include sudden or traumatic loss, loss of a child, lack of social support, and pre-existing depression.

Cultural practices around death and mourning vary enormously and serve important functions in facilitating grief, providing structure and community support, and creating meaning around loss.

Advance directives — including living wills and powers of attorney for personal care — allow individuals to specify their wishes for end-of-life care and to designate someone to make decisions on their behalf if they are unable to do so. Having these documents in place is an important practical dimension of preparing for the end of life.

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Notes compiled from course materials by Hsiao d’Ailly and Debbie Wang, and from the textbook HDEV (6th ed.) by Spencer A. Rathus. SDS 150R, Spring 2021, Renison University College, University of Waterloo.