Lifespan Development: Key Concepts in Developmental Psychology

Lifespan Development

Developmental Psychology Overview

Developmental psychology examines the physical, cognitive, social, and behavioral changes that occur throughout the human lifespan. It seeks to understand how individuals become who they are, from conception to late adulthood.

• Key Focus: How humans change and grow across different life stages.

• Research Methods:

  • Cross-sectional design: Compares different age groups at the same time to identify age-related differences.

  • Cohort effects: Differences between age groups due to unique historical or cultural experiences, not age itself.

  • Longitudinal design: Follows the same individuals over time to observe developmental changes.

Pre-natal Development

Teratogens and Their Effects

Teratogens are substances or environmental factors that can cause harm to a developing fetus, leading to growth problems, birth defects, or miscarriage.

• Bacteria/Parasites (e.g., Toxoplasmosis): Can damage the amygdala, affecting emotional development.

• Alcohol: Causes Fetal Alcohol Spectrum Disorder (FASD); prevalence is about 9 out of 1000 babies in Canada.

• Viruses: Zika virus can cause severe birth defects.

• Radiation: Exposure increases risk of developmental abnormalities.

• Pollution: Lead and mercury exposure can impair cognitive development.

• Drugs: Both prescription and illegal drugs (e.g., Accutane) can be highly teratogenic.

• Maternal Fluoride Exposure: Associated with lower IQ scores in children aged 3-4.

• Thalidomide: Prescribed for morning sickness; caused limb malformations and other defects, leading to new safety protocols.

• Teflon and C-8: "Forever chemicals" found in non-stick pans; can cause eye/mouth deformities and remain in the body indefinitely.

Infancy and Childhood

Biological Maturation and Environmental Exploration

Development during infancy and childhood is driven by biological maturation and active exploration of the environment, with cultural differences influencing activity levels.

• Motor Milestones: Numerous milestones are achieved during the first year, such as crawling and walking.

Visual Perception

Visual perception is foundational for social interaction skills and begins developing early in life.

• Newborns can distinguish their mother's voice and native language from others.

• Imitate adult expressions, showing early social learning.

• Prefer patterns with contours and edges.

Baby Schema (Kindchenschema)

Baby schema refers to a set of physical features in infants that trigger caregiving and affection in adults, an evolutionary adaptation.

• Features include large, round eyes, big head, round cheeks, small nose/mouth, and soft, clumsy movements.

• Activates reward-related regions in the adult brain.

Attachment Theory

Attachment is the emotional bond between a child and caregiver, providing evolutionary advantages for survival.

• Konrad Lorenz: Studied imprinting in goslings during critical periods.

• Harlow's Monkeys: Demonstrated preference for comfort over food.

• Bowlby: Proposed that attachment is innate and evolved for survival; infants are biologically programmed to seek attachment.

• Mary Ainsworth's Strange Situation: Assessed attachment styles by observing child reactions to caregiver separation and reunion.

Attachment Styles

Style	Child Behavior
Secure	Uses caregiver as a base for exploration; distressed when caregiver leaves, seeks comfort upon return.
Avoidant	Does not cry when caregiver leaves; avoids caregiver upon return.
Ambivalent	Distressed when caregiver leaves; ambivalent upon return (mixed feelings).
Disorganized-disorientated	Inconsistent and contradictory behavior.

• Secure attachment at age 1 predicts social competence, emotional stability, and successful relationships later in life.

• Criticisms: Attachment theory may not account for cultural variations, temperament, or shared genetic characteristics.

Types of Parenting

Parenting styles influence child development, morality, and motivation.

Parenting Style	Parent Behavior	Child Outcome
Authoritarian	Rigid, punitive, strict standards	Unsociable, unfriendly, withdrawn
Permissive	Lax, inconsistent, undemanding	Immature, moody, dependent, low self-control
Uninvolved	Detached emotionally, provides basic needs	Indifferent, rejecting behavior
Authoritative	Firm, sets limits/goals, uses reasoning, encourages independence	Good social skills, likeable, self-reliant, independent

Cognitive Development: Piaget's Theory

Piaget's Stages of Cognitive Development

Jean Piaget proposed that children progress through distinct stages of cognitive development, each characterized by unique ways of thinking.

• Schemas: Mental frameworks for organizing information.

• Assimilation: Incorporating new experiences into existing schemas.

• Accommodation: Modifying schemas when new experiences do not fit.

Stages of Cognitive Development

Stage	Age Range	Main Features
Sensorimotor	Birth - 2 years	Understanding through physical interaction; development of object permanence
Preoperational	2 - 7 years	Language development, symbolic thinking, egocentrism
Concrete Operational	7 - 12 years	Logical thinking, principle of conservation, reversibility, bound to concrete reality
Formal Operational	12 - adulthood	Abstract and logical thinking

• Egocentric thought: Child views the world entirely from their own perspective.

• Self-awareness: Emerges around 18-24 months; ability to recognize oneself as an individual.

• Theory of Mind: Emerges at 4-5 years; understanding that others have thoughts and feelings different from one's own.

Social Development

Early Social Understanding

Children develop social understanding early, recognizing when others need help, preferring helpers, and developing a sense of fairness.

• Helper stage observed from 14 months to 7 years, across cultures.

Adolescence

Emotion Regulation and Risky Decisions

Adolescents experience intense emotions, increased anxiety and depression, and are prone to risky decisions due to ongoing brain development.

• Strategies for emotion regulation include changing perspective (e.g., viewing failure as a learning opportunity).

• Teen culture often glorifies risk-taking, influenced by peer pressure and developing reward systems.

• Prefrontal cortex is still maturing, limiting impulse control.

Cognitive Development in Adolescence

• Adolescent egocentrism: Heightened self-focus; belief that the world revolves around oneself.

• Imaginary audience: Belief that others are constantly observing and judging.

• Personal fables: Belief in the uniqueness of one's thoughts and experiences, leading to feelings of invulnerability.

• Emotion often overrides logic; greater tolerance for ambiguity and uncertainty.

Key Developmental Tasks

• Identity formation

• Peer group relationships

• Romantic relationships

Adulthood

Emerging and Middle Adulthood

• Emerging adulthood (18-24 years): Period of self-discovery, peak health, and career exploration.

• Middle adulthood (20s-40s): Considered the "best years"; minor physical decline, increased susceptibility to disease, and less sensitive sense organs.

Marriage and Family

• Marriage is associated with greater health, longevity, financial security, and sexual satisfaction.

• Divorce rate in Canada is approximately 40%.

Four Horsemen of the Apocalypse (Predictors of Marital Dissatisfaction)

• Criticism: Negative comments and picking out flaws.

• Defensiveness: Responding to perceived attacks with counterattacks.

• Contempt: Sarcasm, eye rolling, cutting tone.

• Stonewalling: Shutting down verbally and emotionally.

• Marital satisfaction often decreases after becoming parents.

• Sandwich generation: Adults caring for both children and aging parents.

Late Adulthood

Socioemotional Selectivity Theory

Older adults focus on positive, meaningful experiences, preferring activities that bring joy and connection. Goals shift toward rewarding and meaningful experiences.

• Better attention to positive emotions.

• Wisdom and experience are valued.

The Aging Brain and Dementia

• Reduction in white and grey matter in the cerebral cortex affects memory processing.

• Dementia: Disruption of mental functioning, memory loss, disorientation, poor judgment.

• Alzheimer's disease: Degenerative and terminal; characterized by buildup of tau protein, which kills nerve cells.

Prevention Strategies

• Physical activity

• Cognitive engagement

• Healthy diet

• Social connection

• Gaming can improve real-world skills such as task-switching, short-term memory, reasoning, and cognitive functions.

Additional info: Where original notes were brief or fragmented, academic context was added to clarify concepts and provide examples.