LECTURE 12: Lifespan Development I: Infancy and Childhood

Lifespan Development I: Infancy and Childhood

Introduction to Developmental Psychology

Developmental psychology is the scientific study of how humans change physically, cognitively, socially, and behaviorally throughout their lifespan. This field examines the processes that influence growth from conception through old age.

• Developmental psychology: The study of human physical, cognitive, social, and behavioral characteristics across the lifespan.

• Life periods:

  • Infancy: birth–2 years

  • Childhood: 2–12 years

  • Adolescence: 12–22 years

  • Early Adulthood: 22–45 years

  • Middle & Late Adulthood: 45–60 years, 60+ years

Additional info: Early adulthood often involves forming long-term relationships, starting families, and launching careers.

Chronological Age and Development

Chronological age refers to the number of years since birth, but it does not directly cause development. Other types of age include:

• Biological age: Body/organ function

• Psychological age: Adaptive thinking and coping abilities

• Socioemotional age: Connectedness with others

Research Methods in Developmental Psychology

Researchers use different methods to study development over time:

• Cross-sectional study: Data collected at one point in time from different age groups.

• Longitudinal study: Data collected repeatedly over time from the same individuals.

• Cohort effects: Differences due to being born in different time periods, not necessarily due to development itself.

Zygotes to Infants: Stages of Prenatal Development

Prenatal development occurs in three main stages:

• Germinal stage (0–2 weeks): Conception occurs (sperm + ovum = zygote), and the zygote implants in the uterus as a blastocyst.

• Embryonic stage (2–8 weeks): Formation of physical structures; blastocyst divides into fetus and placenta.

• Fetal stage (9 weeks–birth): Development and specialization of skeletal, organ, and nervous systems.

Sensory Development in Infancy

Infants are born with basic sensory abilities, which develop rapidly after birth.

• Auditory: Preference for mother's voice; can recognize sounds heard in the womb (e.g., The Cat in the Hat study).

• Visual: Poor acuity at birth but highly responsive to faces; visual clarity improves quickly.

• Taste and olfaction: Fairly well developed at birth.

Example: Infants show a preference for faces and can distinguish their mother's voice from others.

Motor Development in Infancy

Motor development involves the progression of muscular coordination required for physical activities.

• Reflexes: Automatic reactions to stimuli (e.g., rooting, sucking).

• Gross motor skills: Large muscle actions such as walking.

• Fine motor skills: Small muscle actions, such as finger dexterity (e.g., using 'sticky mittens' to grasp objects).

Example: The 'sticky mittens' experiment showed that infants given mittens with Velcro were better at object exploration.

Infancy & Childhood: Cognitive and Emotional Development

Piaget’s Cognitive Development Theory

Jean Piaget proposed that children move through distinct stages of cognitive development, each characterized by different ways of thinking and understanding the world.

• Assimilation: Fitting new information into existing belief systems.

• Accommodation: Modifying belief systems based on new experiences.

Sensori-motor Stage (0–2 years)

• Thinking and exploration based on immediate sensory and motor experiences.

• Object permanence: Understanding that objects continue to exist even when out of sight.

Preoperational Stage (2–7 years)

• Language development, use of symbols, and pretend play.

• Egocentrism: Difficulty distinguishing between one's own and others' perspectives.

• Conservation: Understanding that properties such as mass and volume remain the same despite changes in form.

• Scale errors: Mistakes in understanding the size of objects in relation to themselves.

Concrete Operational Stage (7–11 years)

• Logical thinking and manipulation of numbers.

• Understanding transitivity (e.g., if A > B and B > C, then A > C).

• Ability to classify and seriate objects (putting them in order by some property).

Formal Operational Stage (11+ years)

• Advanced cognition, including abstract reasoning and hypothetical thinking.

Example: Syllogistic reasoning (e.g., "If all birds are cats and all parrots are birds, then all parrots are cats").

Attachment

Attachment refers to the close emotional bond that infants develop with their caregivers, which is crucial for social and emotional development.

• Harlow’s monkeys (1958): Demonstrated the importance of comfort and security in attachment.

• Ainsworth’s Strange Situation (1979): Identified different attachment styles based on infants' reactions to caregiver separation and reunion.

Attachment Style	Characteristics
Secure	Uses caregiver as a secure base; mild distress at separation; happy at reunion
Insecure-avoidant	Little engagement with caregiver; indifferent to separation and reunion
Insecure-ambivalent	Clingy; very distressed at separation; ambivalent at reunion
Insecure-disorganized	Confused or contradictory behaviors; may freeze or show fear

Additional info: Infants with insecure attachments are more likely to have difficulties with emotion regulation later in life.

Attachment Styles in Adulthood

• Secure: Positive view of relationships, comfortable with intimacy.

• Avoidant: Hesitant about close relationships, distance themselves.

• Anxious: Crave closeness, less trusting, jealous, possessive.

• Disorganized: Lack of coherent strategy; want closeness but also distance, fear of intimacy.

Attachment & Parenting

Parenting styles and attachment systems influence children's emotional and social development.

• Attachment behavioral system: Regulates proximity to caregivers for safety and security.

• Discipline: Inductive discipline (explaining consequences) is more effective than punishment alone.

• Love and security: Should be unconditional, not something that must be earned.

Example: Children raised with secure attachments tend to have higher self-esteem and better social skills.