Chapter 9: Human Development

Developmental Norms and Theories

This section covers the foundational concepts of human development, including developmental norms, major theories, and stages of growth.

• Developmental Norm: A standard or average age at which children acquire particular skills or behaviors. These norms help identify typical versus atypical development.

• Cognitive Development Theory (Jean Piaget): Piaget proposed that children progress through four stages of cognitive development:

  • Sensorimotor Stage (birth–2 years): Learning through sensory experiences and manipulating objects.

  • Preoperational Stage (2–7 years): Development of language and symbolic thinking, egocentrism.

  • Concrete Operational Stage (7–11 years): Logical thinking about concrete events, understanding conservation.

  • Formal Operational Stage (12+ years): Abstract and hypothetical reasoning.

• Socioemotional Development Theory (Erik Erikson): Erikson outlined eight stages of psychosocial development, each characterized by a central conflict (e.g., trust vs. mistrust in infancy, identity vs. role confusion in adolescence).

• Attachment Theories: Patterns of attachment (secure, avoidant, ambivalent, disorganized) describe the quality of the emotional bond between child and caregiver, influencing later social and emotional outcomes.

Example: A child in the preoperational stage may struggle with understanding that the amount of liquid remains the same when poured into a differently shaped container (lack of conservation).

Chapter 4: Sensation and Perception

Structures and Properties of Sensory Systems

This section explores how sensory information is received and interpreted by the brain, focusing on vision, hearing, and other senses.

• Structures of the Eye: Includes the cornea, lens, retina, iris, and optic nerve. Each part plays a role in focusing light and transmitting visual information.

• Properties of Light: Light is characterized by wavelength (color), amplitude (brightness), and purity (saturation).

• Major Theories of Color Perception:

  • Trichromatic Theory: The retina contains three types of cones sensitive to red, green, and blue.

  • Opponent-Process Theory: Color perception is controlled by opposing neural processes (red-green, blue-yellow, black-white).

• Top-Down vs. Bottom-Up Processing:

  • Bottom-Up Processing: Perception starts with sensory input and builds up to the final perception.

  • Top-Down Processing: Perception is influenced by expectations, prior knowledge, and experiences.

• Gestalt Psychology: A school of thought emphasizing that the whole of perception is more than the sum of its parts. Key principles include proximity, similarity, closure, and continuity.

• Structures of the Ear: Includes the outer ear (pinna), middle ear (ossicles), and inner ear (cochlea). These structures transmit and transduce sound waves into neural signals.

• Major Theories of Auditory Perception:

  • Place Theory: Different frequencies stimulate different places on the basilar membrane.

  • Frequency Theory: The rate of nerve impulses matches the frequency of a tone, enabling pitch perception.

• Sense of Smell vs. Other Senses: Olfaction (smell) is unique because it bypasses the thalamus and has direct connections to the limbic system, influencing emotion and memory more directly than other senses.

Example: The Gestalt principle of closure allows us to perceive a complete shape even when parts of it are missing.

Chapter 5: Variations in Consciousness

Circadian Rhythms, Sleep, and Hypnosis

This section examines the biological and psychological processes underlying consciousness, including sleep, dreaming, and hypnosis.

• Circadian Rhythm: The biological clock regulating physiological processes on a roughly 24-hour cycle, influenced by light and other environmental cues.

• Sleep Stages: Sleep is divided into non-REM (NREM) and REM stages. NREM includes stages 1–3, progressing from light to deep sleep. REM sleep is associated with vivid dreaming and rapid eye movements.

• Major Theories of Dreaming:

  • Freud's Wish-Fulfillment Theory: Dreams represent unconscious desires and conflicts.

  • Activation-Synthesis Theory: Dreams are the brain's attempt to make sense of random neural activity during sleep.

  • Information-Processing Theory: Dreams help process and consolidate memories.

• Major Theories of Hypnosis:

  • Dissociation Theory: Hypnosis causes a split in consciousness, allowing some thoughts and behaviors to occur independently.

  • Social-Cognitive Theory: Hypnotic experiences result from expectations and social influences rather than a distinct altered state.

Example: Jet lag occurs when the circadian rhythm is out of sync with the local time, leading to sleep disturbances and fatigue.