Babies grow fast in their first year, doubling their weight by 4 months. They hit milestones like rolling over, sitting up, and walking. Their senses sharpen too, with vision improving from blurry to clear by age 2.
Piaget said babies learn through their senses in the "sensorimotor stage." They develop object permanence, realizing things exist even when out of sight. Both genes and environment shape a baby's growth, with early experiences crucial for brain development.
Physical Milestones of Infancy
Growth and Motor Development
- Infants typically double their birth weight by 4 months and triple it by 1 year old
- Average growth of 1 inch per month in the first year
- Gross motor skills develop in a cephalocaudal (head-to-toe) and proximodistal (center-outward) pattern
- Rolling over (3-4 months)
- Sitting up unsupported (5-6 months)
- Crawling (6-8 months)
- Walking (10-14 months)
- Fine motor skills involve precise movements and hand-eye coordination
- Reaching and grasping objects (3-4 months)
- Transferring objects between hands (5-6 months)
- Pincer grasp (8-10 months) enables picking up small objects between thumb and index finger
Sensory Development
- Sensory abilities are present at birth but undergo significant development in the first year
- Vision improves from 20/600 at birth to 20/20 by 2 years old
- Newborns have limited visual acuity and color perception
- Depth perception develops around 5 months old
- Hearing is well-developed at birth, allowing infants to distinguish speech sounds
- Infants prefer human voices and can recognize their mother's voice from birth
- Taste and smell preferences are influenced by early experiences
- Infants show preference for sweet tastes and aversion to bitter tastes
- Exposure to various flavors in breast milk or formula can shape later food preferences
Cognitive Development in Infancy
Piaget's Sensorimotor Stage
- Piaget's theory of cognitive development proposes that infants are in the sensorimotor stage (birth to 2 years)
- Characterized by learning through senses and motor actions
- The sensorimotor stage is divided into six sub-stages:
- Simple reflexes (0-1 month)
- Primary circular reactions (1-4 months)
- Secondary circular reactions (4-8 months)
- Coordination of secondary circular reactions (8-12 months)
- Tertiary circular reactions (12-18 months)
- Mental representation (18-24 months)
- Infants display intentional behavior and goal-directed actions by the end of the sensorimotor stage
- Demonstrates the beginnings of symbolic thought and mental representation
Object Permanence
- Object permanence is the understanding that objects continue to exist even when hidden from view
- Develops gradually during the sensorimotor stage
- Infants typically achieve full object permanence by 18-24 months
- Before this, infants display the "out of sight, out of mind" phenomenon
- Piaget's A-not-B error demonstrates incomplete object permanence
- Infants search for a hidden object in its original location (A) even after seeing it hidden in a new location (B)
Nature vs Nurture in Infant Development
Genetic Influences
- Nature refers to the influence of genes and biology on development
- Genetic factors play a significant role in physical development
- Height, weight, and certain health conditions are influenced by genes
- Cognitive development is influenced by genetic predispositions
- Some infants may have a genetic advantage in certain cognitive abilities
Environmental Influences
- Nurture refers to environmental factors such as parenting, culture, and experiences
- Environmental factors like nutrition and healthcare can impact physical growth
- Malnutrition can lead to stunted growth and developmental delays
- Cognitive development is influenced by environmental stimulation
- Infants with rich sensory experiences and responsive caregiving tend to show advanced cognitive skills
- The interplay between nature and nurture is complex and ongoing throughout development
- Epigenetics suggests that environmental factors can influence gene expression without altering the DNA sequence itself
Early Experiences and Brain Development
Critical Period for Brain Development
- The first three years of life are a critical period for brain development
- Brain reaches 80% of its adult size by age 3
- Early experiences shape the architecture of the developing brain through synaptic pruning
- Frequently used neural connections are strengthened
- Unused connections are eliminated
- Positive experiences promote healthy brain development
- Responsive caregiving, adequate nutrition, and sensory stimulation
- Negative experiences can lead to impaired brain development and long-term consequences
- Neglect, abuse, or chronic stress
Serve and Return Interaction
- Serve and return interaction between infants and caregivers is crucial for building neural connections
- Characterized by contingent and reciprocal communication
- Examples of serve and return interaction:
- Infant coos, caregiver responds with eye contact and verbal communication
- Infant reaches for a toy, caregiver responds by handing the toy to the infant
- Serve and return interaction fosters social-emotional development
- Helps infants develop secure attachment relationships
Early Intervention Programs
- Early intervention programs can mitigate the effects of adverse experiences
- High-quality child care, parenting support, and home visiting programs
- Aim to promote optimal brain development in at-risk infants
- Provide stimulating environments, responsive caregiving, and support for families
- Examples of early intervention programs:
- Head Start, Early Head Start, and Nurse-Family Partnership