Child Development: Prenatal to Formal Operations
Head Development Prior to Birth and Postnatal Development
Introduction to Development Types
Physical Development: Refers to the maturation of the body.
Sensory Motor Development: Involves the acquisition of sensory and motor skills.
Social-Emotional Development: Describes changes in how a child understands emotions and interacts with others.
Cognitive Development: Focuses on the growth of intellectual capabilities.
Scope: This discussion primarily covers development in infancy and childhood, with a brief mention of development beyond childhood as provided in the book, though not exam material.
Prenatal Development & Environment
Early Cell Division and Differentiation:
Every individual develops from a single fertilized egg.
This egg divides into multiple identical cells, forming a mass of cells with the same genetic information.
After approximately days, cells begin to differentiate, meaning they develop into specialized, distinct types of cells, despite containing identical genetic information.
Mechanism of Differentiation:
Differences in cell types arise from variations in gene expression patterns; different genes are expressed in different cells.
These differences are caused by variations in the chemical environment inside the cell.
Even an initially homogenous mass of cells has tiny differences (e.g., polarity caused by sperm entry point), which guide cell differentiation based on a cell's position within the mass.
This process, known as cell differentiation, is guided by the interaction between genes and the environment from shortly after conception.
Teratogens:
Substances that disrupt healthy neural development, leading to harmful outcomes.
Examples: Alcohol, tobacco, lead.
Fetal Alcohol Syndrome (FAS):
Caused by alcohol exposure during pregnancy.
Results in physical abnormalities (e.g., specific facial features, as illustrated by Ellen de Wittem's FES Project photos).
Leads to behavioral problems and learning difficulties, interfering with healthy development.
Other Harmful Environmental Factors:
Maternal Stress: A positive correlation exists between a mother's stress during pregnancy and the child's vulnerability to anxiety and depression as an adult.
Maternal Starvation: Associated with an increased risk of schizophrenia, metabolic, and cardiovascular diseases in the adult child.
Epigenetic Influences:
Genes provide developmental guidance, but the prenatal environment rearranges epigenetic marks (e.g., attachment of a methyl group to a gene, preventing its expression).
These epigenetic changes, occurring before birth, can be temporal (affecting gene expression for a short period) or permanent (affecting further development even after birth).
This highlights the critical interaction between genes and environment from conception onwards, shaping development through altered gene expression.
Postnatal Development
Physical and Sensory Motor Development
Continued Development Post-Birth: Development is a lifelong process, with gene-environment interaction remaining crucial.
Brain Maturation:
Cross-sections of the human cortex show significant changes from newborn to years old.
Not only do connections increase, but also pruning occurs, where unnecessary connections disappear.
Sensory System Development:
While senses are well-developed at birth, the perceptual system is not fully finished.
Requires exposure to visual and auditory stimuli for complete maturation.
Example: Stereoscopic Depth Perception:
Newborns cannot perceive stereoscopic depth because they lack binocular disparity cells.
These cells develop through exposure to the visual world via both eyes, enabling the brain to process differences in stimulation between the eyes (binocular disparity), which is essential for depth perception.
Motor Skill Acquisition:
Motor control increases in an orderly manner, marked by motor milestones (e.g., sitting up, crawling, standing alone, walking).
These milestones follow a consistent sequence across individuals and cultures (unless serious issues are present).
However, there are large individual differences in the speed at which children acquire these skills (e.g., some walk earlier, others later).
Social-Emotional Development
Emerging Social Capacity:
Infants show early social predispositions.
Preference for Human Faces:
Researchers use the preferential looking technique (presenting two stimuli simultaneously and monitoring which the infant prefers).
Studies show infants (even very young ones, indicated by red bars in studies) clearly prefer to look at human faces over other stimuli, suggesting an innate preparedness for social interaction.
Facial Imitation: -day-old babies can imitate facial expressions, demonstrating an early capacity for social learning.
Understanding Facial Expressions: Babies around months old react emotionally to facial expressions (e.g., becoming happy with happy faces, sad with sad faces), particularly from primary caregivers, indicating early interpretation of emotional cues.
Social Referencing: Around months, babies use parents' facial expressions as cues when exploring their environment (e.g., in a visual cliff experiment, a baby will check the mother's face to decide whether to crawl across a seemingly deep drop; a smile encourages movement, a fearful expression causes withdrawal).
Attachment to Primary Caregiver:
A strong emotional bond (attachment) to the primary caregiver (often the mother) is crucial for healthy development.
Historical Views on Attachment:
Behavioral Theory (older): Proposed that attachment stemmed from the caregiver providing nutrition and feeding (a form of conditioning).
John Bowlby (1960s): Argued that attachment arises from an innate tendency in children to seek contact comfort and a secure base, fearing unfamiliar persons.
Children seek relationships where they feel safe and protected.
Harlow's Monkey Studies (Support for Bowlby):
Harlow raised rhesus monkeys with two surrogate mothers: one made of wire (provided milk/food) and one wrapped in soft terry cloth (provided comfort).
Observation: Baby monkeys spent significantly more time with the cloth mother, even when the wire mother provided food. When threatened, they ran to the cloth mother for security.
Conclusion: Contact comfort
Nativists → Child seen as a miniature adult; development is mainly about growth, not big changes in thinking/understanding.
Empiricists → Child is like an adult but needs to learn a lot through experience; mind is shaped by environment.
Piaget → Child is qualitatively different from an adult; they think in different ways at different stages (e.g., not just less knowledge, but different kinds of thinking).