4 years: Brain is 80% of adult weight {brain development, 4 years}. Vertical exogenous fibers extend to cortex layer 3b. Layer 3a becomes functional. Limbic system begins.
4 years: Children know if other people can and cannot see and hear them {cognition development, 4 years}. Children can pretend. Children can report facts that they see or know. Children know that others have thoughts just as they do. Girls and boys perform the same on verbal, quantitative, and spatial tests. To identify objects requires many details.
4 years: Dependency is high but on peers, not parents {emotion development, 4 years}. Competitiveness is strong, especially among boys and in lower classes. Aggression does not correlate with competitiveness. Jealousy, fear, sensitiveness, and aggressiveness start to decline.
48 months: Children have 1500-word vocabularies {language development, 48 months}. Children can use 5.3 words in sentences and use compound sentences. Word inflection begins. Toddlers know most regular grammar rules but leave auxiliary words out. Children can name several objects from memory, name pictures containing several items, repeat 10-word sentences, count to four, and tell differences between geometric figures. Relative verbal ability stays the same until adulthood.
4 years: Children can run at different speeds with smooth changes, jump forward, skip but not hop, throw with just arm, draw circles and crosses but not diamonds, trace short straight lines, and fold paper diagonally {physical development, 4 years}. Children can detect differences in spatial orientation, such as reverse, tilt, and rotate, but not react to them. Boys and girls are same size, 1.02 meters and 17 kilograms. From four years on, muscles grow faster than other body parts.
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Description of Outline of Knowledge Database
Date Modified: 2022.0225