Chapter 4: Physical Development in Infancy and Toddlerhood

Affordances

Refers to the actional properties of objects—their nature, opportunities, and limits.

Cephalocaudal Development

The principle that growth proceeds from the head downward; the head and upper regions of the body develop before the lower regions.

Classical Conditioning

A form of learning in which an environmental stimulus becomes associated with stimuli that elicit reflex responses.

Corpus Callosum

A thick band of nerve fibers that connects the left and right hemispheres of the brain, allowing communication.

Cortex

The outermost part of the brain containing the greatest numbers of neurons and accounting for thought and consciousness.

Depth Perception

The ability to perceive the distance of objects from each other and from ourselves.

Dishabutation

The recovery of attention after habituation; signifies that person recognizes a new stimulus.

Experience-Dependent Brain Development

Brain growth and development in response-specific learning experiences.

Experience-Expectant Brain Development

Brain growth and development that are dependent on basic environmental experiences, such as visual and auditory stimulation, in order to develop normally.

Externality Effect

Refers to a particular pattern of infant visual processing.

Fine Motor Development

The ability to control small movements of the fingers, such as reaching and grasping.

Glial Cells

A type of brain cell that nourishes neurons and provides structure to the brain.

Gross Motor Development

The ability to control large movements of the body, such as walking and jumping.

Growth Faltering

A condition in which growth and weight are substantially lower than the norm expected for a child’s age; also known as failure to thrive.

Growth Norms

The expectation for typical gains and variations in height and weight for children based on their chronological age and ethnic background.

Growth Stunting

A reduced growth rate.

Habituation

The gradual decline in the intensity, frequency, or duration of a response when repeatedly exposed to a stimulus; indicates learning.

Intermodal Perception

The process of combining information from more than one sensory system, such as visual and auditory senses.

Kwashiorkor

A malnutrition disease in children caused by deprivation of protein and calories and characterized by lethargy, bloating, and swelling of the stomach.

Lateralization

The process by which the two hemispheres of the brain become specialized to carry out different functions.

Marasmus

A wasting disease in which the body’s fat and muscle are depleted; growth stops and the body wastes away, taking on a hollow appearance.

Myelin

The fatty substance that coats the axons, which speeds the transmission of electrical impulses and neurological function.

Myelination

The process in which neurons are coated in a fatty substance, myelin, which contributes to faster neural communication.

Neurogenesis

The production of new neurons.

Neurons

A nerve cell that stores and transmits information; billions of neurons comprise the brain.

Perception

The mental processing of sensory information, which is interpreted as sight, sound, and smell, for example.

Perception Narrowing

A decline in sensitivity to discriminate faces within unfamiliar groups.

Prefrontal Cortex

Located in the front of the brain, responsible for higher thought, such as planning, goal setting, controlling impulses, and using cognitive skills and memory to solve problems.

Proximodistal Development

The principle that growth and development proceed from the center of the body outward.

Reflex

Involuntary and automatic responses to stimuli such as touch, light, and sound.

Sensation

The physical response of sensory receptors when a stimulus is detected (e.g., activity of the sensory receptors in the eye in response to light); awareness of stimuli in the senses.

Sensitive Periods

A period during which experience has a particularly powerful role in shaping developmental outcomes.

Sudden Infant Death Syndrome (SIDS)

The sudden unexpected death of an infant less than 1 year of age that occurs seemingly during sleep and remains unexplained after a thorough investigation.

Synapses

The intersection or gap between the axon of one neuron and the dendrites of other neurons; the gap that neurotransmitters must cross.

Synaptic Pruning

The process by which synapses, neural connections that are seldom used, disappear.

Synaptogenesis

The process in which neurons form synapses and increase connections between neurons.

Vaccine

A small dose of inactive virus that is injected into the body to stimulate the production of antibodies to guard against a disease.

Visual Acuity

Sharpness of vision.