An average, or standard, measurement, calculated from the measurements of many individuals within a specific group or population
A point on a ranking scale of 0 to 100. Example: a child who is at the 50th percentile for height means that half of all children his age are taller and half are shorter.
shaken baby syndrome
A life-threatening condition that occurs when an infant is forcefully shaken back and forth, rupturing blood vessels in the brain and breaking neural connections
fine motor skills
Physical abilities involving small body movements, especially of the hands and fingers, such as drawing and picking up a coin.
A responsive movement that seems automatic because it almost always occurs in reaction to a particular stimulus.
A situation in which a seemingly healthy infant, at least 2 months of age, suddenly stops breathing and dies unexpectedly while asleep.
primary circular reactions
The first of three types of feedback loops in sensorimotor intelligence, this one involving the infant's own body.
secondary circular reactions
The second of three types of feedback loops in sensorimotor intelligence, this one involving people and objects.
tertiary circular reactions
The third of three types of feedback loops in sensorimotor intelligence, this one involving active exploration and experimentation.
The realization that objects (including people) still exist when they cannot be seen, touched, or heard.
A perspective that compares human thinking processes, by analysis, to computer analysis of data, including sensory input, connections, stored memories, and output,
The extended repetition of certain syllables, such as ba-ba-ba, that begins between 6 and 9 months of age.
An infant's expression of concern-a quiet stare, clinging to a familiar person, or sadness-when a stranger appears.
An infant's distress when a familiar caregiver leaves; most obvious between 9 and 14 months.
A person's realization that he or she is a distinct individual, with body, mind, and actions that are separate from those of other people.
Inborn differences between one person and another in emotion, activity, and self-control.
According to Ainsworth, "an affectional tie" that an infant forms with the caregiver- a tie that binds them together in space and endures over time.
A viral infection that can cause blindness, deafness, and brain damage in a fetus if contracted by a pregnant woman.
In Piaget's theory, the stage (birth to 2 yrs) during which infants know the world mostly in terms of their sensory impressions and motor activities.
trust vs. mistrust
According to Erikson, first stage of personality development in which the infant's basic sense of trust or mistrust develops as a result of consistent or inconsistent care.
An infant's use of another person's emotional cues to interpret unfamiliar events.
Located in the anterior frontal lobe of the brain. Assists in planning, self-control and self regulation. Very immature in the newborn.
Already acute at birth, with infants turning their heads toward sounds, particularly a human voice.