Chapter 4: The First Three Months
Visual acuity
Sharpness of vision
Central Nervous System
Spinal cord, brain stem, cerebral cortex
Basic idea of Op. Cond.
Test subject will tend to repeat behaviors that lead to rewards and will tend to give up behaviors that fail to produce rewards or that lead to punishment (Skinner)
Cerebral Cortex 2
The C.C is divded into two hemispheres: each of which is divided into four sections or lobes.
Example of phonemes
The Spanish /rr/ and /r/ = perro and pero
Reactivity
The characteristic level of arousal or activeness
Affect
The dominant emotional tone, gloomy or cheerful
Infant reflexes are an important window into what?
The infant's developing brain and can be used to diagnose the functioning of the CNS. IE) Brain damage if reflex persists passed time it should
Axon
The main protruding branch of a neuron; it carries messages to other cells in the form of electrical impulses
Claus Von Hofsten
coined prereaching, which he elicited by showing very young infants a large, colorful, slow-moving object such as ball of yarn. Passed by, newborns reached for it. Grasping not able to.
Under naturalistic conditions, newborns only 2-7 hours old
recognize and show preference for their mother's face when it is contrasted with that of a stranger
The characteristic expressions in response to tastes of infants are
remarkably like the expressions made by adults when they encounter the same tastes, evidence that these expressions are innate/evolutionary implications
Occipital lobes
specialized for vision
Fontanels
"soft-spots" - bones of the skull are separated, rather than fused together, they are capable of moving in response to external and internal pressure.
A neuron accomplishes its basic communication task in two ways
1) By sending information via small electrical impulses along its axon ) By receiving info from the axons of other cells through spiky protrusions called dendrites
By two months of age
Ability to perceive different colors appears to approach adult levels
Babies sleep a lot -
About 3/4 of every day in the first month
Neurotransmitter
A chemical secreted by a cell sending a message that carries the impulse across the synaptic gap to receiving cell
Reinforcement
A consequence such as receiving a reward increases the likelihood that a behavior will be repeated
Neuron
A nerve cell
kwashiorkor
A potentially fatal form of malnutrition in which the diet is extremely low in protein
Exuberant synaptogenesis
A rapid growth in synaptic density that prepares the brain for a vast range of possible experiences
learning
A relatively permanent change in behavior brought about by the experience of events in the environment
Conditional Response (CR)
A response to the conditional stimulus (CS)
Myelin
A sheath of fatty cells that insulates axons and speeds transmission of nerve impulses from one neuron to the next
Reflex
A specific, well-integrated, automatic (involuntary) response to a specific type of stimulation
Spinal cord
A tubelike bundle of nerves, is encased in the spinal bones that extend from the base of the brain to below the waist.
The trait of having "soft-spots"
Allows the skull to "mold" during birth in response to EXTERNAL pressures (exerted by narrow birth canal) and to expand in response to INTERNAL pressure (exerted by a rapidly developing brain)
Long term benefits of breast feeding
Associated with decreased risk for immune-related diseases, childhood cancers, and obesity.
Cerebral cortex
Brain's outermost layer and most complex system: processing center for the perception of patterns, motor sequences, planning, decision making, speech.
Action
Complex, coordinated behaviors
Self-regulation
Control over what one attends to and reacts to
Brain stem
Controls such elementary reactions as reflexive blinking, sucking, breathing, sleeping
Rosenstein and Oster (1988)
Found that babies only 2 hours old produce different facial expressions in response to bitter, sour and salty tastes.
Growth charts
Depict average values of height, weight, and other measures of growth
Experience-dependent
Development of neural connections that is initiated in response to experience; allows humans to learn from experience
Experience-expectant
Development of neural connections under genetic controls that occurs in any normal environment; processes of brain devlpmnt. anticipate or expect
Substage 1 (sensorimotor)
Exercising reflex schemas: 4-6 weeks, infants learn to control and coordinate the reflexes present at birth: involuntary rooting, sucking, grasping, looking
Two major classes of brain development
Experience-expectant and experience-dependent
In just 12 short weeks, babies will:
Gain approx. 6 pounds and grow more than 4 inches in length.
Jean Piaget
Grand theorist provided explanation for infant's transition from reflexive behavior to coordinated behavior
Conditional Stimulus (CS)
In classical conditioning, a stimulus that elicits a behavior that is dependent on the way it is paired with the unconditional stimulus (UCS)
Unconditional response (UCR)
In classical conditioning, the response such as salivation, that is invariably elicited by the unconditional stimulus (UCS)
Unconditional stimulus
In classical conditioning, the stimulus, such as food in the mouth, that invariably causes the unconditional response (UCR)
Baby's head
Infant's skull is composed of seven flat membraneous bones that are relatively soft and elastic.
By 7 or 8 months of age
Infants are able to crawl and visual acuity is close to the adult level
Phonemes
Infants are sensitive to the smallest sound categories of human speech: basic language sounds.
Between 2 and 3 months
Infants can coordinate the vision of both their eyes
6-8 months of age
Infants have ability to make phonemic distinctions narrowly in their own language
Moro Reflex
Infants make grasping motion with their arms in response to a loud noise or when they are suddenly experiencing a feeling of being dropped. Disappears in 6-7 months; significance is disputed
Operant conditioning
Learning in which changes in behavior are shaped by the consequences of that behavior, thereby giving rise to new and more complete behaviors
classical conditioning
Learning in which previously existing behaviors come to be elicited by new stimuli.
Exogenous
Looking that is stimulated by the external enviornment (IE) early sensitivity to light change
Developmentalists take a middle ground:
Maintaining that initial sensory capacities are biologically determined, but only to the extent that they guide how experience shapes later development
When neuron arrives at the synapse, the sending neuron secrets a chemical
Neurotransmitter
Stepping reflex
Newborns held in upright position with their feet touching a flat surface, they make rhythmic leg movements as if they were walking: stop around 3 mo/age.
Early stepping disappears because
Not changes in cortex, but because changes in baby's muscle mass and weight that make stepping difficult
Integration
Occurs as separate actions become coordinated into new patterns of behavior IE) Reaching becomes coordinated with grasping
Endogenous
Originating in the neural activity of the CNS. (IE) Eye movements of infants
Sensorimotor stage
Piaget's term for the stage of infancy during which the process of adaptation consists largely of coordinating sensory perceptions and simple motor behaviors to acquire knowledge of the world
Substage 2 (sensorimotor)
Primary circular reactions: *accommodation; 1-4 months of age Repeat pleasurable actions for their own sake IE) Qualitative change in purposefully sucking thumb
Substage 3 (preoperational)
Secondary circular reactions: 4-8 months; dawning awareness of the effects of one's own actions on the environment; extended actions that produce interesting change in the environment
Habituation
The process in which attention is novelty decreases with repeated exposure; grew bored
Synaptic pruning
The process of selective dying off of nonfunctional synapses; "use it or lose it" process
Synaptogenesis
The process of synapse formation
Dendrite
The protruding parts of a neuron that receive messages from the axons of other cells
Temperament
The term for the individual modes of responding to the environment that appear to be consistent across situations and stable over time. Typically included under the rubric: children's activity level, intensity of reaction, ease with which they become upset, characteristic responses to novelty, sociability
Dishabituation
The term used to describe the situation in which an infant's interest is renewed after a change in the stimulus - infant perceived the change
Synapse
The tiny gap between axons and dendrites
Intermodal Perception
The understanding that a certain object or event can be simultaneously perceived by more than one sensory system
At birth, the brain contains
The vast majority of all the cells it will ever have - more than 10 billion! However, it will become four times as large.
Crying voluntarily
There is a peak in frequency in infant crying @ 6 weeks of age, followed by a decline at approx 12 weeks
The average baby
Weighs more than 7 pounds, 19.5 inches long, and 14 circumference of head.
It has been estimated that fully 70% of the neurons in the human cortex
are pruned between the 28th week after conception and birth
Other intensive periods of synaptic pruning have
been found in infancy, middle childhood, and adolescence
Two month olds can
distinguish among a variety of phonemes
frontal lobes
for control and coordination of other cortical areas to enable complex forms of behavior and thought
temporal lobes
for hearing and speech
parietal lobe
for spatial perception
Sweet taste
has a calming effect on crying babies and diminishes indications of pain, both physiological and behavioral
Visually guided reaching emerges
in 3 months of age; visual and motor area of cerebral cortex improved: infants locate object, adjust reach and get hands around object, open hands in anticipation of object: **can excelerate if they are given support
Enriched conditions of Rosenzweig's rat experiment concluded
increased rates of learning, overall weight of cerebral cortex (sensory information), increased enzyme of enhanced learning, and larger cell bodies with larger glial cells, and more synaptic connections
In the US, the length of the longest sleep shows
index of infant's maturation
Motion critically
influences newborns' perception of faces
The schema, according to Piaget:
is the most elementary form of understanding - a mental structure that provides a model for understanding the world.
Newborns' senses of touch and smell are considerably
more advanced than their sharpness of vision
Another reason for growth in brain size is because of
myelin, a sheath of fatty cells that insulates certain axons and speeds the transfer of information from one neuron to the next.
Newborns are very
near-sighted, they can see at 20 feet what an adult with normal vision can see at 300 to 600 feet
Normal full term-newborns enter the world with all sensory systems functioning, however
not all of these systems have developed to the same level
Differentiation
occurs as actions become increasingly fine-tuned and flexible, so that infants can modify them in response to variations in the environment IE) sucking on nipple and thumb differently
The brain stem at birth is
one of the most highly developed areas of the CNS.
The evolution of the visual cortex
prepares the baby for certain types of visual experiences such as seeing patterns and borders between light and dark
As a consequence of the rapidly developing brain,
the circumference of the head will increase by more than an inch.
As the nerve fibers connecting the cortex with the brain stem and spinal cord become myelinated,
the infant's abilities expand
Growth in brain size occurs by adulthood because
there is an increase in the size and complexity of the information-receiving dendrites and information-transmitting axons
Because the spinal cord and brain stem are relatively matured
they can enable movement, respond to visual stimuli, and even elementary forms of learning without cortical involvement can be done
He argued that schemas developed:
through adaptation, a twofold process involving 1) assimilation 2) accommodation
Infants may be born prepared
to perceive certain stimuli as inherently connected to each other IE) Mother's smell, voice, face
Myelinated axons
transmit signals anywhere from 10 to 100 times faster than unmyelinated axons, making possible more effective interconnections and communication.
