PSYC 206 Lifespan Development Bilge Yagmurlu

Chapter Overview Temperament Physical Growth Sensing the Environment The Organization of Behavior Becoming Coordinated with the Social World

Physical Growth In 12 weeks, infants Gain about 6 pounds Grow more than 4 inches Expanding head circumference Growth charts: Show the average values of height, weight, and other measures of a normally developing infant.

Growth Chart

Brain Development The brain at birth Contains most of the neurons it will ever have. Will grow four times larger by adulthood

Brain Development Growth in brain size as a results of: Neuronal connections Synaptogenesis: process of synapse formation Synapse: Site where a nerve impulse is transmitted from one neuron to another.

Brain Development Myelination Insulates axons and speeds transmission of impulses 7

Central Nervous System Brain, brain stem and spinal cord

Central Nervous System Spinal cord: extends from below the waist to the base of the brain. Brain stem: controls reflexes as blinking and sucking and vital functions such as breathing. Relatively more mature at birth Enable movement, responses to stimuli etc.

Central Nervous System Cerebral cortex: outermost layer and center for perception of patterns, decision making, speech, planning and execution of complex motor sequences Less mature at birth 10

Development of the Brain Two major classes of development: Experience-expectant process Under genetic controls, occur in any environment Example: evolution of parts of the brain responsible for language. When expected experiences lack in sensitive periods, then the brain will fail to develop normally Synaptic pruning: 70% pruned in four months

Development of the Brain Experience-dependent process Initiated in response to experience These processes have evolved to allow the organism to take advantage of new and changing information in the environment. 12

Development of the Brain Experience-dependent process Example: work on enriched environments by Rosenzweig and colleagues Impoverished environment Rat brain cell Enriched 13

Sensing the Environment Newborns’ sensory systems Variations in functioning show importance of systems for survival Indications of sensation Habituation Dishabituation

How to measure sensory reactions? Measure reaction to stimuli Does a baby turn her head in the direction of a sound? Habituation paradigm: relies on infants’ tendency to pay less and less attention to a repeatedly presented stimulus (habituation) If the stimulus changes in a way that makes it seem new to the infant, he will once again pay attention (dishabituation)

Sensing the Environment Newborns’ sensory systems Variations in functioning show importance of systems for survival Indications of sensation: perceiving an object or event Habituation: attention to novelty decreases with repeated exposure Dishabituation

Early Sensory Capacities as opposed to the views of earlier century thinkers (e.g., John Locke’s tabula rasa), babies enters the world with some well-organized behaviors sensory capacities: visual, auditory, taste-related, and tactile capacities are all functioning but, some capacities are more mature than others looking, sucking, and crying are 3 behaviors that, unlike reflexes, are often not elicited by a discrete, identifiable stimulus

Early Sensory Capacities

Hearing Sensitivity to phonemes 2-month-olds can perceive distinctions used in all the world’s languages By about 6 to 8 months of age, only the sounds made in the language(s) they hear

Hearing Infants can distinguish the sound of the human voice from other kinds of sounds, and seem to prefer it Are particularly interested in speech with the high pitch and slow, exaggerated pronun- ciation (i.e., “baby talk”) Evidence that by 2 days old, some babies would rather hear the language that has been spoken around them than a foreign language

Vision Newborns are very nearsighted Newborns are able to: scan their surroundings perceive patterns and distinguish among forms. perception of contrast show a preference for faces distinguish their mother’s face

Vision

Perception of Faces Infants show a preference for patterned stimuli over plain stimuli Babies as young as 9 minutes old will look longer at a schematic moving face than a scrambled one

Taste and Smell Responses to Sweet tastes and smells Example: breast milk Calming effect Pain relief Sour, bitter, and salty tastes

Taste sensitivity to taste may be present before birth when saccharin was added to the amniotic fluid of a near-term fetus, increased swallowing was observed newborns prefer sweet substances than plain water-- suck longer with fewer pauses

Intermodal Perception The simultaneous perceiving of an object or event by more than one sensory system

The Organization of Behavior Behavioral organization is important for Interacting more effectively and adaptively with their surroundings Increasing physical control and coordination Smiling in response to the smiles of others Performing deliberate actions

The Organization of Behavior Reflexes Highly organized specific involuntary responses to specific types of stimulation Building blocks for action Some are adaptive, temporarily or permanently Unusual patterns may be informative about development

Grasping Reflex When a finger or some other object is pressed against the baby’s palm, the baby’s fingers close around it Disappears in 3-4 months; replaced by voluntary grasping

Piaget’s Theory of Developing Action Sensorimotor Stage Perspective Infants gain knowledge largely by coordinating sensory perceptions and simple motor responses

Piaget’s Theory Sensorimotor Stage: Substage 1 (0 - 1.5 months): Exercising reflex schemas. infants learn to control and coordinate inborn reflexes Substage 2 (1.5 - 4 months): Primary circular reactions. New forms of behaviors appears. accommodation first appears, with infants’ prolonging pleasant sensations arising from reflex actions

Becoming Coordinated with the Social World Infants’ survival depends on: Responsive caregivers Coordinate their own actions with those of caregivers Infant to caregiver Caregiver to infant Sleeping and feeding

Crying Primitive means of communication The effects of infant crying: Evokes a strong emotional response in adults Warning that something may be wrong Certain distinctive patterns may indicate difficulties