Development Flashcards
What is development?
Study of continuity and change across life span, from conception/birth to adolescence to adulthood.
Process of fertilization
200 million sperm travels through the vagina and uterus to the Fallopian tubes. There, 1 in every million get close enough to release enzymes that breaks down the protective layer of the egg. The egg reseals this layer, and the sperm sheds its tail and fertilizes it.
Zygote
Fertilized egg that contains chromosomes from both an egg and a sperm. XX = Female and XY = Male
Germinal stage
2 weeks after conception. The zygote divides into trillions of cells, and migrates and implants itself in the uterus. Once it’s implanted, it’s called an embryo.
Embryonic stage
2nd week -> 8th week.
Embryo continues to divide and cells undergo differentiation. It becomes an inch long and has a beating heart and arms and legs. By 3rd or 4th week after conception, cells that become brain are already dividing.
What do embryos with XY chromosomes do in the embryonic stage?
Produce testosterone to masculinize reproductive organs
Fetal stage
9th week-birth.
Develops skeleton, muscles and ability to move; thick insulting layer of fat beneath skin; maturing of digestive and respiratory systems; and brain is developing, neurons undergoing myelination.
Why does 75% of brain development occur outside the womb?
Otherwise, the head would be too big for the baby to exit the birth canal safely
Prenatal environment
Bloodstreams of mother and embryo/fetus are linked; permits exchange of chemicals.
Teratogens
Substance that passes from mother to unborn child that impairs development (e.g. environmental poisons like lead, alcohol which can cause abnormalities, tobacco which can cause death/low birth weight, caffeine in excess and sugar which can lead to diabetes mellitus)
Infancy stage
Birth to 18-24 months - this range is determined by developmental milestones.
What is perception like in the infancy stage?
Limited range of vision, but visually responsive. Attentive to social stimuli; mimic facial expressions.
What is motor development like in the infancy stage?
Ability to execute physical actions. Born with reflexes, which are patterns of motor responses triggered by patterns of sensory stimulation (e.g. sucking)
Childhood
18-24 months to about 11-14 years.
Rules for development
Cephalocaudal rule and proximodistal rule
Cephalocaudal rule
Greatest development takes place at the top of the body, i.e. the head, and physical development moves gradually downwards: e.g. neck, shoulders, trunk, etc.
Proximodistal rule
Development from centre of the body outwards - tendency for more general functions of limbs to develop before more specific or fine motor skills.
Cognitive development
Emergence of ability to think/understand.
What are the 3 goals of cognitive development?
1) How physical world works
2) How minds represent the world
3) How other minds represent the world
Piaget’s 4 stages
- Sensorimotor stage
- Preoperational stage
- Concrete operational stage
- Formal operational stage
Sensorimotor stage
Developing the ability to sense and move to acquire information about the world.
Age range: Birth to end of infacy
Develops schemas, assimilation and accomodations; lack complete objective permanence (belief that objects exist even when they are not visible)
Schemas
Theories about the world
Assimilation
Apply schemas in novel situations
Accomodations
Infants revise schemas in light of new information.
Preoperational stage
Preliminary understanding of the physical world.
Age range: 2-6 years.
Involves centration and egocentrism.
Centration
Focus on one property of an object to exclusion of others. Lack of reversibility. (e.g. 2+4 = 6 or 3+3 = 6)
Egocentrism
Failure to understand world is different for different people. If they’ve master the false belief task, AKA to recognize that others can have beliefs about the world that are diverging, then they’ve advanced out of this stage.
Concrete operational
Learn how actions or operations transform concrete objects of physical world.
Age range: 6-11 years.
Involves conservation. Realization that things in the world are not what they always seem.
Conservation
Quantitative properties of an object are invariant despite changes in the object’s appearance.
Formal Operational
Can reason systematically about abstract concepts (e.. love, liberty), hypotheticals and counterfactuals (things that aren’t necessarily true). Starts around age 11. Includes theory of the mind.