PSYA02H3 Chapter Notes - Chapter 12: Stereopsis, Stethoscope, Social Change

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3 Apr 2011
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Prenatal Development
Prenatal period9 months between conception and birth
Factors direct the mechanisms of replication:
1) one of the 2 X chromosomes that women bear, most of its genes do not synthesize
the proteins they normally would
it limits the total amount of proteins produced by genes
without this limit, the metabolism of a developing female would be very
different from that of a developing male
silenced” chromosome is passed along to descendant cells
A modification of cell inheritance that is not due to alterations of the DNA
sequence itself
2) Epigenetic changes include the way the DNA molecule is folded within other
proteins, chemical changes in the structure of the nucleotide cytosine, and
complex modifications in the way DNA information is mapped into protein
synthesis
-cells chemical environment moderates the expression of its genetic code
-wile the genetic information contained within the individual remains the same
throughout development, the reproducing cells become specialized as blood
cells, neurons, and muscle cells
Stages of Prenatal Development
Zygote stage (2 weeks) – single new cell that is formed at conception, divides many
times and the internal organs begin to form
- the end of the 1st week – the zygote consists of about a 100cells (2 layers)
1) skin, hair, nervous system, and sensory organs
2) digestive and respiratory systems ad glands
- the end of this stage – 3) muscles and the circulatory and excretory systems
Embryonic stage (2 weeks – 8 weeks after conception) – the heart begins to beat
-the brain starts to function, and most of the major body structures begin to form
-the end of this stage – the major human body (arm, finger, toe, eye) are defined
-most susceptible to external chemical influences (alcohol, drugs)
teratogens (Greet eras = malformation) – any substance, agent, or event that can
cause birth defects
androgensthe primary class of sex hormones in males (testosterone is most
important); gennan meansto produce”
- female sex organs does not need to be stimulated by a hormone
Fetal Stage (7months) – beginning with the appearance of bone tissue
the end of 3rd month – show some movement(kicking) – major organs, bones, muscles
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the end of 4th month – sleeping and waking regularly
-heartbeat is loud enough to be heard through stethoscope
Threats to Normal Prenatal Development
-teratogens cause birth defects
tetracycline (a common antibiotic) – cause irregularities in the bones and
discoloration of the teeth
Cocaine - an increased risk of premature birth, low birth weight, and a
smaller-than-normal head circumference
- consequences in the areas of arousal and attention
- babies are born addicted and show withdrawal symptoms such as
hyperactivity, irritability, tremors, and vomiting
Cigarette (lower arousal levels)carbon monoxide reduces the supply of
oxygen to the fetus harmful during last half of pregnancy (because it
develops most rapidly and demand for oxygen)
deficits to process speech sounds
Alcohol (FAS)– effects both pre- and postnatal growth deficits
deformations of the eyes and mouth, low brain mass, other brain and
central nervous system abnormalities, and heart deformation
their physical and intellectual development still falls short of others
Agricultural pollutionorganophosphorus pesticides had a much larger
risk of damage to the chromosome structure of their sperm cells
Physical and Perceptual Development in Infancy and Childhood
Motor Development (nervous system and practice)
-normal motor development is dictated by maturation of the muscles and the
nervous system
Maturationan relatively stable change in thought, behaviour, or physical growth
that Is due to the aging process and not to experience
-infants most important movements are reflexes: rooting ( , ), sucking,
and swallowing responses
Perceptual Development
Form Perception
-visual perceptual abilities
1 month - babys gaze seems to betrapped” by the edges
2 month – baby scans across the border to investigate the interior of a figure
1 or 2 month – babies dont perceive complete shapes; their scanning strategy
is limited to fixations on a few parts of the object at which are looking
3 month – clear signs of patter recognition (human face)
4 or 5 months – discriminate between even very similar faces
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Distance Perceptionthe ability to perceive 3D space
- (retinal disparity) perception of depth occurs when the two images are fused
through visual processing
-stereopsis (“solid vision”) will not develop unless animals have experience
viewing objects with both eyes during a period early in life
-if eyes are crossed = same points on the two retinas receive the same information
= no disparity and no depth perception through stereopsis
Critical and Sensitive Periods in Perceptual Development
Critical perioda specific time in development during which certain experiences
must occur for normal development to occur
Sensitive perioda period of time during which certain experiences have more of an
effect on development than they would have if they occurred at another time
e.g. second language is learned more easily in childhood than later
Cognitive Development in Infancy and Childhood
12 months are able to form memories of specific events
The Work of Jean Piaget
Operationin Piagets theory, a logical or mathematical rule that transforms an
object or concept into something else
-Piaget proposed that schemata are first defined in terms of objects and actions
but that later they become the basis of the concrete and abstract concepts that
constitute adult knowledge
Assimilationthe process by which existing schemata are modified or changed by
new experiences
e.g. meets new children and adults, they will usually fit into his existing schemata
Accommodationthe process by which existing schemata are modified or changed
by new experiences
Piagets Four Periods of Cognitive Development
Equilibrationa process within Piagets theory that reorganizes schemata
1) Sensorimotor period (0-2) – is marked by an orderly progression of increasingly
complex cognitive development: reflexes, permanence, a rough approximation of
causality, imitation, and symbolic thinking
-during this period, cognition is closely tied to external stimulation
object permanencethe idea that objects do not disappear when they are out of sight
(6 months) – children lose all interest in an object that disappears from sight (thinking
is doing)
Last half of the 1st year – look at an object form various angles
- out of sight is no longer out of mind
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Document Summary

Prenatal period 9 months between conception and birth. Factors direct the mechanisms of replication: one of the 2 x chromosomes that women bear, most of its genes do not synthesize the proteins they normally would. it limits the total amount of proteins produced by genes. without this limit, the metabolism of a developing female would be very different from that of a developing male. silenced chromosome is passed along to descendant cells. Wile the genetic information contained within the individual remains the same throughout development, the reproducing cells become specialized as blood cells, neurons, and muscle cells. Zygote stage (2 weeks) single new cell that is formed at conception, divides many times and the internal organs begin to form. The end of the 1st week the zygote consists of about a 100cells (2 layers) 1) skin, hair, nervous system, and sensory organs. The end of this stage 3) muscles and the circulatory and excretory systems.

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