Early development

1
Early development

• Depiction of the Fetus at 10 weeks
• Gender typically determined by sonogram at 20
  weeks (not always accurate)
• Gender test can be done sooner and more
  accurately by extracting amniotic fluid from the
  placenta

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Development of humans

• Zygote conception 2 weeks genetic structure
  is formed
• Embryo 2 to 8 weeks All of the organs are
  formed and will begin to function shortly limbs
  have also begun to form
• Fetus 9 weeks to birth
• Prior to the 11th week, a yoke sac provides blood
  cells for the fetus. After the 11th week, the
  fetus own liver, spleen, and bone marrow take
  over blood production.
• Umbilical cord provides food and oxygen removes
  waste
• Thumb sucking may occur if the limb floats around
  the mouth
• Toxic agents at different developmental periods
  will result in different types of damage (e.g.,
  late limbs vs. early organs)

3
Early abilities of the infant

• Reflexes (rooting, sucking, babinski or palmer,
  stepping, orienting, gag, etc.)
• Can recognize mothers voice within 2 days
• Initially the visual system is only accurate up
  to 6 inches (distance from babys face to
  mothers when breast feeding).

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Important environmental factors

• Physical contact warmth, contact, feeding
• Harlows (1958) monkeys choice of mothers
• Familiarity strong attraction to facial
  features that were ingrained during critical
  periods
• Lorenz (1952) demonstrated the importance of
  imprinting in ducks
• Humans show periods of sensitivity rather than
  critical periods
• Deprivation typically results in aggression, and
  asocial behavior

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Early parental learning

• Attachment styles in animals (Bowlby) and in
  humans (Ainesworth)
• Secure, avoidant, anxious-ambivalent
• Parenting styles although there are innate
  differences between children, the childs
  environment (which includes parenting) can also
  alter outcomes
• authoritarian, permissive, authoritative

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Theoretical stages of development

• Piaget (1969, 1972)
• Sensorimotor, 12-18 months reflexes, movement
• Preoperational, 2-7 yrs internal mental
  representations (object permanence), egocentric
• Concrete operations, 7-12 yrs conservation of
  mass, reversible processes, etc.
• Formal Operations, 12 yrs - abstract thinking,
  second order relations
• Vygotsky (1934) zone of proximal development
  difference between observable abilities and
  potential (given the right context)

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Eriksons Developmental Stages (lifespan model)
1. Trust vs. mistrust - infant learns to trust parents for survival needs 4. Industry vs. Inferiority - trial and error with mastery, learn which tasks you can do. 7. Generativity vs. stagnation - Have you achieved anything productive?
2 Autonomy vs shame - learn to act independent of parents 5. Identity vs. Role confusion - self identity begins to form (why now?) 8. Integrity vs. despair - Happiness with ones life, though resigned to the fact its ending
3. Initiative vs. guilt - learn to initiate actions, thoughts, and emotional experiences 6.Intimacy vs isolation adult relationships decision is often made more than once Numerous ego crises occur throughout (e.g., adolescence, midlife, late life)
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Eriksons lifespan development

• Most development occurs early in life (5 of 8
  stages by adolescence)
• A series of conflicts which must be resolved by
  achieving a balance
• Stage theory implies that early problems
  negotiating stages leads to later problems
• Most research suggests that the developmental
  nature of the stages is largely determined
  socially

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Moral Development

• Preconventional
• Dont get caught
• Whats in it for me
• Conventional
• I am good/nice
• Preserve social order
• Postconventional
• Ensuring the rights of all
• What is best for everyone
• Theoretical dilemmas vs. reality,men vs. women

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Sensation and Perception

• Information from the environment is transferred
  to our brain by way of a series of neurochemical
  messages.
• Primed to detect changes in the environment
  (i.e., to notice differences) detection when
  neurons fire
• Absolute threshold amount of a stimulus needed
  to detect it 50 of the time.

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JNDs (just noticeable differences)

• Difference threshold (JND) the amount of change
  in a stimulus necessary to detect that change 50
  of the time
• The JND can be calculated as a constant
  proportion of the original stimulus e.g.,
  electric shock (.01), heaviness (.02), loudness
  (.05), brightness (.08), salty taste (.20)

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The firing and resting of neurons

• Sensory adaptation neurons become fatigued from
  constant firing, so this process slows down. This
  results in decreased sensitivity for unchanging
  stimuli
• Why do the receptors in our eyes not grow
  fatigued from unchanging stimuli? (less
  sensitivity not seeing them)
• Eyes are constantly quivering so that the same
  information does not appear on the same
  photoreceptors. When eyes are held steady,
  objects disappear

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Context effects

• The brain uses information surrounding any
  stimulus to define the stimulus
• Sometimes the surrounding info can result in
  erroneous conclusions by the brain (e.g., the
  blind spot example figure-ground comparisons,
  the Muller-Lyer illusion, the size of the sun on
  the horizon, contrast effects, etc.)
• Occipital lobes primarily for vision

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Color vision

• Opponent process theory of color vision a
  single neuron is responsible for the detection of
  two colors, one while firing and one while
  inhibited
• Red-green, blue-yellow, black-white
• Explains after image effects and color blindness
• About 1/50 are color blind (more males) and most
  common type is red-green color blindness
• Cones detect color and detail concentrated in
  the fovea (7-8 million) adapt faster to changes
  in light
• Rods more sensitive to the detection of light
  mostly in the periphery of the retina (120-125
  million) slower adaptation to light

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Cues for visual distance

• Binocular cues
• 1) convergence (muscular)
• 2) retinal disparity
• How can you convey distance on a two-dimensional
  plain?
• Monocular cues
• Relative size, relative height, relative
  brightness, overlap, texture (smooth from greater
  distance), linear perspective, relative motion
  (fixation point beyond it objects move with us,
  vs. before it)

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Hearing

• Two theories on how it works
• 1) place theory we hear different pitches
  because sound waves of different frequencies
  trigger receptors at different points along the
  membrane (high pitch sounds occur at the
  beginning of the membrane near the cochlea) the
  guitar string analogy

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Hearing

• 2) frequency theory membrane vibrates (neurons
  fire) with the same frequency as the incoming
  sound waves
• Problem is that a neuron can only fire 1000/sec
  and we hear sound waves beyond such frequencies
• Solution the volley principle neural cells
  fire alternatively in order to reach the higher
  frequencies (e.g., 2 cells can reach 2000/sec)
• Sound intensity ranges from 0 decibels (lowest
  sound audible to humans) to 180 decibels (rocket
  launch pad where hearing loss is inevitable in
  front of speakers at Rock concert 120dB)
• Loudness (dB 1/10th of bell), Pitch (frequency
  in Hertz), Timbre (complexity a single sound
  wave or many)
• Echolocation use of sound to locate source of
  sound
• Equilibrium fluid in the vestibular sacs of the
  inner ear for balance

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Sense of smell

• Olfactory functioning a more developed sense in
  other species (e.g., larger portion of the dog
  brain is devoted to smell they experience the
  world in this way, olfactory memories, dream?)
• Memories based on smell have very long duration
• Pheromones secreted by animals to trigger
  reactions (identification, territory, sexual
  availability, etc.)
• Female have more discriminating sense of smell
• Can ID women from smell of sweat (at 1.5 inches)
• Can be damaged from infection, disease, smoking
  (2 packs/day for 10 years will need 10 more years
  of abstinence for sense of smell to return to
  normal)

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Taste and the other senses

• Taste four basic tastes of sour (sides), bitter
  (back), salty (sides), sweet (tip). (Umami
  taste for glutamates such as MSG)
• Locations are just concentrations of sensitivity
• Saliva spreads tastes to all parts of the tongue
• Olfactory sense enhances taste (apple potato
  taste the same without smell only 5 correctly
  identified garlic, chocolate, and coffee without
  smell)
• Attractiveness of food is influenced by its
  color, temperature, and texture, along with
  social/cultural experiences (a bowl of worms?)
• Kinesthesia skeletal receptors in the muscles
  joints that inform brain of position of limbs
• Synesthesia A neurological disorder involving a
  mingling of the senses (sensory info is
  interpreted by the wrong sense). Taste how a
  shape feels?

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Adaptive senses

• Adaptation of the brain is evidenced when sensory
  information is altered to facilitate functioning
  (how long does it take the brain to adapt?)
• Glasses that invert the visual field (QB from
  Stanford)
• Demonstrated through Gestalt (organizational)
  principles
• 1) Proximity, 2) Closure, 3) Similarity, 4)
  Continuity

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Maladaptive senses

• Extra-sensory perception! knowledge of the
  world without using the usual sensory channels
• Most evidence is anecdotal which is not accurate
  (e.g., forget premonitions that dont occur)
• Studies in parapsychology focus on ESP with the
  general conclusion that there is no effect
• Secrets of the psychics
• Recall that we can perceive without knowing it
  (subliminal perception), but this is not ESP

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Exam Review

• Questions for next weeks exam? (Bring narrow
  scantron and 2 pencil)
• Review sections to be covered
• Please sign up for experiments ASAP
• Next The brain and CNS how neurotransmitters
  work.