Dr' Jamie Drover

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HUMAN DEVELOPMENT 1PSYCHOLOGY 3050Biological
Bases of Cognitive Development

• Dr. Jamie Drover
• SN-3078, 737-8383
• e-mail jrdrover_at_mun.ca
• Winter Semester, 2009

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Developmental Systems Approach

• Why do species members develop in the species
  typical pattern.
• We inherit species-typical genes and a species
  typical environment (see duck example, p 35).
• Behavior is influenced by subtle aspects of the
  environment.

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Developmental Systems Approach

• Humans develop in species-typical environments
  (prenatal and postnatal)
• Experience directs us in species typical ways.
• E.g., Development of hemispheric asymmetries.
• May be due to the timing of the nature of
  prenatal auditory experiences (Turkewitz, 1993).
• Exposed to socially important sounds when the
  left hemisphere of the brains is hitting a growth
  spurt.

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Developmental Systems Approach

• Hemispheric asymmetries are due to an interaction
  between genetically paced maturation and prenatal
  experience.

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Last Class

• Extended juvenile period
• Biologically Primary and Secondary Abilities
• Selectionist Theories
• Models of gene-environment interaction
• Developmental Systems Approach
• Epigenesis
• MAOA example
• Species typical development

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Developmental Timing

• Critical Period A time in development when a
  skill or ability is most easily acquired.
• If the required experience occurs outside this
  period, it will not be easily acquired (or not
  acquired at all).
• Language (1st and second 2nd) are most easily
  acquired during childhood.
• Overall, timing of perceptual experience is
  crucial.

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Developmental Timing

• Too much early stimulation is not always good
• e.g., In vertebrates, vision develops more slowly
  than hearing
• Lickliter (1990) suggested that slower vision
  allows hearing to develop without competition
• Gave bobwhite quail pre-hatching visual
  experience
• Cut a window in shell chicks could see
• Unnatural normally they only hear

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Developmental Timing

• Tested post-hatching on call of quail vs chicken
• No early vision preferred quail call
• Early vision no preference for quail or
  chicken, but showed better visual discrimination

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Developmental Timing

• Is there a possibility of sensory
  over-stimulation?
• What about parents providing extra stimulation to
  infants?
• Is it an advantage or a disadvantage for
  development?
• Question of what exactly is extra and when is it
  given
• Question has not been properly evaluated

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Developmental Timing

• Some evidence that over-stimulation beyond what
  is normal does not provide any advantage
• Coached young monkeys on a discrimination
  learning problem beginning at 60, 90, 120, or 150
  days
• At 120 days more complex task
• Young coached problem-solvers were poorer that
  older coached
• Similar effects have been found in humans

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Developmental Timing

• Premature infants may experience deficits due too
  much sensory exposure.
• May lead to enhanced performance in some domains
  at the expense of functioning in others.
• Could have an adverse effect on brain development

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Developmental Timing

• Could over-stimulation require them to process
  info from the postnatal environment before they
  are ready
• Could this have an adverse effect on brain
  development?
• Some extra stimulation is needed to ensure life
  and health
• These are important and still controversial
  issues

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Genotype-Environment Theory

• Behavior genetics studies genetic effects on
  behavior and complex psychological
  characteristics such as intelligence and
  personality.
• Scarr McCartney genes drive experience

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Genotype-Environment Theory

• A childs inherited characteristics influence
  which environments he/she encounters and the type
  of experiences he/she has, which in turn
  influences his/her development
• niche picking
• Parents are also in the loop
• Their genes influence the type of environment
  they feel comfortable in and the genotype of the
  children

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Genotype-Environment Theory

• There are multiple levels of influence.

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Genotype-Environment Theory

• There are three types of genotype-environment
  effects that influence development.
• Passive effects
• Parents provide genes and environment
• Effects cant be separated
• Effects lessen with age

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Genotype-Environment Theory

• Evocative effects
• Childs characteristics (e.g., temperament)
  elicit reactions from others
• Effects constant with age
• Active effects
• Child seeks out environments consistent with
  genotype
• Effect increases with age as child becomes more
  independent