week 2 developmental psych module

Development is:

Multi-directional: losses & gains at every age

• Plastic: within-person variability

• Fetal (foetal) brain is a dynamic structure

Timing and sensitive periods for fetal development

What are Effects of Environment \n Poverty, associated with ?

– Increased stress \n – Fewer but more hostile interactions \n – External environmental risks \n – Serious developmental risks

Child’s intellectual ability by environment

Genes don’t work alone:

• As shown, due to unique genetic \n makeup, we respond differently to \n the same environments \n • But the same genes also respond \n differently to the same environments \n when exposed at different periods of \n development

What are Teratogens?

harmful environmental \n agents/conditions that impair \n prenatal development and lead to \n death, birth defects, or later \n emotional, behavioural, and/or \n intellectual impairments \n • Key stages of prenatal period, harms \n fetus in different ways

What are some examples of teratogens ?

Prescription drugs: thalidomide, accutane \n (Vitamin A) \n Illegal drugs: marijuana, cocaine \n alcohol and tobacco \n (Pre-natal exposure to smoking alters gene \n expression, linked to ADHD) \n Environmental hazards: X-rays, pollution \n disease: Rubella, HIV/AIDS, STDs \n Parental factors: maternal malnutrition, \n stress, age; paternal age, Vitamin C \n deficiency, exposure to toxins, smoking

what are some teratogens Risk Factors ?

Dose: Generally larger dose over \n longer time more damage \n May be safe thresholds. \n However, for example: alcohol \n WHO recommends no known safe \n level of alcohol during pregnancy \n Australian NHMRC Guidelines- \n safest = no alcohol during pregnancy \n or breastfeeding.

What are some teratogen risk factors ?

\n Heredity e.g., alcohol \n dehydrogenase gene \n • Interaction effects e.g., alcohol + \n marijuana, no safe thresholds \n • Timing sensitive and critical periods \n See Fig 3.2 \n • Also environmental interactions (e.g. \n low SES, smoking, & developmental \n delays, Perera et al., 2006)

Australian NHMRC Guidelines re: alcohol and pregnancy

“A ‘no-effect’ level has not been established, and limitations in the available evidence make it impossible to set a ‘safe’ or ‘no-risk’ drinking level for women to avoid harm to their unborn children, although the risks to the fetus from low-level drinking (such as 1 or 2 drinks per week) during pregnancy are likely to be low. A conservative, public health approach has therefore been taken in recommending that ‘not drinking alcohol is the safest option’ for pregnant women and women planning a pregnancy.”

Result from exposure to alcohol (again a \n teratogen)

• 1 – 3 per day: ARND (Alcohol-related \n Neurodevelopmental Disorder) or Fetal \n Alcohol Effects \n • > 3 per day or binging (5+) in early \n pregnancy: Fetal Alcohol Syndrome

Expression of FAS depends on:

– Timing of alcohol consumption relative \n to the stage of fetal development \n • Incl. exposure prior to pregnancy, incl. by \n father \n • Most vulnerable between 3 – 6 weeks \n – Dose and frequency of consumption \n – Socio-behavioural risk factors (maternal \n age/duration of drinking, low SES, race, \n genetic differences, polydrug use) \n (O’Leary 2004)

Infant Brain Development

• At birth \n – birth: 25% adult brain weight \n • 2 years: 80% \n – Increases due to dendrite growth and \n myelination

Determinants of brain \n development

Maturation + Stimulation \n • Deprivation studies \n e.g., Rozenweig’s (1984) rat experiments \n e.g. Human deprivation studies (Beckett et al., \n 2006)

What is face perception ?

preference for mother’s face and the still face experiment

What is depth perception ?

Ability to judge distance of objects • Tied to motor development, esp. crawling –the Visual Cliff

Toddler imitation :

• Depends on motor and cognitive \n skills necessary to carry out the \n action to be imitated. \n • @ 15 months, children this age are \n usually mobile and have some hand- \n eye coordination. \n • “Serve and return” (video, Kingston \n & his dad)