Slides Week 2 Flashcards
Causes of Development
- Philosophical debate around the cause of human development
- Nature - Biology/Heredity/Maturation (Rousseau)
- Nurture - Locke’s tabula rasa, Bandura
Maturation
- Aspect of Nature
- Natural growth that unflods in a fixed sequence
- Growth that is independant of the environment
Behaviourism
- All behaviour is learned
- There is no such thing as free will
- Watson & Skinner
Contemporary Approaches to Developmental Psychology
- Heredity and biology creates predispositions
- Predisposition interacts with environmental influences
- How much nature or nurture combinations are still not certain due to
- Need to differentiate simple vs. complex Characteristics (e.g. height v. intelligence).
- Reciprocal interaction between heredity and environment are correlated, e.g., intelligence.
- Children are Niche Pickers they actively choose
environments that best suit their genetic predispositions.
Prenatal Development
- Development begins at fertilisation of ovum
- New cell nucleus is created from genetic material of both parents
- One celled organism is created call a zygote
Three Stages of Prenatal Development
- Germinal Stage
- Embryonic Stage
- Foetal Stage
Germinal Stage
- Fertilisation to two weeks gestation
-
Zygote begins to divide 24-36 hours after
fertilisation - Travels down the fallopian tubes
to the uterus. -
Blastocyst is formed (150 cells), attaches to
the walls of the uterus and is fully embedded
in the wall of the uterus.

Embryonic Stage
- Two weeks gestation to two months gestation (i.e., week 3 to week 8 after conception
- Rapid development of major organs
- Placenta Develops
e.g., heart, nervous system, stomach, sex organs.
- By end of this stage embryo Measures 2.5cm in length.
- Develops eyes, ears, nose, jaw, mouth,lips, arms, hands, fingers, legs, feet, toes.
Foetal Stage
- Two months Gestation to nine months gestation
- Six months gestation
- Eyelids open.
- Foetus can breathe regularly for 24 hour length periods.
- Viable (but not guaranteed) of surviving outside of the womb.
- Eight months gestation (i.e. from approx.
- Responds to light and touch.
- Learning occurs
- habituation.
Habituation
- a decrease in response to a stimulus after repeated presentations
Factors affecting prenatal development
- The timing and stages of prenatal development are Biologically determined
- Affected by the environment in the womb
- Effects of teratogens especially important.
Teratogens
- External substances that can penetrate the placenta,
- Cause spontaneous abortion or birth defects.
- Affect development when ingested by during rapid organ development

Teratogen Examples: Maternal Illness
- Bacteria and protozoa
- Toxoplasmosis (raw meat/fish, cat feces).
- Effects: blindness, deafness, intellectual disabilities
- Toxoplasmosis (raw meat/fish, cat feces).
- Viruses
- Rubella ( esp 1st trimester)
- Effects: blindness, deafness, intellectual disabilities, heart defects, cerebral palsy, microcephaly, risk of miscarriage, fetal death
- Cytomegalovirus (CMV) → flu like symptoms
- Effects: blindness, deafness, intellectual disabilities, neurological deficits, risk of miscarriage, fetal death
- Herpes Simplex (C section recommended to avoid exposure to virus)
- Effects: eye/vision problems, early exposure = brain damage/death
- HIV/AIDS (contracted through blood exchange, breastfeeding)
- Rubella ( esp 1st trimester)
Teratogen Exmples: Drug Use
- Nicotine
- Alcohol
- Thalidomide
Teratogens - Environmental Factors
- Maternal Nutrition
- Environmental toxins and hazards, pesticides, lead & mercury
- Emotional Stress
Newborn Physical Development
- The physical body grows rapidly from birth throughout infancy
- Weight:
- 3kg at birth; infant’s weight doubles by 4 months; gradual weight increase to 2 years as bones & muscles grow.
- Length:
- Babies gain 2.5cm per month for each of the first 12 months .
Newborn Physical Development
- By infancy’s end, 2 year olds achieved:
- 50% adult height.
- 20% adult weight.
- Brain undergoes massive development and growth
- 2 years old: 75% of adult brain weight.
Newborn Vision
- Newborn vision is blurry (20/300 eyesight).
- Able to see large objects at close range.
- Stare longest at objects that have qualities and contours resembling those of a human face.
- Depth perception Develops at 7 months of age.
Newborn Depth Perception
- The visual cliff
- A test of acquired depth perception
- Depth perception acquired around the same time
Newborn Hearing
- Hearing attuned to sounds of speech with a preference for:
- Rising tones (women/children; men tend to use the same tone of voice for infants, children and adults).
- High pitched, exaggerated, expressive speech, parentese
- Hearing does not develop adult like acuity until childhood.
Newborn Smell
- Odor preferences from birth
- Affected by mother’s diet during pregnancy
- Can locate odors and identify mother by smell from birth
Newborn Taste
- Prefer sweet tastes at birth
- Aversion to sour and bitter tastes
- Preference for salty foods by 4 months
- Quickly learn to like new tastes
Newborn Touch
- Develops before all other senses
- Helps stimulate early physical growth
- Vital for emotional development
- Gentle stroking can reduce distress in infants
- Physical touch releases endorphins
Pain Sensitivity in Newborns
- Sensitive to pain, even at birth
- Pain increases levels of cortisol which can impact development
- Relieve pain with:
- anesthetics
- breast milk
- sugar
- gentle holding
Newborn Motor Development
- Refers to the progression of muscular co-ordination required for physical activities.
- Gross Motor
- Fine Motor
Cephalocaudal Development
Head to foot direction of motor development
Proximodistal Development
- Centre to outward extremities
- Gain control of core then extrimities
Newborn Reflexes
- Important aspect of newborn motor development
- Are involuntary
- Unlearned behaviours that occur in response to external stimuli
- Tonic neck Reflex
- Grasp Reflex or Palmer Grasp
- Step Reflex
- Crawl Reflex
- Rooting
- Moro Startle Reflex - may have adaptive value
Developmental Motor Norms
- Motor abilities develop spontaneously and in the same order
- Motor skills develop at roughly the same rate
- Biological norms as a consequence of maturation
Median Ages for Motor Norms
- Lifts head - 2 weeks.
- Rolls over - 2.5 months.
- Sits - 5.5 months.
- Stands alone - 11.5 months.
- Walks alone - 12.5 months.
Variations up to 2 - 4 months
Challenge to Maturation Perspective
- Recent research indicates motor development results from maturation and experience
- Motor development relies on nature and nurture
Physical Development 2-6 years
- Pace of growth slower in childhood than during infancy:
- 6 - 8cm gain in height per year between ages 2 - 6 years.
- 2 - 3kg gain in weight per year between ages 2 - 6 years.
- Not meeting these milestones: failure to thrive; cause for further investigations/assessments to ascertain why
- Girls and boys grow at similar rates during childhood.
- Growth trajectory same for girls and boys then shifts with pre pubertal growth spurt in girls.
Chart Motor Skills in Childhood

Growth Trends in Middle Childhood
- Regular gains in height and weight:
- Yearly increase of 6cm
- Yearly weight gain of 2.25kg.
- Gains in delicate fine motor control and co ordination
- Necessary for artistic, musical, and athletic accomplishments.
- Brain approaches full adult size early in middle childhood 90% adult volume at 6 years
- Additional 10% that occurs in middle childhood crucial
- Contributes to plasticity of human brain.
Obesity
- Prevalence of overweight/obesity in children and adolescents increased by 47% worldwide from 1980 2013 (Ng et al. 2013).
- Globally, number of overweight children < 5 years ~ >41 million in 2016
- US - 18.4% children between 6 12 years are obese (body weight > 20% above ideal weight) (CDC)
- Australia - 1 4 Australian children (ages 2 17) overweight/obese in 2017/18 (AIHW)
- Causes: dietary intake, physical activity, sedentary behaviour (Sahoo et al. 2015)
- Genetics can play a role but is not cause of dramatic increase in childhood obesity
- Can be subject to stigmatisation and teased/bullied about weight
- May face discrimination, social marginalisation, exclusion from activities (i.e., physical activities
- Can negatively affect school performance
Adolescence 13-20 years
- Profound changes in physical development at adolescence affect developments in cognition and personal psychology:
- Affect how adolescent perceives self
- Affect how adolescent is perceived by others
- Biological event of PUBERTY elicits neurological, cognitive, and social changes in adolescence.
Puberty
- Pubertal changes relate only to universal changes of adolescence
- Physical maturation of child into adult capable of reproduction.
- Triggered by hormonal changes
- Regulated by the endocrine system (glands, hormones)
Puberty involves
- Growth of the reproductive organs.
- Changes in body fat/muscle distribution.
- Onset of menstruation in women ( menarche
- First ejaculation of sperm in males ( spermarche
- Pubertal changes take from 2 years to 4 years to complete.
Secular Trend in Puberty
- Tanner (1968)
- Tendency for puberty to begin at earlier ages than in previous generations.
- The secular trend involves:
- Decrease in the age of menarche
- Age at menarche has dropped by 3 to 4 months every ten years.
- Increase in growth rate
- Increase in height and weight
Why has the Secular Trend in Puberty occured
The secular trend is believed to result from:
- “Improved” nutrition - food is more available
- Food is now hormone enhanced
- Better health care and knowledge of childhood illnesses.
- Improved sanitation
Effects of Pubertal Timing
- Differences in the rate of physical maturation at puberty has THREE consequences for adolescents.
- Some mature earlier .
- Some will mature at approximately the same time
- Some will mature later
- Theories account for effects of pubertal timing
- Deviance hypothesis - partial support.
- Stage Termination Hypothesis - partial support.
Body Image
- Self evaluation that the individual makes of his/her own body.
- Multidimensional construct comprising evaluation of:
- Weigh
- Muscularity.
- Body strength and condition.
- Shape and size of various bodily parts.
Two Components of Body Image
- Body image has TW O components:
- Perceptual - what we see.
- Affective - How we feel about what we see (also known as body esteem).
Female body image:
- Based on amount of body fat.
- Consistently worse than males’ body image.
Male body image
- Based on amount of body fat + muscularity.
- Previously more positive, but rates of eating disorders rising.
Adulthood
- THREE unique stages of the lifespan, each with their own
- biological, cognitive, and social changes:
- Early adulthood 20 years 39 years.
- Middle Adulthood 40 years 64 years.
- Late Adulthood 65 years + .
Early Adulthood
- Physical growth continues with increases in:
- Shoulder width.
- Height.
- Chest size.

Middle Adulthood
Most common physical changes are loss of sensory sharpness
- Hearing loss.
- Less sensitive to light.
- Increased farsightedness.
- Menopause in Women
Menopause
- Cessation of menstrual period 45-55 years
- Lowering of oestrogen levels in blood
- Decreased fertililty and fewer ova produced
- Symptoms such as hot flashes, dizziness, headache, weight gain.
- Increased risk for heart disease.
- Decreases in bone mass.
Middle Adulthood Changes
- Osteoporotic changes
- Peak bone density in 30s
- Osteoporosis reduced density and strength in bones
- More bone cells are metabolised than are created
- Men are also at significant risk of osteoporosis
- Almost 25% of those diagnosed in Australia with osteoporosis are men.
Late Adulthood
- Decreases in height from thinning cartilage
- Men 1 inch, women 2 inches).
- Hardening of arteries and build up of fat on artery walls - heart disease
- Digestive system slows and becomes less efficient.
- Decrease in brain size and flow of blood to brain.
5 theories to explain Old Age Development
- Evolutionary theory.
- Cellular clock theory.
- Free radical theory.
- Mitochondrial theory.
- Hormonal stress theory.
Not known which of the five thories best accounts for ageing, research exists to support all of them
Evolutionary Theory
- Benefits granted by evloutionary selection decrease with age
- Natural selection does not eliminate harmful conditions or non-adaptive characteristics in older adults
- Natural selection is connected to reproductive fitness and only present in early adulthood
- If Alzheimers occured earlier in development it may have been eliminated centuries ago
Cellular Clock Theory
- Hayflick Number - Cells can divide a maximum of 75 to 80 times.
- As humans age, cells become less capable of dividing.
- Limit to human lifespan 120 to 125 years.
- It all depends on telomeres
Telomeres
- DNA sequences that cap chromosomes
- Each time cells divide Telomeres become shorter
- Cells can no longer divide after about 70-80 replicaitons
- Telomeres become so reduced they can no longer reproduce and the cell dies
- Lifespan length = maximum life of cells
Cellular Clock Theory - Supporting Research
- Injecting telomerase into human cells extends life of cells beyond 70-80 replicaitons in a laboratory
- Healthy Centenarians have longer telomeres than unheathy ones
-
Issues
- Telomerase is present in approx 85% of cancerous cells
- May not produce healthy life extension of cells
-
Current Research
- Gene therapis that lead to death of cancerous cells while maintaining lifespan of healthy cells
Free-Radical Theory
- When cells lmetabolsie energy by products include free radicals
- Free Radicals bounce areound cells and damage DNA and cellular structures
- Damage leads to range of disorders like cancer & arthritis
- Free radical increase associated with overeating
- Low calorie diet maintains nutrients reduces oxidative damage caused by free radicals
Free Radicals
Free Radical Theory - Supporting Research
F
Mitochondria
- Minute bodies within cells that supply energy for cell function, growth and repair
- Decay in mitochondria leads to aging
- Decay caused by:
- Oxidative damage by free radicals
- Loss of critical micronutrients supplied by cell
- Defects in mitochondria associated with:
- Cardiovascular disease.
- Neurodegenerative diseases; e.g., Parkinson’s Disease and dementia.
- Decline in liver functioning.
- Not known if defects in mitochondria cause aging or accompany the ageing process
Hormonal Stress Theory
- When individuals experience stress, body responds by releasing hormones like adrenaline and corticosteroids
- Individually levels of hormones remain at elevated levels for longer than when younger
- Prolonged, elevated levels of stress hormones associated with high risk of many diseases
- cardiovascular disease, cancer, diabetes, hypertension.
