1. Factors influencing development of behaviour
Chapter 30

2. Maturation
Progression through a sequence of inherited development stages
E.g walking – begins at 9-15 months
- aided by myelination
But genetically ‘preprogrammed’ series of events lead up to walking (crawling etc.)
Speech development – crying, babbling, ‘mama’ etc
Cognitive abilities – perception, intuition, thinking, reasoning
- influenced by environment & inherited factors

3. Cognitive Abilities Object permanence
– understanding that something exists, even if it is out of view
Egocentric thinking
– idea that the environment is determined by your actions
Conservation
– Understanding that physical properties remain the same despite of physical changes
Concrete operations
– ability to classify, sequence, reverse sequence
Formal operations
- testing hypothesis, dealing with abstract ideas

4. Inheritance Genotype partly influences behaviour
Certain genes code for protein synthesis
Proteins can be used for nerve cells, receptors etc
Huntington’s Chorea :
Causes premature neurone death
Decreased NT production
Leads to:
- impaired movement
- personality change
- mental deterioration
- decreased brain weight (20-30%)
- death in middle life
PKU:
Excess phenylalanine accumulating – converted to toxins
Enzymes in brain cell pathways inhibited
Causes severe learning difficulties

5. Intelligence
The capacity to develop a wide range of intellectual skills
Many distinct intelligence abilities
E.g linguistic, logical, spatial, musical, psychological, social skills, humour, etc.
Intelligence tests must be ‘culture-free’
IQ (Intelligence Quotient) measures intelligence
Limited – only 3 types of ability measured

6. Environment Twin (monozygotic) studies:
Effect of environment on behaviour can be identified
Genetic factors should be identical (complete correlation)
If reared apart, differences in IQ and behaviour apparent
– due to environment
Alcoholism tends to run in the family, but not more so in twins
Problem is mainly due to imitation & social factors
– environmental influence
Schizophrenia incidence higher in monozygotic twins
– genetic influence
Intelligence, behaviour etc all influenced by heredity & environment