1) Progression through a genetically preprogrammed sequence of developmental stages which leads to the development of , speech, cognitive abilities, etc. is called .
2) Development of behaviour is in part influenced by the person's (certain genes are needed to code for the proteins involved in the production of nerve cells, and neuroreceptors).
3) Development of behaviour is in part influenced by the . Studies of twins reared apart allow scientists to investigate the influence of the environment on .
4) Intelligence can be regarded as the capacity to develop a wide range of skills. Measurement of is attempted using tests, the results of which are expressed as an intelligence (IQ). Studies of monozygotic show that IQ is affected by both and environmental factors.
5) All forms of human behaviour are influenced by inherited, maturational and environmental factors.