ABSTRACT
Chapter summary
Evolutionary psychology has provided original explanations of why humans behave in the ways they do. However, such explanations are often speculative and fail to account adequately for individual differences.
Twin studies provide an effective way of addressing the nature–nurture issue. Such studies mostly indicate that genetic factors often play an important role (in interaction with environmental factors) in influencing individual differences in behaviour.
An individual’s genetic endowment influences their behaviour in various ways, including active covariation, passive covariation, and reactive covariation.
The nervous system consists of the central nervous system and peripheral nervous system. The latter is divided into the somatic nervous system and the autonomic nervous system.
The autonomic nervous system controls the heart, lungs, eyes, stomach, and the blood vessels of the internal organs. It is divided into the sympathetic nervous system and the parasympathetic nervous system.
The brain can be divided into three main regions: forebrain; midbrain; and hindbrain. The forebrain consists of cerebrum (used in thinking), the limbic system (involved in aggression, fear, learning, and memory), the thalamus (a relay station), and the hypothalamus (used in the control of several autonomic functions). The midbrain is of relevance to the 80control of movement, sleep, arousal, and wakefulness. The hindbrain consists of the medulla, pons, and cerebellum.
The cerebral cortex consists of the frontal lobe (front of the brain), the occipital lobe (back of the brain), the parietal lobe (top of the brain), and temporal lobe (lower part of the brain). The frontal lobes are especially involved in complex cognitive activities and motor processing, the occipital lobes in visual processing, the temporal lobes in auditory processing, and the parietal lobes in language processing and somatosensation.
Many cognitive processes (e.g., attention; reasoning) do not show localisation of function within the brain but instead involved integrated activity across large regions of the brain.
There is some hemispheric specialisation with language abilities typically centred in the left hemisphere and spatial processing in the right hemisphere. However, the brain exhibits considerable plasticity and flexibility (especially following brain damage).
fMRI provides precise evidence about where in the brain’s various processes occur and ERPs indicate precisely when such processes occur. These (and other) techniques for studying brain activity have proved increasingly useful in resolving theoretical controversies.
