THE BIOLOGICAL APPROACH TO PSYCHOLOGY
Biology is defined as the study of life (from the Greek bios meaning ‘life’ and logos
meaning ‘study’). A biological perspective is relevant to the study of Psychology in
1. Comparative method: different species of animal can be studied and compared.
This can help in the search to understand human behaviour.
2. Physiology: how the nervous system and hormones work, how the brain
functions, how changes in structure and/or function can affect behaviour. For
example, we could ask how prescribed drugs to treat depression affect behaviour
through their interaction with the nervous system.
Investigation of inheritance: what an animal inherits from its parents,
mechanisms of inheritance (genetics). For example, we might want to know
whether high intelligence is inherited from one generation to the next.
Each of these biological aspects, the comparative, the physiological and the genetic,
can help illuminate human behaviour. If we want to understand all aspects of
behaviour, perhaps we should start with one of the smallest units, the basic building
block of the body, the cell.
There are a number of different kinds of cells in the body, but the one Psychologists
are most interested in is the nerve cell or, as it is more often called, the neuron. The
human brain is made up of around 10,000,000,000 neurons. The total collection of
nerve cells in the body is called the nervous system and the major part of the nervous
system, consisting of the brain and the spinal cord, is called the central nervous
system (CNS). Neurons outside the CNS, which take information to and fro between
the CNS and various regions of the body, are called peripheral neurons.
How do neurons function? If a neuron is probed with a piece of apparatus, a small
electrical voltage can be detected. When this electrical voltage doesn’t change, when it
remains constant, the cell is said to be resting. However, when the voltage changes up
and down, the cell is said to be active. Many n