Levels of explanation — These are different ways of viewing the same phenomena in Psychology e.g. socio-cultural, psychological, physical, physiological and neurochemical. Reductionism suggests that lower-level explanations will eventually replace higher-level explanations, according to the reductionist hierarchy of science i.e. Sociology, Psychology, Biology, Chemistry and Physics (from top to bottom). Explanations begin at the highest level and progressively reduce down to the bottom of the hierarchy.
Highest level — Cultural and social explanations of behaviour e.g. depression being explained by a withdrawal from social activities, low energy levels and insomnia, which is viewed as odd by society.
Middle level — Psychological explanations of behaviour e.g. depression being explained by
Beck’s Cognitive Theory (the product of the cognitive triad of automatic negative thoughts, faulty information processing and negative self-schemas) and Ellis’ ABC model (an activating event produces an irrational belief which leads to an emotional or behavioural consequence).
Lower level — Biological explanations of behaviour e.g. depression being explained by the action of candidate genes (e.g. 5HT1-D beta controlling the efficiency of synaptic serotonin transport) and neural factors (e.g. abnormal functioning of the left parahippocampal gyrus and the lateral frontal lobes).