A biological relative against which comparisons can be made.

Memory that includes knowledge of skills, of ‘knowing how’ (such as swimming, riding a bike, driving a car).

Term describing a large group of enzymes that digest (break down) proteins and peptides into their constituent amino acids, by hydrolysing the peptide bonds between them.

A protein molecule comprises one or more chains of amino acids joined together by peptide bonds. In proteins made up of more than one polypeptide chain, the chains are held together by non-covalent interactions.

Positively charged particle present in all atomic nuclei.

A disorder of behaviour or personality without obvious brain damage. Sometimes called a functional disorder.

Term used by Pavlov to describe secretions of saliva evoked by such stimuli as people entering the room. We would now see these as a type of conditional stimulus.

Explanation that seeks the origins of a disorder within an individual’s own life history.

The study of the behaviour of humans (and other animal species) and of their mental states.

The link between sensory information and motor reactions made on the basis of it. A process impaired by, for example, alcohol.