n. the theory that complex mental processes, such as thinking, learning, and memory, can be mainly explained by the associative links that connect ideas, according to specific laws and principles (see association of ideas). Although Greek philosopher Aristotle (384-322 BCE) cited some of these laws (similarity, difference, contiguity in time or space, etc.), the theory stated systematically for the first time by English philosopher Thomas Hobbes (1588-1679). Hobbes held that all knowledge becomes compounded by relatively simple sense impressions. The laws and applications of association were further developed and clarified by John Locke (1632-1704) and other members of the British empiricist school (see empiricism), notably George Berkeley (1685-1753), David Hume (171 1-1776), James Mill (1773-1836), and John Stuart Mill (1806- 1873). Although the approach taken by such thinkers was fairly hypothetical and non-experimental, there are echoes of it in much of the known historical and contemporary psychologies. Most importantly, this concept has been used to explain the pairing of stimuli and responses.