ABSTRACT
Incongruity humour theory directs attention towards stimulus variables amongst which is similarity-dissimilarity. Historically the concept of incongruity is ancient but its constituents appear not to have been explicitly recognized until the time of Joseph Addison and David Hartley (cf. Piddington, 1963). Addison, in answering John Locke, said that resemblance and opposition are what may call forth laughter in response to wit. Hartley mentions similarities and differences in connection with what is funny.
