‘Jokes and The Psycho–pathology of Everyday Life’ investigates the concept of ‘Freudian slips’, as well as examining the science of jokes. Freud saw Freudian slips as arising from interference by unconscious thoughts, and came up with ingenious explanations to fit his theory to real life slips. However, this is not true of all instances of memory failure. Freud also attempted to examine the technique of jokes. He explained that jokes and dreams used many similar mechanisms, and distinguished between ‘innocent’ jokes (e.g. puns) and ‘tendentious’ jokes (ones displaying hostility or obscenity). Freud was criticized for downplaying the pleasure obtained from joke structure, saying that the tendentious content was more important.