Letter: Infected by a small mental parasite

Sir: Keith Williamson's "earworm" (letter, 5 June) is indeed known to science, and was described by Professor Richard Dawkins in his 1976 book The Selfish Gene under the name "meme". To quote Dawkins, a meme is

a unit of cultural transmission, or a unit of imitation ... Memes propagate themselves in the meme pool by leaping from brain to brain ... When you plant a fertile meme in my mind you literally parasitise my brain, turning it into a vehicle for the meme's propagation."

"Una Paloma Blanca" is a rather minor mental parasite.