In cognitive psychology, the missing letter effect refers to the finding that, when people are asked to consciously detect target letters while reading text, they miss more letters in frequent function words (e.g. the letter "h" in "the") than in less frequent, content words. Understanding how, why and where this effect arises becomes useful in explaining the range of cognitive processes that are associated with reading text. The missing letter effect has also been referred to as the reverse word superiority effect, since it describes a phenomenon where letters in more frequent words fail to be identified, instead of letter identification benefitting from increased word frequency.