Conceived of at least as early as 1880,[1] the term was used in 1881 by the economist Francis Ysidro Edgeworth to describe "an ideally perfect instrument, a psychophysical machine, continually registering the height of pleasure experienced by an individual.
"[2] More recently, it has been used to refer to a tool developed by Peter Dodds and Chris Danforth to gauge the valence of various corpora, including historical State of the Union addresses, song lyrics, and online tweets and blogs.
[6] A version of the tool is available at hedonometer.org, which they call a sort of "Dow Jones Index of Happiness",[7] and hope will be used by government officials in conjunction with other metrics as a gauge of the population's well-being.
[8] Computer scientists trained the hedonometer to recognize the emotion behind data as tweets with sentiment analysis techniques.
Danforth preferred a lexicon approach, that measures the weight of a word, due to the energy required for neural nets.