The frequency with which 58 selected 'emotion terms' appeared in the subject index of each of the 121 books on emotion published in English between 1880 and 2001 was enumerated. The mean percentage appearance of each of the emotion terms, an index of the popularity of the term among psychologists, was compared with the frequency with which these terms appeared in the Brown Corpus, an index of the popularity of the term among lay people. The popularity was a function of the strength of emotion among both psychologists and non-psychologists. Psychologists tended more to be interested in negative rather than positive emotions, whereas non-psychologists showed the opposite tendency. The top four popular emotions based on the subject-index analysis were anger, fear, anxiety and depression in that order, but the top four based on PsycLIT data were depression, anxiety, fear and anger in that order, depression being by far the most popular emotion especially after 1980's. Psychologists' interest in positive emotions and in higher-order emotions has increased since the 1970s. Possible causes for the above discrepancies and tendencies were discussed.
