Positivity bias in the English language: normalized frequency distributions (solid black curves) of happiness scores for the 5000 most frequently used words in four corpora.

<p>Average happiness ratings for 10,222 words were obtained using Mechanical Turk with 50 evaluations per word for a total of 501,110 human evaluations (see main text). The yellow shade indicates words with average happiness scores above the neutral value of 5, gray those below. The symbols show normalized frequency distributions for words with given usage frequency ranks (see legend) suggesting a rough internal scale-free consistency of positivity Upper inset plots show percentile locations and the lower inset plots show the number of words found when cumulating toward the positive and negative sides of the neutral score of 5.