Fig 1.
The solid blue line shows the average yearly sentiment of headlines across 47 popular news media outlets.
The shaded area indicates the 95% confidence interval around the mean. A statistical test for the null hypothesis of zero slope is shown on the bottom left of the plot. The percentage change on average yearly sentiment across outlets between 2000 and 2019 is shown on the top left of the plot.
Fig 2.
Average yearly sentiment of headlines grouped by the ideological leanings of news outlets using human ratings of outlets political bias from the 2019 AllSides Media Bias Chart v1.1 [24].
The figure displays the standard error bars of the average yearly sentiment for outlets within each color-coded political orientation category. For each ideological grouping, statistical tests for the null hypothesis of zero slope are shown on the bottom left of the plot.
Fig 3.
Average yearly prevalence of news articles headlines denoting different types of emotionality in 47 popular news media outlets.
The shaded gray area indicates the 95% confidence interval around the mean. Note the different scale of the Y axes for the different emotion types. For each emotional category, statistical tests for the null hypothesis of zero slope are shown on the bottom left of each subplot. Reported p-values have been Bonferroni-corrected for multiple comparisons. The percentage changes between 2000 and 2019 are shown on the top left of each subplot.
Fig 4.
Yearly prevalence of headlines denoting different types of emotionality in 47 popular news outlets grouped by human ratings of news media ideological leanings from the 2019 AllSides Media Bias Chart v1.1 [24].
Note the different scale of the Y axes for the different emotion types. Only statistical tests within each ideological grouping for which the null hypothesis of zero slope was rejected (after Bonferroni correction for multiple comparisons) are shown on the bottom left of each plot.