Using 4.4 million tests of implicit and explicit attitudes measured continuously from an Internet population of U.S. respondents over 13 years, we conducted the first comparative analysis using time-series models to examine patterns of long-term change in six social-group attitudes: sexual orientation, race, skin tone, age, disability, and body weight. Even within just a decade, all explicit responses showed change toward attitude neutrality. Parallel implicit responses also showed change toward neutrality for sexual orientation, race, and skin-tone attitudes but revealed stability over time for age and disability attitudes and change away from neutrality for body-weight attitudes. These data provide previously unavailable evidence for long-term implicit attitude change and stability across multiple social groups; the data can be used to generate and test theoretical predictions as well as construct forecasts of future attitudes.
Keywords: implicit association test; implicit attitude change; long-term change; open data; open materials; time-series analysis.