Trigger warnings had no significant effect on changes to affect or learning but did significantly increase perceptions of warnings as necessary (not for oneself, obviously, but for the others)

Boysen, G. A., Isaacs, R. A., Tretter, L., & Markowski, S. (2019). Trigger warning efficacy: The impact of warnings on affect, attitudes, and learning. Scholarship of Teaching and Learning in Psychology, http://dx.doi.org/10.1037/stl0000150

Abstract: The purpose of trigger warnings is to prevent distress by giving prior notice about sensitive topics, but there is little empirical evidence to support their effectiveness in psychology education. The current research examined the effects of trigger warnings on affect, learning, and attitudes. Study 1 (N = 353) presented an online sample of adults with a video lecture about sexual assault, and participants reported their positive and negative affect before and after the video. They also took a test on the content and reported their attitudes about the necessity of warnings. Learning about sexual assault led to significant changes in affect for participants with and without personal experience related to the topic. Trigger warnings had no significant impact on changes in affect or test scores. However, participants who received a trigger warning had significantly increased belief that warnings are necessary for the topic of sexual assault. Study 2 (N = 412) replicated Study 1 using the topic of suicide. Trigger warnings had no significant effect on changes to affect or test scores but did significantly increase perceptions of warnings as necessary. Study 3 examined a sample of college students (N = 105) learning about sexual assault, and it also showed no significant effect of trigger warnings on changes to affect or test scores but a significant effect on belief that warnings are necessary. Overall, trigger warnings appear to have little impact on affect or learning, but they do increase people’s belief that warnings are necessary for sensitive topics.