Virtually all general psychology textbooks recount the story of Phineas Gage, one of the most famous case studies in neuroscience. Gage was a railroad construction foreman. On September 13, 1848, he and his crew were clearing boulders along a route, a process that involved drilling a shaft deep into the rock, tamping gunpowder down into the shaft, and then blowing the boulder apart. Gage was using an iron rod to press a charge into a shaft when the gunpowder ignited. The explosion shot the rod up through Gage’s left cheek and out the top of his head, taking out a large chunk of his prefrontal cortex. Remarkably, Gage remained conscious, and ultimately, he survived. After the accident, however, his personality changed. He became highly temperamental and impulsive, which is consistent with what we now know about the role of the prefrontal cortex in emotion regulation and behavioral inhibition. When I teach about Gage, I show digital images of his skull and the route of the tamping rod, which are fairly innocuous. To illustrate that these kinds of injuries are not that uncommon, I show images of similar but more recent cases. One of them is of a Brazilian construction worker who, in 2012, fell from a building onto a piece of rebar that penetrated completely through his head from front to back and lodged there. Like Gage, he survived. Surgeons were able to successfully remove the rebar, and the worker made a full recovery. Unlike with Gage, I show photos of the worker before surgery, with the rod stuck in his head. Before I show that slide, however, I warn students that if they are squeamish, they should look away. In other words, I give a trigger warning.
Trigger warnings have long been the subject of controversy and debate. In 2015, the National Coalition Against Censorship (NCAC) summarized the controversy and issued survey results of faculty attitudes and experiences (see also Bellet et al., 2018). Students requested faculty to give trigger warnings before discussing deeply disturbing topics, such as childhood trauma and sexual assault. Some institutions considered mandating that faculty provide them before discussing certain topics or works that might be deemed offensive or disturbing. Advocates asserted that trigger warnings were necessary to create safe spaces for students, especially those with a history of trauma. Faculty groups were concerned that such mandates violated academic freedom and were a form of censorship. Critics of trigger warnings worried that they coddled students by allowing them to avoid difficult topics when a rigorous education should challenge beliefs and make students uncomfortable.
The key issue was whether trigger warnings reduced discomfort and prevented students from experiencing or reexperiencing trauma when exposed to disturbing materials. Several researchers addressed this issue. Bellet et al., for example, had subjects read 10 passages, of which five were neutral and five distressing. Half of the subjects received a trigger warning before each distressing passage and the other half did not. Trigger warnings had little effect on relieving anxiety when subjects dealt with distressing stimuli. In fact, they were related to some negative outcomes, such as promoting the belief that trauma survivors cannot function as well as others can. Jones et al. (2020) found that trigger warnings had no positive effect for trauma survivors and, in fact, tended to reinforce their belief that trauma was a dominant factor in their identity. Sanson et al. (2019) found that trigger warnings had only negligible effects, positive or negative, for both people who had experienced trauma and those who had not. Taken together, the evidence seems clear that trigger warnings aren’t really effective, and teachers, therefore, don’t have to worry about them. Right? Well, from my point of view, not quite. I’m going to argue that the assumptions and the research about trigger warnings have missed a crucial point. Trigger warnings are about building student trust.
Let’s start with a definition. The NCAC defines them as “warnings to alert students in advance that material assigned in a course might be upsetting or offensive.” Now let’s talk about how teachers should use them. Any teaching method can fail if the teacher implements it inappropriately. To show that a pedagogical technique is truly ineffective, implement it in the way most likely to lead to success and then assess it for effectiveness. Here is where I believe the research falls short. When a teacher issues a trigger warning, they should accompany it with an explanation of the purpose and importance of the activity that might lead to distress. Students should know why they are being asked to engage in tasks, especially unpleasant ones. In the example I used to start this essay, I stated that the purpose of showing a photo of a man with his head impaled on a bar was to illustrate that head injuries like Phineas Gage’s are not that rare. In the research on trigger warnings I cited, experimenters never gave participants a pedagogical reason for engaging with the stressful material.
Imagine this scenario. I’m teaching a psychology class, and without warning, I show the class a graphic video of a person having their leg amputated. Now imagine the same scenario, but this time I give a trigger warning: “Some of you may find this video distressing to watch.” Would the warning reduce anxiety? I doubt it. Now what if I provided both a trigger warning and a purpose? “Today we are learning about the emotion of disgust. To study disgust, researchers show subjects videos of disturbing scenes, like an amputation. So that you will get a sense of how this research is conducted, I’m going to show you an example of such a video. If you find it too distressing, look away.” In this case, the trigger warning is more likely to have an impact. It may or may not reduce distress, but I can see three possible benefits for students. First, the choice to opt out gives students autonomy over their learning (Patall et al., 2022). Second, proper trigger warnings may help students to reframe any distress in a constructive way through cognitive reappraisal (Jamieson et al., 2013). In cognitive reappraisal, students regulate their emotional response by interpreting their distress as a necessary part of learning important information. Finally, proper trigger warnings build student trust in the teacher.
The example I just described gave students a chance to opt out of the activity. I allow students to opt out of a distressing activity if I don’t think it is crucial to my learning goals. I also allow for alternative activities if I feel there are ways to achieve the same learning outcome that aren’t so distressing. In the Phineas Gage example, the point that head injuries aren’t that rare is not critical compared to understanding the function of the prefrontal cortex. In the amputation example, seeing the video isn’t central to understanding the emotion of disgust. In both cases, then, allowing students to opt out is fine. There are times though, when the activity is so vital to learning that opting out is not justifiable. If I have a student conducting research on disgust, they should view the amputation video so they will know what they are asking of subjects. When I teach statistics, many students have math anxiety, but omitting the course is not an option because a knowledge of statistics is critical for the psychology major.
Let’s return to the idea that trigger warnings build student trust in the teacher. As I’ve written about before, high student trust causes students to work harder and take on greater challenges. Providing trigger warnings demonstrates teacher integrity. It says to students, “I respect you as a person with feelings.” It also shows teacher beneficence. It says, “I wouldn’t ask you to experience something distressing unless I felt it was best for your learning and development.”
Under my supervision, a group of undergraduate students tested the hypothesis that trigger warnings build student trust. Subjects imagined themselves in a hypothetical class and scenario. The teacher assigned the class to watch a video. Unbeknownst to subjects, half of them were assigned to watch a high-distress video and half to watch a low-distress video. Before they watched the video, participants were randomly assigned to one of three conditions. The control group received no trigger warning. A second group received the trigger warning just before the assigned video was shown. The third group was given the warning during the previous class period and given the option of skipping the class if the video might upset them. All subjects then viewed their assigned video. Afterward, the students rated their trust in the teacher. For the low-distress video, there was no effect of trigger warnings on trust. For the high-distress condition, however, there was a small but significant increase in student trust when students were given the trigger warning with the option to skip the class. There was also a small but significant decrease in trust when they were given the trigger warning just before seeing the video with no chance of opting out. Getting a trigger warning without the ability to act on it was worse than no trigger warning at all. This small study indicates, then, that the nature and timing of trigger warnings influence student trust.
In the NCAC survey, faculty who used trigger warnings cited student trust as a major reason. The NCAC report attempted to distinguish between trigger warnings and informing students about what they would be doing in class, stating that “offering students information about course content, including that some materials may be challenging or disturbing, is not a ‘trigger warning.’” The report, however, offers no criteria for distinguishing between the two, nor can I think of any meaningful distinction.
Boysen et al. (2018) conducted a survey of psychology students about trigger warnings and found that they appreciate trigger warnings, especially about sensitive topics, but they also reported little discomfort in discussing such topics. They believed that discussing distressing and uncomfortable topics was a necessary part of their education.
From the perspective of student trust, trigger warnings are simply a manifestation of good teaching. Teachers should always explain the purpose of what they are asking students to do and why it is important for their learning.
 Thanks to Bekah Caldwell, Katie Earnest, Rachel McCarley, and Julianne Spruiell for conducting the study.
 Both videos covered the same school shooting, but the high-distress video included footage of the actual incident while the low-distress video did not.
Bellet, B. W., Jones, P. J., & McNally, R. J. (2018). Trigger warning: Empirical evidence ahead. Journal of Behavior Therapy and Experimental Psychiatry, 61, 134–141. https://doi.org/10.1016/j.jbtep.2018.07.002
Boysen, G. A., Prieto, L. R., Holmes, J. D., Landrum, R. E., Miller, R. L., Taylor, A. K., White, J. N., & Kaiser, D. J. (2018). Trigger warnings in psychology classes: What do students think? Scholarship of Teaching and Learning in Psychology, 4(2), 69–80. https://doi.org/10.1037/stl0000106
Jamieson, J. P., Mendes, W. B., & Nock, M. K. (2013). Improving acute stress responses: The power of reappraisal. Current Directions in Psychological Science, 22(1), 51–56. https://doi.org/10.1177/0963721412461500
Jones, P. J., Bellet, B. W., & McNally, R. J. (2020). Helping or harming? The effect of trigger warnings on individuals with trauma histories. Clinical Psychological Science, 8(5), 905–917. https://doi.org/10.1177/2167702620921341
National Coalition Against Censorship. (2015). What’s all this about trigger warnings? https://ncac.org/resource/ncac-report-whats-all-this-about-trigger-warnings
Patall, E. A., Zambrano, J., Kennedy, A. A. U., Yates, N., & Vallín, J. A. (2022). Promoting an agentic orientation: An intervention in university psychology and physical science courses. Journal of Educational Psychology, 114(2), 368–392. https://doi.org/10.1037/edu0000614
Sanson, M., Strange, D., & Garry, M. (2019). Trigger warnings are trivially helpful at reducing negative affect, intrusive thoughts, and avoidance. Clinical Psychological Science, 7(4), 778–793. https://doi.org/10.1177/2167702619827018
Stephen L. Chew, PhD, is a professor of psychology at Samford University. Trained as a cognitive psychologist, he endeavors to translate cognitive research into forms that are useful for teachers and students. He is the recipient of multiple awards for his teaching and research. Author contact: firstname.lastname@example.org.