The term "trigger warning"-- defined as statements that warn of a negative emotional response to potentially distressing stimuli-- originated in online communities for the benefit of people with post-traumatic stress disorder. Within the past 5 years, the term has spread everywhere in popular culture. This includes college campuses where college professors are incorporating trigger warnings into their syllabi. One survey found that half of professors have used trigger warnings in their classroom, and some universities are even instituting policies that require trigger warnings.

For some, the widespread use of trigger warnings is a really great and compassionate thing, and for others, this is a serious infringement on free speech and may even signal the beginning of the end of civilization as we know it.

In their book Coddling of the American Mind, Greg Lukianoff and Jonathan Haidt argue that "today's college students were raised by teachers who may have had children's best interests at heart but who often did not give them the freedom to develop their antifragility." According to Lukianoff and Haidt, trigger warnings are a form of overprotection which prevent students from learning to cope effectively with uncomfortable emotions, thus making students weaker and less resilient.

Pushing back against the pushback, Kate Manne argued in her article "Why I Use Trigger Warnings" that the point of trigger warnings is "not to enable-- let alone encourage-- students to skip these readings or subsequent class discussion... Rather, it is to allow those who are sensitive to these subjects to prepare themselves for reading about them, and better manage their reactions."

From a psychological perspective, one could make a case either way. On the one hand, it may be the case that trigger warnings prompt people to better regulate their emotions. It's true that being able to anticipate a response can make you more proactive in regulating your stress if you have such skills. On the other hand, the same research also suggests that anticipating a particular response can also cause one to exaggerate the anticipated response.

For instance, people who were told that a suspenseful film clip contained graphic violence experienced significantly more distress than people who were told that graphic violence content had been cut. Other studies suggest that providing patients with a detailed enumeration of every possible adverse event can actually increase side effects. As Paul Bloom argues in his book "How Pleasure Works", the experience of pleasure is so dependent on expectations. The same goes for pain.

It's also possible that trigger warnings lead people to have even more intrusive thoughts afterwards. After all, if I tell you not to think about a pink elephant, you're likely to think even more about pink elephants. Of course, trigger warnings don't tell you to definitely skip the material, but it's possible that people who choose to avoid the material may be setting themselves up to think even more about the content (or even worse, make the content out to be worse in their mind than it is in actuality).

This is all well and good, but what does the evidence actually suggest about the effectiveness of trigger warnings?

The Science of Trigger Warnings

In the past few years, researchers have started to systematically investigate the effectiveness of trigger warnings. In their paper with the clever title "Trigger warning: Empirical evidence ahead", Benjamin Bellet and his colleagues found evidence that trigger warnings may inadvertently undermine resilience (consistent with the thesis of Lukianoff and Haidt).

They found that people who were randomly assigned to receive trigger warnings prior to reading literary passages reported greater anxiety in response to reading potentially distressing passages, but only if they believed that words can cause harm. According to a tweet by one of the authors, however, anyone with a history of exposure to an extremely distressing event was not permitted to complete the experiment-- which comprised roughly 50% of those who started it!

In a separate set of studies, Izzy Gainsburg and Allison Earl found that trigger warnings increased expectations of negative emotions to warned-of content and increased avoidance of the content. This finding was particularly strong for those who believed trigger warnings are protective (versus coddling). What’s more, those who believed trigger warnings to be protective (versus coddling) were particularly likely to expect negative emotions, which caused an increased avoidance of the warned-of content.

In the most recent and comprehensive study so far on the topic, Mevagh Sanson and colleagues systematically and empirically examined the consequences of trigger warnings for three symptoms of people’s distress: (1) negative affect following exposure to negative material, (2) intrusive thoughts related to the negative material, and (3) avoidance of reminders of the negative material. Across six experiments, they presented some people (but not others) with a trigger warning, exposed everyone to distressing material, and measured their symptoms of distress. Then they conducted summary statistics on the overall data (totaling 1,394 people) to estimate the effect size of trigger warnings.

They found that people who saw trigger warnings judged the material to be just as negative, felt similarly frequently intrusive thoughts and avoidance, and understood subsequent material just as much as those who did not see trigger warnings. Whatever positive effects of trigger warnings that were found were "so small as to lack practical significance."

Their findings are consistent with the idea that over-accessible memories of traumatic experiences can contribute to symptoms of PTSD, and are also consistent with the idea that the same cognitive processes are at play during traumatic experiences of differing levels of severity.

While they did not actually recruit people with a diagnosed psychopathology (e.g., PTSD, generalized anxiety disorder, depression), they did find that most of their participants reported a traumatic experience (consistent with findings conducted on the general popular more broadly). Also, while they didn't ask their subjects their socioeconomic status or education level, their samples were drawn from college students-- a population for whom trigger warnings are often provided.

With that said, I do think we need more research particularly on populations who have experienced the most severe traumatic experiences. It's possible that there might really be a critical difference between college students who report a traumatic experience and those who have been diagnosed with PTSD or generalized anxiety disorder.

The researchers conclude that "trigger warnings are at best trivially helpful" and further note: "college students are increasingly anxious... and widespread adoption of trigger warnings in syllabi may promote this trend, tacitly encouraging students to turn to avoidance, thereby depriving them of opportunities to learn healthier ways to manage potential distress."

Of course, this research has implications not just for college students. The scientific study of trigger warnings has begun, and I personally hope that this research can be less about who is right vs. wrong in this cultural war, and more about simply getting at the truth about the best method of helping all people become resilient-- and even thrive-- after trauma.