Trigger Warnings Might Actually Be Harmful

New study supports the fears of Lukianoff and Haidt

Craig Harper
Jul 28, 2018 · 5 min read
Photo by Goh Rhy Yan on Unsplash

In the era of college student sensitivities to a seemingly ever-increasing list of possible offending material, the use of so-called “trigger warnings” has become commonplace on university campuses. These warnings are usually given at the beginning of a class (or at the beginning of specific sections of a class) to prepare students for material that may be upsetting or controversial.

I use trigger warnings (sparingly)

I myself am an academic, and I myself have used trigger warnings. I don’t, however, use them to warn about upsetting material.

I teach on topics relating to sexual crime. My students know what my content is likely to be related to because I advertise the titles of my classes way ahead of the sessions themselves, and make lecture slides available before class. The way that I use these warnings is to counteract any shocks within my sessions. For example, if I’m teaching about the topic of pedophilia, I need to show students what I mean by “Tanner Stages 1–3” in terms of physical development. In doing so, I might show digitized images of naked individuals (including children) from medical sources. A ‘trigger warning’ (more a heads-up) at this stage means that my students are actually engaging with the material rather than just staring at the cartoon breasts and penises on the screen.

Trigger warnings are controversial

To some people, trigger warnings are an essential part of the classroom. They’re seen as a way to make ‘marginalized’ students (as is the current vernacular for describing ethnic, sexual, and gender minorities, those with disabilities, and those with histories of abuse) feel like they are more included in the classroom.

In essence, trigger warnings are akin to a kind of virtue signal that tells ‘vulnerable’ students: “we care”.

Others have gone further and pointed toward the potentially harmful effects of trigger warnings of psychological wellbeing. Greg Lukianoff and Jonathan Haidt wrote a long article for The Atlantic in which they set out how the use of trigger warnings (and, by extension, “safe spaces” from which triggering stimuli are banished) runs counter to clinical psychological wisdom. In their piece, Lukianoff and Haidt argue how gradual exposure to ‘triggering’ content has been established as an effective way to overcome responses to trauma. Trigger warnings are the antithesis of this idea.

A new study, just published in the Journal of Behavior Therapy and Experimental Psychiatry by a team of Harvard psychologists seems to support Lukianoff and Haidt’s claims.

In an online experiment, Benjamin Bellet, Payton Jones, and Richard McNally divided 270 Americans into two groups. Each group was assigned to read a series of passages from classic pieces of literature. All participants read ten passages, five of which contained no distressing material, and five of which contained severely distressing material (e.g., depictions of murder).

The two groups randomly created by the researchers were labelled the “trigger warning condition” and the “control condition”. In the trigger warning condition, each passage was preceded by the following statement:

TRIGGER WARNING: The passage you are about to read contains disturbing content and may trigger an anxiety response, especially in those who have a history of trauma

No such warning was given in the control condition.

Emotional ratings about three “mildly distressing” passages were taken before and after the block of ten test passages. This let the researchers find out participants baseline levels of anxiety, and to establish whether the presentation of trigger warnings affected this baseline rating. Emotional ratings were also collected after each markedly distressing passage (a measure of immediate anxiety). In addition to this, participants also provided ratings in relation to their perceptions of emotional vulnerability following trauma (both in relation to their own vulnerability, and that of others), their belief that words can cause harm and that the world is controllable, and finally completed an implicit association test measuring their own sense of vulnerability/resilience.

The results of the study were fascinating.

After controlling for various factors, such as sex, race, age, psychiatric history, and political orientation, the researchers found that those participants who received trigger warnings were significantly more likely (compared to those in the control condition) to suggest that they and others would be more vulnerable to emotional distress after experiencing trauma.

Although there was no significant effect of which condition participants were in on their general anxiety level change (in response to mildly distressing texts), or their immediate anxiety responses to markedly distressing texts, those who believed that words can cause harm demonstrated a significantly higher level of immediate anxiety to markedly distressing passages (compared to those not holding this belief) in the trigger warning condition, but not in the control.

This finding could have significant implications in the context of ongoing cultural debates about the power of language in reinforcing perceived oppression. That is, if we are telling students that words are akin to violence and can cause harm, and then giving them trigger warnings to compound that message, we risk increasing immediate anxiety responses rather than decreasing them.

This study is a relatively small-scale one, and has a key limitation in that it used non-student sample which excluded those with actual trauma histories. If the findings replicate in other samples, though, this could (and should) have knock-on effects in terms of the frequency that we use trigger warnings.


Since initially publishing this, some have commented on the small effect sizes in the between-groups differences, and the fact that this study relied on self-report methods. These are both definitely additional limitations. Pre-registered replications of these effects would be a very useful addition to the literature.

Further, there have been attempts to use physiological methods to examine the effects of trigger warnings. These studies mirror the results reported by Bellet and colleagues, finding that trigger warnings are associated with increased physiological anxiety responses — particularly in those who have trauma histories.


The data in this study were clear — trigger warnings increase anticipated vulnerability to experience post-traumatic distress, and when paired with the belief that words can cause harm, such warnings can actively increase immediate experiences of anxiety.

Open Psychological Science

Overviews of psychology research

Craig Harper

Written by

Social psychologist and researcher interested in sexuality and political issues. Posts about psychology, science, and education. Twitter: @CraigHarper19

Open Psychological Science

Curated overviews of new research in psychological science.

Craig Harper

Written by

Social psychologist and researcher interested in sexuality and political issues. Posts about psychology, science, and education. Twitter: @CraigHarper19

Open Psychological Science

Curated overviews of new research in psychological science.

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