The Batman effect and the psychology of patient behaviour

I laughed and nearly scrolled past it. Fortunately, it triggered my interest. Once you look past the mask and cape, this is a study about something we wrestle with every day in dental practice: how to interrupt the automatic, habitual behaviour that quietly undermines so much of what we do.

What they did

The design was an investigation run on the Milan underground. In the control condition, a female researcher wearing a prosthetic pregnancy belly boarded a carriage with an observer. The experimental condition was identical except for a second researcher dressed unmistakably as Batman (suit, cape and logo, but holding rather than wearing the mask so as not to alarm anyone). The researchers boarded through different doors about 3 metres apart, and Batman and the “pregnant” woman never interacted.

Both conditions ran simultaneously in different carriages of the same train, which is a nice touch because it helped control for time of day, line and crowding. For an observation to be valid, every seat had to be occupied and no more than five people could be standing. This allowed passengers a genuine chance to notice what was going on. The team recorded whether any passengers offered their seat, and when possible, they asked these passengers why they had done so and, in the Batman carriages, whether they had seen Batman. In total, the research team logged 138 rides: 61 with Batman, 77 without.

What they found

In the control, someone offered their seat 38% of the time. With Batman present, that jumped to 67%, close to double. The logistic regression was highly significant (p < 0.001), and the odds ratio was a hefty 3.4.

Then comes the finding that made me think: when the passengers in the Batman carriages who offered their seat were interviewed, 44% said they had not even noticed Batman. None spontaneously credited the hero in the cape. Yet the effect was there.  That 44% figure refers to the interviewed helpers in the Batman group, not every person who did or did not help by giving up a seat.

The authors christened this the “Batman effect”, and their proposed explanation is elegant. An unexpected, non-threatening event jolts people out of autopilot. It pulls attention back to the present, and someone whose attention has been drawn back to the present is more likely to notice the pregnant woman standing there. The authors suggested that this kind of situational “mindfulness” can spread socially through a group, that is, more people looking up, moving, rustling, which would explain how people who never consciously registered Batman still behaved differently.

Breaking routine changes behaviour, sometimes below the level of awareness

A good story, but read the fine print

I enjoyed this paper and think that the central observation is real, but apply the brakes before we all start hiring superheroes for orthodontics. While an odds ratio of 3.4 is sizable, only about 11% of the variance was explained. In short, there are plenty of other things that drive this behaviour that this single manipulation does not account for. The effect is genuine though partial, and the headline figure flatters it.

The authors openly conceded that they cannot say why the presence of Batman had this effect. Their preferred mindfulness mechanism is plausible, but another explanation is that a superhero is a prosocial primer. Batman activates cultural ideas about heroism, chivalry and helping (also "I'm Batman"). The trouble is that social priming effects have a notoriously poor record in replication studies, as the authors themselves noted. A third explanation is the pique technique, in which an odd or unexpected stimulus directly disrupts a person’s automatic mental scripts to make them more responsive, but pique cannot explain those who did not actively see Batman but had changes to their behaviour. Whether the effect was driven by heightened awareness, prosocial priming or some other process, the study cannot say, and to their credit, the authors do not pretend otherwise.

So, this is a charming, well-conducted field study accompanied by a sensible, self-aware discussion. It is not a blueprint, but the underlying idea is that breaking routine changes behaviour, sometimes below the level of awareness. This is something orthodontists already exploit, whether we are aware of it or not.

Why this should interest general dentists and orthodontists: The compliance problem

Strip away the costume, and the Batman effect is really about interrupting habit, and so much of orthodontic practice is a quiet battle against habit. Aligner compliance is perennial conference fodder, and for good reason. Aligners only work if they are worn for 20–22 hours a day, and the moment they are in the case instead of the mouth, the beautiful digital plan starts to drift away from reality. My best aligner cases are not always the ones I planned best or in which I placed the attachments best, but the ones in which patients wore their aligners most consistently.

Studies on aligner compliance are sobering. In a retrospective cohort study of 2,644 aligner patients who used a mobile app for remote follow-up, only about 36% were classified as fully compliant; the rest were fairly or poorly compliant.² That tells you something important: non-compliance is usually less about defiance and more about regressing to the patient’s normal behaviour. The well-meaning teenager who a few months ago “really, really wanted” aligners and promised to wear them has drifted back into a routine (school, sport, dinner, homework, forget) where the aligners simply slip out of mind.

I had a 15-year-old like this not long ago. She was so keen at the start, but a few months in, the plastic told the real story. She was not rebelling. She had just gone on autopilot. What turned her treatment around was not a lecture. We took a scan and pulled up a simulation showing where her teeth were at the start of treatment, their planned position at 12 months and their current position. We superimposed the current position on the planned position and got her to set a phone alarm with a message she had chosen herself. Through a small, deliberate self-directed disruption to the routine, her wear time recovered.

Anxious children and the value of the unexpected

The second obvious application is paediatric anxiety, and here the literature is on firmer ground than the metro study. Distraction is a recognised behaviour guidance technique and is included in the American Academy of Pediatric Dentistry’s guidelines. It involves diverting a child’s attention from the procedure through stories, music, audio-visual aids or a well-designed clinic.³ Most of our standard toolkit (tell–show–do, positive reinforcement, desensitisation) is built on predictability, making the unknown known.

The Batman paper hints at a complementary and somewhat opposite idea: that pleasant unpredictability might also short-circuit a fear response by giving the brain something genuinely interesting to consider. There is real evidence for this. A 2025 systematic review and meta-analysis of magic distraction therapy found that performing magic tricks during paediatric dental treatment produced a significant reduction in dental fear and anxiety, and the biggest benefit was observed for local anaesthesia and in younger children.⁴ The technique goes back to Peretz and Gluck’s original description two decades ago.⁵ It is, in effect, a controlled dose of pleasant surprise, a tiny Batman.

Now, I cannot do magic, but I tell stories and jokes (much to my staff’s chagrin) and have a box of sensory toys that work on the same principle. It is a silly thing. But anticipation, choice and having something to play with genuinely shift the feel of a visit.

The contagion of mood and why the waiting room matters

(Patients do not mind calling it a waiting room if you do not keep them waiting.)

The detail that 44% of helpers never saw Batman points to something every experienced clinician knows: attention and emotion are socially contagious. The authors acknowledge that their interpretation is speculative, framing it as a hypothesis rather than a finding. But the wider phenomenon is well documented elsewhere and in our own dental literature.

Anxious parents transmit their anxiety to their children, who is the kid going to believe, you or their nervous parent? Reviews of thousands of parent–child pairs consistently link higher parental dental anxiety to greater fear and poorer cooperation in the child.⁶ The flow runs the other way too. When a tense 7-year-old in the waiting room sees a relaxed 10-year-old stroll out grinning with a sticker, playing a game, some of the tension eases. A warm, playful and visually interesting practice with less reverberation (we have noise reduction panels to make it not only pleasant for us but quieter too—pun intended), for every patient who walks through the door. Walk into a practice that feels clinical and impersonal, and your guard goes up. You want your practice to be unique and to be the embodiment of you. Do not bait and switch: feel free to show your inner Batman to get patients out of their shell, but make sure that it reflects your personality. Our practice is made to feel like home with comfy chairs, coffee and an eighties games machine, along with subtle things like colourful acoustic panels, whereas the practice of US orthodontist Dr Jay Bowman is made to feel like the Hard Rock Cafe meets the coolest rock museum you have ever been to. When you arrive somewhere with a bit of personality and familiarity, your guard drops before anyone has said a word.

Takeaways

If there is a clinical message in all this, it is that behaviour change in our patients is rarely about information alone. It is about interrupting habits, tying old habits to new ones and managing attention:

• Treat poor aligner compliance as drift, not defiance. Re-engage the patient with something novel. Re-explaining the importance of 22 hours, again, is the least effective lever.
• Build in surprise. Distraction is in the guidelines for a reason; pleasant novelty, magic, humour, a treasure chest, an unexpected bit of fun has a real, measured effect, especially in younger children.
• Read and set up the room. Parental and peer emotion spreads. The atmosphere of your practice is a clinical variable, not just décor.
• Stay sceptical of tidy stories, including this one. The Batman study is fun and well-meaning, but it is a small field experiment that cannot tell us its own mechanism. Take the idea; leave the certainty.

The bottom line

Unexpected, non-threatening events may nudge people towards kindness by breaking routine and bringing people into the present, sometimes without their even knowing it. The psychology that increased the number of strangers giving up their seats resembles what we try to harness every day (even if we do not know it), helping a child through a first visit or a patient back into wearing aligners.

You do not need a man in a cape (as fun as that would be). You just need to remember that most of our patients arrive on autopilot and that a small, well-placed surprise can do more than another well-meaning lecture ever will.

Special thanks to Dr Jay Bowman for allowing me to reference his (awesome) practice, which reflects, importantly, his personality and is not just décor.