Why a Batman costume made subway riders far more likely to give up their seat
A Milan subway study found commuters were much more likely to help a pregnant passenger when Batman boarded the train too.
A team of psychologists in Italy tested a strange idea on the Milan metro: could an unexpected sight snap commuters out of their travel trance and make them kinder? Their answer came from a crowded train, a fake pregnancy bump, and a man dressed as Batman.
Anyone who has taken a packed subway knows the routine. People keep to themselves, focus on their own trip, and often slip into a kind of mental autopilot.
Researchers at the Università Cattolica del Sacro Cuore in Milan wanted to interrupt that pattern and see what happened. In a field study published in npj Mental Health Research in November 2025, the team led by clinical psychology professor Francesco Pagnini set out to measure altruism in a public setting.
Their setup was simple but unusual. Across 138 observations on the Milan metro, a female researcher wearing a prosthetic pregnancy belly boarded a crowded train. In the control version of the experiment, she got on alone while observers tracked how many seated passengers offered her a place to sit.
What happened when Batman entered the carriage
Under those ordinary conditions, about 37% of commuters gave up their seats for the apparently pregnant passenger.
Then the researchers added the disruption they thought might shake people out of their routine. A man dressed as Batman boarded through a different door at the exact same time. The costume was clearly recognizable, but it did not cover his whole face. That choice was made so the scene would not cause panic.
With Batman on board, the share of passengers who offered their seats jumped to 67%.
The researchers gave the effect a name: the Batman effect. The result suggested that an unexpected and slightly absurd detail in a familiar environment could change how people responded to someone nearby who might need help.
The most surprising part came after the ride
The numbers were striking on their own, but the follow-up interviews added another twist. When passengers who had offered their seats were asked why they did it during the Batman runs, the expectation was that they might point to the superhero image itself, perhaps as a reminder of justice, duty, or doing the right thing.
Many did not say that at all. In fact, 44% of the people who gave up their seats said they had not even consciously noticed Batman was there.
Pagnini said that points to something deeper than people simply reacting to a comic book character. According to his interpretation, the odd presence of a superhero created what he described as a kind of involuntary mindfulness inside the subway carriage. The interruption broke commuters out of their usual autopilot and made them pay closer attention to their surroundings.
Once they were more present, the researchers suggested, they were also more likely to notice the pregnant woman standing nearby and respond with empathy. In other words, Batman may not have inspired kindness directly. He may simply have made people look up.
Why standout clothing changes behaviour
On crowded public transport, many people slip into autopilot. They look at phones, avoid eye contact and miss subtle social cues. A costume, uniform or other unusual outfit cuts through that background noise. It makes one person instantly more noticeable, which can prompt quicker reactions from strangers.
Distinctive clothing can also change how people interpret a situation. Outfits linked to heroes, workers or care can trigger expectations about helping, politeness or attention. Even humour plays a role. When something feels playful and memorable, people may respond more openly than they would to an ordinary request.
The psychology of giving up a seat
Seat giving is often less about kindness than about clarity. Many riders are willing to help but hesitate because they are unsure who needs a seat, whether they should intervene, or whether they might embarrass someone. A strong visual signal removes some of that uncertainty.
People also copy what seems socially approved. Once a need is obvious, helping becomes easier and more public, which nudges others to act.
What you can do in real life
If you need a seat, being clear usually works better than hoping others notice. Stand where seated riders can see you, make brief eye contact and ask directly in a calm sentence. Any visible cue can help, from a mobility aid to a badge or simply holding your stomach or leg.
If you can offer a seat, keep it simple: ask once, politely, and accept the answer.
