John RegehrNov 24

"We conducted a quasi-experimental field study on the Milan metro, observing 138 rides. In the control condition, a female experimenter, appearing pregnant, boarded the train with an observer. In the experimental condition, an additional experimenter dressed as Batman entered from another door. Passengers were significantly more likely to offer their seat when Batman was present"

https://www.nature.com/articles/s44184-025-00171-5

Unexpected events and prosocial behavior: the Batman effect - npj Mental Health Research

Prosocial behavior, the act of helping others, is essential to social life, yet spontaneous environmental triggers for such behavior remain underexplored. This study tested whether an unexpected event, such as the presence of a person dressed as Batman, could increase prosocial behavior by disrupting routine and enhancing attention to the present moment. We conducted a quasi-experimental field study on the Milan metro, observing 138 rides. In the control condition, a female experimenter, appearing pregnant, boarded the train with an observer. In the experimental condition, an additional experimenter dressed as Batman entered from another door. Passengers were significantly more likely to offer their seat when Batman was present (67.21% vs. 37.66%, OR = 3.393, p < 0.001). Notably, 44% of those who offered their seat in the experimental condition reported not seeing Batman. These findings suggest that unexpected events can promote prosociality, even without conscious awareness, with implications for encouraging kindness in public settings. Trial registration: ClinicalTrials.gov n° NCT06481748; registered on July 1, 2024.

Nature
Show threadBadmusicvideos
@regehr What do you think the reason for this behavior is? It could be that Batman just reminded them of law and order, or the presence of batman made them more alert and attentive enough to notice the woman.
Nov 24 at 5:45amWeb
Show threadHilaryNov 24

@badmusicvideos @regehr

The article says that 44% of people who offered their seat in the presence of Batman reported that they didn't see Batman.

So, my assumption is, a few people notice Batman, look up, maybe say something, just act in ways that aren't usual on public transport. This slight disturbance triggers other people to look around themselves more, and in some cases notice the apparently pregnant woman. So even people who don't themselves see Batman are affected by him.