I would like to think that humans intrinsically care about the welfare of others and are altruistic in their intentions. However, I suspect that many of our selfless actions may be motivated, at least in part, by a self-serving desire. The famously wise Joey Tribbiani could be correct in saying that there is no such thing as a truly selfless good deed.[1]
A study completed recently on the metro in Milan investigated whether people would be more likely to give up their seat to a pregnant woman if someone dressed as Batman was in the carriage.[2] The idea was to determine whether an unexpected event might affect people’s motivation to help others. The researchers observed 138 train rides and had two conditions. In the control condition, a female experimenter wearing a prosthetic pregnant belly entered the train alone. In the experimental condition, on the same train but at the opposite end of the carriage, another female experimenter entered with a man dressed as Batman. There was no interaction between the pretend pregnant woman and the Batman character. Observations were only included if all seats were occupied and there were no more than five people standing, ensuring passengers had a clear view.
It found that passengers were significantly more likely to give up their seat when Batman was present. The authors suggest this may be because the unexpected presence helped passengers become more aware of the moment, increasing their prosocial behaviour. They also propose that Batman himself may have played a part: as a superhero associated with justice and protection, he may have reminded passengers of their own morals.
This study certainly has its limitations, and there could be many other reasons why these passengers chose to give up their seat. Still, it shows that even subtle prompts can shift our behaviour, reminding us that context can play a bigger role in our decisions than we think.
[1] Friends. The One Where Phoebe Hates PBS. Season 5, Episode 4. Directed by Shelley Jenson, written by Michael Curtis. NBC; 1998 Oct 15.
[2] Pagnini F, Grosso F, Cavalera C, Poletti V, Minazzi GA, Missoni A, Bogani L, et al. Unexpected events and prosocial behavior: the Batman effect. npj Mental Health Res. 2025;4:57. doi:10.1038/s44184-025-00171-5.