A man viciously rained blows on another in full view of commuters on a train on the Downtown Line on Sunday morning (Suspect arrested over assault on MRT train, May 24).

To my great bewilderment, none stepped forward to aid the victim.

Why did the rest of the commuters keep a distance from the ongoing affray, and allow the assailant to carry on with his assault without any protest?

One would think that the more people there are around, the higher the chance that someone would step in and offer help. Unfortunately, this was not the case.

This case highlights the bystander effect and diffusion of responsibility.

The bystander effect refers to how people are less likely to help in an emergency when other bystanders are present.

In this case, diffusion of responsibility could be why commuters did not offer help.

This is a phenomenon that occurs when people witness a situation and they do not intervene because they believe someone else will.

More people present during an event may make an individual feel less pressure to take action, therefore resulting in a diffusion of responsibility.

It would be folly to assume that because there are other people present, someone else is going to help.

Rather, the moral obligation to help does not fall on only one person, but the whole group of commuters who witnessed the affray.

Henry Koh Chiew Phor