Bystander Apathy

Isn't somebody else going to make a comment?

There's a similar opposite effect - people are more likely to riot or commit violent acts in large crowds than in small ones.

The explanation that "choking" is disadvantageous seems to explain a great deal of this behaviour. However, as Eliezer points out, fear to take on the risk of action doesn't explain the whole thing: one person with a gallantry gene tears that model apart.

It strikes me as possible that there's a large cultural role here. It may be that we don't intervene not because of selfish evolutionary decision-making, but because of an overdeveloped sense of inferiority to the collective. I remember reading more than once that the placebo effect is much more pronounced in Germany and other Northern European countries than it is in the United States or Brazil on account of the Northern European cultural trust in figures of authority, which isn't as strong in the New World.

I wonder if that translates to bystander apathy. It seems plausible that someone from a usually orderly, law-abiding country like the US or Germany might see an emergency or hear cries for help and think to himself "I'm sure the Police of Fire Department or somebody have that under control. I don't know what I'm doing, so it's best not to get involved." This seems consistent with the pluralistic ignorance explanation: everyone looks around furtively for some official with a bold look and a colorful hat to signal whether we should be worried.

Have there been any studies comparing the bystander effect across different cultures? Do they tell us anything?

this was a basic leadership lesson in boy scouts. never address a group when asking for actual action.

On only 38% of the occasions will anyone report the smoke. Put the subject with two confederates who ignore the smoke, and they'll only report it 10% on the time - even staying in the room until it becomes hazy.

How big are the variances and measurement errors on those numbers? If everyone reports only 10% of the time when no one else does, then a group of three should report 1-0.9\^3 ~= 27% of the time. 38% seems quite a lot bigger than that. Is it possible that the confederates in the one-subject experiment were not merely not-reacting in the way that "real" people commonly do, but were behaving in a way that ordinarily means "I know what's going on, and it's fine"? (I don't think it's quite fair to classify that as pluralistic ignorance.)

I do also wonder, about the three-real-subjects case: if these people knew they were in a psychology experiment, it must have occurred to some of them that the smoke might be part of the experiment. (Unless subjects then were very naive about the tricks psychologists play.) With a group of people, it must be more likely that someone will think of that possibility. What does the article by Latane and Darley say about the actual behaviour of the subjects?

(My guess is that that last effect isn't a major contributing factor, because it presumably doesn't apply in the two-stooges case but the response rate there was lower.)

It actually seems like a rather elegant and efficient way of analyzing a situation, that just happens to backfire in some cases. Instead of trying to understand exactly what is going on, we just try to understand what everyone else understands. I don't have to bother trying to figure out why something is happening and the appropriate response, I just have to do what everyone else is doing. It's probably one of many adaptations we have for acting as a group, and I'd imagine its very effective most of the time.

Perhaps it's so effective that we (subconsciously) rely on it more than other methods of analysis, so it can overrule what might otherwise be a strong reaction to something. So if there's smoke coming from under the door but everyone else doesn't seem to mind, we don't say anything.

Funny, when I read this article I had to think about the current economic crisis and global warming. Maybe most people are apathetic about these because they look around and see that everyone else is acting like normal so they suppose it's not as big a deal as it really is and that everything is going to turn out ok.

Come to think, I can't actually recall seeing shyness discussed in analyses of the bystander effect, but that's probably just my poor memory

Shyness is beeing discussed in analyses of the bystander effect. A psychology lecture i attended in 2001 mentioned it as the third important factor. This effect:

If I recall correctly, if the experimental subjects know each other, the chances of action also go up

was said to proof the role of shyness (beeing with a friend reduces shyness)

The wikipedia article on the bystander effect mentions it, too: "People may also experience evaluation apprehension and fear losing face in front of the other bystanders"

My intuition is the bystander effect is highly related to the fact that most crowds/groups in audiences will not speak, or even that most people at a social gathering hate to be the first to go to the buffet. At work I make a point of asking questions of presenters early on, of volunteering somewhat unfiltered interaction with the presenter when he asks for it. I believe my action greatly increases the rate of participation of co-workers in the interactive presentations in which I do this. My intuition is this is related to "warming up an audience," a process where if you ever go to a TV filming you will be encouraged to yell, scream, answer silly questions, and just generally abandon your inhibitions before the filming actually starts. They WANT filmable (at least audible) audience reaction and presumably they have learned that 'warmed up" audiences provide a lot more of that.

The reticence in all cases may have more to do with an evolved wariness of strangers than anything else. If someone I knew reasonably well were lying on the ground looking like he might POSSIBLY need help, I would not ignore him just because everybody else was ignoring him.

If I recall correctly, if the experimental subjects know each other, the chances of action also go up.

You do recall correctly according to the first guy you cited, and Experiment 2 in the paper you cited had 70% of friend pairs and 40% of stranger pairs helping.