Bystanders not just standing by

The press release below does an excellent job of completely ruining the message of a pretty good paper. You can read the paper here, it's not terribly long or difficult.

First, from the press release :

It’s one of the most enduring urban myths of all: If you get in trouble, don’t count on anyone nearby to help. Research dating back to the late 1960s documents how the great majority of people who witness crimes or violent behaviour refuse to intervene. Psychologists dubbed this non-response as the “bystander effect” — a phenomenon which has been replicated in scores of subsequent psychological studies. 

That was my naive understanding of the bystander effect too : simply that very few people will intervene in dangerous situations, and consequently that should you find yourself in trouble, it can be difficult to get people to help you. Yale's online "introduction to psychology" course suggested ways of beating this include appealing to individuals rather than groups, e.g. by calling on specific features of individuals to get them to help.

But strictly speaking the bystander effect is something different : a "phenomenon in which individuals are less likely to offer help to a victim when other people are present. The greater the number of bystanders, the less likely it is that one of them will help." This is not the same at all. If individuals are all uniformly unlikely to help, then all you need to get people to help is sheer numbers of people. If, on the other hand, it's a group effect, then this won't work - if everyone sees that everyone else is failing to intervene, then this becomes evidence that they shouldn't interfere, and thus an indefinite number of people will continuously fail to do anything.

The press release does a terrible job of conveying what the point of the study is. It does not find that individuals are actually all quite likely to intercede, which is what the text implies. The numbers quoted tell a better story :

Each event had an average of 16 bystanders and lasted slightly more than three minutes... The study finds that in nine out of 10 incidents, at least one bystander intervened, with an average of 3.8 interveners.

In other words most people (typically 75%, though we should be careful with these averages) don't intervene. The crucial detail is that in most incidents, someone does intervene, and usually more than one person. That's the key message of the paper that the authors are very explicit about :

The knowledge that an individual’s likelihood to intervene reduces in the presence of others does not establish, however, the aggregated likelihood that at least someone will help. From the perspective of the victim this remains the most important question (Latané & Nida, 1981) — will I receive help if needed? 

And so they set out to look at this from an observational perspective, using real-world CCTV data of violent incidents. They're very careful to note the limitations of their study. They looked only at incidents involving personal conflict, not emergencies like car crashes or fires. They're limited to public spaces in the inner regions of three cities, without a police presence, but in principle the footage should be a reasonably complete sample within this domain :

All data were recorded by municipality employed camera operatives, who according to identical guidelines were instructed to record all incidents of public space aggression that contained any level of conflict—from the mildest animated disagreements to grave physical violence.

So it seems at least persuasive that in incidents of this type, most people don't stop to intervene, but there's no group effect that prevents those who do wish to intervene from doing so. Consequently most incidents do receive intervention. They also note that there was no significant difference in intervention rates between the three cities examined, and that theirs is not the first study to have found that intervention rates per incident can be high.

They're careful to detail at some length the possible limitations to this study :

• How they define "intervention", which is quite liberal - but on the other hand they don't have audio, so there may have been additional interventions that were not detectable with pure video footage.
• The propensity of inner-city footage to favour regions of high social activities and alcohol consumption, so they can't say anything about what would happen in other conditions.
• That their investigation is observational, not experimental.

And I would add that they don't comment on the people who didn't intervene, e.g. to try and identify any common factors that may be at work. This might be beyond the possible scope of the analysis given the quality of the CCTV footage, but it would be interesting to at least look at how many people typically walk past before someone intervenes... of the approximate 75% of people who walk on, what fraction simply don't notice, look but realise the situation is already being dealt with, and how many look and choose not to interfere ? Those fractions are also surely going to vary given the specific circumstances.

Another study on how nice people really are : they're more likely to return wallets if they contain money. Apparently the presence of cold hard cash makes people feel more like thieves than if they simply collect and empty wallet, but those numbers too vary dramatically from places to place - from 7% returned in China to 73% in Switzerland.

We should always be wary of saying that any one study refutes all the others. For example, here's an earlier study which apparently found that incident intervention rates were much lower (with the interesting angle as to whether laws actually influence moral behaviour). But I could not find any resulting paper from this. The authors of the present study finish with :

In shifting the perspective from an absence of help to an almost ever-presence, we leave behind the question of ‘why don’t individuals help?’ and explore a new avenue of enquiry asking: ‘what makes intervention successful?

But I would spin it slightly differently. I would rather ask, "under what conditions does intervention occur and what conditions reduce its occurrence ?"

Here's my sneaking suspicion as to why statistical studies sometimes find very different results : it's simply because they're not comparing things in similar contexts. Whether it be planar structures of satellite galaxies, or intervention rates in dangerous situations, a global average rate may be a nonsensical figure : there may well be no such thing as a typical case. Instead, one can only quote rates within very narrow, very carefully-defined parameters. Stating the average height of a human will get you something correct to within an order of magnitude, but it you compare only people of similar ages you'll get a very much more useful, meaningful number.

Of course this a huge, wholly unjustified extrapolation, but I don't think it's a crazy idea. Any suggestions of a "replication crisis" ought to be taken with tremendous caution : unless an experiment is an attempt at an almost identical repeat of an earlier project, it cannot really be called a replication study - and consequently each experiment explores a new part of parameter space, rather than necessarily implying that all psychology research is crap, which is a bandwagon some people are keen to jump on. I would say that if you want to state that there are problems with research, that's fine - that's the nature of research, by definition. So if you want to then go on to say, "and this means the field isn't doing its job properly", then you need to be able to explain exactly why this is any different from the normal, self-correcting-by-design approach of any scientific discipline. You might well have a point, but it's not enough to say, "this research is wrong" to conclude that "this field is poor". Mistakes in methodology are every bit as integral to the scientific process as mistaken findings.

Surveillance Cameras Show Good Samaritans Prevail Over Bystander Effect

It's one of the most enduring urban myths of all: If you get in trouble, don't count on anyone nearby to help. Research dating back to the late 1960s documents how the great majority of people who witness crimes or violent behavior refuse to intervene.