People are more likely to turn from passive bystanders to good Samaritans in situations that are dangerous or violent, German researchers report.
Occasions when a crowd of people stand back and ignore a person in trouble are well known. Psychologists call it the "bystander effect".
But a new study, published in the European Journal of Social Psychology, shows that if the victim is thought to be in real danger, bystanders can become knights in shining armour.
An experiment in which actors pretended to be in a fight revealed that in situations that might lead to violence and injury, people were more - not less - likely to step in.
The study, conducted by the Ludwig-Maximilian University, Munich, included 54 women and 32 men who were told to monitor the interaction between a man and a woman they had never met. These two people were actually actors who had been instructed to stage an increasingly violent confrontation.
The researchers wanted to observe the time it took for individual study participants attempted to break up the fight. The researchers used male and female actors of different sizes to vary the degree of apparent danger. In some situations, the study participant was accompanied by a second person, who had been told not to respond to the situation.
When there was a low level of danger and they were alone, half the study participants tried to help the victim. That dropped to 6 percent when they were with a bystander who took no action. Previous research has noted this "bystander effect," where the level of intervention decreases as the number of bystanders watching rises.
However, when the level of danger was high and the onlooker was alone, 44 percent of participants tried to help the victim. Of them, 40 percent of the participants tried to help, even when there was a bystander who took no action.