We've all done it: if someone next to us crosses, so do we. Now scientists have found we're up to 2.5 times more likely to step onto a pedestrian crossing if someone standing next to us starts to cross. And men tend to follow the herd sooner than women do.
The study is the first time scientists have unequivocally shown that when we cross a busy road we use information about what people around us are doing. It's also the first time anyone has been able to put a figure on this.
The researchers behind the study were trying to understand how people use so-called social information to make decisions. Biologists have long been interested in how animals use what they see around them to make decisions. How do shoaling fish or herding sheep use information about what others around them are doing, for example?
'Certainly it's better if we just wait for the green man, but most of us are in a rush and when we're in a hurry, we're more likely to take risks.'
Jolyon Faria, University of Leeds
Penguins jumping off of an ice floe probably rely on information from their neighbours to make a decision about whether or not to go back in the water. Similarly, swallows taking off from a perch most likely use social cues to make that decision.
More often than not, for animals that live in groups, using social information is beneficial. Wildebeest herd together to confuse their predators and to reduce the likelihood they'll be singled out. Fish form huge shoals also to avoid being eaten. But research shows that, sometimes, using cues from others might not always be a good idea.
Jolyon Faria from the University of Leeds and colleagues from the Lübeck University of Applied Sciences and the Leibniz-Institute of Freshwater Ecology and Inland Fisheries – both in Germany – decided to find out how people use cues from their neighbours in a potentially dangerous situation.
'We thought a pedestrian crossing would be a good place to start, because there is a potential advantage to following others, a potentially quick cross, and a disadvantage, that you may be injured by a vehicle,' says Faria.
In a study published in Behavioural Ecology, Faria and his colleagues describe how they filmed people using a busy pedestrian crossing near the centre of Leeds in northern England between 8am and 9am over two three-day periods.
Simulation
They then analysed the behaviour of 365 of these pedestrians to find out if a crossing pedestrian's neighbours followed. Once they'd got an answer, they compared what they found with a simulation in which the probability that a pedestrian crossed the road was independent of what others did.
'If there was a difference between the two, it gave us the evidence we were looking for,' explains Faria.
The comparison showed that people are up to 2.5 times more likely to cross if one of their neighbours does, while men followed sooner than women do.
'It could just be that men are often bolder than women,' says Faria.
'This shows that we pay attention to our nearest neighbour. If we're aware that our own behaviour is affected by others' behaviour, we might be less likely to just blindly follow someone next to us next time we cross a busy road,' he adds.
The researchers point out that children aren't nearly as good as adults at judging whether or not a gap in the traffic is safe and may be more susceptible to following others.
'Certainly it's better if we just wait for the green man, but most of us are in a rush and when we're in a hurry, we're more likely to take risks,' Faria says.
Faria is keen to take this research further using CCTV and tracking software to collect 'hours and hours of data' at different junctions.