Researchers at the University of Michigan watched students in dining halls and coffee shops around campus between January and April 2011. They unobtrusively observed pairs of students sitting at tables for as long as 20 minutes and documented their cellphone use at 10-second intervals.
Overall, the students used their cellphones in an average of 24 per cent of the intervals, the researchers found, LiveScience reported.
However, they were significantly more likely to use their phones (39.5 per cent) when their companion had just done so in the previous 10-second interval, the researchers said, adding that this behaviour was often repeated.
"Some of this could be people being primed to check their e-mail or phone messages, but this contagious use was happening several times in a 15 minute interaction," study researcher Daniel Kruger said.
Kruger believes this pattern could be related to the effects of social inclusion and exclusion. If one person in a pair engages in an external conversation through their phone, his or her companion may feel excluded. That companion then might be compelled to connect with others externally so as not to feel left out.
The researchers noted that they might not observe the same results in a study of different demographics