15:32DiscoveryWhy do people shout on their cellphones?BBC World Service Duration: 27 minutes Tue 6th Sep 2016, 15:32 on BBC World Service OnlineAvailable for over a yearListen nowWhat causes traffic jams? And why do people shout on their cellphones? Show more GenresFactualScience & NatureFormatsMagazines & ReviewsBrandDiscovery Source: BBC Online