(CNN) -- You've seen this person. Maybe you've even been this person.
We're talking about someone shuffling along a sidewalk or through a shopping mall, so entranced by the phone in their hands that they bump into people or almost get run over.
Yes, this behavior can be annoying. Now we have scientific evidence it can be dangerous. A new study has found that people who type or read on their phones while walking are less likely to look at their surroundings, keep their balance or walk in a straight line.
This may seem obvious to anyone who has been jostled by an oblivious text messager. But researchers at Australia's University of Queensland say theirs is the first study to measure how typing text on a cellphone impacts "gait performance" and kinematics, or the study of body motion.
"Texting, and to a lesser extent reading, on your mobile phone affects your ability to walk and balance," said Siobhan M. Schabrun, an honorary senior fellow at the University of Queensland and the lead author of the study. "This may impact the safety of people who text and walk at the same time."