A Cornell University psychology graduate student says overhearing someone talking intermittently does not provide the predictability of hearing a two-way exchange, and thus proves inherently unsettling, ScienceNews.com reported Friday.
That makes it harder to focus on one's own immediate business, whether it is reading a book, contemplating a work presentation or driving a car, Lauren Emberson says.
The results raise the unsettling possibility that drivers operate vehicles poorly not only while talking on cellphones but also when passengers are using their phones.
"Drivers should be aware that one's attention is drawn away from current tasks by overhearing someone on a cellphone … and that this effect is beyond conscious control," Emberson says.
Overhearing a whole conversation while focusing on something else does not drain listeners' attention, researchers say.
Individuals who overhear cellphone chatterers often try to guess what the unheard talker has just said or thought, contributing to distraction, another researcher says.
"I bet people are often trying to fill in the blanks when they hear half of a conversation," psycholinguist Benjamin Bergen of the University of California, San Diego, says.