Do you get busy with your cell phones during lectures? Study says you will score less. You have been warned 

Allowing smartphones in class may affect the students' ability to concentrate, eventually hampering their academic performance, a study warns. "While ever-smarter digital devices have made many aspects of our lives easier and more efficient, a growing body of evidence suggests that, by continuously distracting us, they are harming our ability to concentrate," said researchers from Stellenbosch University in South Africa.

It should not be surprising that university lecturers are encouraged to develop blended learning initiatives and bring tech - videos, podcasts, Facebook pages - into the classroom more and more to offer students the enhanced experiences enabled by digital media, researchers said.

However, an important effect of these initiatives has been to establish media use during university lectures as the norm, researchers warn. Previous studies show that students constantly use their phones when they are in class."But here is the kicker: if you think they are following the lecture slides or engaging in debates about the topic you are mistaken," said Daniel le Roux from Stellenbosch University.

"In fact, this is hardly ever the case. When students use their phones during lectures they do it to communicate with friends, engage in social networks, watch YouTube videos or just browse the web to follow their interests," le Roux added.

There are two primary reasons why this form of behaviour is problematic from a cognitive control and learning perspective. "The first is that when we engage in multitasking our performance on the primary task suffers. Making sense of lecture content is very difficult when you switch attention to your phone every five minutes," researchers said.

A strong body of evidence supports this, showing that media use during lectures is associated with lower academic performance. "The second reason is that it harms students' ability to concentrate on any particular thing for an extended period of time," researchers said.

They become accustomed to switching to alternative streams of stimuli at increasingly short intervals. The moment the lecture fails to engage or becomes difficult to follow, the phones come out.