London, Feb 14 : If a student's friends are doing academically better than them at school, their own marks improved over time, a study has revealed.

The US researchers said that the study's findings suggested that academic success is infectious - or spread through networks of friends, the Daily Mail reported.

They asked 16 and 17-year-old students in a school in New York State if they were willing to take part in the study.

The students who agreed were given a list of participants and asked to mark each as a friend, best friend, acquaintance or stranger.

A year later, the researchers compared the students' marks over the next 12 months with their social network.

This revealed a strong connection between friendship and the rise and fall academically.

Researcher Hiroki Sayama, of the State University of New York, said that this may be because people choose close friends who are similar to them, which created less room for change.

Sayama believes one possibility is that people view their friends' behaviour as the norm and begin to act in a similar way.

He said that another possibility is that when the pupils named their friends, they might have unconsciously added in people that they weren't that close to but they admired.

The study has been published in the journal PLOS ONE. (ANI)