The findings indicate that while some students had concerns about the lack of privacy or their home environment, 41 per cent of the 276 respondents cited their appearance as the reason for keeping their cameras off.

"Students enjoy seeing each other when they work in groups. And the instructors like seeing the students, because it's a way to assess whether or not they understand the material. But when we switched to online learning, that component got lost. We wanted to investigate the reasons for that," said researcher Mark Sarvary from the Cornell University in the US.

For the study published in the journal 'Ecology and Evolution', the researchers surveyed 312 students in the class at the end of the semester to figure out why they weren't using their cameras -- and try to come up with ways to turn that trend around.

More than half of those who selected "other" as their reason for keeping their cameras off explained that it was the norm. This suggested that explicitly encouraging camera use could boost participation without adverse effects, the researchers said.

"We felt it would create an undue burden and add stress in an already stressful time to require the cameras to be on, and we found this could disproportionately affect certain groups of students, such as underrepresented minorities," said researcher Frank Castelli from the varsity.

In the survey, the team found that among underrepresented minorities, 38 per cent said they were concerned about other people being seen behind them, while 26 per cent were concerned about their physical location being visible; while among non-underrepresented minorities, 24 per cent were worried about people behind them and 13 per cent about their physical locations.

"It's a more inclusive and equitable strategy to not require the cameras but to instead encourage them, such as through active learning exercises," Castelli noted.