Michelle Obama says social media magnifies feelings of political and cultural division, underlining a need for people to get out of their online silos.

The former first lady of the United States made the remarks Thursday at an event hosted by the Greater Vancouver Board of Trade, where she spoke to thousands of women and many teenagers from local high schools.

She says for more than a decade, she and former president Barack Obama travelled the United States and found that people mostly got along peacefully.

While social media can bring people together, she says it can also embolden people to make nasty remarks from behind a computer screen.

Obama says she tries to teach her daughters, 16-year-old Sasha and 19-year-old Malia, to be cautious and not to tweet everything that鈥檚 on their minds.

She says history is a bumpy road with many ups and downs, but society has come a long way, as shown by her husband becoming the first African-American to be elected president and then winning re-election.

The Canadian Press