Schools should teach young people about how to identify "fake news", says the Organisation for Economic Co-operation and Development's education director.
Andreas Schleicher is planning to include questions about such "global competencies" in the next round of the influential international Pisa tests.
He wants teenagers to look beyond the social media "echo chamber", where they might hear only views like their own.
Students need more places to "exchange ideas", says Mr Schleicher.
The OECD aims to develop global policies focused on improving economic and social well-being.
Its education chief says schools need to equip young people with the skills needed to navigate the digital world, with unreliable claims on social media and falsified news.
"In the past, when you needed information, you went to an encyclopaedia... and you could trust that the information would be true," says Mr Schleicher,
But now he says young people go to Facebook or news websites and need to be able to evaluate what is reliable.
"Distinguishing what is true from what is not true is a critical judgement," says Mr Schleicher, who will be addressing the Global Education and Skills Forum in Dubai.
"Exposing fake news, being aware that there is something like fake news, that there is something that is not necessarily true, that you have to question, think critically - that's a very important task."
Mr Schleicher, who runs the international Pisa rankings, is going to introduce written tests in 2018 on global competency, which will assess how well young people are ready for a diverse and "interconnected world".
The tests currently assess teenagers' abilities in maths, science and reading - but the OECD is going to add this new measure of global competency.
"This assessment is about the capacity of young people to see the world through different perspectives, appreciate different ideas, be open to different cultures," he says.
"It is increasingly important for young people to engage with diversity, to be open to that, to draw value out of it, to see diversity not as a problem."
Mr Schleicher links this with young people from Europe going to the Middle East to fight for so-called Islamic State.
He says they want to turn "multi-religious, multi-ethnic" countries into "mono-cultures", which he says is "an outcome of the thinking that there is only one truth and there's only one way to live".
And he warns that social media can encourage people to "communicate and collaborate increasingly just with people who are similar".
"People are not prepared to see diversity as something positive, you see that level of disengagement," he says.
"I think that social media can reinforce that.
"The algorithms tend to relate people to people who are similar, rather than creating spaces for people to discuss debate and find common ground."
Against a backdrop of growing tensions around migration and national identity, Mr Schleicher says: "Europe has always been at its best when people were moving around, contrasting different ideas, different concepts.
"The Renaissance was a great example. There were different populations getting together. Open societies, diverse societies, were able to attract the best talent."
He forecast that the UK as an "open society" would do well on such "global competencies" - and highlighted that schools in the UK were much more successful at integrating migrants compared with France.