In the wake of a tragedy like last weekend’s mass shooting in Orlando, Florida, people come together to react — to process, to grieve, to raise funds, to push for change. And a lot of this coming together happens online.

Facebook news feeds fill with articles and stories — photos, videos, opinions. Twitter is flooded with updates, friends reach out through social media, and the news seems amplified by algorithms. 

Then, often, as quickly as it began, it ends. The rapid pace of the news cycle takes over and the social feed moves on to the next topic. But do our minds?

The social media landscape has had an enormous impact on global response to tragedy. To learn more about it, Marketplace Weekend spoke to Karen North,  director of USC Annenberg’s Digital Social Media program.

To listen to the full interview, tune in using the audio player above.