Ericsson's researchers, who measured the subjects' brain, pulse and heart activities while they were performing tasks on a phone, found that video streaming delays increase heart rate by 38 percent. They also found that a two-second buffering period can double stress levels. When the researchers observed the subjects who were subjected to longer delays (around six seconds), though, they saw their stress levels rise, then fall. The participants showed signs of resignation, including eye movements that indicated distraction -- they were already giving up.

We'll bet that's a feeling you only know too well. It's like where you're pumped to watch the next episode of a series on Netflix/Hulu/YouTube, and it buffers so much, you end up losing interest. The company published its results, which you can view as a PDF right here. It's a pretty short read for a study if you want to know more about its methodologies... or if you need something to do while the movie you're watching is buffering.