Sally Kohn: I'd like to revisit your mention of using highlighters in reviewing your notes. What have we learned about the way that the brains work and maybe our highlighters, in some cases ought to be put aside? She says before you pick up your laptop or your iPad to read something, set your purpose. And then on the cover of your PDF, write those key takeaways so that as a practical sense, when you're thumbing through all your PDFs, it's right on the top.