Chief Community Evangelist for VizThink, Ryan Coleman presented a fascinating look at how the human brain sees and understands information and what this means (or what it should mean) for your designs. This is a massive topic that Coleman says he could easily dedicate a whole day workshop to. We didn't have time for that, so Coleman gave us an overview of the topic in three buckets:
1) What is your story?
2) How we see.
3) Designing for visual efficiency.
The first block, "what is your story?" was end user goal oriented. Understand what story you're trying to tell and how you want your user to act. Do you want he or she to learn, acknowledge, act? Know your story before you start design.
You could tell that the "how we see" block was the tip of a massive iceberg capable of sinking the Titanic. Coleman talked about how the eye focuses on features, how the brain excels at pattern recognition, but isn't so hot at keeping entire objects in recent memory. Each piece was brought back to why understanding how the eye and the brain works is useful to creating effective designs that people can use with ease.
Coleman got us to try this: hold your arm straight out in front of you and make a thumbs-up gesture. Focus on your thumbnail. That thumbnail sized space is the area that your eye focuses 1/2 of its processing power on at any given time. Information outside of that space is perceived, but not with nearly as much clarity. This is also how much of your design people will really focus on at one time. This has quite an impact on spacial placement of items within your design.
Block three, "designing for visual efficiency" was all about combining your understanding of what your story is with your new comprehension of how the human brain and eye perceive to create designs that maximize efficiencies of visual queries -- that is to say, how to make your designs effective.
Coleman suggested two books to help designers and clients who want to understand visual design more.
I encourage you to check out this presentation at presenter Ryan Coleman's website.