Pre-attentive psychology tries to explain how our brains perceive visual information and organise it into meaningful patterns and structures, all in a fraction of a second. Understanding how this works gives us crucial building blocks for how to structure user interfaces. This talk looked at some of the principles and how they give us guidelines for layout and structure. Most of us already do this without realising it but understanding why and how we do it makes us more effective when we come to design (or evaluate) user interactions!