Jakob Nielsen says that: Horizontal Attention Leans Left

While evidence from neuroscience, as described by Jeremy Tunnell (Product Manager for Stack Exchange) suggests that "the brain’s visual system is biased to the right of one’s focus":

Most of the text processing capabilities of the brain reside in the left hemisphere. This means that visual stimuli appearing on the right side of the visual field have a decided advantage.

In fact, information on the left side of the visual field has to enter the right hemisphere of the brain and be transferred through the corpus callosum to the left hemisphere – through two centimeters of callosal cable. As a result, words on the left side of the visual field are recognized more slowly and are subject to more errors.

Why does there appear to be a disconnect between the fields of neuroscience and usability on this question? Do you have any first-hand observations which can back-up one or the other propositions?

1 Answer 1


I don't see any disconnect at all between the two. Most people will have a faster response to objects on the right side of their visual field. So that applies to moving balls; tigers that want to eat you; etc. It is about a tiny increase in visual perception.

This has nothing to do with learned importance. Reading from left to right has taught us that we start reading on the left, and so text on the left will be processed first. It's important to remember that the processing of what we read takes significantly longer that the tiny delay in perception for items on the left when compared to items on the right.

As a result of our left to right reading (for most people), interfaces have put the more important things, or things that the designers want us to read first, on the left. This has re-enforced our concept of the left being where we start.

TL;DR: Speed of perception is not the same as importance

Something else to note is that most content is on the left side of the page, and so Nielsen's graph is misleading. Of course we spend most of our attention on where content is.

  • Ah - good point about the difference between visual perception and learned importance. Thanks - that pretty much clarified it for me. So if they are both correct, it means that the design pattern of left first/important has overcome our natural (neurological) right to left bias. Interesting! I wonder if this holds true in non left-right reading cultures. Jan 22, 2013 at 0:08

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