Nobody likes to wait. In the past several weeks, web performance has gotten a lot of attention because of the time some websites take to load.

Why do we want faster pages? Slow pages cause web stress: Poorer concentration and increased agitation.

Why do we stress? It is mainly because of our short-term memory. Information stored in our short memory evaporates quickly. That is why we don't perform as well when we have to wait. Even after just 10 seconds, we have lost our chain of thought.

At any moment, there are three basic types of memory processing at work in your brain. There are sensory, short term memory, and working memory. Sensory memory works in 100ms bursts.
There are three types of sensory memories; iconic memory, sound memory, and touch memory. Iconic memory is every time you see something, this visual information is taken in by photoreceptor cells in your eyes and they send to the occipital lobe in your brain. Your short term memory can store information for 10-15 seconds, enough time for your working memory to process, manipulate, and control it.

The goal is to get page load times down to 100 millisecond to keep us from losing information through the cracks in our iconic memory. Also, this gives our short term and working memories time to soak up all they can before they start losing information.

This is where we get into flow. Human beings are hard-wired to perform tasks seamlessly. Our day to day tasks have been a series of minute actions that flow more or less seamlessly into the next. This is hard-wired. It’s only in the past 40 or so years that we’ve imposed an entirely new way of processing information on our unsuspecting brains. And simply put: we aren’t wired to deal with the fits and starts of human-computer interaction.

The noteworthy aspect of this study is that the doorway effect persists in computer simulations. The act of going from virtual room to room is directly analogous to the act of navigating from page to page. It’s easy to conclude that the visual stimulus of watching a page refresh could purge the previous page’s “event model”.

http://www.webperformancetoday.com/2012/03/21/neuroscience-page-speed-we...