8. Memory

People have what is known as 'short term memory'.

This is the capacity to hold a small amount of detail in memory for a brief amount of time - typically 7 elements for a matter of seconds. Then unless further effort is made by the person, those details are forgotten.

This is an useful trait as an awful lot of things we do only require the briefest of concentration before moving on to the next task. For instance, keeping track of your location in a web site is only relevant whilst you are visiting it.

Keep this in mind when considering laying out a multi-page interface.

A regular visitor may be very familiar with some of the site and can easily remember their way around. But if they come across part of the site they are not familiar with, then it is important that everything remains consistent - layout, colour, navigation logic and so on. You are taking advantage of their memorised skills and knowledge to offer an intuitive and effortless experience.

An inconsistent design would mean they have to re-learn interface details leading to an uncomfortable user experience.