Cognitive Load vs. Functionality
Cognitive load is the amount of mental effort required to engage in a process. On a web page, clutter, animation, confusing content, background sounds, complex information, and other aspects of poor accessibility and usability increase cognitive load. Try to provide necessary functionality while minimizing cognitive load. This can be particularly difficult on site home pages where much functionality is provided, which generally results in a very high cognitive load. Good usability and accessibility techniques, often as identified in user testing, can help site authors maintain necessary functionality while decreasing the cognitive load.