Introduction

There are many different types of attention, and each types of attention can be disrupted in many ways. The fact that attention has numerous hypothetical types is variably defined, and that these multiple definitions obscure the implications of experimental work is not a new idea. There are many processes that are involved in attention, and each of them can be disrupted in their own right. These separate processes are often combined in complex human tasks, further complicating the picture. Problems with definitional inconsistency and lack of clarity abound in our psychological understanding of what is and is not attention or the cognitive processes that constitute its components. As a result, research into attention has been limited and skewed by these definitional constraints, thus our understanding of how the brain works has been delayed.