A general definition - Attention is the concentration of mental activities.
Attention is limited and selective.
Functions of Attention Focus processing resources on some inputs rather than others. We get better with practice Easier to do two tasks in different modalities than in the same modality Selective Attention Shadowing a message in a dichotic listening task. Cocktail party phenomenon. Some information gets through un-shadowed channel. The filter or bottleneck can move around Capacity Theory of Attention Tasks require mental effort, and there is only a certain amount of mental energy available at any given time.