Attention is the ability to maintain and dedicate focus to a particular task. There are multiple theories within the cognitive perspective that deal with attention. There have been many theories formed to discuss how attention may arise.
British researcher Donald Broadbent proposed a filter model of selective attention based an a "sensory buffer". In this view, the mind blocks out information irrelevant to what one is focusing on, such as, say, ignoring another conversation going on at the same time. For example, assume that you are at a party, engrossed in conversation with another party goer. You are able to tune out all other words from other conversations, and yet you can hear your name called out on the other side of the room.
This brings us to Treisman's attenuation model.
Treisman's Attenuation Model
Triesman's attenuation model is a similar theory to that of Broadbent, but it has one exception. Rather than completly blocking "irrelevant" information, Triesman proposes that the mind merely reduces the scale of the information. This attenuation is similar to having water running through two faucets. Triesman proposes that one conversation in the party example would be like having one faucet completly open (the primary conversation) and your name being the second faucet (you recieve it, but you miss the rest of the conversation.) In a nutshell, this theory states that the mind does not block other information, but that it instead limits information, and lets through important information. Examples of blocked information would be, for example, the word "chair" which, in the party situation, would be irrelevant to your conversation.
The Deutsch-Norman memory selection model
Unlike the previous models, the Deutsch-Norman theory states that a second selection process occurs in the procedure of determining what is and what is not irrelevant information. In this model, recieved information is filtered for size, proximity, and other factors that determine how much attention is paid to an object, an example being as follows