Attention is the ability to maintain and dedicate focus to a particular task. Attention is believed to originate from sustained activity within certain areas of the brain, as of yet unknown. There are multiple theories within the cognitive perspective that deal with attention. There have been many theories formed to discuss how attention may arise.
Broadbent's Filter Model
British researcher Donald Broadbent was the first researcher to present a hypothesis as to how attention would occur, and how one can focus on specific events. Broadbent’s filter model proposes that the mind blocks out information irrelevant to what one is focusing on, such as, say, ignoring another conversation going on at the same time. This idea has received criticism owing to the following situation. Assume that you are at a party, engrossed in conversation with another partygoer, and you hear your name on the side. By all likelyhood, your attention would be diverted, which contridicts Broadbent's theory.
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 receive 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, received information is filtered for size, proximity, and other factors that determine how much attention is paid to an object, an example being as follows
As per the memory selection model, more attention was paid to the larger A, followed by a close inspection, which noticed the smaller A.