This filter symbolizes the location of selection to attention. This model asserts that the selective filter allows information to come in from only one channel at a time, into working memory. Studies utilizing the dichotic listening task, help to illustrate Broadbent's filter model . In these studies the participant is asked to put on a set of headphones, and requested to listen to only one ear, and report that information. The information presented to the participant is different between the two ears, and therefore fits the filter model perfectly.
Participants tend to lack awareness of the unattended ear's content, or even language.
Those who do know that the other ear's information varies from the attended ear's information can only report whether it was a human voice, and whether it was a male's voice or a female's voice. An extension on Broadbent's Dichotic listening task is the Shadowing task, which requires participants to repeat the attended ear's information out loud. Shadowing a message provides proof that the participant is following instructions, and is attending to the correct ear. During a shadowing task, subjects are completely unaware of the unattended ear's message. Furthermore, when information is switched from one ear to the other in a contextual flow, the participant follows that switch.