Selective attention allows us to focus in on what we want focus on and drown out what we do not. The part of the brian controlling Selective attention is the reticular activating system, which then activates regions of the cerebral cortex during selective attention. An important psychologist dealing with selective attention was Donald Broadbent. His filter theory of attention see attention as a bottleneck through which information is passed. This filter allows us to pay attention to what we want and ignore what we don't. To prove his theory he used dichotic listening where one message would be delivered to the left ear and a separate message would be delivered to the right ear. The subjects would be told to ignore one message. when asked about the ignored message they had little to no knowledge of the message. Anne Treidman replicated his finding by using shadowing. Only the subjects in her tests would sometime mix the two messages together if it made logical sense. Also another important part of selective attention is the cocktail party effect, which is our ability to pick up important messages in a conversation that doesn't involve us. I know I use selective attention almost every day, whether it be while I'm doing homework and the television is or when two people are talking and I only want to hear one conversation. I find the cocktail party effect working all the time, like when I hear my name I start to pay attention to where i heard it. The only question I have is how much of the ignored part of our selective attention is being processed?