of dichotic listening to test how participants selectively attend to stimuli when overloaded with auditory stimuli; Broadbent used his findings to develop the filter model of attention in 1958. Broadbent theorized that the human information processing system has a "bottleneck" due to limited capacity and that the brain performs an "early selection" before processing auditory information. Broadbent proposed that auditory information enters an unlimited sensory buffer and that one stream of information is filtered out and passes through the bottleneck to be cohesive, while all others that are not selected quickly decay in salience and are not processed. Broadbent's model contradicts with the cocktail party phenomenon because Broadbent's model predicts that people would never respond to their names from unattended sources since unattended information is discarded before being processed. Deutsch & Deutsch's late selection model that was proposed in 1963 is a competing model to Broadbent's early selection model. Deutsch & Deutsch's model theorizes that all information and sensory input are attended to and processed for meaning. Later in the processing routine, just before information enters the short-term memory, a filter analyzes the semantic characteristics of the information and lets stimuli containing relevant information pass through to short-term memory and removes irrelevant information. Deutsch & Deutsch's model for selective auditory attention suggests that weak response to unattended stimuli comes from an internal decision on informational relevance, where more important stimuli are prioritized to enter the working memory first. In 1964, Anne Treisman, a graduate student of Broadbent, improved Broadent's theory and proposed her own attenuation model. In Treisman's model, unattended information is attenuated, tuned down compared to attended information, but still processed. For example, imagine that you are exposed to three extraneous sources of sound in a coffee shop while ordering a drink (chatter, coffee brewer, music), Treisman's model indicates that you would still pick up on the latter three sounds while attending to the cashier, just that these extraneous sources of noise would be muffled as if their "volumes" were turned down. Treisman also suggests that a threshold mechanism exists in selective auditory attention in which words from the unattended stream of information can grab one's attention. Words of low threshold, higher level of meaning and importance, such as one's name and "watch out", redirects one's attention to where it is urgently required. Recent research Recently, researchers have attempted to explain mechanisms implicated in selective auditory attention. In 2012,