Where does the bottleneck occur in Broadbent's filter model?

In Broadbent's filter model, the bottleneck occurs at the selective filter stage, where sensory information is filtered based on its physical characteristics, such as pitch or loudness. This filter allows only one stream of information to pass through for further processing, while other streams are temporarily blocked. This mechanism explains how individuals can focus on a specific conversation in a noisy environment, but it also limits the processing of unattended stimuli. Consequently, important information can be lost if it doesn't capture attention at this stage.