Which component of Broadbent's flow diagram of the mind blocks unattended messages?

The component of Broadbent's flow diagram that blocks unattended messages is the filter. In Broadbent's model, the filter acts as a mechanism that selects which sensory information will be processed for further analysis while blocking out information that is deemed irrelevant or not attended to. This selection occurs early in the cognitive process, enabling individuals to focus on specific stimuli, such as a conversation in a noisy room, while disregarding distractions, thereby simplifying the processing workload.

The filter helps in managing the vast amount of sensory information we encounter, ensuring that only relevant signals are passed on to the next stages of cognitive processing, such as short-term memory. In contrast, short-term memory and long-term memory serve as storage systems for information that has already been processed, while the decoder relates to the conversion of messages into a suitable format for further processing. Thus, the filter's primary role is to control attention, making it integral to understanding how we manage multiple streams of information simultaneously.