WHat is a cocktail party effect? WHy does it challenge Broadbent's model?

WHat is a cocktail party effect? WHy does it challenge Broadbent's model?

Coctail party effect- A phenomenon when e person is selectively listening to one message among other message/many other messages and still is able to detect some other distinctive message that is not being attended. For example a person can be instructed (for instance during a lecture) to listen to a short story in order to reproduce it later on or at least to know what it was about. Let's say a professor during a lecture reads a long parograph about categorization and a student is listening to it in order to learn what it really means to categorize etc. During the process of reading the student hears his/her two colleagues sitting on the other side of the room mention a word 'accident'. At that moment instead of listening to the professor and the different 'exemplar or prototype approaches to categorization'; the student focuses his/her attention on what might have happened and why the word 'accident' have been used by his/her friends.

This phenomenon challenges Broadbent's model:
According to this model, information in the unattended message (the 'accident information') should not be accessible to consciousness. However from the example mentioned above and many other experiments, it can be seen and said that the certain information presented to the unattended ear is processed in a way that it actually does provide the listener with ''some awerness of its meaning'';(as cited by Goldstein, page 85). This shows that some information that should be 'filtered out' during the second stage as proposed by Broadbent's model; isn't really, but rather analyzed in a way to provide the listener with a certain meaning to it.