Final answer:
Broadbent's single filter model is limited in that it assumes unattended information is completely filtered out and not processed at all, which is contradicted by evidence showing that some unattended stimuli can still capture attention.
Step-by-step explanation:
The limitation of Broadbent's single filter model is that it assumes unattended information is completely filtered out, with no further processing. In reality, research has shown that on some level, there is still processing of unattended information. This is seen in instances where unattended stimuli, especially if they are poignant or personally relevant, can capture one's attention despite the focus being elsewhere. Moreover, Broadbent's model does not explain the phenomenon where individuals can still process and respond to certain unattended stimuli, like hearing their name in a crowded room. This suggests that there is more to attention processing than the strict early filtering proposed by Broadbent.