Final answer:
According to Treisman's Attenuation Model, Idris will automatically shift his attention to the person who mentioned his name, even if he is engrossed in a conversation, due to an attentional filter allowing personally relevant information through.
Step-by-step explanation:
According to Treisman's Attenuation Model, the correct statement about Idris's attention when his name is mentioned at a party is that a) Idris will automatically shift his attention to the person who mentioned his name. This model explains that although a person may be deeply engrossed in a conversation, certain stimuli like their own name have a higher threshold for being noticed amidst distraction. This phenomenon is due to an attentional filter that weakens but does not eliminate stimuli not being actively attended to. Thus, when Idris hears his name, the attenuation filter will allow this personally relevant piece of information to capture his attention, despite the ongoing conversation.