Which of the following can impact a listener's attentiveness during lipreading?

The choice regarding the stress profile significantly impacts a listener's attentiveness during lipreading because a person's emotional and psychological state can influence their focus and processing ability. When a listener is under stress, they may struggle to concentrate fully on visual cues, including lip movements and facial expressions, which are crucial for effective lipreading. Stress can also divert cognitive resources away from the task at hand, making it more challenging to decode speech from lip movements.

On the other hand, the speaker's diction influences clarity and understanding but may not directly affect the listener's attentiveness. Similarly, message complexity can present challenges, but it is more about the difficulty of the content rather than the listener's engagement level. Background music can be distracting, yet the core of this question focuses on what impacts attentiveness, which is more directly linked to personal stress levels. Thus, the interplay between emotional state and attentiveness during lipreading makes the stress profile the most relevant factor among the options provided.