Final answer:
Broadbent's single filter theory explains why Betty heard the violin at the concert, as her attention selectively filtered and processed the sound due to her preference for classical music.
Step-by-step explanation:
The question asks which model best explains why Betty, a classical music enthusiast, could hear a violin being played while her friends could not during a rock concert. The correct model to explain this phenomenon is Broadbent's single filter theory. This model proposes that individuals have a single, limited-capacity channel for processing information, and thus must filter out unattended stimuli. Betty's preference and attention to classical music likely caused her to unconsciously filter and attend to the sound of the violin amidst the noise of the concert, a process known as selective listening.
Broadbent's model is based on the idea that attention is a selective process, and only certain stimuli are filtered and processed for meaning. In Betty's case, her love for classical music meant that her filter was tuned to the frequencies of the violin, allowing that sound to be processed preferentially over other sounds at the concert.