Final answer:
The ability to focus on a single voice among many in a noisy environment is known as the cocktail party effect, which is an example of selective attention.
Step-by-step explanation:
The ability to pay attention to only one voice at a time is known as the cocktail party effect. This term refers to the phenomenon where a person can focus their auditory attention on a particular stimulus while filtering out a range of other stimuli, much like when one focuses on a single conversation in a noisy environment. Similar to the concept of selective attention, this effect allows individuals to concentrate on one source of sound without being overwhelmed by other noises in the background.
Interestingly, our attention can be suddenly diverted if something stands out, such as a significant unexpected event or hearing one's name called, which demonstrates how both bottom-up and top-down processing can influence what we attend to. Cognitive biases like the confirmation bias and availability heuristic can also affect how we perceive and pay attention to information in our environment.