Having to focus on one voice in a crowded room of boisterous speakers is a common experience for most of us, and we humans are extremely good at it, yet the latest algorithms running on the fastest modern computers fail miserably at isolating a single voice from a noisy background in all but the simplest cases. This demonstrates that attending to desired sounds in our everyday environment poses a surprisingly challenging computational problem for the brain—a problem whose solution would provide insight into the workings of the conscious mind and new approaches for designing man-made machines capable of intelligently processing real-world data.