Historically, most psychoacoustic studies measured performance on tasks limited by bottom-up, sensory factors. However, in the everyday world, sensory sensitivity does not always determine performance. The problem in many everyday settings is not that components of an important sound source cannot be heard, but rather that they are not noticed amidst the clutter caused by competing sound sources. In particular, recent evidence suggests that competition for central resources is often the primary limitation on performance in tasks in complex, uncertain environments. This talk will review results of recent studies demonstrating that spatial cues are one important feature that can enable a listener to focus attention on a sound source of interest and mediate competition for central resources. Psychophysical results will be interpreted in light of physiological measures from visual and auditory tasks illustrating the importance of top-down factors on neural activity. Parallels and differences in the role of spatial attention for visual and auditory tasks will be discussed. Speculations about these similarities and differences will be offered, driven by the hypothesis that similarities derive from common control circuitry, while differences arise from differences in peripheral neural coding. [Work supported by AFOSR, ONR, and NIDCD.]