PROJECT SUMMARY / ABSTRACT Listening effort has large impact on quality of life, and thus warrants detailed and thorough study. There has long been a conundrum over what effort is and how to measure it. We propose three new branches of work that follow in the spirit of our previous grant cycle, building off of the key observations that listening effort is tightly related to comprehension rather than phonetic accuracy, and that effort can emerge at distinct moments in time before, during and after the listening process. The new aims focus on the effort of preparing to listen, the effort of aiming attention at particular moments during listening, and the effort that lingers while a person is comprehending the meaning of what was heard. The experiments are guided by the lived experiences of people with cochlear implants, who regularly offer interpretation and suggestions on studies that illuminate the situations that pose recurring problems in their daily communication. Our team of clinically trained scientists and language/hearing experts integrates this input into rigorous designs that capitalize on our strength in creating stimuli, measuring listening effort, and sharing our resources with the field. Different aspects of effort need to be distinguished in order to better alleviate the associated costs. For example, effort of recovering from mistakes is different than the anxiety of listening. Overall high overexertion could be distinguished from exertion that simply lasts too long. The proposed work will build understanding of how effort changes on a moment-to-moment basis before, during, and after listening, and how this is affected by hearing difficulty – particularly the use of a cochlear implant.