Retired Senior Volunteers RSVs. RSVs were participants in the national Senior Corp program, part of the Corporation for National and Community Service. They were recruited from (blinded for review) and (blinded for review). The RSV program is open to all U.S. citizens, nationals, or lawful permanent resident aliens aged 55 or older (http://www.nationalservice.gov/programs/senior-corps/rsvp). Within this program, volunteers receive standard pre-service orientation and training, supplemental insurance while on duty, and, potentially, reimbursement for costs such as travel incurred during service. RSVs receive no pay for the services they perform. In this study, RSVs were included if they: (1) had a high school education; (2) read and spoke English; and (3) had a car and drove independently.