Researchers found that a performance gap between blacks and whites on a 20-question test administered before Obama’s nomination nearly vanished when the exam was given at key periods in the campaign.

Sei Jin Ko is a visiting professor in management and organizations at Northwestern University and she worked on the study, and explained how they went about gathering their data.

Music Button: Benny Golson, “Grove’s Groove”, from the CD New Time New ‘Tet, (Concord records)