The most striking thing about "Action/Reaction," the anthemic debut single from Choir of Young Believers' full-length This Is for the Whites in Your Eyes, is, appropriately enough, the use of voices. Choir leader Jannis Makrigiannis is blessed with a one-of-a-kind instrument-an elastic, versatile keen that he sprinkles liberally throughout "Action/Reaction." A neatly criss-crossed figure of Jannis' wordless "ah"s open the song, weaving in and out of the arrangement and chasing his lead melody until they reach the song's chorus, a classic call-and-response between Jannis' invocations of "a better place" and some robust group harmonies. "Action/Reaction"'s loping beat and air of symphonic grandeur may be the first things you notice, but it's Choir of Young Believers' namesake vocal polyphony that keeps the goosebumps a-coming.