Only four tracks feature a single strongly established key. The rest feature a primary and secondary key or a weak tonal center. Tertian key modulations feature throughout the album and many of the choices of key signatures in themselves were unusual. For example, "You Still Believe in Me" is in B, which keyboardists avoid due to the number of sharps/flats, while "That's Not Me" is in F, the most distant key from C. Submediants, major or minor, are invoked in a manner that Lambert calls "an important source of overall unity". With the exception of "God Only Knows", every composition on the album that shifts keys or has an ambiguous tonal center "uses essentially the same tonic–submediant relation." Fussili offered that Wilson's tendency to "wander far from the logic of his composition only to return triumphantly to confirm the emotional intent of his work" is repeated numerous times in "Pet Sounds", but never to "evoke a sense of unbridled joy" as Wilson recently had with "The Little Girl I Once Knew".