Perrone stated that the song represented a type of impressionistic psychedelia, in particular for its cello playing repeated bass notes and its theremin. Professor of American history John Robert Greene named "Good Vibrations" among examples of psychedelic or acid rock. Stebbins wrote that the song was "replete with sunshine [and] psychedelia". Steve Valdez says that, like Pet Sounds, Brian was attempting a more experimental rock style. Comparing "Good Vibrations" to Wilson's previous work Pet Sounds, biographer Andrew Hickey said that the "best way of thinking about [the song] is that it's taking the lowest common denominator of 'Here Today' and 'God Only Knows' and turned the result into an R&B track. We have the same minor-key change between verse and chorus we've seen throughout Pet Sounds, the same descending scalar chord sequences, the same mobile bass parts, but here, rather than to express melancholy, these things are used in a way that's as close as Brian Wilson ever got to funky." Author Jon Stebbins adds that "unlike Pet Sounds the chorus of 'Good Vibrations' projects a definite 'rock and roll' energy and feel." According to academic Rikky Rooksby, "Good Vibrations" is an example of Brian Wilson's growing interest in musical development within a composition, something antithetical to popular music of the time. Suppressing tonic strength and cadential drive, the song makes use of descending harmonic motions through scale degrees controlled by a single tonic and "radical disjunctions" in key, texture, instrumentation, and mood while refusing to develop into a predictable formal pattern. It instead develops "under its own power" and "luxuriates in harmonic variety" exemplified by beginning and ending not only in different keys but also in different modes. Verses and refrains (0:00–1:40) "Good Vibrations" begins without introduction in a traditional verse/refrain format, opening with Carl Wilson singing the word "I", a triplet eighth note before the downbeat. The sparse first verse contains a repetition of chords played on a Hammond organ filtered through a Leslie speaker; underneath is a two-bar Fender bass melody. This sequence repeats once (0:15), but with the addition of two piccolos sustaining over a falling flute line. For percussion, bongo drums double the bass rhythm and every fourth-beat is struck by either a tambourine or a bass-drum-and-snare combination, in alternation. The beat projects a triplet feel despite being in time; this is sometimes called a "shuffle beat" or "threes over fours". The chord progression used