"Rubber Soul" saw the band expanding rock and roll's instrumental resources, most notably in Harrison's use of the Indian sitar on "Norwegian Wood". Having been introduced to the instrument on the set of the band's 1965 film "Help!", Harrison's interest was fuelled by fellow Indian music fans Roger McGuinn and David Crosby of the Byrds, partway through the Beatles' US tour. Using fuzz bass on "Think for Yourself", and employing a piano made to sound like a baroque harpsichord on "In My Life" added to the exotic brushstrokes on the album.