The band recently revealed that they were working on the LP with M83 and Beck producer Justin Meldal-Johnsen.
Williams praised Johnsen's work on the album so far, which includes a track called 'Daydreaming'.
"At this point, we have recorded one song with Justin," she told Buzznet. "That time in the studio was easily the most relaxed, inspired, and liberating experiences we have had in any studio thus far.
"We are huge fans of his work not only as a producer but as a musician, writer and musical director. He wears all those hats well and with a lot of humility."
Williams added that her positive outlook on life has influenced the album's overall sound.
"I am laughing things off a lot more easily these days than I was at 19, when I wrote the last album. Even the songs with the more serious subject matter feel less toiled and troubled.
"Musically, I am most inspired by the personality captured in every instrument. That, to me, is actually what is making up this newer sound that is happening."
Paramore are currently recording their as-yet-untitled fourth studio album, the follow-up to 2009's Brand New Eyes.
They will play at this year's Reading and Leeds Festivals on August 24 and 25.
Watch the video for Paramore's 'Monster' below: