Four albums into M.I.A.'s career, it's arguable that success may have been the worst thing to happen to her music.

After "Paper Planes"' breakthrough, Maya Arulpragasam seemed determined to appear ever more rebellious in the face of increasing mainstream acceptance; her one-finger salute during the Super Bowl half-time show while performing with Madonna and Nicki Minaj was a perfect example.

That attitude trickled down to her music: /\/\/\Y/\'s abrasive electronics, which reflected her mistrust of the information age, were equal parts tedious and thrilling.

Matangi -- named after an emerald-green Tantric goddess as well as a riff on M.I.A.'s birth name, Mathangi -- has weaknesses similar to /\/\/\Y/\'s: many songs are so claustrophobic that they feel twice as long as they actually are, and her wordplay hovers somewhere between the club and the nursery.

Her litany of countries on the title track feels alternately meaningful and parodic, while "aTENTion"'s reliance on words with "tent" in them works better as a rhythmic device highlighting the song's blippy electro-pop than a key to any deeper significance.

Top-loading the album with some of its most aggressive tracks, M.I.A. makes listeners wait for her still formidable skills with hooks and melodies.

She displays them most stunningly on "Bad Girls," a sinewy, menacing track whose origins date back to 2007 sessions with Danja.

Throughout Matangi, Arulpragasam proves she's as adept as ever at blending different sounds and cultures into a mix that is unmistakably hers, alluding to Shampoo's bratty Brit-pop single "Trouble" at one moment and proclaiming herself the female Slick Rick at another.

Indeed, the moments inspired by rap and R&B are among the highlights, such as her karmic questioning of Drake's ubiquitous motto on "YALA" or the sultry, surprisingly straightforward ballad "Know It Ain't Right." "Exodus," a collaboration with the Weeknd, finds a mostly successful middle ground between her outbursts and his chilly R&B dirges (although the closing reprise "Sexodus" probably wasn't necessary).

While she remains an ambitious synthesist, it often feels like M.I.A. is having less fun as time goes on, and moments like the fizzy, hypnotic "Lights" or "Boom Skit," which harks back to Arular's brazen exuberance, are welcome respites from her mission to be the edgiest.

In its mix of confrontational moments and moves toward the rap/R&B center, Matangi is a frustrating portrait of an artist challenging herself on some levels and retreating on others.