Shyamalan's suspense-challenged 'Split' showcases McAvoy's versatility

James McAvoy plays 24 personalities in “Split,” and you can't be sure if M. Night Shyamalan intended this to be a suspense-diluted horror film or a professional resume reel showcasing the actor's astonishing versatility.

Ever since his 1998 supernatural tale “Wide Awake,” Shyamalan has made big reveals his stock-in-trade device, and the modest ones he provides in “Split” won't be pushing many viewers to the edges of their seats.

“Split” begins with three teenage girlfriends — Claire (Haley Lu Richardson), Marcia (Jessica Sula), and Casey (appealing “The Witch” star Anya Taylor-Joy) — being kidnapped by a mad gasser who turns out to be one of 23 additional personalities inhabiting the body of a guy named Kevin (McAvoy).

The young women wake up confined to some sort of rundown bunker with one locked door and a sparkling-clean shower stall.

Two of them go nuts whenever one of Kevin's “alters” confronts them, including the bossy Patricia, 9-year-old Hedwig, control-freak Dennis, fashion-designer Barry and the rest of the gang.

But Casey keeps cool under pressure, having been brought up by her dad to anticipate the relative stupidity of male animals while hunting them with shotguns.

Shyamalan reveals this in flashbacks that also clue us in on how Casey's sexual predator uncle traumatized Casey as a little girl.

In a parallel development, psychiatrist Dr. Fletcher (Betty Buckley), an expert on DID (dissociative identity disorder), suspects something might be very wrong with her prize patient Kevin.

She keeps receiving emergency meeting email requests from him — or one of his “alters” — leading her to suspect that the dominating Dennis has taken control of all the personalities.

Meanwhile back at the bunker, Hedwig keeps the girls terrorized by telling them they've been selected as prey for a mysterious entity called “the beast,” which Fletcher pooh-poohs as fantasy. She apparently doesn't realize she's in the Shyamalan Zone.

Fletcher tries to convince a skeptical medical community that DID can produce supernatural effects, such as a personality that can lift more than two times her body weight, impossible for the other personalities in the same body.

“We can become what we believe we are” becomes the spooky, promising mantra of Kevin's collective.

Shyamalan has his choice of genres to work with in “Split,” among them an abduction thriller, psychological mystery and supernatural horror tale.

He combines them all with ham-handed coincidences and loud foreshadowing that dissipate what meager suspense the setups generate.

The pacing of “Split” moves ever-so slowly, with Shyamalan piling ridiculous complications on his characters. (A segment with Marcia using a wire hanger to unlock her cell goes on forever. Casey can't just find a loaded shotgun — she must locate a shotgun in a storage unit, then find the shells inside a locker in another part of the building, then try to load the weapon while being attacked. Sheesh!)

And why would Kevin's group leave a wire hanger around for Marcia to find? Hasn't any of them watched “Halloween” to see how a hanger can be used as a weapon by a terrified teenage girl stuck in a closet?

“It Follows” cinematographer Mike Gioulakis makes excellent use of winding staircases, plus Taylor-Joy's expressive face and brown pools of empathy where her eyes should be.

But “Split” belongs to McAvoy, whose distinctly separate characters are as much a result of shifting mindsets as changing clothes and evolving body language.

“Split”

★ ★

<b>Starring:</b> James McAvoy, Anya Taylor-Joy, Jessica Sula, Haley Lu Richardson, Betty Buckley

<b>Directed by:</b> M. Night Shyamalan

<b>Other:</b> A Universal Pictures release. Rated PG-13 for language, violence. 116 minutes