After auditioning for the Italian reality show “Grande Fratello” on a lark, Luciano (Aniello Arena) becomes obsessed with winning one of the television roles. (Oscilloscope Laboratories)

The observer effect, in science, describes circumstances under which the behavior of an object under observation changes as the result of being observed. A thermometer inserted into a glass of water, for example, doesn’t merely measure the temperature, but alters it slightly.

That, in a nutshell, explains why the term “reality TV” is such an absurd misnomer.

But the Italian film “Reality” takes it one step further: Does being watched make you a better or worse person? And what if you’re not being watched but only think you are?

In this subtly satiric film from writer-director Matteo Garrone — a light change of pace from his brutally violent 2008 crime drama “Gomorrah” — Luciano (Aniello Arena) is a genial Neapolitan fishmonger who becomes obsessed with getting on the television show “Grande Fratello,” the wildly popular Italian version of “Big Brother.” After auditioning on a lark, the clownishly lovable husband and father of three becomes convinced that he is a shoo-in and that undercover producers have been dispatched from Rome to surreptitiously evaluate his suitability for the show.

Suddenly, Luciano’s life turns upside down.

He quits his job, selling his market stall so he can be ready when the call comes. Then he starts giving away clothing, food and furniture to homeless people, thinking that his altruism will increase his odds of getting on the show. (All I can say is, the Italian version must be looking for a very different caliber of contestant than our own.)

Gradually, Luciano becomes a kind of compulsive Good Samaritan, helping the helpless on the off chance that one of them might have a hidden camera. He also loses his mind a bit.

At first, it seems plausible that Luciano might get on the show. He’s funny and easy on the eyes in an everyman sort of way. It’s notable that Luciano is young, fit and trim, while many of his friends, neighbors and relatives are old, sedentary and fat. Arena, a newcomer to film, doesn’t look like a movie star, but he does look like he could be on the tube.

Nowadays, what does that even mean?

Garrone is interested in this question and others. But he’s not so interested in answers. The satire here is finespun, and the film’s conclusions ambiguous. There’s a strong undertone of faith, with several scenes taking place in religious settings. Is man’s selflessness a natural state or an artificial one? And what is the evolutionary advantage of letting someone else win? Survival of the fittest, right?

Those are good questions. “Reality” raises them, obliquely, but its points are blunted by a somewhat obscure, open-ended final scene, set at the “Grande Fratello” house on the famed Cinecitta studio lot. (It’s telling that the Italian TV show is actually filmed there, where so many unreal films were made. It’s the home of Fellini.)

As “Reality” fades to black, the goings-on inside the house seem oddly banal, even boring, with the events of Luciano’s life — at least as he perceives them from inside his head — spinning wildly out of control.

R. At Cinema Arts Theatre and Landmark’s E Street Cinema. Contains obscenity and brief sensuality.
In Italian with English subtitles. 115 minutes.