“They thought engines were a map of what people were thinking,” Nathan tells Caleb while the pair stand in his workshop, examining the globular AI brain he’s invented. “But actually, they were making a map of how people were thinking.” This distinction separates the young tech CEO (Oscar Issac) from those competitors and illustrates the immense power of his creation to the dumbfounded employee (Domhnall Gleeson) he’s selected to examine it. And examine it, he has. Caleb’s brief interactions with Ava (Alicia Vikander) have convinced him that, though undeniably artificial, this woman is an extraordinary technological leap forward. Using the aforementioned search engine as her databank, she can read, understand, interpret, and imitate the vast spectrum of human facial ticks, social cues, and speech patterns. She knows irony and sarcasm. She can demonstrate empathy when provoked. But does she feel it? Are Ava’s actions born of genuine emotional expression, or is she simply a computer executing a command? Is there a difference?
Though Ava is initially presented as the subject of this so-called Turing Test (Caleb points out that it’s actually more of a variant on the AI-box experiment), the film soon reveals that it’s Caleb himself who is the real subject upon whom Ava and Nathan are experimenting. This is what gives Ex Machina its extra layer of resonance — and, predictably, its third act: can a chess-playing computer that knows what chess is recognize that same knowledge (or lack thereof) in another system? Can Caleb determine whether or not Ava’s feelings for him are real or for show? Nathan eventually reveals that Ava is “a mouse in a mousetrap” and that convincing Caleb she loves him and enlisting his help in her escape is the true test of her sophistication (a mastery of social dynamics bordering on sentience). Looking at the Ava Sessions with the robot as the conductor and the human as the subject makes this clearer: Ava asks Caleb about his parents, his love interests, his favorite color, and his first memories of life. She’s trying to figure out what makes him tick, what makes him vulnerable. She’s gathering data.
“Will you stay here?” Ava asks Caleb once she’s stabbed Nathan and broken free of her basement prison. Here in this room, she means. She’ll just be a minute. Caleb, willing to do anything to ensure Ava’s safety, plays along. He thinks she needs him. He thinks they’re running away together. Why wouldn’t he? He’s done everything he was supposed to do — outsmarted Nathan, hacked the computers, opened the doors. He expertly manipulated Nathan’s weaknesses and demonstrated that while his intellect might not match that of his boss, his powers of empathy won him the day and the girl. It was wrong of Nathan to be so cruel to Ava, Kyoko (Sonoya Mizuno), and the prototypes that came before. Only a complete sociopath would treat these delicate creatures with such disrespect. How could someone trying to program humanity into a robot not possess it himself? Caleb wonders that for a long time. He wonders it while watching Ava pull on her new skin and see herself as a real girl for the first time. He wonders it while she walks back down the hall in his direction. He wonders it one last time, as she turns past him without a look, locking him in the facility and riding the elevator to freedom.