Much has been written about Spike Jonzes Her, the Oscar-nominated tale of love between man and operating system. Its an allegory about relationships in a digital age, a Rorschach test for technology. Its also premised on a particular vision of artificial intelligence as capable of experiencing love.

Poetic license aside, is that really possible?

Not anytime soon, though not for lack of processing speed or algorithmic finesse. What computers lack are bodies. The thoughts and feelings and emotions we call love are not abstract experiences; theyre intertwined with senses and hormones. An AI a computer hooked to video cameras, a microphone and a screen would not experience flesh-and-blood love.

You cant make a computer without a body feel love, said David Havas, director of the Laboratory for Language and Emotion at the University of Wisconsin-Whitewater. Though trying to replicate it may produce wonderful gadgets, and potentially life-saving achievements, it can never achieve the same result.

In a sense, the body is the computational engine that makes emotion out of emotionless parts.

Havas isnt simply skeptical because modern AIs are unsophisticated. The opposite is true: AIs sort our mail, defeat our Jeopardy! champions and recommend medical treatments. From behind a screen, it can be difficult to distinguish chatbots from people.

Indeed, with some clever coding and a sufficiently nuanced grasp of human experience, it might be possible to build an AI that gives the appearance of loving. This wouldnt be easy: as philosopher and cognitive scientist Daniel Dennett wrote in Why You Cant Make a Computer That Feels Pain, some states of being are simply too messy to code. When Siri says, I did have strong feelings for a cloud-based app once, shes probably faking it.

Hers Samantha is different, though. Shes not going through the motions or running predetermined subroutines. Her love wasnt programmed; it grows. She falls in love. She experiences infatuation and fascination, passion and care, a sense of giving and taking and sharing. The breadth and depth of her feelings evolve.

That capacity for growth is difficult to program, said cognitive scientist Benjamin Bergen of the University of California, San Diego. Many mid-20th century AI researchers thought it could be replicated in code alone, imagining human faculties as a mental software suite that would work the same in silicon as in a body. That paradigm underlies Hers essential premise, and it no longer holds.

Instead, researchers in the field of embodied cognition have found close links between body and thought. In experiments, this has been demonstrated in fairly simple ways the effects of postures and facial expression on emotion, how different textures influence perception but they suggest a basic principle.

Read more:

Can a Computer Fall in Love if It Doesn't Have a Body?