From invisibility to superhuman strength to telekinesis, a wave of emerging technologies promise to give people powers once reserved for comic-book characters. Which raises an important question: If humans become superhuman, will we turn out to be superheroes—or supervillains?

You might think the answer would depend on each individual’s moral compass. Batman uses human-enhancement technologies to fight crime because he loathes injustice, while the Joker uses them to wreak mayhem because he’s a psychopath. In reality, though, most people possess the capacity for both good and evil. Which one wins out at any given time depends not only on our genes and our upbringing, but the circumstances in which we find ourselves. For Peter Parker, a shy and neurotic kid, the transformation into Spider-Man brings out a deep sense of social responsibility. For Otto Octavius, once a respected scientist, becoming Dr. Octopus means becoming a vengeful megalomaniac. Comic books typically provide pop-psychological back stories to explain the choices each character makes in response to the pressure of being extraordinary. But what if it also turns out that some types of powers inherently lend themselves to altruism, while others make us more likely to lie, cheat, steal, or kill?

Last year, Stanford researchers recruited 60 volunteers for an experiment on how virtual superpowers could influence moral decisions. In an immersive virtual-reality simulation, 30 of the subjects were granted the power of flight, like Superman, while the other 30 rode as passengers in a helicopter. Each volunteer had the same mission—to cruise over a city following an earthquake in search of a stranded child. The experiment was rigged so that everyone would find the boy in the same amount of time and save his life.

After the simulation, an experimenter sat down to debrief each subject. As they talked, the experimenter “accidentally” knocked over a canister full of pens, then waited five seconds before beginning to pick them up. The volunteers in the helicopter group took an average of six seconds to start helping clean up the spill, and some didn’t pitch in at all. But those in the Superman group jumped right in, with most coming to the experimenter’s aid even before she started gathering the pens herself.

The findings suggest that acquiring a superpower can spark benevolent tendencies. Give someone Superman’s abilities, and she’ll start to behave a little more like Superman. Clinical psychologist Robin Rosenberg, who helped design the experiment, said its outcome supported her hypothesis that people might treat an extraordinary ability as a sort of gift that brings with it a responsibility to help others. That’s an encouraging finding, particularly in light of Lord Acton’s maxim that power corrupts.

But wait—what if the researchers had given their subjects a different superpower? Rosenberg’s co-author, Stanford communications professor Jeremy Bailenson, explained that they chose the power of flight partly because it seemed like a classic “do-gooder” sort of ability. “We thought about giving them X-ray vision, but that would have been a little creepy,” he noted.

It would be nice to think that morality emanates from the sheer goodness of people’s souls, but research has consistently shown that people behave far better when they think they’re being watched. In a 2010 study, Newcastle University researchers found that just hanging posters of a pair of staring eyes on the walls of a cafeteria was enough to cut littering in half. That’s why Rosenberg, who has written a book on the psychology of superheroes, draws a distinction between visible powers and stealth powers. Soaring above the masses is a highly conspicuous activity, so it would behoove the flyer to be on his best behavior. X-ray vision is stealthier—you could use it for nefarious purposes without making a scene.

The ultimate stealth power, of course, is invisibility. Its promise is that of impunity—the ability to do things that would otherwise get you in trouble. In Plato’s Republic, Glaucon recounts the story of an otherwise decent shepherd who came into possession of an invisibility ring. Unable to resist temptation, he used it to seduce the queen, kill the king, and claim the crown for himself.* H.G Wells’ invisible man went on a similar spree. And in a classic episode of This American Life, John Hodgman went around asking people which superpower they’d prefer: flight or invisibility. Those who pondered invisibility couldn’t resist premeditating a slew of illicit deeds. One fellow was so spooked by his own impulses that he ended up changing his answer to “flight” because the mere thought of invisibility “leads me down a dark path.”

Powers that inherently violate other people’s autonomy, like mind control, would also seem to lend themselves to abuse. A utilitarian might be able to dream up some applications that redound to the public welfare, but the German philosopher Immanuel Kant would argue that mind control is immoral no matter how it’s used. Mind-reading would be similarly invasive. A form of telepathy that required both parties’ active participation, on the other hand, might be stealthy, but it would be fundamentally social and consensual. That ups the odds that it would be used for virtuous ends. Other powers, like supreme intelligence, time travel, and indestructibility, are morality-agnostic and could be employed equally for good or ill. Likewise incredible strength, which Bruce Banner’s Hulk uses mostly for good but which also bedevils him by amplifying the consequences of his rage.

That example suggests another way of looking at the risks and benefits of human-enhancement technologies. By definition, they enable people to transcend their natural limitations. That can obviously be a good thing, but it also carries heightened risks, because civil society and human morality have evolved against a background in which those constraints are taken for granted. That’s why emerging technologies like drones and 3-D printing scare so many people—they enable behaviors that our laws and norms have not evolved to regulate. Imagine the panic that would ensue if hypothetical superpowers like mind-reading suddenly became widely available.

It’s probably fortunate, then, that we’re nowhere near as close to the technological singularity as Ray Kurzweil would have us believe. We have jet packs, but they’re grossly impractical. Headlines about real-life invisibility cloaks tend to be exaggerated. Muscle suits so far are clunky enough that they’re only really useful for people with disabilities. Brain-computer interfaces let you move things with your mind, but only if you’re willing to undergo brain surgery and practice for months just to feed yourself a bite of chocolate. Promises of super-longevity or immortality are premature.

That said, each of these human-enhancement technologies, and several more that Slate will explore in the coming weeks, are progressing at various rates along a path that could someday lead to real-world viability. Before they do, it might be wise to take a little time to think about whether each one is likely to make people better—or just more potent.

Read more from Slate’s Superman series.

Correction, May 3, 2013: This article originally misstated that the shepherd seduced the king and killed the queen in Glaucon’s story from Plato’s Republic. He seduced the queen and killed the king. (Return to the corrected sentence.)

