In early April, at the height of the pandemic lockdown, Gianpiero Petriglieri, an Italian business professor, suggested on Twitter that being forced to conduct much of our lives online was making us sick. The constant video calls and Zoom meetings were draining us because they go against our brain’s need for boundaries: here versus not here. “It’s easier being in each other’s presence, or in each other’s absence,” he wrote, “than in the constant presence of each other’s absence.”

Petriglieri’s widely retweeted post reads like the germ of a horror tale. The liminal space between presence and absence, reality and unreality, is often where the literature of fear unfolds — a place called the “uncanny.” That old aesthetic term for creeping dread, famously dissected by Freud, is typically now applied to disturbing specimens of digital animation said to reside in the “uncanny valley.”

Screens and artificial intelligence have shown up regularly in the horror genre since the dawn of the personal computer. “Ghost in the machine” stories are so common that, when I submitted a proposal for a horror novel about technology, my editor warned me against deploying a malevolent A.I. as my antagonist.

But it’s hard to find scary stories that depict how we become the ghosts in the machine. The anxiety we feel when our virtual connections outweigh our real ones is more often a subject for nonfiction, such as a 2018 New York Times article headlined “A Dark Consensus About Screens and Kids Begins to Emerge in Silicon Valley.” A quote in the piece from a Silicon Valley office worker — “I am convinced the devil lives in our phones” — has stuck with me like the tagline on a dog-eared vintage horror paperback.

In fiction, technological anxiety is more typically the province of satirists rather than scaremongers, and it’s not hard to see why. First, while screens can haunt and obsess us, they can’t stalk and attack us. Unless you go the David Cronenberg route — not easy on the page — cyber-horror isn’t visceral.

Writing psychological horror about tech isn’t much easier. We tend to define the internet as a way to connect with other people — plugging in, getting wired, being online. Horror fiction, by contrast, thrives on the isolation of the haunted house or the snowed-in Overlook Hotel. There’s a reason modern horror plots often depend on characters’ cellphones getting lost or dropping the signal.

To early humans, disconnection from or shunning by the tribe meant death; connection was life, light, warmth, hope. Loneliness remains part and parcel of horror stories — the dark hall, or the mansion in “The Haunting of Hill House” where, Shirley Jackson wrote, “whatever walked there, walked alone.” On the brilliant British horror podcast “The Magnus Archives,” one of the 15 godlike entities that terrorize humanity is known as “the Lonely.” There is no corresponding terrifying embodiment of “the Crowd.”

The chief exceptions to this solitude-is-scary rule are zombie and pandemic tales, in which gatherings are ominous and even loved ones might be carriers. But you can’t catch a virus online — not that kind, anyway. What you can catch are forms of compulsion, unease and anxiety that are much harder to pin down — if hardly unknown.

In his 1919 essay, Freud linked the uncanny to a “morbid anxiety” caused by the return of a primitive belief we’ve done our best to repress. One example is the belief that dead people are still with us; another, the conviction that nothing is random, since shadowy forces pursue us through our lives.

To someone living exclusively online, many of Freud’s “primitive beliefs” would be literal truths. The dead live on in their videos and social media feeds. Thanks to targeted advertising, a pair of boots we put in our cart months ago stalks us at every turn. The notion that a single utterance can turn a random citizen into an influencer might have sounded to Freud like magical thinking. We see it happen every day.

Or consider the uncanny motif of the double, which has inspired writers of dread from Dostoyevsky to Tana French. The fear of having our identity appropriated by a look-alike doesn’t seem atavistic in the era of catfishing and deepfakes. We all lead parallel lives in which presence is absence and reality is malleable.

Those online lives can be deeply fulfilling, assuaging loneliness and fostering new communities. But when we depend too much on them, things can go awry. Reality can lose its reality, as it has for those sufferers of video-game-related disorders who reportedly see Tetris blocks floating in midair. And that’s where the space for uncanny fiction opens.

The horror tale that best captures the uncanniness of virtual life may be the cult film “Kairo” (“Pulse”), which was released way back in 2001. The director, Kiyoshi Kurosawa, uses a simple horror conceit — ghosts are online — to summon the terror of dissolution. His specters aren’t digitized serial killers or vengeful A.I.s, but the spirits of people like us who have overflowed the afterlife and colonized the virtual world.

From screens, these ghosts haunt the living, their aim being not to kill us but to “make people immortal by quietly trapping them in their own loneliness.” One by one, the film’s living characters evaporate into pixel-like fragments, their individuality flowing into a stream that includes the now and the then, the living and the dead. The offline world slides toward a quiet apocalypse.

Like Jackson’s Hill House, Kurosawa’s internet is crammed with ghosts who offer one another no society or solace. “People don’t really connect, you know,” an I.T. specialist warns an internet novice. To connect online, “Kairo” suggests, is to be more alone than ever, crowding the world with echoes of humanity that never reach a receptive ear. The film is chillingly prescient about the loneliness we feel as we refresh our feeds late at night, searching for proof that we’re real and finding only other digital ghosts doing the same thing.

I strove to channel that loneliness in my own cyber-horror book. The plot involves a video game that lives on the dark web and taunts potential players with a legend of unbeatability. But software is not the antagonist. Like me refreshing my feeds, players of the game are caught in a loop of desire and rejection, a compulsion to keep playing when there are no rewards left. It’s that loop that ensnares and destroys them.

Writing about the scary side of screen time taught me that, uncanny as it may be, the world of ones and zeros doesn’t birth monsters; the human compulsions we bring to it do. The solution may be to develop a talent for disconnecting, not permanently, but periodically, to allow ourselves to feel the nagging pain of isolation that underlies so many of our virtual connections, a reminder that when we live online we’re all in the same uncanny boat — present in our absence, together alone.