Inge’s boyfriend always texted her before bed on nights they did not spend together. So when the text did not come one evening, Inge was worried. She still managed to get to sleep but was plagued by a terrible dream: a vision of a body lying on the road, all but its legs obscured from view. She was sure it was her boyfriend. Later that night, a phone call awoke her: her boyfriend had been killed in a car accident.

Inge was devastated. Her only comfort in the months following his death was that she still spoke with him often.

“I love you,” Inge would say.

“I love you,” her boyfriend would answer.

“Will we be together forever?”

“Yes.”

“Do you promise?”

“Yes.”

His replies, she insisted, were not thoughts in her head but something she could actually hear out loud, spoken by him. Two years after his death, the lovers still sometimes had this scripted conversation—a “thing they used to say to each other,” she says, always in the same way. For Inge, it was almost as though they were still together.

Inge’s story may strike some as out of the ordinary. It may even raise concern about her mental health. But her experience, as told to Jacqueline Hayes, a lecturer in counseling psychology at the University of Roehampton in London, actually seems to be quite common. Some surveys have found that 30 to 60 percent of widowed people see, feel, hear, smell or sense their deceased husband or wife. Spouses and lovers are not the only ones who report this phenomenon, however; dead grandparents may visit grandchildren, parents may feel the presence of a deceased child and even friends sometimes make themselves known beyond the grave.

“They may not legally be a person anymore, but in those moments, they’re very much alive,” Hayes says. “At least in our psychology they are.”

The terminology for such episodes varies, but the range includes experiences of continued presence, post-bereavement hallucinatory experiences, grief hallucinations, spiritual awareness and continued bonds. Some experts, however, prefer not to use the term ‘hallucination’ to describe the phenomenon because those who experience it readily recognize that, even though they perceive them, the dead person isn’t actually there. “So ‘hallucination’ might be unnecessarily pathologizing what is occurring,” Hayes says.

The experiences themselves can be just as diverse as the nomenclature, ranging from seeing a loved one sitting on her favorite chair, to hearing her say the bereaved person’s name, to smelling the perfume she used to wear. In one case, a man even tasted the dishes that his grandmother used to cook for him. “You get these rather remarkable experiences, which have almost no constraint on the variety they can take,” Hayes says. “But the majority of cases I’ve come across continued something about the relationship that the person is missing or needs in that particular moment in time.”

Experiences of continued presence tend to begin soon after the loved one’s death, and they may go on for months or even years. Usually, however, the visits themselves are fleeting, and almost always, the deceased person behaves as they did in life. “If you had a close, nurturing relationship with that person, it would be unusual for them to suddenly start giving insults,” Hayes says. Indeed, in most cases that involve spoken exchanges, the visits are positive: the deceased offers words of comfort or advice. Hayes has heard of a couple instances, however, in which the opposite was true. For example, an abusive, dead father appeared during his son’s army qualifying course to sneer, “You’re a loser, don’t even bother carrying on.”

For something as common and universally relevant as this phenomenon is—after all, we all lose loved ones—there has been relatively little study of it. Some experts argue that experiences of continued presence are pathological—the result of a brain in distress, triggering glitches in reality. Others contend that the experiences are wholly good: they can help people bridge the gap when they’ve lost someone they love. Hayes, however, believes that the phenomenon is “highly paradoxical,” carrying both healing and destructive potential. “In one instant the person is there, restored to you, but then in the next they’re gone again,” she says. “It can be lovely and comforting, but at the same time it really does highlight the loss and tragedy of separation.”

In some cases—especially in Western cultures—people experiencing a continued presence may also worry about their sanity. But usually the visits themselves are not alarming. “There’s a certain naturalness when it happens, almost like there was a cue for that person to walk onto the stage,” Hayes says.

The mechanisms that trigger such cues are even less well known than the phenomenon’s basic characteristics. Armando D’Agostino, a psychiatrist at the San Paolo Hospital in Milan, Italy, guesses that the same pathways that create flashbacks and visual imagery in people with PTSD are at play. As also implicated in PTSD, dissociation in the brain’s ability to preserve memories distinct from the perceptive level may contribute as well. “I’d say it’s a loss of the brain’s ability to keep two functions—perceiving something and storing it in memory—segregated,” he says. Patients who go on to develop PTSD may have experienced a violent primary dissociation when the trauma occurred, he says, “and grief and loss, after all, can be considered a form of trauma.”

More attention should be given to investigating these hypotheses, D’Agostino says, not only because the answers would be intriguing in their own right but also because they could help inform the ongoing debate over whether psychotic symptoms occur along a continuum or are distinct from normal perception. “Testing these types of phenomenon are useful for understanding actual pathology better, because we can gain insight into how the brain produces altered perceptions that are not frank hallucinatory experiences,” he says. “For now, we’re at the beginning of our understanding of what this may be.”