Scientists Asked 50 People to Map Their Near-Death Experiences. An Eerie Pattern Emerged.

Of all the strange trappings associated with the near-death experience, none is so familiar as the tunnel into the light.

People who have skirted perilously close to the brink of death – or even beyond it for a few moments – sometimes describe moving through darkness, like a tunnel, towards a dazzling luminous portal – like a passage into elsewhere.

It's an image so deeply embedded in popular culture that it has become a powerful symbol of the end of life.

But not everyone who reports a near-death experience sees a tunnel. Some describe vast, luminous spaces, curved horizons, or an overwhelming sense of being surrounded by light.

Even in spite of these differences, though, a new study has found that otherwise varying experiences of death's waiting room may have something peculiar in common.

When researchers asked 50 people to draw maps of the spaces they remembered encountering during near-death experiences, an intriguing pattern emerged: The geometry of those spaces appeared to be linked to the colors people recalled seeing.

The findings hint that these otherworldly experiences may not be quite as unpredictable as they seem – and that their strange geometry could offer clues to what happens in the brain at the boundary between life and death.

Near-death experiences fascinate most people – including scientists. However, they're not easy to study. People who experience them report something intense – emotionally, personally, or spiritually – that they often struggle to articulate.

The clinical questions posed by the standard scientific surveys are able to record some aspects of the near-death experience, but are incapable of distilling the full complexity of it down to words on a page.

Although researchers have identified recurring features, such as tunnels, lights, and out-of-body sensations, comparatively little attention has been paid to the spatial structure of these experiences – or how people perceive themselves moving through them.

Neurophenomenology researcher France Lerner of the University of Haifa in Israel and colleagues wanted to approach the question in a different way – visually. They thought that asking people to draw their experiences might reveal patterns mere words could not.

They recruited 50 people who reported having had near-death experiences, and asked them to reconstruct their memories in a series of guided online sessions, using a catalog of geometric pictograms to help represent the spaces they recalled.

Participants were asked to break their experiences into separate stages, then represent the shape of each space they recalled encountering.

They were also asked to indicate where they perceived themselves to be within those spaces, how they moved through them, and what colors they remembered seeing.

The researchers then compiled a database of these reconstructions and compared them, looking for similarities in the geometry of the spaces and the qualities associated with them.

And despite the intensely personal nature of the experiences, certain shapes kept cropping up.

There were, the researchers found, four main categories – conical spaces, which included the familiar tunnel; broad, curved spaces, like archways; flatter, more gently curving spaces; and spaces that seemed to surround the observer completely, like the inside of a sphere or oval.

But the most intriguing pattern wasn't in the shapes alone – it was in the colors the study participants associated with them.

Of the 28 conical spaces reconstructed by participants, 22 were achromatic – perceived in black, white, gray, or light without discernible color.

By contrast, 27 of the 31 broad, curved spaces were perceived in color.

The other two geometric categories showed a mixture of colorful and colorless experiences, but the contrast between the tunnels and the broad, curved spaces was particularly striking.

That relationship – between shapes and color – could offer clues to the perceptual processes underlying these eerie experiences.

According to Lerner and her colleagues, neurological and perceptual research has already documented some similar visual relationships.

One example is tunnel vision, which can occur when the supply of oxygen to the retina or brain is disrupted, restricting the field of vision.

The predominance of black, white, and gray in the tunnel-like spaces also has a possible parallel in ordinary vision. In low-light conditions, our eyes become less sensitive to color as the light-sensitive cells responsible for seeing in dim conditions take over.

Meanwhile, some of the more expansive, enveloping spaces recalled by participants bear similarities to a phenomenon called the Ganzfeld effect, in which an unchanging, blank visual field can give rise to unusual perceptual experiences, including hallucinations.

These similarities don't establish what caused the participants' experiences, however.

The researchers emphasize that their study was designed to describe and compare the recalled spaces, not identify the mechanisms responsible for them.

There are also some important limitations.

The participants were a relatively small, self-selected group, and they reconstructed experiences from memories that, in some cases, were many years old.

Moreover, although the geometric pictograms were based on earlier research, presenting participants with a selection of shapes may have influenced how they reconstructed their experiences. The researchers also guided the sessions, which may have introduced subtle biases.

Finally, without a comparison group reconstructing other kinds of unusual experiences, it's impossible to know whether these geometric patterns are unique to near-death experiences.

Still, the patterns that emerged from visually recording recollections of the experience reveal something that previous research has largely overlooked – suggesting that tapping into the uncanny may require asking questions in a different kind of language.

The research has been published in Frontiers in Psychology.