Zen Garden's Calming Effect Due to Subliminal Image?

Hillary Mayell
for National Geographic News
September 25, 2002
It's the kind of thing you simply have to experience for yourself. Otherwise, the Zen rock garden of the Ryoanji Temple in Kyoto, Japan, a United Nations World Heritage site, simply defies the imagination.

The garden, after all, has no plants—no flowers, no trees, not even any weeds.

It's a 30- by 10-meter (roughly 98- by 32-foot) rectangle surrounded by earthen walls on three sides and a wooden veranda on the fourth. Inside the rectangle is a vista of white pebbles and 15 rocks. And it is world famous for the peace and serenity anyone and everyone who visits it feels.

Visual-imaging scientists in Japan say they've figured out what it is about the garden that engenders this serenity. The secret: The more than 500-year-old garden is harboring a subliminal message in the form of a tree.

Zen, Meditation, and Rock Gardens

The Ryoanji Temple (Temple of the Peaceful Dragon), is a Zen place of worship and meditation first built sometime during the 1450s. It burned when most of Kyoto was leveled by fire during the Onin Wars, and was rebuilt in 1486. The rock garden, which fronts the abbot's quarters, was laid out around this time as a place for the monks to meditate.

Thought by many to be the quintessence of Zen art, the garden is in the dry landscape style called Karesansui ("withered landscape").

The garden's 15 rocks are of various sizes, placed in five separate groupings. The white gravel that surrounds them is raked every day; perfect circles around the rocks, perfectly straight lines in the rest of the space. The rocks are arranged so that no matter where a visitor stands, only 14 can be seen. It is said that only when you attain spiritual enlightenment as a result of Zen meditation will you see the 15th stone.

Over the centuries, various explanations for the garden's layout have been given: That the white gravel represents the ocean and the rocks the islands of Japan; that they represent a mother tiger and her cubs, swimming in the river of the white sand toward a fearful dragon; or that the rocks represent the Chinese symbol for "heart" or "mind."

Unconscious Eye

However, it's the empty space created by the placement of the rocks and the void created by the white gravel that has long intrigued visitors.

Now the mystery may have been resolved.

Gert van Tonder, a postdoctoral fellow of the Japanese Society for the Promotion of Science at Kyoto University, and Michael J. Lyons, a senior scientist at ATR Media Information Labs in Kyoto, applied a shape-analysis technique that can reveal hidden structural features to the garden's empty space.

Earlier studies of how humans and other primates process visual images suggest that we have an unconscious sensitivity to the medial axis of shapes, said Van Tonder.

"Imagine starting two fires in a field of dry grass," he said. "Where the fires meet, at points equidistant between the two starting locations, is the medial axis."

His analysis indicates that the same unconscious sensitivity is able to discern the image of a trunk and branches of a tree within the Zen garden's pattern of rocks and stones. Viewed from the verandah, the image is apparent to the subconscious but is invisible to the eye.

The authors conclude in a report published in the September 26 issue of the journal Nature that the unconscious perception of this pattern is the source of the garden's calming effect.

If the rocks were to be rearranged, the invisible tree structure is lost, they say.

Van Tonder believes the garden's designer intended to create the subliminal feature—demonstrating an understanding of the physics of the human eye and subconscious hundreds of years ago.

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