(PhysOrg.com) -- Intensive mental training has a measurable effect on visual perception, according to a new study from the Center for Mind and Brain at the University of California, Davis. People undergoing intensive training in meditation became better at making fine visual distinctions and sustaining attention during a 30-minute test.

A paper describing the results will be published in an upcoming issue of the journal Psychological Science and was posted on the journal website May 11. It is the first paper to be published from a major scientific study of meditation training, the Shamatha Project.

"These results show for the first time that improved perception, often claimed to be a benefit of meditation practice, underlies improvements in sustained attention," said project leader Clifford Saron, associate research scientist at the UC Davis Center for Mind and Brain.

Saron has been interested in meditation since the 1970s. In the 1990s, under the auspices of the Dalai Lama's private office and of the Boulder, Colo. -based Mind and Life Institute, he organized a field study of adept practitioners. During that project he was inspired by meeting exiled Tibetan monks and yogis in the Indian foothills of the Himalayas, who had achieved remarkable emotional calm, focus and joyfulness in their lives, sometimes despite great hardship and suffering.

Saron and his colleagues wanted to know: Can these states be achieved only by individuals with an unusually serene disposition? Or can they be achieved by most people through intensive training?

The Shamatha Project is an attempt to answer those questions. It is the first long-term, detailed, control-group study of the measurable effects of meditative training on physiology, mental functioning and emotional state, Saron said.

In the project, 30 participants attended a three-month meditation retreat at the Shambhala Mountain Center in Red Feather Lakes, Colo. They received ongoing instruction in meditation techniques from Buddhist scholar B. Alan Wallace of the Santa Barbara Institute for Consciousness Studies, while attending group sessions twice a day and engaging in individual practice for about six hours a day. Wallace had worked with Saron on the field study in India and brought the idea for the Shamatha project to Saron and his UC Davis colleagues in 2003.

At the beginning, end, and in the middle of the course, participants were tested on attention and cognition, psychological and emotional measures, and physical and physiological changes.

A control group of 30 people matched for age, sex, education, ethnicity and meditation experience was assessed at the same time and in the same place, but did not otherwise attend meditation training at that time. The control group did undergo identical training later.

The visual attention experiments were led by UC Davis graduate student Katherine MacLean. Based on tests long used to assess vigilance in radar operators and other professions requiring long durations of uninterrupted attention, participants had to watch lines appearing on a screen and click a mouse when they saw lines that were shorter than others.

By midway through the retreat, meditators had become better at making fine visual distinctions. They were able to identify a smaller difference between "long" and "short" lines, and were better able to sustain attention during the half-hour test. Those findings are consistent with Buddhist claims that meditation cultivates "attentional vividness."

People who continued practicing meditation after the retreat still showed improvements in perception when they were retested about five months later.

Meditation training may free up mental resources so that attentional focus can be sustained more easily for extended periods of time, Saron said. Meditators may also be more aware of normally subtle changes in experience that others miss, and have better emotional regulation.

The Shamatha Project shows that women and men of diverse age, ethnicity, education, and meditation experience can achieve measurable changes in their mental state and capabilities if they can commit to intensive training, Saron said.

While few individuals have three months to commit to such training, other studies have shown improvements in aspects of health and well-being with a less demanding regime. The minimum level of training required to produce the perceptual improvements seen in the Shamatha study remains to be determined, Saron said.

While the Shamatha Project is the largest and most comprehensive attempt yet to study changes brought about by mental training, its results cannot capture the full, first-person subjective experience of meditation, Saron said.

"We're not trying to bottle someone's experience," he said. The project may, however, give insights into the nature of the mind and the relation between psychological and physiological traits using data from both first- and third-person perspectives.

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