To gain insight into how visual perception is regulated within the brain, researchers in [an Australian study reported in Current Biology] study chose to investigate the extent to which certain types of trained meditative practice can influence the conscious experience of visual perceptual rivalry. ...

Perceptual rivalry arises normally when two different images are presented to each eye, and it is manifested as a fluctuation--typically, over the course of seconds--in the "dominant" image that is consciously perceived. The neural events underlying perceptual rivalry are not well understood but are thought to involve brain mechanisms that regulate attention and conscious awareness. ...

The researchers tested the experience of visual rivalry by [experienced Tibetan Buddhist] monks during the practice of two types of meditation: a "compassion"-oriented meditation, described as a contemplation of suffering within the world combined with an emanation of loving kindness, and "one-point" meditation, described as the maintained focus of attention on a single object or thought, a focus that leads to a stability and clarity of mind.

Whereas no observable change in the rate of "visual switching" during rivalry was seen in monks practicing compassion meditation, major increases in the durations of perceptual dominance were experienced by monks practicing one-point meditation. Within this group, three monks, including two of the retreatists, reported complete visual stability during the entire five-minute meditation period. Increases in duration of perceptual dominance were also seen in monks after a period of one-point meditation.

In a different test of perceptual rivalry, in this case prior to any meditation, the duration of stable perception experienced by monks averaged 4.1 seconds, compared to 2.6 seconds for meditation-naïve control subjects. Remarkably, when instructed to actively maintain the duration, one of the retreatist monks could maintain a constant visual perception during this test for 723 seconds.

posted by michael  2:48:14 PM  
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