A COMBINATION OF FOCUSING AND DEFOCUSING THROUGH YOGA REDUCES OPTICAL ILLUSION MORE THAN FOCUSING ALONE
Shirley Telles*, R. Nagarathna, P. Ramana Vani and H.R. Nagendra
Vivekananda Kendra Yoga Research Foundation
No.9, Appaiappa Agrahara, Chamarajpet, Bangalore 560 018
(Received on February 19, 1996)
Abstract: The degree of optical illusion was assessed using standard Muller- Lyer lines in two groups (yoga and control) of thirty subjects each. All subjects were between eighteen and forty two years of age. The difference between the reading at which the lines were actually equal and the reading at which the subject felt them to be equal, was noted as the degree of illusion ("di"). Each subject was assessed at the beginning and end of a month. During the month the yoga group received training in yoga, while the control group carried on with their usual routine. At the end of the month the yoga group showed a significant (two factor ANOVA, Tukey test, P <.001) decrease in the
"di" (86%), whereas the control group showed no change. The improvement following yoga could he attributed to the combination of focusing and defocusing involved in yoga practice, as these factors are known to influence the
"di". Previous results which mentioned a 79% decrease in "di" with focusing alone, provided a comparison.
Key words: optical illusion; defocusing; Focusing; yoga.
When an observer views certain patterns and is asked to describe them, the subjective assessment of the size, shape or direction of pattern components often differs from what might be expected based on direct physical measurements of the stimulus. These patterns are called visual-geometric illusion (1). With greater accuracy of perception there will be an increasingly smaller disparity between the actual stimulus and what is perceived.
Perception of a geometric illusion is influenced by retinal, cortical and cognitive- judgmental factors (2).
It has been shown that training in focusing the gaze on the stimulus reduces the optical illusion by 79 percent (3). The present study aimed at assessing the effect of yoga practices (which involved both focusing and defocusing of the gaze and the attention), on the degree of optical illusion perceived.