Concentrative Meditation Influences Visual Awareness: a Study with Color Afterimages

While many studies have shown that meditation enhances attentional processing, very few studies have investigated the effect of enhanced attentional processing on visual awareness. We investigate the attentional effects on visual awareness in focused attention meditators using a task that manipulates scope of attention using hierarchical letter stimuli (local and global processing) and single letter stimuli of varying size (small and large). In addition, working memory load was manipulated using a 0-back and 2-back task. Data were collected from Sahaj Samadhi Meditators and an age-matched control group of non-meditators. Visual awareness was tapped using negative color afterimages by measuring the duration and more importantly the clarity and color of afterimages using a rating scale. The afterimage durations were significantly longer for Sahaj Samadhi meditators compared to non-meditators. In addition, the afterimages were sharper for meditators compared to non-meditators suggesting that better attentional focusing associated with meditators might lead to phenomenal changes in visual awareness. Scope of attention influenced not only afterimage durations but also clarity indicating that changes in scope also influence aspects of visual awareness. The results indicate meditation training not only modifies attentional processes but also results in changes in conscious visual perception.