過去許多研究發現靜坐、冥想或禪定能改善認知功能，但大多研究並無法清楚說明改善的機制，而且此議題包含許多難以有效控制的混淆變項，包括受試者招募不易，所受的禪定訓練時間及方式不同，生活型態及人格差異等因素，都是研究常遇到的限制，因此本研究盡可能排除上述限制，探討禪定對注意力的影響，若有影響，並進一步探討其背後的神經機制。本研究招募大學禪學社平均受過2.9年禪定訓練的社員參與實驗，控制組則是未受過任何禪定、氣功或瑜珈訓練的學生，兩組各26人。所有受試者必須在不同天參加實驗兩次，一次禪定30分鐘；另一次則是放鬆休息30分鐘，禪定及放鬆休息之前與後各做240題注意力測驗。此注意力測驗為快速連續視覺呈現(rapid serial visual presentation)，在左或右視野隨機置入干擾物(distractor)誘發依附性導引(contingent reorienting)以干擾受試者觀察視野中央的目標物，使得測驗表現變差。我們的研究發現，長期禪定訓練能有效避免分心物的干擾，有效地將注意力從干擾物轉回到原本該專注的地方。從腦波分析觀察到經禪定訓練者，有較大的Pd成分(distractor positive)，Pd是注意力抑制(attentional suppression)的指標，代表受試者抑制干擾物的程度。若受試者愈能抑制與實驗無關的分心物，Pd愈大，愈能正確作答。因此本研究不只觀察到禪定訓練注意力表現變好，並發現表現變好的原因來自有效率的注意力抑制。從腦波時頻分析可觀察到，只有禪學社員的腦波可清楚區分有無干擾物的呈現，當有干擾物出現時，枕葉delta (2-4 Hz)強度顯著變小；然而控制組不論有無干擾物出現，腦波皆無差異。數年禪定練習，可能會改變注意力調控的效能，減少受干擾物影響而能聚焦在需專注的事物上。;Prior studies have demonstrated that meditation may improve cognitive functions such as attention and executive control. However, meditation effect on attentional control to target-like distractor, which induced contingent reorienting, involves both top-down and button-up processes remain unclear. Therefore, we aimed to investigate the modulating effect of meditation on the mechanism of contingent reorienting in a rapid serial visual presentation (RSVP) task with electrophysiological recording. We recruited 26 meditators who had averaged 2.9 year of meditation experience and 26 non-meditators without any prior experience of meditation. All subjects were college students and completed two sessions of experiment on two different days. The two sessions differed in the manipulation of resting versus meditating state for 30 minutes in a counterbalanced order. Both before and after meditating/resting, they performed the RSVP task. The questionnaires (STAI, BAI, MAAS, BIS/BAS and MCSD) were collected before the experiment showed that meditators had lower trait of anxiety and less avoidance from unpleasant things as compared to the control group, but displayed equal degree of mindful trait between the groups. In behavioral results, meditation condition had showed attenuated interference of distractor as compared to resting condition in both the groups. A significant two-way interaction of groups and distractor types in accuracy and Pd (distractor positive, index of attentional suppression) of event-related mode component revealed that meditators were more accurate and more efficient in attentional suppression towards distractors than the control group. Thus, the findings suggested that better attentional suppression to distractor may be improved by acquiring skills of meditation. Results of EEG analysis demonstrated meditators were more efficient to respond to target-like distractor reflected by occipital delta power. The findings suggested that better attentional control to distractor might be facilitated by acquiring skills of meditation.
