Mediumship: review of quantitatives studies published in the 21st century

Abstract Background Mediumship can be defined as the alleged ability to communicate with deceased persons. The last decade has been particularly productive for this field of research and the study of mediumship can help the understanding of the human mind-brain relationship and provide objective data to the scientific community and to the general population. Objective The aim of this review is to summarize and discuss the results found on recent studies investigating mediumship. Furthermore, we aim to discuss the psychophysiology underlying mediumship and future perspectives for this study topic. Methods A literature search for articles in English, Portuguese and Spanish published from January 2000 up to June 2015 was conducted using three electronic databases (PubMed, Lilacs and Web of Science). Review articles, qualitative studies and studies investigating altered states of consciousness caused by psychoactive substances were excluded. The original search returned 150 articles, but the application of exclusion criteria resulted in the inclusion of 19 articles for final analysis. Results The general findings were: (1) an association of mediumship with good mental health, predominantly in experienced mediums, (2) heterogeneous findings regarding the ability of mediums to provide accurate information what may be due to different study methodologies and (3) incipient studies assessing physiological correlations during mediumistic communications (i.e. hypoactivation of brain regions responsible for cognitive processing and writing planning during psychography compared to a control task; electroencephalographic (EEG) changes and a slight predominance of the sympathetic nervous system). Discussion There is a paucity of empirical data available in this controversial research field. New studies employing rigorous design (e.g.triple-blind protocols to test accuracy of mediumistic communications), and sensitive methods are required.

【摘要 背景】通灵（mediumship）可被定义为据称可与逝者沟通的能力。近十年该研究领域成果颇丰，对通灵现象的研究有助于厘清人类心智与大脑的关联，并为科学界与普通民众提供客观数据。
【研究目的】本综述旨在总结并探讨近期有关通灵现象研究的成果，此外还将讨论通灵现象背后的心理生理学机制，以及该研究主题的未来发展方向。
【研究方法】本研究通过PubMed、Lilacs与Web of Science三个电子数据库，检索2000年1月至2015年6月期间发表的英文、葡萄牙语及西班牙语文献。本研究排除综述类文章、质性研究，以及探讨精神活性物质所致意识状态改变的相关研究。初始检索共获取150篇文献，经排除标准筛选后，最终纳入19篇文献用于最终分析。
【研究结果】总体研究结论如下：（1）通灵行为与良好的心理健康状况存在关联，这一现象在经验丰富的通灵者中尤为显著；（2）关于通灵者提供准确信息的能力，现有研究结果存在异质性，这可能源于不同研究采用的方法学差异；（3）已有初步研究探讨了通灵沟通过程中的生理相关性，例如：与对照任务相比，通灵书写（psychography）时负责认知加工与书写规划的脑区呈现低激活状态；脑电图（EEG）存在变化，且交感神经系统活动略占优势。
【讨论】该领域作为颇具争议的研究方向，目前仍缺乏充足的实证数据。未来需采用严谨的研究设计（例如用于检验通灵沟通准确性的三盲试验方案）与高灵敏度的研究方法开展相关研究。