When sickness strikes, people around the world pray for healing. Many of the faithful claim that prayer has cured them of blindness, deafness and metastasized cancers, and some believe they have been resurrected from the dead.
Can, and should, science test such claims? A number of scientists say no, concerned that empirical studies of prayer will be misused to advance religious agendas. And some religious practitioners agree with this restraint, worrying that scientific testing could undermine faith.
If prayer affects health -- for better or for worse -- then patients, doctors and policymakers should all want to know. Scientific research has returned mixed results. Some studies conclude that prayer improves health, while others show no effect -- or suggest that prayer may lead to worsening health.
Part of the confusion stems from how prayer is studied. Most research is on distant intercessory prayer. Intercessors are given the first name and condition of someone they do not know and told to pray. Researchers set up double-blinded trials -- because this is how they are accustomed to studying health interventions -- and base conclusions on the efficacy of prayer solely on whether subjects in the experimental group exhibit better health than those in the control group.
But when people actually pray for healing, they usually get up close to someone they know, touch the person and empathize with their sufferings -- what I call proximal intercessory prayer, or PIP. Double-blinded, controlled trials are not the only -- or even the best -- way to gauge the effects of this kind of prayer practice.
I have spent the past eight years studying PIP by Pentecostal and Charismatic Christians -- the groups most likely to pray for healing and claim that their prayers work -- in the United States, Canada, Brazil and Mozambique. And I used multiple methods, each one suited to answering a particular question about prayer for healing. Each method is like a different type of camera, offering complementary perspectives on how prayer affects health.
Camera 1: Medical Records: Are healing claims documented?
Comparison of medical records from before and after prayer provides a check on whether people claiming healing exhibited improvements for which there is no obvious explanation. For example, in the course of my research, I met Daisy, who had worn hearing aids for 30 years. She had a progressively worsening, hereditary inner-ear problem. In 1999, tests showed moderate hearing loss; by 2004, Daisy's hearing loss was moderately severe to severe. In 2008, Daisy received PIP and "felt my fingers on fire and the warmth of the Holy Spirit inside of me," after which she could hear without hearing aids. She had her hearing retested two weeks later, showing normal thresholds in lower frequencies with moderate loss in higher frequencies. A 2010 screening still showed normal hearing in speech frequencies. Medical records do not prove that "God" healed Daisy through prayer, but do confirm Daisy's claim of improved hearing.
I also came across Frank, who claimed improved vision after prayer. He produced an optometrist's note stating that "On 02" his left eye uncorrected visual acuity was "20/200"; in 2007, it was "NOW 20/40." I followed up with Frank's optometrist, who revealed that the record had been "altered." The phrases "On 02" and "Now 20/40" had been added. The unaltered record shows visual acuity of 20/200 in 2007 -- after Frank's supposed healing. Such cases of apparent fraud do not seem to be common, but medical records are one way of sifting out which claims are less credible.
Camera 2: Surveys: How do sufferers perceive healing prayer?
Surveys shed light on how supplicants perceive sickness, prayer and healing. In one set of surveys I carried out, 72 percent of respondents had a current need for healing; the most common complaint was pain. Fifty-two percent reported healing. Few "claimed healing by faith," instead defining healing as noticeable improvement of symptoms. Those who self-reported high faith were no more likely to experience healing than those who admitted weak faith. Most received multiple prayers for the same problem, noting progressive improvements with each prayer. Most also went to doctors, viewing prayer and medicine as complementary.
Camera 3: Clinical Trials: Can health outcomes of prayer be measured?
Clinical trials can show whether PIP results in measurable changes in health markers. In a prospective study of hearing and vision in Mozambique, I found highly significant improvements in hearing and statistically significant improvements in vision following PIP. Two of 11 hearing subjects had thresholds reduced by over 50 dBHL. One subject, Jordan, was presented as deaf and mute since birth and made no responses to sounds at 100 dBHL; after PIP, he responded to 60 dBHL tones, imitating sounds in a hoarse, raspy voice. Three of 11 vision subjects improved from 20/400 or worse to 20/80 or better. Before prayer, Maryam could not count fingers from one foot away; after one minute of PIP, she was reading the 20/125 line on a vision chart.
Camera 4: Follow-up: Do healing experiences produce lasting effects?
Multi-year observations and interviews assess whether changes are temporary or enduring. Many informants -- such as George, who reported healing from an untreatable brain tumor through prayer alone -- claimed they were still healed as many as eight years later. George and others had subsequently prayed for others who in turn reported healing, and this new cohort prayed for still others, sometimes traveling to other countries to do so. Such ripple effects of healing prayer largely account for the wildfire spread of global pentecostalism.
Bringing these four cameras into focus produces a more complete picture of how prayer affects health than using any single study method. Can science prove the healing power of prayer? Science cannot prove the existence or nonexistence of a suprahuman force or whether such an entity answers prayer. But it is an empirical question how prayer practices affect health. And we can -- and should -- use empirical methods to answer this question.
Candy Gunther Brown, author of Testing Prayer: Science and Healing (Harvard University Press, 2012).