, To AARREANEG, Bar. Eelease:2000/08/10 : CIA-RDP96-00792R000100130002-1 Still subject to final editing. Version 4.2 Does Psi Exist? Replicable Evidence for an Anomalous Process of Information Transfer Daryl J. Bem Cornell University Charles Honorton University of Edinburgh Most academic psychologists do not yet accept the existence of psi, anomalous processes of in- formation or energy transfer (like telepathy or other forms of extrasensory perception) that are currently unexplained in terms of known physical or biological mechanisms. We believe that the replication rates and effect sizes achieved by one particular experimental method, the ganzfeld procedure, are now sufficient to warrant bringing this body of data to the attention of the wider psychological community. We review competing meta-analyses of the ganzfeld database, one by Hyman (1985), a skeptical critic of psi research, the other by Honorton (1985), a parapsychologist and major contributor to the ganzfeld database. Next we summarize the re- sults of 11 new ganzfeld studies that comply with guidelines jointly authored by Hyman and Honorton (1986). Finally, we discuss issues of replication and theoretical explanation. The term psi denotes anomalous processes of informa- tion or energy transfer, processes like telepathy or other forms of extrasensory perception that are currently unex- plained in terms of known physical or biological mecha- nisms. The term is purely descriptive: It neither implies that such anomalous phenomena are paranormal nor con- notes anything about their underlying mechanisms. Does psi exist? Most academic psychologists don’t think so. A survey of over 1,100 college professors in the United States found that 55% of natural scientists, 66% of social scientists (excluding psychologists), and 77% of academics in the arts, humanities, and education believed that ex- trasensory perception is either an established fact or a likely possibility. The comparable figure for psychologists was only 34%. Moreover, an equal number of psycholo- gists declared extrasensory perception to be an impossibil- ity, a view expressed by only 2% of all other respondents (Wagner & Monnet, 1979). Psychologists are probably more skeptical about psi for several reasons. First, we believe that extraordinary claime require extraordinary proof. And although our col- leagues from other disciplines would probably agree with ane Sadly, Charles Honorton died of a heart attack on November 4, 1992, nine days before this article was accepted for publication. He was 46. Parapsychology has lost one of its most valued con- tributors. I have lost a valued friend. This collaboration had its origins in a 1983 visit I_made to Honorton’s Psychophysical Research Laboratories (PRL) in Princeton, New Jersey, as one of several outside consultants brought in to examine the design and implementation of the ex- perimental protocols. Preparation of this article was supported, in part, by grants to Charles Honorton from the American Society for Psychical Re- search and the Parapsychology Foundation, both of New York City. The work at PRL summarized in the second half of this ar- ticle was supported by the James S. McDonnell Foundation of St. Louis, Missouri, and by the John E. Fetzer Foundation of Kala- mazoo, Michigan. Helpful comments on earlier drafts were received from Debo- rah Delanoy, Edwin May, Donald McCarthy, Robert Morris, John Palmer, Robert Rosenthal, Lee Ross, Jessica Uits, Philip Zim- bardo, and two anonymous reviewers. Correspondence should be addressed to Daryl J. Bem, Depart- ment of Psychology, Uris Hall, Cornell University, Ithaca, NY 14853. this dictum, we are more likely to be familiar with the methodological and statistical requirements for sustaining auch claims—as well as with previous claims that failed either to meet those requirements or to survive the test of euccessful replication. Even for ordinary claims, our con- ventional statistical criteria are conservative. The sacred p= .05 threshold is a constant reminder that it is far more sinful to assert that an effect exists when it does not (the Type I error) than to assert that an effect does not exist when it does (the Type II error). Second, most of us distinguish sharply between phe- nomena whose explanations are merely obscure or contro- versial (e.g., hypnosis) and phenomena like psi, which would appear to fall outside our current explanatory framework altogether. (Some would characterize this as the difference between the unexplained and the inexplica- ble.) In contrast, many laypersons treat all exotic psycho- logical phenomena as epistemologically equivalent—many even consider déja vu to be a psychic phenomenon. The blurring of this critical distinction is aided and abetted by the mass media, “new age” books and mind-power courses, and by “psychic” entertainers who present both genuine hypnosis and fake “mindreading” in the course of a single performance. Accordingly, most laypersons would not have to revise their conceptual model of reality as radi- cally as we would in order to assimilate the existence of psi. For us, psi is simply more extraordinary. And finally, research in cognitive and social psychology has sensitized us to the errors and biases that plague in- tuitive attempts to draw valid inferences from the data of everyday experience (Gilovich, 1991; Nisbett & Ross, 1980; Tversky & Kahneman, 1971). This leads us to give virtually no probative weight to anecdotal or journalistic reports of psi—the main source cited by our academic col- leagues as evidence for their beliefs about psi (Wagner & Monnet, 1979). Ironically, however, psychologists are probably not more familiar than others with recent experimental research on psi. Like most psychological research, parapsychological research is reported primarily in specialized journals; un- like most psychological research, however, contemporary parapsychological research is not usually reviewed or summarized in psychology’s textbooks, handbooks, or mainstream journals. For example, only 1 of 64 introduc- Approved For Release 2000/08/10 : CIA-RDP96-00792R000100130002-1
Approved For Release SU0UUH) 10 PUIR EDP ee.00482H000100130002-1 tory psychology textbooks recently surveyed even men- tions the experimental procedure reviewed in this article, a procedure that has been in widespread use since the early 1970s (Roig, Icochea, & Cuzzucoli, 1991). Other sec-_ ondary sources for nonspecialists are frequently inaccu- rate in their descriptions of parapsychological research (Child, 1985; Palmer, Honorton, & Utts, 1989). This situation may be changing. Discussions of modern psi research have recently appeared in a widely-used in- troductory textbook (Atkinson, Atkinson, Smith, & Bem, 1990, 1993), two mainstream psychology journals (Child, 1985; Rao & Palmer, 1987), and a scholarly but accessible book for nonspecialists (Broughton, 1991). The purpose of the present article is to supplement these broader treat- ments with a more detailed, meta-analytic presentation of evidence issuing from a single experimental method: the ganzfeld procedure. We believe that the replication rates and effect sizes achieved with this procedure are now suf- ficient to warrant bringing this body of data to the atten- tion of the wider psychological community. The Ganzfeld Procedure By the 1960s, a number of parapsychologists had be- come dissatisfied with the familiar ESP testing methods pioneered by J. B. Rhine at Duke University in the 1930s. In particular, they felt that the repetitive forced-choice procedure in which a subject repeatedly attempts to select the correct “target” symbol from a set of fixed-alternatives failed to capture the circumstances that characterize re- ported instances of psi in everyday life. Historically, psi has often been associated with medita- tion, hypnosis, dreaming, and other naturally occurring or deliberately induced altered states of consciousness. For example, the view that psi phenomena can occur during meditation is expressed in most classical texts on medita- tive techniques; the belief that hypnosis is a psi-conducive state dates all the way back to the days of early mes- merism (Dingwall, 1968); and cross-cultural surveys indi- cate that most reported “real-life” psi experiences are me- diated through dreams (Green, 1960; Prasad & Stevenson, 1968; Rhine, 1962; Sannwald, 1959). There are now reports of experimental evidence consis- tent with these anecdotal observations. For example, sev- eral laboratory investigators report that meditation facili- tates psi performance (Honorton, 1977). A meta-analysis of 25 experiments on hypnosis and psi conducted between 1945-1981 in 10 different laboratories suggests that hyp- notic induction also facilitates psi performance (Schechter, 1984). And dream-mediated psi was reported in a series of experiments conducted at Maimonides Medical Center in New York, and published between 1966 and 1972 (Child, 1985; Ullman, Krippner, & Vaughan, 1973). In the Maimonides dream studies, two subjects—a “receiver” and a “sender”—spent the night in a sleep labo- ratory, The receiver’s brainwaves and eye movements were monitored as he or she slept in an isolated room. When the receiver entered a period of REM sleep, the ex- perimenter pressed a buzzer that signaled the sender— under the supervision of a second experimenter—to begin a sending period. The sender would then concentrate on a randomly chosen picture (the “target”) with the goal of in- fluencing the content of the receiver’s dream. Toward the end of the REM period, the receiver was awakened and asked to describe any dream just experi- enced. This procedure was repeated throughout the night 26 with the same target. A transcription of the receiver's dream reports was given to outside judges who blindly rated the similarity of the night’s dreams to several pic- tures, including the target. In some studies similarity rat- ings were also obtained from the receivers themselves. Across several variations of the procedure, dreams were judged to be significantly more similar to the target pic- tures than to the control pictures in the judging sets. (Failures to replicate the Maimonides results are also re- viewed by Child (1985).) These several lines of evidence suggested a working model of psi in which psi-mediated information is concep- tualized as a weak signal that is normally masked by in- ternal somatic and external sensory “noise.” By reducing ordinary sensory input, these diverse psi-conducive atates are presumed to raise the signal-to-noise ratio, thereby enhancing a person’s ability to detect the psi-mediated in- formation (Honorton, 1969, 1977). In order to test the hy- pothesis that a reduction of sensory input itself facilitates psi performance, investigators turned to the ganzfeld pro- cedure (Braud, Wood, & Braud, 1975; Honorton & Harper, 1974; Parker, 1975), a procedure originally introduced into experimental psychology during the 1930s to test propositions derived from Gestalt theory (Avant, 1965; Metzger, 1930). Like the dream studies, the psi ganzfeld procedure has ’ most often been used to test for telepathic communication _between a sender and a receiver. The receiver is placed in a reclining chair in an acoustically-isolated room. Translucent ping-pong ball halves are taped over the eyes and headphones are placed over the ears; a red floodlight directed toward the eyes produces an undifferentiated vi- sual field and white noise played through the headphones produces an analogous auditory field. It is this homoge- neous perceptual environment that is called the Ganzfeld (“total field”). In order to reduce internal somatic “noise,” the receiver typically aleo undergoes a series of progres- give relaxation exercises at the beginning of the ganzfeld period. The sender is sequestered in a separate acoustically- isolated room, and a visual stimulus (art print, photo- graph, or brief videotaped sequence) is randomly selected from a large pool of such stimuli to serve as the target for the session. While the sender concentrates on the target, the receiver provides a continuous verbal report of his or her ongoing imagery and mentation, usually for about 30 minutes. At the completion of the ganzfeld period, the re- ceiver is presented with several stimuli (usually four) and, without knowing which stimulus was the target, is asked to rate the degree to which each matches the imagery and mentation experienced during the ganzfeld period. If the receiver assigna the highest rating to the target stimulus, it is scored as a “hit.” Thus, if the experiment employs judging pools containing four stimuli (the target and three “decoys” or control stimuli), then the hit rate expected by chance is .25. The ratings can also be analyzed in other ways; for example, they can be converted to ranks or standardized scores within each set and analyzed para- metrically across sessions. And, as with the dream stud- ies, the similarity ratings can also be made by outside judges using transcripts of the receiver’s mentation re- port. Meta-analyses of the Ganzfeld Database In 1985 and 1986, the Journal of Parapsychology de- voted two entire issues to a critical examination of the Approved For Release 2000/08/10 : CIA-RDP96-00792R000100130002-1
Approved For Releaseianomusin’ OB RDPIBA0782R000100130002-1 3 ganzfeld database. The 1985 issue comprised two contri- butions: (a) a meta-analysis and critique by Ray Hyman. (1985), a cognitive psychologist and skeptical critic of parapsychological research; and (b) a competing meta- analysis and rejoinder by Charles Honorton (1985), a parapsychologist and major contributor to the ganzfeld database. The 1986 issue contained four commentaries on the Hyman-Honorton exchange, a joint communiqué by Hyman and Honorton, and six additional commentaries on the joint communiqué itself. We summarize the major issues and conclusions here. Replication Rates By study. Hyman’s meta-analysis covered 42 psi ganz- feld studies reported in 34 separate reports written or published from 1974 through 1981. One of the first prob- lems he discovered in the database was multiple analysis. As noted above, it is possible to calculate several indices of psi performance in a ganzfeld experiment and, further, to subject those indices to several kinds of statistical treat- ment. Many investigators reported multiple indices or ap- plied multiple statistical tests without adjusting the crite- rion significance level for the number of tests conducted. Worse, some may have “shopped” among the alternatives until finding one that yielded a significantly successful outcome. Honorton agreed that this waa a problem. Accordingly, Honorton applied a uniform test on a common index across all studies from which the pertinent datum could be extracted, regardless of how the investiga- tors had analyzed the data in the original reports. He se- lected the proportion of hits as the common index because it could be calculated for the largest subset of studies: 28 of the 42 studies. The hit rate is also a conservative index because it discards moat of the rating information; a sec- ond place ranking—a “near miss”—receives no more credit than a last place ranking. Honorton then calculated the exact binoraial probability and its associated z score for each study. Of the 28 studies, 23 (82%) had positive z scores (p = 4.6 x 10-4 exact binomial test with p = g = .5). Twelve of the studies (43%) had z scores that were independently significant at the 5% level (p = 3.5 x 10-9, binomial test with n = 28 studies, p = .05, and g = .95) and 7 of the studies (25%) were independently significant at the 1% level (p = 9.8 x 107 2 The composite Stouffer z score across the 28 studies was 6.60 (p = 2.1 x 10—14).1 A more conservative estimate of significance can be obtained by including 10 additional studies that also used the relevant judging procedure but did not report hit rates. If we as- sign these studies a mean z:score of zero, then the Stouffer z across all 38 studies becomes 5.67 (p = 7.3 x 107%). Thus, whether one considers only the studies for which the relevant information is available or includes a null es- timate for the additional studies where the information is not available, the aggregate resulta cannot reasonably be attributed to chance. And by design, the cumulative out- come reported here cannot be attributed to the inflation of significance levels through multiple analysis. By laboratory. One objection to estimates like those above is that studies from a common laboratory are not Istouffer’s z is computed by dividing the sum of the z scores for the individual studies by the square root of the number of studies (Rosenthal, 1978). independent of one another (Parker, 1978). Thus it is pos- ‘gible for one or two investigators to be disproportionately responsible for a high replication rate while other, inde- pendent investigators are unable to obtain the effect. The ganzfeld database is vulnerable to this possibility. ' The 28 studies providing hit rate information were con- ducted by investigators in 10 different laboratories. One laboratory contributed nine of the studies; Honorton’s own laboratory contributed five; two other laboratories con- tributed three each; two contributed two each; and the remaining four laboratories each contributed one. Thus half of the studies were conducted by only two laborato- ries, one of them Honorton’s own. Accordingly, Honorton calculated a separate Stouffer z score for each laboratory. Significantly positive outcomes were reported by 6 of the 10 laboratories and the com- bined result across laboratories yielded a z of 6.16 (p = 3.6 x 10719. Even if all the studies conducted by the two most prolific laboratories are discarded from the analysis, the Stouffer z across the eight other laboratories remains significant (z = 3.67, p = 1.2 x 1074). Four of these studies are significant at the 1% level (p = 9.2 x 10-6, binomial test with n = 14 studies, p = .01, and g = 99), and each was contributed by a different laboratory. Thus, even though the total number of laboratories in this database is small, a majority of them have reported significant studies, and the significance of the overall ef- fect does not depend on just one or two of them. Selective Reporting ‘ In recent years, behavioral scientists have become in- creasingly aware of the “file-drawer” problem, the likeli- hood that successful studies are more likely to be pub- lished than unsuccessful studies—which are more likely to be consigned to the file drawers of their disappointed investigators (Bozarth & Roberts, 1972; Sterling, 1959). Parapsychologists were among the first to become sensi- tive to the problem; and, in 1975, the Parapsychological Association Council adopted a policy opposing the selec- tive reporting of positive outcomes. As a consequence, negative findings have been routinely reported at the As- sociation’s meetings and in its affiliated publications for almost two decades now. As we have already seen, more than half of the ganzfeld studies included in the meta- analysis yielded outcomes whose significance falls short of the conventional .05 level. There is a variant of the selective reporting problem which arises from what Hyman (1985) has termed the “retrospective study.” An investigator conducts a small set of exploratory trials. If they yield null results, they remain “exploratory” and never become part of the official record; if they happen to yield positive resulta, they get defined as a study after the fact and are submitted for publication. In support of this possibility, Hyman notes that there are more significant studies in the database with fewer than 20 trials than one would expect under the assumption that, all other things being equal, statistical power should increase with the square root of the sample size. Although Honorton questions the assumption that “all other things” are in fact equal across the studies and disagrees with Hyman’s particular statistical analysis, he does agree that there is an apparent clustering of significant studies with fewer than 20 trials. (Out of the complete ganzfeld Approved For Release 2000/08/10 : CIA-RDP96-00792R000100130002-1
Approved For Releast bb Asa) 10! CHEATERS GRI0tGR000100130002-1 4 database of 42 studies, 8 have fewer than 20 trials, and 6 of these report statistically significant results.) Because it is impossible, by definition, to know how many unknown studies—exploratory or otherwise—are languishing in file drawers somewhere, the major tool for estimating the seriousness of selective reporting problems has become some variant of Rosenthal’s “file drawer” statistic, an estimate of how many unreported studies with z scores of zero would be required to exactly cancel out the significance of the known database (Rosenthal, 1979). For the 28 direct-hit ganzfeld studies alone, this es- timate is 423 fugitive studies, a ratio of unreported-to-re- ported studies of approximately 15 to 1. When it is re- called that a single ganzfeld session takes over an hour to conduct, it is not surprising that—despite his concern with the retrospective study problem—Hyman concurs with Honorton and other participants in the published debate that selective reporting problems cannot plausibly account for the overall statistical significance of the psi ganzfeld database (Hyman & Honorton, 1986).2 Methodological Flaws If the most frequent criticism of parapsychology is that it has not produced a replicable psi effect, the second most frequent criticism is that many, if not most, psi experi- ments have inadequate controls and procedural safe- guards. A frequent charge is that positive results emerge primarily from initial, poorly controlled studies and then vanish as better controls and safeguards are introduced. Fortunately, meta-analysis provides a vehicle for empir- ically evaluating the extent to which methodological flaws may have contributed to artifactual positive outcomes across a set of studies. First, ratings are assigned to each study that index the degree to which particular method- ological flaws are or are not present; these ratings are then correlated with the studies’ outcomes. Large positive correlations constitute evidence that the observed effect may be artifactual. In psi research, the most fatal flaws are those that might permit a subject to obtain the target information in normal sensory fashion, either inadvertently or through deliberate cheating. This is called the problem of sensory leakage. Another potentially serious flaw is inadequate randomization of target selection. Sensory leakage. Because the ganzfeld is itself a percep- tual isolation procedure, it goes a long way toward elimi- nating potential sensory leakage during the ganzfeld por- tion of the session. There are, however, potential channels of sensory leakage following the ganzfeld period. For ex- ample, if the experimenter who interacts with the receiver knows the identity of the target, he or she could bias the receiver’s similarity ratings in favor of correct identifica- tion. Only one study in the database contained this flaw, a study in which subjects actually performed slightly below chance expectation. Second, if the stimulus set given to the receiver for judging contains the actual physical target handled by the sender during the sending period, there might be cues (e.g., fingerprints, amudges, or temperature differences) that could differentiate the target from the 24 1980 survey of parapsychologists uncovered only 19 com- pleted but unreported ganzfeld studies. Seven of these had achieved significantly positive results, a proportion (.37) very similar to the proportion of independently significant studies in the meta-analysis (.43) (Blackmore, 1980). Approved For Release 2000/08/10 decoys. Moreover, the process of transferring the stimulus materials to the receiver's room itself opens up other po- tential channels of sensory leakage. Although contempo- rary, ganzfeld studies eliminate both of these possibilities by using duplicate stimulus sets, some of the earlier stud- ies did not. Independent analyses by Hyman and Honorton agreed that there was no correlation between inadequacies of se- curity against sensory leakage and study outcome. Honor- ton further reported that if studies that failed to use du- plicate stimulus sets were discarded from the analysis, the remaining studies are still highly significant (Stouffer z = 4,35, p = 6.8 x 10-6) Randomization. In many psi experiments, the issue of target randomization is critical because systematic pat- terns in inadequately randomized target sequences might be detected by subjects during a session or might match subjects’ pre-existing response biases. In a ganzfeld study, however, randomization is a much less critical issue be- cause only one target is selected during the session and most subjects serve in only one session. The primary con- cern is simply that all targets be sampled about equally over the course of the study. Similar considerations gov- ern the second randomization, which takes place after the ganzfeld period and determines the sequence in which the target and decoys are presented to the receiver (or exter- nal judge) for judging. Nevertheless, Hyman and Honorton disagreed over the findings here. Hyman claimed there was a correlation be- tween flaws of randomization and study qutcome; Honor- ton claimed there was not. The sources of this disagree- ment were in conflicting definitions of flaw categories, in the coding and assignment of flaw ratings to individual studies, and in the subsequent statistical treatment of those ratings. Unfortunately, there have been no ratings of flaws by independent raters who were blind to the studies’ out- comes (Morris, 1991). Nevertheless, none of the contribu- tors to the subsequent debate concurred with Hyman’s conclusion whereas four nonparapsychologists—two statisticians and two psychologists—explicitly concurred with Honorton’s conclusion (Harris & Rosenthal, 1988b; Saunders, 1985; Utts, 1991a). For example, Harris and Rosenthal (one of the pioneers in the use of meta-analysis in psychology) used Hyman’s own flaw ratings and failed to find any significant relationships between flaws and study outcomes in each of two separate analyses: “Our analysis of the effects of flaws on study outcome lends no support to the hypothesis that Ganzfeld research results are a significant function of the set of flaw variables” (1988b, p. 3). (For a more recent exchange over Hyman’s analysis, see Hyman (1991), Utts (1991a), and Utte (1991b).) Effect Size Some critics of parapsychology have argued that even if current laboratory-produced psi effects turn out to be replicable and non-artifactual, they are too small to be of theoretical interest or practical importance. We do not be- lieve this to be the case for the psi ganzfeld effect. In psi ganzfeld studies, the hit rate itself provides a straightforward descriptive measure of effect size, but this cannot be compared directly across studies because they do not all use a four-stimulus judging set and, hence, do : CIA-RDP96-00792R000100130002-1
Approved For Release 2000/08/70 GlAsRIORI600292R0001 00130002-1 5 not all have a chance baseline of .25. The next most obvi- ous candidate, the difference in each study between the hit rate observed and the hit rate expected under the null hypothesis, is also intuitively descriptive but is not appro- priate for statistical analysis because not all differences between proportions that are equal are equally detectable (e.g., the power to detect the difference between .55 and .25 is different from the power to detect the difference be- tween .50 and .20). In order to provide a scale of equal detectability, Cohen (1988) devised the effect size index k, which performs an arcsine transformation on the proportions before calculat- ing their difference. Cohen’s fA is quite general and can as- sess the difference between any two proportions drawn from independent samples or between a single proportion and any specified hypothetical value. For the 28 studies examined in the meta-analyses, & is .28, with a 95% confi- dence interval from .11 to .45. But because values of hk do not provide an intuitively descriptive scale, Rosenthal and Rubin (1989; Rosenthal, 1991) have recently suggested a new index, .% which ap- plies specifically to one-sample, multiple-choice data of the kind obtained in ganzfeld experiments. In particular, m expresses all hit rates as the proportion of hits that would have been obtained if there had been only two equally likely alternatives—essentially a coin flip. Thus, z ranges from 0 to 1, with .5 expected under the null hy- pothesis. The formula is: _ P«-D P(k-2) + 1 where P is the raw proportion of hits and k is the number of alternative choices available. Because a has such a straightforward intuitive interpretation, we will use it (or its conversion back to an equivalent four-alternative hit rate) throughout this article whenever it is applicable. For the 28 studies examined in the meta-analyses, the mean value of 2 is .62, with a 95% confidence interval from .55 to .69. This corresponds to a four-alternative hit rate of 35%, with a 95% confidence interval from 28% to 43%. Cohen (1988, 1992) has also categorized effect sizes into small, medium, and large, where medium denotes an ef- fect size that should be apparent to the naked eye of a careful observer. For a statistic like 2, which indexes the deviation of a proportion from .5, Cohen considers .65 to be a medium effect size: A statistically unaided observer should be able to detect the bias of a coin that comes up heads on 65% of the trials. Thus, at .62, the psi ganzfeld effect size falls just short of Cohen’s naked-eyeball crite- rion. From the phenomenology of the ganzfeld experi- menter, the corresponding hit rate of 35% implies that he or she will see a subject obtain a hit approximately every third session rather than every fourth. It is also instructive to compare the psi ganzfeld effect with the results of a recent medical study that sought to determine whether aspirin can prevent heart attacks (Steering Committee of the Physicians’ Health Study Re- search Group, 1988). The study was discontinued after six years because it was already clear that the aspirin treat- ment was effective (2 = 25.01, p < .00001) and it was con- sidered unethical to keep the control group on placebo medication. The study was widely publicized as a major medical breakthrough. But despite its undisputed reality and practical importance, the size of the aspirin effect is quite small: Taking aspirin reduces the probability of suf- fering a heart attack by only 0.008. The corresponding ef- fect size (h) is .068~—-about 1/3 to 1/4 the size of the psi ganzfeld effect (Atkinson et al., 1993, p. 236; Utts, 1991b). In sum, we believe that the psi ganzfeld effect is large enough to be of both theoretical interest and potential practical importance. Experimental Correlates of the Psi Ganzfeld Effect We saw above that the technique of correlating vari- ables with effect sizes across studies can help to assess whether methodological flaws might have produced arti- factual positive outcomes. The same technique can be used more affirmatively to explore whether an effect varies systematically with conceptually relevant varia- tions in experimental procedure. The discovery of such correlates can help to establish an effect as genuine, sug- gest ways of increasing replication rates and effect sizes, and enhance the chances of moving beyond the simple demonstration of an effect to its explanation. This strat- egy is only heuristic, however. Any correlates discovered must be considered quite tentative, both because they emerge from post hoc exploration and because they neces- sarily involve comparisons across heterogeneous studies that differ simultaneously on many interrelated variables, known and unknown. Two such correlates emerged from the meta-analyses of the psi ganzfeld effect. Single versus multiple-image targets. Although most of the 28 studies in the meta-analysis used single pictures as targets, 9 of the studies (conducted by three different in- vestigators) used View Master stereoscopic slide reels which presented multiple images focused on a central theme. Studies using the View Master reels produced sig- nificantly higher hit rates than did studies using the sin- gle-image targeta (50% vs. 34%), ¢ (26) = 2.22, p = .0385, two-tailed. Sender / receiver pairing. In 17 of the 28 studies, partici - pants were free to bring in friends to serve as senders. In 8 studies, only laboratory-assigned senders were em- ployed. (Three studies used no sender.) Unfortunately, there is no record of how many participants in the former studies actually brought in friends. Nevertheless, those 17 studies (by six different investigators) had significantly higher hit rates than did the studies that used only labo- ratory-assigned senders (44% vs. 26%), ¢ (23) = 2.89, p = .025, two-tailed. The Joint Communiqué Following their published exchange in 1985, Hyman and Honorton agreed to contribute a joint communiqué to the subsequent discussion which was published in 1986. First they set forth their areas of agreement and dis- agreement: We agree that there is an overall significant effect in this data base that cannot reasonably be explained by selective reporting or multiple analysis. We continue to differ over the degree to which the effect constitutes evidence for psi, but we agree that the final verdict awaits the outcome of fu- ture experiments conducted by a broader range of investiga- tors and according to more stringent standards. (Hyman & Honorton, 1986, abstract, p. 351) Approved For Release 2000/08/10 : CIA-RDP96-00792R000100130002-1
Approved For Releasen20QG RAP ciGlATRAPAGRG722R000100130002-1 They then spelled out in detail the “more stringent ments. These include strict security precautions against sensory leakage, testing and documentation of randomiza- tion methods for selecting targets and sequencing the judging pool, statistical correction for multiple analyses, advance specification of the status of the experiment (e.g., pilot study, confirmatory experiment), and full documen- tation in the published report of the experimental proce- dures and the status of statistical tests (e.g., pre-planned or post hoc). The NRC Report In 1988, the National Research Council (NRC) of the National Academy of Sciences released a widely publi- cized report commissioned by the U. S. Army which as- sessed several controversial technologies for enhancing human performance, including accelerated learning, neu- rolinguistic programming, mental practice, biofeedback, and parapsychology (Druckman & Swets, 1988; summa- rized in Swets & Bjork, 1990). The report’s conclusion concerning parapsychology was quite negative: “The Committee finds no scientific justification from research conducted over a period of 130 years for the existence of parapsychological phenomena’ (p. 22). An extended refutation strongly protesting the Commit- tee’s treatment of parapsychology has been published elsewhere (Palmer et al., 1989). The pertinent point here. is simply that the NRC’s evaluation of the ganzfeld stud- ies does not reflect an additional, independent examina- tion of the ganzfeld database but is based on the same meta-analysis by Hyman that we have discussed in this article. Hyman chaired the NRC’s Subcommittee on Parapsy- chology; and, although he had concurred with Honorton two years earlier in their joint communiqué that “there is an overall significant effect in this data base that cannot reasonably be explained by selective reporting or multiple analysis” (p. 351) and that “significant outcomes have been produced by a number of different investigators” (p. 352), neither of these points is acknowledged in the Committee’s report. The NRC also solicited a background paper from Harris and Rosenthal (1988a), who provided the Committee with a comparative methodological analysia of the five contro- versial areas listed above. Harris and Rosenthal noted that of these areas, “only the Ganzfeld ESP studies [the only psi studies they evaluated] regularly meet the basic requirements of sound experimental design” (p. 53), and they concluded that “it would be implausible to entertain the null given the combined p from these 28 studies. Given the various problems or flaws pointed out by Hy- man and Honorton...we might estimate the obtained ac- curacy rate to be about 1/3...when the accuracy rate ex- pected under the null is 1/4” (p. 51).3 3In a troubling development, the chair of the NRC Committee phoned Rosenthal and asked him to delete the parapsychology section of the paper (R. Rosenthal, private communication, September 15, 1992). Although Rosenthal refused to do 50, that section of the Harris-Rosenthal paper is nowhere cited in the NRC report. a : vege The Autoganzfeld Studies standards” they believed should govern future experi- ..” In “1983, Honorton and his colleagues initiated a new series of ganzfeld studies designed to avoid the method- ological problems he and others had identified in earlier .studies (Honorton, 1979; Kennedy, 1979). These studies complied with all the detailed guidelines that he and Hy- “man were to publish later in their joint communiqué. The program continued until September of 1989, when a loss of funding forced the laboratory to close. The major innovations of the new studies were the com- puter control of the experimental protocol—hence the name “autoganzfeld”—and the introduction of videotaped film cHps as target stimuli. Method* The basic design of the autoganzfeld studies was the same as that described earlier: A receiver and sender were sequestered in separate, acoustically-isolated chambers. Following a 14-minute period of progressive relaxation, the receiver underwent ganzfeld stimulation while de- scribing his or her thoughts and images aloud for 30 min- utes. Meanwhile, the sender concentrated on a randomly selected target. At the end of the ganzfeld period, the re- ceiver was shown four stimuli and, without knowing which of the four had been the target, rated each stimulus for its similarity to his or her mentation during the ganzfeld. The targets consisted of 80 still pictures (Static Targets) and 80 short video segments complete with squndtracks (Dynamic Targets), all recorded on videocassette. The static targets included art prints, photographs, and mag- azine advertisements; the dynamic targets included ex- cerpts of approximately one minute duration from motion pictures, TV shows, and cartoons. The 160 targets were arranged in judging sets of four static or four dynamic targets each, constructed to minimize similarities among targets within a set. Target selection and presentation. The VCR containing the taped targets was interfaced to the controlling com- puter, which selected the target and controlled its re- peated presentation to the sender during the ganzfeld pe- riod, thus eliminating the need for a second experimenter to accompany the sender. Following the ganzfeld period, the computer randomly sequenced the four-clip judging pool and presented it to the receiver on a TV monitor for judging. The receiver used a computer game paddle to make his or her ratings on a 40-point scale which ap- peared on the TV monitor after each clip was shown. The receiver was permitted to see each clip and to change the ratings repeatedly until he or she was satisfied. The com- puter then wrote these and other data from the session into a file on a floppy disk. At that point, the sender moved to the receiver's chamber and revealed the identity of the target to both the receiver and the experimenter. Note that the experimenter did not even know the identity of the four-clip judging pool until it was displayed to the receiver for judging. eee 4Because Honorton and his colleagues have complied with the Hyman-Honorton specification that experimental reports be suf- ficiently complete to permit others to reconstruct the investiga- tor’s procedures, readers who wish to know more detail than we provide here are likely to find whatever they need in the archival publication of these studies in the Journal of Parapsychology (Honorton et al., 1990). Approved For Release 2000/08/10 : CIA-RDP96-00792R000100130002-1
Approved For ReledseMOnorosniBorMATRDPAEGG7F22R0001 00130002-1 7 Randomization. The random selection of the target and sequencing of the judging pool were controlled by a noise- based random number generator interfaced to the com- puter. Extensive testing confirmed that the generator was providing a uniform distribution of values throughout the full target range (1-160), a uniform distribution of targets from among the four alternatives within each judging set, and a uniform distribution of judging sequences from among the 24 permutations of 4 stimuli. Additional control features. Both the receiver’s and sender’s rooms were sound-igolated, electrically-shielded chambers with single-door access that could be continu- ously monitored by the experimenter. There was two-way intercom communication between the experimenter and the receiver but only one-way communication into the sender’s room; thus neither the experimenter nor the re- ceiver could monitor events inside the sender’s room. The archival record for each session includes an audio tape containing the receiver’s mentation during the ganzfeld period and all verbal exchanges between the experimenter and the receiver throughout the experiment. The automated ganzfeld protocol has been examined by — several dozen parapsychologists and behavioral re- searchers from other fields, including well-known critics — of parapsychology. Many have participated as subjects or observers. All have expressed satisfaction with the han- dling of security issues and controls. Parapsychologists have often been urged to employ ma- gicians as consultants to ensure that the experimental protocols are not vulnerable either to inadvertent sensory leakage or to deliberate cheating. Two “mentalists,” magi- cians who specialize in the simulation of psi, have exam- ined the autoganzfeld system and protocol. Ford Kross, a professional mentalist and officer of the mentalist’s pro- fessional organization, the Psychic Entertainers Associa- tion, provided the following written statement “In my pro- fessional capacity as a mentalist, I have reviewed Pay- chophysical Research Laboratories’ automated ganzfeld system and found it to provide excellent security against deception by subjects” (private communication, May, 1989). . The first author of this article has aleo performed as a mentalist for many years and is a member of the Psychic Entertainers Association. As noted in the author footnote, this article has its origins in a 1983 visit he made to Hon- orton’s laboratory, where he was asked to critically exam- ine the research protocol from the perspective of a mental- iat, a research psychologist, and a subject. Needless to say, this article would not exist if he did not concur with Ford Kross’s assessment of the security procedures. Experimental Studies Altogether 100 men and 141 women participated as re- ceivers in 355 sessions during the research program. The participants ranged in age from 17 to 74 years (mean = 37.8, SD = 11.8), with a mean formal education of 15.6 years (SD = 2.0). Eight separate experimenters, including . Honorton, conducted the studies. The experimental program included three pilot and eight formal studies. Five of the formal studies employed novice (first-time) participants who served as the receiver in one seasion each. The remaining three formal studies employed experienced participants. Pilot Studies. Sample sizes were not preset in the three pilot studies. Study 1 comprised 22 sessions and was con- Approved For Release 2000/08/10 : ducted during the initial development and testing of the autoganzfeld system. Study 2 comprised 9 sessions testing a procedure in which the experimenter, rather than the receiver, served as the judge at the end of the session. Study 3 comprised 36 sessions and served as practice for participants who had completed the allotted number of sessions in the ongoing formal studies but who wanted additional ganzfeld experience. This study also included several demonstration sessions when TV film crews were present. Novice Studies. Studies 101-104 were each designed to test 50 participants who had had no prior ganzfeld experi- ence; each participant served as the receiver in a single ganzfeld session. Study 104 included 16 of 20 students re- cruited from the Juilliard School of Music in New York City in order to test an artistically gifted sample. Study 105 was initiated to accommodate the overflow of partici- pants who had been recruited for Study 104, including the four remaining Juilliard students. Sample size for this study was set to 25, but only 6 sessions had been com- pleted when the laboratory closed. For purposes of exposi- tion, we have divided the 56 sessions from Studies 104 and 105 into two parts: Study 104/105 (a) comprises the 36 non-Juilliard participants; Study 104/105 (b) comprises the 20 Juilliard students Study 201. This study was designed to retest the most promising participants from the previous studies. The number of trials was set to 20, but only 7 sessions with 3 participants had been completed when the laboratory closed. Study 301. This study was designed to compare static and dynamic targets. Sample size was set to 50 sessions. Twenty-five experienced participants each served as the receiver in two sessions. Unknown to the participants, the computer control program was modified to ensure that they would each have one session with a static target and one session with a dynamic target. Study 302. This study was designed to examine a dy- namic target set which contained one target that had of- ten been correctly identified in the previous studies and another target that had never been correctly identified. The study involved experienced participants who had had no prior experience with this particular target set and who were unaware that only one target set was being sampled. Each served as the receiver in a single session. The design called for the study to continue until 15 ses- sions were completed with each of the targets, but only twenty-five seasions had been completed when the labora- tory closed. The 11 studies just described comprise all sessions con- ducted during the 6-1/2 years of the program. There is no “file drawer” of unreported sessions. Results Overall hit rate. As in the earlier meta-analysis, re- ceivers’ ratings were analyzed by tallying the proportion of hits achieved and calculating the exact binomial prob- ability for the observed number of hits compared with chance expectation of .25. As noted above, 241 partici- pants contributed 355 sessions. For reasons discussed be- low, Study 302 is analyzed separately, reducing the num- ber of sessions in the primary analysis to 330. As Table 1 shows, there were 106 hits in the 330 ses- sions, a hit rate of 32% (z = 2.85, p = .002, one-tailed), with a 95% confidence interval from 30% to 35%. This cor« CIA-RDP96-00792R000100130002-1