Covert observation increases skin conductance in subjects unaware of when they are being observed: a replication

Journal of Parapsychology, The, Sept, 1997 by Marilyn J. Schlitz, Stephen LaBerge

Over the past few decades we have witnessed an increasing interest in the possibility that mental influences can affect living systems (for reviews, see Benor, 1990; Dossey, 1995; May &: Vilenskaya, 1994; Solfvin, 1984). In a typical experiment, some physiological activity or other selected behavior is monitored in the context of a formal laboratory experiment. The experimental participants try to influence a distant biological target system, and the results of this "influence" period are compared with those of a "noninfluence" or control condition. Target systems for these experiments have included micro-organisms, plants, animals, and humans (Schlitz, 1983, 1994).

One promising area of research involves the influence of a distant person on human autonomic nervous system activity. Schlitz and Braud (1997) reported statistically significant differences across a series of 13 experiments in which periods of intentional attempts to affect the physiology of a distant person were interspersed with counterbalanced control periods. This research led to the development of a protocol designed to measure the degree to which people are able to unconsciously detect a person observing them from a distance.

Many people have had the experience of being stared at from a distance, then turning around and discovering a pair of eyes focused on them. Indeed, survey data support the widespread distribution of these experiences. As early as 1913, Coover reported that 68% to 86% of respondents in California had had this type of experience on at least one occasion. A survey of an Australian population reported that 74% of the respondents had had such an experience (Williams, 1983). Further surveys revealed experiences by 85% of a student population at Washington University in St. Louis (Thalbourne & Evans, 1992) 94% of those surveyed in San Antonio, Texas (Braud, Shafer, & Andrews, 1990), and 80% of those informally surveyed in Europe and America (Sheldrake, 1994).

Several attempts have been made to explore these claims within a laboratory setting. A review of this literature was reported by Braud et al. (1990), who identified four studies. The earliest was conducted by Titchener (1898), a Cornell University psychologist, during the late 1800s, but although a brief article on his work reported negative results, he did not provide details of his study.

It was slightly later that Coover (1913) conducted his experiment on remote staring in his initial work as the Thomas Welton Stanford Psychical Research Fellow in the Psychology Department of Stanford University. In this study, each of 10 subjects made 100 guesses as to whether or not he or she was being stared at by an experimenter seated behind them in the same room. A random schedule of covert observation and nonobservation periods was determined by the rolling of a die. Each observation period was 15-20 s in duration and lasted several hours in a series of sittings that spanned a period of weeks. Having obtained chance results, Coover interpreted his findings as support for the belief that staring detection was empirically groundless.

A second laboratory study was carried out in 1959 by Poortman (1959) of Leyden University in the Netherlands. In this study, the two participants were separated; they were in different rooms, but within sensory range. The experiment spanned a 13-month period. The covert observation and control intervals were 2-5 min in duration and were based on a random sequence determined by card shuffling. This resulted in a 59.6% accuracy rate (p = .04, 1 - t).

A experiment that was better controlled than the previous two was reported by Peterson (1978). Following two informal pilot studies, he positioned his subjects in separate, adjacent closed cubicles. One-way mirrors and special lighting limited vision to one direction, and button pushes were used to measure the subject's discrimination of covert-observation versus nonobservation periods. In 36 experimental sessions, each of 6-min duration, there was a significant effect, p = .012, 2 - t.

This experimental design was further improved by Williams (1983), a student in the Psychology Department of the University of Adelaide (South Australia). Subjects were positioned in rooms at a 60-ft distance and were monitored via a closed-circuit video camera/monitor arrangement. Through the use of carefully controlled randomization procedures, Williams reported significant covert-observation detection guesses, p = .04, 1 - t.

On the basis of these four experimental studies, Braud, Shafer, and Andrews (1990) concluded that there was suggestive evidence to support the hypothesis that people can consciously discriminate periods of covert observation from nonobservation under conditions that control for subtle sensory cues. The effect size in these studies was not particularly strong, however. According to Braud and his colleagues, this was due to the fact that "the testing method used in these studies was not the most appropriate one" (p. 17). In particular, the authors argued that the use of conscious guessing might be less relevant to everyday life experiences, in which covert-observation detection takes the form of bodily sensations and spontaneous behavioral changes. For example, people frequently report the prickling of neck hairs or the tingling of the skin.