In 2 separate experiments involving 39 subjects the incidence of sensing a presence or Sentient Being while being exposed to weak complex magnetic fields over the right hemisphere was moderately correlated with increased global geomagnetic activity during the 3-h periods of the experiences. Analyses of magnetometer values near the laboratory indicated the intensity of the east-west component of the geomagnetic field had been increasing consistently at about 1 pT/s for at least 10 min for a cumulative change of about 15 to 20 nT. The ratios of the durations of alpha rhythms over the temporal lobes compared to the occipital lobes were correlated significantly with both increased geomagnetic activity and the reports of a presence. Removal of the shared variance between the sensed presence and various psychometric inferences of temporal lobe sensitivity and the history of dissociation increased and decreased, respectively, the strength of the partial correlations between geomagnetic activity and the reports of a sensed presence. The results suggest the culturally and historically ubiquitous phenomena of sensed presences are generated by right hemispheric processes that once enhanced by a variety of stimuli, including weak complex magnetic fields, can be encouraged by increased global geomagnetic activity.