Several thousand such trials have been conducted by dozens of investigators over the past 25 years, involving hundreds of participants. The cumulative database strongly indicates that information about remote photos, actual scenes, and events can be perceived. Some of these experiments have also been used to successfully study precognition by having a participant describe a photo that would be randomly selected in the future. Methodologies Parapsychology uses methods commonly employed in other scientific disciplines. Laboratory studies use research methods from psychology, biology and physics.
Field research uses methods from sociology and anthropology.
There are plenty of textbooks on research methods in these fields, and we won't attempt to summarize them here. Therefore, an important part of parapsychological research is eliminating known contact methods from laboratory setups and thinking carefully about them when evaluating reports of people's experiences. In ESP research, this requires knowing about the psychology of sensation, perception, memory, thinking, and communication, and about the biology and physics of sensation and movement. In field studies, and in most laboratory studies, it's important to know about the ways in which people can interact with each other. Even when known contact methods are well controlled or eliminated, there is always the possibility that what we observe could have occurred by chance .