In parapsychology, precognition (from the Latin præ-, “before,” + cognitio, “acquiring knowledge”), also called future sight, and second sight, is a type of extrasensory perception that would involve the acquisition or effect of future information that cannot be deduced from presently available and normally acquired sense-based information or laws of physics and/or nature. A premonition (from the Latin praemonēre) and a presentiment are information about future events that is perceived as emotion.
The existence of precognition, as with other forms of extrasensory perception, is not accepted by the mainstream scientific community.
Scientific investigation of extrasensory perception (ESP) is complicated by the definition which implies that the phenomena go against established principles of science. Specifically, precognition would violate the principle that an effect cannot occur before its cause. However, there are established biases, affecting human memory and judgment of probability, that create convincing but false impressions of precognition.
There are a number of organizations which collect self-reported "psychic" experiences from the public at large. Classifications of these (self-reported) experiences by type provide a sense of the prevalence of belief in particular kinds of parapsychological phenomena in the public at large.
In the particular case of precognition, belief is widespread. In one review of a U.S. case collection, submitted to Duke University's Parapsychology Laboratory, 75% of 1777 dream-based experiences were categorized as precognitive, as were 60% of 1513 wakeful experiences. A similar distribution was identified for a separate collection of 157 cases reported by children; here, the largest category of reports was again of precognitive dreams (52%), followed by precognitive intuitions (52%). A German case collection produced a similar figure: 52% of 1,000 cases were categorized as precognitive. A British study of 300 volunteered cases showed 34% to be apparently precognitive.
The mainstream scientific community does not take public belief in precognition (or any other phenomenon) as evidence for its veracity or even credibility, though widespread reports of interesting phenomenon might inspire scientific inquiry. Such inquiries are conducted using the scientific method, and the evidence collected in such methodological studies is used to determine the credibility of precognition and other psychic phenomena.
Case collections 
History records many instances of apparent precognition (see Ides of March), and belief in its occurrence as a form of seeing into the future (this can be through visions, déjà vu or through dreams which is usually the cause of recognition). The first thorough collection and critical review of such spontaneous cases was created by the British Society for Psychical Research (SPR). Reports of these cases were authored by Eleanor Sidgwick in 1888, and Herbert Saltmarsh in 1938. Sidgwick believed the evidence warranted further investigation as to the validity of the concept of precognition, and Saltmarsh offered that the evidence, if it did not scientifically establish the phenomenon, at least excluded alternative hypotheses. Nicol, however, in a later review, came to the conclusion that their evidence was not so suggestive, given, in particular, the long length of time between the occurrence of some of the most suggestive cases, and their first report to the SPR.
J. W. Dunne, a British aeronautics engineer, recorded each of his dreams as they occurred to him, identifying any correspondences between his future experiences and his recorded dreams. In 1927, he reported his findings, together with a theory, in An Experiment with Time. In this work, at least 10% of his dreams appeared to represent some future event, pertaining to some relatively trivial incident in Dunne's own life, or some major news events appearing in the press a day or so after the dream. Dunne concluded that precognitive dreams are common occurrences: many people have them without realizing it, largely because they do not recall the details of the dream. Also reported in the book was an experiment Dunne conducted with several other people who studiously recorded their dreams and sought to associate them with subsequent experiences. Dunne felt these confirmed his theory, but a 1933 independent experiment failed to replicate his findings.
Experimental approaches 
Free-response studies 
With free-response methods, experiments have been conducted in precognitive dreaming at the sleep laboratory of the Maimonides Medical Center, in precognitive Ganzfeld hallucinations and visions. While such experiments have produced some suggestive evidence for precognition, they have been somewhat limited to studies of selected participants, and have involved procedures that can be too expensive for other researchers to replicate, or too complex to theoretically interpret.
Forced-choice studies 
Most experiments on precognition have involved a forced-choice procedure. The first such ongoing and organized research program on precognition was instituted by J. B. Rhine in the 1930s at Duke University's Parapsychology Laboratory. Rhine used a method of forced-choice matching in which participants recorded their guesses as to the order of a deck of 25 cards, each five of which bore one of five geometrical symbols. The test of precognition was based on the fact that these "guesses" were made before the deck was shuffled by the experimenter. In an effort to distinguish between different parapsychological accounts of precognition, and to better understand its conditions, experiments were conducted in which the order of the target deck of cards was determined by hand versus machine, or by reference to macroscopic events, such as randomly selected meteorological readings, or by complex algorithms. Early experiments also sought to determine the temporal scope of precognition by organizing the target deck only 1-2 versus 10 days, or even a year, after responses had been recorded and secured.
Experiments by Samuel G. Soal, a mathematician, and colleagues seemed to provide impressive evidence of precognition. They ran forced-choice ESP experiments in which someone attempted to identify which of five animal pictures a subject in another room was looking at. Their performance on this task was at chance, but when the scores were matched with the card that came after the target card, three of the thirteen subjects showed a very high hit rate. These experiments were hailed as "the most impressive data ever reported" for ESP, with controls that "seem to be absolutely watertight". Rhine described Soal's work as "a milestone in the field". A dissenting view came from research chemist George Price who reviewed Soal and Bateman's book Modern Experiments in Telepathy for the journal Science in 1955. Price argued that since ESP was so unlikely, the positive results not attributable to error were more likely the result of deliberate fraud. This prompted several replies that Price's criticism was unfair, resting on the mere possibility of fraud rather than actual proof. In 1978, the experiments were in fact exposed as totally fraudulent. The statistician and paragnost Betty Markwick, while seeking to vindicate Soal, discovered that he had altered his data to create all the extra hits and give the study its statistical significance. The untainted experimental results showed absolutely no evidence of precognition in the hits or the ratios.
A meta-analysis of all reports in the parapsychological literature of card-calling experiments on precognition was conducted in the late 1980s. This encompassed 309 experiments reported by 62 different investigators and published between 1935 and 1987. 23 of the 62 investigators reported positive results. The overall result offered precognition as a reliable but small effect over these studies, and an effect that could not be accounted for by levels of methodological reliability (as assessed by rating the studies on eight attributes of method), nor any publication bias against reporting null results.
Other researchers, including Smithsonian Executive Secretary Charles Greeley Abbot and British psychologist R. H. Thouless, introduced the study of precognition in the displacement of guesses to targets. This involved a set of target symbols, and "guesses" as to their identity, but, rather than precognizing the order of a whole deck of symbols, scored for precognition by checking the correspondence between each response and the target assigned to one or more trials ahead of that to which the response was originally assigned. Several studies using this method have continually offered displacement as reliable evidence for precognition.
Following these experiments, a more automated technique of experimentation was introduced that did not rely on hand-scoring of equivalence between targets and guesses, and in which the targets could be more reliably and readily tested as random. This involved testing for precognition with the use of high-speed random event generators (REG), as introduced by Helmut Schmidt in 1969 and further conducted, in particular, at the Princeton Engineering Anomalies Research Lab (1979–2007). In this procedure, participants indicate when they believe (by whatever means available to them) that the REG has produced an event that either conforms or differs from one of two target events. In comparison to the card-guessing type of experiments, this procedure permits much more data to be collected in an experimental session, while reducing the number of alternatives that need to guessed.
Unconscious perception studies 
Another class of experiments have tested for precognition by unconscious signs. These have involved physiological responses, such as of skin conductance and electroencephalographic activity, or indirect psychological measures, such as ratings of preference for one or another target alternative. In these experiments, participants are not asked about their experiences, and do not need to be informed that they are participating in an experiment on ESP. Dick Bierman and Dean Radin have reported positive evidence of precognition in experiments of these kinds.
Various psychological processes have been offered to explain experiences of apparent precognition.
Cognitive failure/distortion models 
Suited to explaining at least naturalistic occurrences of apparent precognition are several more or less hypothetical unconscious cognitive processes. These include:
- Selection bias where people remember the "hits" and forget the "misses," remember coincidences more often than other non-coincidences, or when they were correct about a future event rather than instances when they were wrong. Examples include thinking of a specific person before that person calls on the phone. Human memory, it is argued, has a tendency to record instances when the guess was correct, and to dismiss instances when the guess was incorrect.
- Unconscious perception by which people unconsciously infer, from data they have unconsciously learned, that a certain event will probably happen in a certain context. As with cryptomnesia, when the event occurs, the former knowledge appears to have been acquired without the aid of recognized channels of information.
- Self-fulfilling prophecy and Unconscious enactment in which people bring events that they have precognized to pass, but without their conscious knowledge.
Some psychologists have explained the apparent prevalence of precognitive dreams in terms of memory biases, namely a selective memory for accurate predictions and distorted memory so that dreams are retrospectively fitted onto subsequent events. In one experiment, subjects were asked to write down their dreams in a diary. This prevented the selective memory effect, and the dreams no longer seemed accurate about the future. Another experiment gave subjects a fake diary of a student with apparently precognitive dreams. This diary described events from the person's life, as well as some predictive dreams and some non-predictive dreams. When subjects were asked to recall the dreams they had read, they remembered more of the successful predictions than unsuccessful ones.
There are several ways by which precognition can be conceived as occurring without fundamental dependence on normally recognized processes of perception and cognition, i.e., by psi.
Firstly, there are several ways to explain precognition as a form of extrasensory perception. Precognition can be conceived as an extraordinary process of clairvoyance, involving no direct perception of the future. If, as is offered by the philosophy of determinism, all future events are determined by present conditions, then it can be suggested that it is clairvoyance of all the relevant present conditions that permits one to know their future outcomes. Alternatively, if somebody in the present is aware of what will happen in the future, then it can be suggested that it is telepathy of that information that grants oneself a like knowledge of the future. "Seeing into the future" can also be conceived as not a direct perception of a future event, but only a perception of one's own future experience of that event; what J. B. Rhine called precognitive sensory perception. Support to this suggestion is given by the meta-analysis which includes the study of a subset of experiments in which details were provided about the feedback of target information given to subjects in the future. The study shows that when no feedback was given, the significance of the results fell to chance-expectation. This does suggest that the contacts were being made with the subject's future experience of receiving the target information, and not with the targets themselves.
The construct of psychokinesis permits another set of ways to think about precognition. It can be suggested that precognition involves the influence of present conditions so that they conform with what is precognized. Alternatively, a retrocausal process can be proferred as an explanation, raising the idea that, at a future time, the ostensibly present conditions are influenced backward in time.
As for theories of precognition itself, parapsychologists have offered several phenomenological theories that – like most psychological theories themselves – do not presume to provide a physical explanation of how precognition occurs, but only seek to describe the processes that must, it seems, be occurring at a psychological level of explanation. There are two classes of such theories, which are not exclusive to each other.
Subliminal awareness 
One class of theories – principally as discussed, albeit in quite disparate ways, by Dunne (1927) and Saltmarsh (1938) – supposes that awareness is fundamentally trans-temporal, acquiring information beyond the "specious present" of information that is typically available for immediate awareness. While we are only ever consciously aware of some limited temporal range of information, these theories assert that, unconsciously, a much wider temporal range of information is sampled and used for the benefit of the organism.
Tachyon theory 
Influenced by Gerald Feinberg's concept of a tachyon, some parapsychologists such as Martin Ruderfer (1974) theorised that tachyons can travel backwards in time and may be able to explain cases of precognition. The British physicist and mathematician Adrian Dobbs (1965) proposed a theory in which precognition occurs due to “psitrons,” hypothetical particles similar to tachyons that travel backward in time which may contact an observer's brain to produce a precognitive experience. The major problem with the tachyon theory of precognition is that tachyons have never been observed to exist; they remain theoretical constructs. Arthur Koestler discussed the theory of Dobbs in his book The Roots of Coincidence.
Psi-mediated instrumental response (PMIR) 
This theory, offered by then psychologist Rex G. Stanford, proposes that humans unconsciously and automatically scan their environment for motivationally relevant information, including - as the subliminal awareness models suggest - information that will only occur in the future of each conscious observer. This information will be used, by those who are so disposed, to place the person in a goal-relevant position with respect to its environment. This creates the experience of precognition, should some of this information have been represented in conscious imagery or other representational forms.
Observational theories 
One class of parapsychological theories makes reference to the measurement problem in quantum mechanics, particularly as it implicates the constructive role of human observation. Precognition, in the context of these theories, is generally conceived in the manner of retroactive psychokinesis, but without recourse to any notion of the transmission of psychophysical energy. According to some observational theories, it is at the point of observation of a future event that the event is, in fact, determined, and, under certain conditions of motivation, randomness and feedback, this future observation can inform the present observer.
Resonance theories 
Another class of theories is based on the block universe model, in which future events already exist in spacetime, according to the special theory of relativity. The theories explain precognition as the retrieval of memories from the brain in the future, which could occur in a similar way to that in which ordinary memories are retrieved from the brain in the past.
The theory proposed by Jon Taylor is based on David Bohm's theory of the implicate order, which suggests that if similar structures are created at different places and different times, the structures resonate with a tendency to become more closely similar to one another. Taylor applies the principles to the neuronal spatiotemporal patterns that are activated in the brain, to show how an information transfer could be produced. For example, a precognition would occur when the pattern activated at the time of the future experience of an event resonates with any similar pattern that is spontaneously activated in the present. This might enable the present activation to be sustained until it produces the conscious awareness of an event similar to the one that will be experienced in the future.
The experimental research into ostensible precognition has, like much of the research into extrasensory perception, been subject to various critiques of its methodology. This concerns the fundamental logic of the methods, and particular aspects of procedure. A general issue is concerned with the possibility that the phenomena contradict generally recognized principles of science, coupled with the absence of a method to demonstrate precognition on demand.
In dreams 
Louisa Rhine at the Parapsychology Laboratory at Duke University compiled the best-known and largest body of dream evidence. Dr. Rhine collected over 7000 accounts of ESP experiences. The majority of these accounts were dream related and were seemingly precognitive in nature. The material for this work was collected by advertisements in various well-known popular media.
David Ryback, a psychologist in Atlanta, used a questionnaire survey approach to investigate precognitive dreaming in college students. His survey of over 433 participants showed that 290 or 66.9 percent reported some form of paranormal dream. He rejected many of these claims and reached a conclusion that 8.8 percent of the population was having actual precognitive dreams.
An early inquiry into this phenomenon was done by Aristotle in his On Divination in Sleep. His criticism of these claims appeals to the fact that "the sender of such dreams should be God", and "the fact that those to whom he sends them are not the best and wisest, but merely commonplace persons." Thus: "Most [so-called prophetic] dreams are, however, to be classed as mere coincidences...", here "coincidence" being defined by Aristotle as that which does not take "place according to a universal or general rule" and referring to things which are not of themselves by necessity causally connected. His example being taking a walk during an eclipse, neither the walk nor the eclipse being apparently causally connected and so only by "coincidence" do they occur simultaneously.
Other researchers in this area are more guarded in their reports on the value or use of dreams. In his book The Interpretation of Dreams, first published at the end of the 19th century, Sigmund Freud argued that the foundation of all dream content is the fulfillment of wishes, conscious or not and devoid of psychic content. On the other hand, Freud's view of precognition evolved. According to Jung, Freud's "materialistic prejudice" and "shallow positivism" lead him to reject the entire complex of questions relating to precognition and the occult as "nonsensical." But years later, adds Jung, Freud both "recognized the seriousness of parapsychology and acknowledged the factuality of 'occult' phenomena."
Dreams which appear to be precognitive may in fact be the result of the "Law of Large Numbers". Robert Todd Carroll, author of "The Skeptic's Dictionary" put it this way: "Say the odds are a million to one that when a person has a dream of an airplane crash, there is an airplane crash the next day. With 6 billion people having an average of 250 dream themes each per night, there should be about 1.5 million people a day who have dreams that seem clairvoyant."
See also 
- Anomalous cognition
- Déjà vu
- Dune (novel)
- List of parapsychology topics
- Premonition (film)
- Premonitions (novel)
- Second sight
- Beare, Hedley (2001). Creating the future school. Routledge. p. 192. ISBN 978-0-415-23868-7.
- Campbell, J. G. (1974). Witchcraft and second sight in the Highlands and Islands of Scotland. Originally published 1902.
- Cohn, S. A. (1999). Second sight and family history: Pedigree and segregation analyses. Journal of Scientific Exploration, 13, 351-372.
- Insulanus, T. (1763). A treatise on the second sight, dreams and apparition. Edinburgh, UK.
- Parapsychological Association (2006). Glossary of key words frequently used in parapsychology. 
- Randi, James (1995). An Encyclopedia of Claims, Frauds, and Hoaxes of the Occult and Supernatural. St. Martin's Press. ISBN 0-312-13066-X.
- Hyman, Ray (2007). "Evaluating Parapsychological Claims". In Robert J. Sternberg, Henry J. Roediger III, Diane F. Halpern. Critical Thinking in Psychology. Cambridge University Press. p. 217. ISBN 0-521-60834-1.
- Hines, Terence (2003). Pseudoscience and the Paranormal. Prometheus Books. pp. 78–81. ISBN 978-1-57392-979-0.
- Stokes, D. M. (1997). Spontaneous psi phenomena. In S. Krippner (Ed.), Advances in parapsychological research (Vol. 8, pp. 6-87). Jefferson, NC, US: McFarland.
- Drewes, A. A. (2002). "Dr. Louisa Rhine's letters revisited: The children". Journal of Parapsychology 66: 343–370.
- Sannwald, G. (1959). "Statistische Untersuchungen an Spontanphänomene [Statistical analysis of spontaneous cases]". Zeitschrift für Parapsychologie und Grenzgebiete der Psychologie 3: 59–71.
- Green, C. E. (1960). "Analysis of spontaneous cases". Proceedings of the Society for Psychical Research 53: 97–161.
- Dodds, E. R. (1971). "Supernormal phenomena in classical antiquity". Proceedings of the Society for Psychical Research 55: 189–237.
- Sidgwick, E. M. (1888). "On the evidence for premonitions". Proceedings of the Society for Psychical Research 5: 288–354.
- Saltmarsh, H. F. (1934). "Report on cases of apparent precognition". Proceedings of the Society for Psychical Research 42: 49–103.
- Nicol, J. F. (1961). "Apparent spontaneous precognition: A historical review". International Journal of Parapsychology 3 (2): 26–39.
- Dunne, J. W. (1927). An experiment with time. Hampton Roads Publishing Co. I. ISBN 978-1-57174-234-6.
- Besterman, T. (1933). "Report of an inquiry into precognitive dreams". Proceedings of the Society for Psychical Research 41: 186–204.
- Krippner, S.; Honorton, C.; Ullman, M. (1971). "A precognitive dream study with a single subject". Journal of the American Society for Psychical Research 65: 192–203.
- Krippner, S.; Honorton, C.; Ullman, M. (1972). "A second precognitive dream study with Malcolm Bessent". Journal of the American Society for Psychical Research 66: 269–279.
- Sargent, C. L.; Harley, T. A. (1982). "Precognition testing with free-response techniques in the ganzfeld and the dream state". European Journal of Parapsychology 4: 243–256.
- Rhine, L. E. (1967). ESP in life and lab: Tracing hidden channels. New York, NY, US: Macmillan.
- Berger, Arthur S.; Berger, Joyce (1991). The Encyclopedia of Parapsychology and Psychical Research. Paragon House Publishers. ISBN 1-55778-043-9.
- Rhine, J. B. (1938). "Experiments bearing on the precognition hypothesis: I. Pre-shuffling card calling". Journal of Parapsychology 2: 38–54.
- Hutchinson, L. (1940). "Variations of time intervals in pre-shuffle card-calling tests". Journal of Parapsychology 4: 249–270.
- Rhine, J. B. (1941). "Experiments bearing upon the precognition hypothesis: III. Mechanically selected cards". Journal of Parapsychology 5: 1–57.
- Rhine, J. B. (1942). "Evidence of precognition in the covariation of salience ratios". Journal of Parapsychology 6: 111–143.
- Colman, Andrew M. (1988). Facts, Fallacies and Frauds in Psychology. Unwin Hyman. pp. 175–180. ISBN 0-04-445289-6.
- Hyman, Ray (2007). "Evaluating Parapsychological Claims". In Robert J. Sternberg, Henry L. Roediger, Diane F. Halpern. Critical Thinking in Psychology. Cambridge University Press. pp. 219–223. ISBN 0-521-60834-1.
- Honorton, C.; Ferrari, D. C. (1989). "Future telling": A meta-analysis of forced-choice precognition experiments, 1935-1987". Journal of Parapsychology 53: 281–308.
- Crandall, J. E. (1991). "The psi-missing displacement effect: Meta-analyses of favorable and less favorable conditions". Journal of the American Society for Psychical Research 85: 237–250.
- Tart, C. T. (2002). Improving real-time ESP by suppressing the future: Trans-temporal inhibition. In C. T. Tart, H. E. Puthoff & R. Targ (Eds.), Mind at Large: IEEE Symposia on the Nature of Extrasensory Perception (pp. 125-156). Charlottesville, VA, US: Hampton Roads. Originally published 1979.
- Schmidt, H. (1969). "Precognition of a quantum process". Journal of Parapsychology 33: 99–109.
- Odling-Smee, Lucy (March 1, 2007). "The lab that asked the wrong questions". Nature 446 (7131): 10–11. doi:10.1038/446010a. PMID 17330012. Retrieved 2007-06-29.
- Bierman, D. J.; Radin, D. I. (1997). "Anomalous anticipatory response on randomized future conditions". Perceptual and Motor Skills 84 (2): 689–690. PMID 9106864.
- Bierman, Dick J.; Dean Radin (1999). "Conscious and Anomalous Nonconscious Processes: A reversal of the arrow of time?". In Stuart R. Hameroff, Alfred W. Kaszniak. Toward a science of consciousness III: the third Tucson discussions and debates. MIT Press. pp. 367–386. ISBN 978-0-262-58181-3.
- Alcock, James E. (1981). Parapsychology: Science or Magic?: a psychological perspective. Oxford: Pergamon Press. ISBN 0-08-025773-9. via Hines, Terence (2003). Pseudoscience and the Paranormal. Prometheus Books. pp. 78–81. ISBN 978-1-57392-979-0.
- Madey, Scott; Thomas Gilovich (1993). "Effects of Temporal Focus on the Recall of Expectancy-Consistent and Expectancy-Inconsistent Information". Journal of Personality and Social Psychology 62 (3): 458–68. doi:10.1037/0022-3518.104.22.1688. PMID 8410650. via Kida, Thomas (2006). Don't Believe Everything You Think: The 6 Basic Mistakes We Make in Thinking. Prometheus Books. ISBN 978-1-59102-408-8.
- Morris, R. L. (1982). "Assessing experimental support for true precognition". Journal of Parapsychology 46: 321–336.
- Rhine, J. B. (1945). "Precognition reconsidered". Journal of Parapsychology 9: 264–277.
- Eisenbud, J. (1982). Paranormal foreknowledge. New York, NY, US: Human Sciences.
- Schmidt, H. (1976). "PK effect on pre-recorded targets". Journal of the American Society for Psychical Research 70: 267–292.
- Ruderfer, M. (1974). Comments on Chari’s discussion of the neutrino theory of ESP. [Letter to the Editor.] Journal of Parapsychology, 38, 338–340.
- Dobbs, H. (1965). Time and extrasensory perception. Proceedings of the Society for Psychical Research, 54, 249–361.
- Stanford, R. G. (1974). "An experimentally testable model for spontaneous psi events. I. Extrasensory events". Journal of the American Society for Psychical Research 68: 34–57.
- Stanford, R. G. (1990). An experimentally testable model for spontaneous psi events: A review of related evidence and concepts from parapsychology and other sciences. In S. Krippner (Ed.), Advances in Parapsychological Research (Vol. 6, pp. 54-161). Jefferson, NC, US: McFarland.
- Schmidt, H. (1984). "Comparison of a teleological model with a quantum collapse model of psi". Journal of Parapsychology 48: 261–276.
- Walker, E. H. (1984). "A review of criticisms of the quantum mechanical theory of psi phenomena". Journal of Parapsychology 48: 277–332.
- Walker, E. H. (1987). "Measurement in quantum mechanics revisited: A response to Phillips' criticism of the quantum mechanical theory of psi". Journal of the American Society for Psychical Research 81: 333–369.
- Millar, B. (1988). "Cutting the Braudian loop: In defense of the observational theories". Journal of the American Society for Psychical Research 82: 253–271.
- Marshall, N. (1960). "ESP and memory: A physical theory". British Journal of the Philosophy of Science 40: 265–286.
- Taylor (2007). "Memory and precognition". Journal of Scientific Exploration 21: 553–570.
- Bohm, D.; Weber, R. (1982). "Nature as creativity". ReVision 5: 35–40.
- Scott, Christopher (1987). "Paranormal phenomena: the burden of proof". In Richard L. Gregory. The Oxford Companion to the Mind. Oxford University Press. pp. 578–581. ISBN 0-19-860224-3.
- Rhine, L.E. (1969). "Case study review". Journal of Parapsychology 33: 228–66.
- Rhine, L.E. (1977). Research methods with spontaneous cases. In B.B. Wolman (Ed) Handbook of Parapsychology (pp. 59-80). New York: Van Rostrand Reinhold.
- Ryback, David, PhD. “Dreams That Came True”. New York: Bantam Doubleday Dell Publishing Group, 1988.
- Aristotle, On Divination in Sleep
- Jung, C.G. (1989, Memories, Dreams and Reflections, New York: Vintage.
- Law of Truly Large Numbers
Further reading 
- Guiley, Rosemary Ellen: Harper's Encyclopedia of Mystical and Paranormal Experience, New York: HarperCollins, 1991, pages 465-466
- Robertson, Morgan and Stevenson, Ian, M.D.: The Wreck of the Titan: The Paranormal Experiences Connected with the Sinking of the Titanic. Cutchogue, NY: Buccaneer Bks, 1991.
- Spence, Lewis: An Encyclopedia of Occultism, New York, Carol Publishing Group Edition, 1996, pages 329
- Stevenson. "A Review & Analysis of Paranormal Experiences Connected with the Sinking of the Titanic". Journal of American Society for Psychical Research 54: 1961.
- Barrett, Deirdre, PhD .”The Committee Of Sleep”. New York: Crown Publishers, 2001
- Quinn, Adriene. “Dreams of History That Came True”. Tacoma: Dream Research, 1987.
- Reed, Henry, PhD. “Getting Help From Your Dreams”. Virginia Beach: Inner Vision Publishing, 1985.
- Thurston, Mark. PhD. “Tonight’s Answers To Tomorrow’s Questions”. San Francisco: Harper & Row, 1988.
- Precognition, Presentiment & Remote Viewing - Dean Radin
- "Precognition and Second Sight" in Robert Todd Carroll's The Skeptic's Dictionary
- Definition of "precognition" in James Randi's An Encyclopedia of Claims, Frauds, and Hoaxes of the Occult and Supernatural
- The Best Case for ESP?
- Failed Psychic Predictions for 1998
- Online Psi Experiments Links to precognition experiments (Parapsych.org affiliate of the AAAS)
- International Association for the Study of Dreams Guidance on dreams from a clinical approach with little emphasis on precognition
- Intuitive Connections
- Wait, what? Study Finds Evidence for Precognition - LiveScience