Extrasensory Perception ESP Types of ESP ESP is

Extrasensory Perception (ESP) Types of ESP • ESP is knowledge gained by means other than the conventionally recognized senses – Sight, hearing, touch, taste, smell, balance, … 3 Common type of ESP that are discussed: • Telepathy – Knowing what someone is thinking • Remote Viewing – Seeing (or sensing) something that is not normally seeable • Precognition – Knowing something that is going to happen in advance

Why Do People Believe in ESP? Most people will cite anecdotal evidence • Coincidences: • “Last night I had a dream that I saw plane crash, and today there was a plane crash” • At one point in their life, many people have dreams like this – For some reason, this is not an uncommon dream for me • In a world of 7 billion people, it is hardly surprising if sometimes there are coincidences • Remember the hits and forgetting the misses • Of course, many times we have dreams that don’t come true • We tend to forget these • Lucky “Guesses” • Sometimes, it is not difficult to use conventional methods to anticipate results • For example, if you predict outcome of presidential races, you have 50% chance • Those who seriously research ESP don’t discount these incidents, but they don’t rely on anecdotes for evidence

Typical Tests of ESP • A common test of ESP uses some sort of randomly chosen object • Common to use Zener cards – Usually black and white, but I like colors • Make a big stack of them • One person concentrates on a card • Another tries to guess which card it is • Analyze data according to methods similar to what I’ve already taught you • If results are statistically better than 20%, then you have evidence of ESP • If the effect is not too small, you can measure it if you have enough trials

How Many Trials are Necessary? • That depends on how reliable ESP is • Typical results might be 25% • If you do 1000 cards, then the null hypothesis says: • We would expect 200 12. 7 hits • If we are getting 25% success, then we would actually get x = 250 • So the z-value would be • So if we do a bit more than 1000 trials we should get pretty significant results

An Obvious Error to Avoid • How do we randomize the cards? • Suppose you were foolish enough to simply put five cards in random order, and try to guess the result • Then have someone guess the cards, with immediate feedback • Because I know which cards have come up, I know not to guess that card in the future • Naïve computation says 20% chance on each, so in five cards, expect 1. 00 correct out of 5 • But if you follow this procedure, you can expect 2. 28 cards right out of 5 • Parapsychology researchers know this, and don’t make this obvious error

Results of ESP Experiments • • What are the results of tests like this one? Depends on who is doing the experiment “Believers”, who tend to think ESP is real, usually get positive results “Skeptics”, who think ESP isn’t real, tend to get negative results • Most experiments are done by believers • Results of believers are themselves disparate: • Some claim that everyone has a little bit of ESP, and get small effects with anyone • Others claim that some individuals are especially talented, and most people have little (if any) ESP

Possible Explanation of ESP Experiments • • True ESP Luck Fraud (by the experimenter) (Deliberate) cheating by the subject (Unintentional) sensory leakage Systematic errors File drawer effect • Can luck explain it? • Some small scale experiments could be due to luck • But some large scale experiments have exhibited effects much larger than z = 5 • Unlikely that luck is the entire explanation

Fraud and Cheating by the Subject • In conventional science, fraud is rare, but does happen – Made up data has been published and later caught • Though this is possible in ESP research, it is probably rare – That’s just my opinion • Because of the large number of trials involved, it is necessary to compensate (pay) those who agree to have trials done • In some tests, successful psychics are rewarded (financially) when they are right – Some studies indicate that this vastly increases their fraction of “hits” • Even if you don’t have specific rewards for success, those who are unsuccessful are unlikely to be invited back (to earn more money) • There is incentive for unscrupulous subjects to cheat • Even if deliberate cheating is rare, it may be those individuals who are willing and skillful at cheating that account for the successes

Catching Cheaters is What Magicians Do • Most scientists are ill-equipped to catch someone cheating – Electrons don’t cheat to get more money • Strict protocols can be followed to minimize the opportunity for cheating • In some cases, ESP labs have been infiltrated by skeptics with skills as magicians to test how careful these labs are at catching cheaters • In many cases, these “plants” were able to convince the experimenters that they had psychic powers • In fact, security was often very poor – Subjects had the opportunity to “mark” the cards – Backs were visible to the subjects – The order of targets were printed out in advance with no precautions taken to keep people from peeking at them • If you really want to prevent cheating, hire a magician

Sensory Leakage • There a lot of ways that you can accidentally leak information • Any deck of cards with identical backs will get random dents/scrapes/etc. over time, which allows you to identify the cards from the back • In professional gambling, decks of cards are regularly swapped out to avoid this problem • It is possible to see the reflection of cards in someone’s eyes or glasses – Though this probably only happens with deliberate cheating • Best way to avoid sensory leakage is to put people in different rooms

Sensory Leakage – An Anecdote • Many years ago I visited the Edgar Cayce Institute • My young daughter (5 -10) and I decided to do an ESP test • The test had us facing each other, looking at front/back of a machine • On my side, one of five Zener card symbols would be illuminated • She saw the same five symbols, and had to press a button to indicate which one was illuminated • We decided to see how well we could do • I told her to watch my eyes, and pick a button on the opposite side from where I was looking • We scored over 50% success

Systematic Effects • There can also be subtle systematic effects, even without cheating or sensory leakage • In one experiment, when you pressed a button, a light would indicate one of several randomly chosen cards would be chosen • The experimenter would concentrate on that card • The subject could guess the card, or could decide to pass • If they chose, it was recorded, if they passed, it was discarded • The result (success/failure) was immediately reported to the subject • The experimenter would then press the button again for the next trial • The results, after many trials, showed slightly better than chance • But statistically significant

So What’s Wrong With This? • Much later, when the data was examined, it was found that the same card was almost never chosen twice in a row – How could that happen? • It could be a bad randomizer, but more likely … • • The experimenter pressed the button, asking for a new card to be chosen By chance, the randomizer sometimes picks the same card There is no obvious change, as far as the experimenter can tell So he pressed the button again • Most people when guessing won’t guess the same card twice in a row • So the series wasn’t truly random, and the guesses weren’t truly random • If you never pick the same card twice, your odds are 25%, not 20%

File Drawer Effect • Not every study gets published • Suppose I’m testing ESP, and I see no effect: – Will anyone read the paper? – Will the referees think it’s worth publishing? • Some of the positive results from ESP may be due to the fact that negative results don’t get published • Of course, it can go the other way too – Referees may demand much stricter controls if you are claiming a positive effect • This is a problem with ESP, but also with medicine • Often negative results don’t get published

ESP In Summary • Despite many decades of study, no consistently reproducible effects have been found • The data is sometimes not statistically significant, but sometimes very statistically significant • Some of these results have been shown to have systematic errors – These errors can sometimes be very difficult to eliminate • Scientists are by and large not good at detecting deliberate fraud – In the case of extraordinary claims like this, magicians should be called in