decline effect - The Skeptic's Dictionary

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class="header"> <div class="logo"> <img src="_images/logo_01.png" alt="The Skeptic's Dictionary" width="270" height="60" border="0" />           <br /> by <a href="http://skepdic.com/refuge/bio.html">Robert Todd Carroll</a> * est. 1994 </div> <div class="slogan"> <img src="_images/slogan_01.gif" alt="A Collection of Strange Beliefs, Amusing Deceptions, and Dangerous Delusions" width="362" height="30" /> </div> </div> <div class="menu"> <ul> <li></li><li><a href="http://skepdic.com/">Home</a></li> <li><a href="http://skepdic.com/news/">Newsletter</a></li> <li><a href="http://skepdic.com/feedback.html">Feedback</a></li> <li><a href="http://skepdic.com/faq.html">FAQ & Interviews</a></li> <li><a href="http://skepdic.com/tour.html">Site Map</a></li> </ul> </div> <div class="middle"> <div class="left"> <h2>Topical Indexes</h2> <ul class="nav_1"> <li><a href="http://skepdic.com/tialtmed.html">Alternatives to Medicine</a></li> <li><a href="http://skepdic.com/ticriticalthinking.html">Critical 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href="http://skepdic.com/contents.html#Z">z</a></li> </ul> <webContent><h1 align="left">decline effect</h1> <p align="left"><font face="Arial" size="3">The decline effect is the notion that <a href="psychic.html"> psychics</a> lose their powers under continued investigation. This idea is based on the observation that subjects who do significantly better than chance in early trials tend to do worse in later trials. (<a href="parapsy.html">Parapsychologists</a> refer to <i>the incline effect</i> to describe those subjects who tend to do better in the later trials.)</font><p align="left"> <font face="Arial" size="3">The terms was coined by J. Beloff, who wrote:</font><blockquote> <p align="left"><font face="Arial" size="3">...it soon transpired that a decline effect, for <a href="esp.html">ESP</a> no less than for <a href="kinesis.html">PK</a>, could persist across sessions and, ultimately, across an entire career. Nearly all the high-scorers eventually lost their ability. Even <a href="http://www.amazon.com/exec/obidos/ISBN=0879755121/roberttoddcarrolA/">Pavel Stepanek</a>, whose 10-year career as an ESP subject earned him a mention in the Guinness Book of Records, eventually ran out of steam. When, after a long break, he was retested recently by Dr Kappers in Amsterdam, he could produce only chance scores. I do not think it was loss of motivation or boredom in his case, as has sometimes been put forward as an explanation for the long-term decline effect, for it was Stepanek's great strength that he was constitutionally incapable of ever being bored! Nor can we take seriously Martin Gardner's attempt to explain how he might have relied throughout on trickery. If indeed he was a trickster, he should have steadily improved as he became more practiced. Whatever the explanation of these long-term declines, it must surely be something deep and pervasive.<a href="http://www.science-frontiers.com/sf093/sf093p15.htm">*</a></font></blockquote> <p align="left"><font face="Arial" size="3">Beloff is incorrect in assuming that a trickster should steadily improve as he becomes more practiced. This is likely only if those testing the trickster are incompetent at detecting deception.</font><p align="left"> <font face="Arial" size="3">An alternative explanation for the decline effect is that as time goes on or as others do the testing, tighter controls and better experimental protocols are used, leading to the poorer scores. For example, transparent Zener cards were used in some of J. B. Rhine's experiments. Observers may have been brought in for later trials, making it more difficult for the subject to cheat.</font><p align="left"><font face="Arial" size="3">Another alternative explanation for why subjects who do well in early trials tend to do worse in later trials, and vice-versa, is <a href="regressive.html">regression toward the mean</a>. That is, one would expect, over time, that a subject without psychic ability would approach chance levels in guessing experiments but that there would be occasional runs where the subject would do better than chance and runs where the subject would do worse than chance. These deviations would have nothing to do with the waxing and waning of psychic powers but to the very natural tendency of regression toward the mean.</font><p align="left"> <font face="Arial" size="3">Beloff's explanation for the decline effect was that paranormal phenomena represent a "violation of the natural order" and Nature "reacts to these rents in the fabric of the cosmos by healing them just as our bodies heal wounds."<a href="http://www.science-frontiers.com/sf093/sf093p15.htm">*</a> This is pure speculation on Beloff's part, however.</font><p align="left"> <font face="Arial" size="3">Others blame boredom, fatigue, or the inability to control the unconscious processes underlying psi.<a href="http://www.survivalafterdeath.org/articles/koestler/country.htm">*</a></font><p align="left"> <font face="Arial" size="3">The alternative explanations have the merit of not only being more plausible than the decline effect theory, but also of  applying to <i>types</i> of psi tests, such as <a href="zener.html">Zener card</a> tests, over time. That is, it is likely that scientific experimenters have simply gotten better at evaluating their data and at designing their experiments to control for such things as <a href="sensoryleakage.html">sensory leakage</a> or cheating, and that is why scores have declined.</font><hr color="#000000" align="left" width="25%"><p align="left"> <font face="Arial" size="3"><b> See also</b> <a HREF="clairaudio.html">clairaudience</a>, <a HREF="clairvoy.html">clairvoyance</a>, <a href="displacement.html">displacement</a>, <a HREF="esp.html">ESP</a>, <a href="experimentereffect.html">experimenter effect</a>, <a href="ganzfeld.html">ganzfeld experiment</a>, <a href="geller.html">Uri Geller</a>, <a href="medium.html">medium</a>, <a href="moody.html">Raymond Moody</a>, <a href="nostrada.html">Nostradamus</a>, <a href="opstart.html">optional starting and stopping</a>, <a HREF="parapsy.html">parapsychology</a>, <a href="pastlife.html">past life regression</a>, <a HREF="precog.html"> precognition</a>, <a href="psi.html">psi</a>, <a href="psiassumption.html">psi assumption</a>, <a href="psimiss.html">psi-missing</a>, <a href="psychic.html">psychic</a>, <a href="psychdet.html"> psychic detective</a>, <a href="psurgery.html">psychic surgery</a>, <a HREF="kinesis.html">psychokinesis</a>, <a href="psychomet.html">psychometry</a>, <a href="randi.html">James Randi psychic challenge</a>, <a href="remotevw.html">remote viewing</a>, <a HREF="retrocog.html">retrocognition</a>, <a href="seance.html">s茅ance,</a> <a href="tart.html">Charles Tart</a>, <a href="kinesis.html">telekinesis</a>, <a HREF="telepath.html">telepathy</a>, and <a href="vanpraagh.html">James Van Praagh</a>.</font><p align="left"> <font face="Arial" size="3"><b>further reading</b></font><p align="left"> <b><font face="Arial" size="3">books</font></b><p style="text-align: left"> <font face="Arial" size="3"> <a href="http://www.amazon.com/exec/obidos/ISBN=0080257720/roberttoddcarrolA/"> Alcock, James E. (1981)<i>. Parapsychology: Science or Magic?</i> Pergamon Press.</a></font></p> <p style="text-align: left"></p> <p style="text-align: left"> <font face="Arial" size="3"> <a href="http://www.amazon.com/exec/obidos/ISBN=0690268157/roberttoddcarrolA/"> Christopher, Milbourne (1970). <i>ESP, Seers & Psychics </i>(Thomas Y. Crowell Co.</a></font></p> <p style="text-align: left"> <font face="Arial" size="3"> <a href="http://www.amazon.com/exec/obidos/ISBN=0879755121/roberttoddcarrolA/"> Gardner, Martin (1989). <i>How Not To Test a Psychic: Ten Years of Remarkable Experiments With Renowned Clairvoyant Pavel Stepanek</i>. Prometheus Books.</a></font></p> <p style="text-align: left"><font face="Arial" size="3"><a href="http://www.amazon.com/exec/obidos/ISBN=0879755040/roberttoddcarrolA/">Hyman, Ray (1989). <i>The Elusive Quarry: a Scientific Appraisal of Psychical Research</i>.  Prometheus Books.</a> </font> <p align="left"> <b><font face="Arial" size="3">website</font></b><p> <font face="Arial" size="3"> <a href="http://www.survivalafterdeath.org/articles/koestler/esp.htm">The ABC of ESP</a> by Arthur Koestler</font></p> <font face="Arial" size="3"> <a href="http://www.survivalafterdeath.org/articles/koestler/country.htm"> The Country of the Blind</a> by Arthur Koestler</font><p> <font face="Arial" size="3"> <a href="http://www.survivalafterdeath.org/articles/johnson/telepathy.htm"> Telepathy and Clairvoyance</a> by Raynor C. Johnson</font></p> <p></webContent> Last updated 29-Oct-2013 </p> </div> </div> <div class="right"> <div class="right_it"> <div class="search"> <form method="get" action="http://www.google.com/custom" target="_top"> <input type="hidden" name="domains" value="skepdic.com" /> <input type="text" name="q" maxlength="255" value="" size="20" /> <input type="submit" name="sa" value="Search" /> <br /> <div class="search_2"> <input type="radio" name="sitesearch" value="" /> Web     <input type="radio" name="sitesearch" value="skepdic.com" checked="checked" /> Skepdic.com <br /> <img src="_images/logo_google.gif" alt="Google" width="48" height="19" /> </div> <input type="hidden" name="client" value="pub-3542920166946725" /> <input type="hidden" name="forid" value="1" /> <input type="hidden" name="ie" value="ISO-8859-1" /> <input type="hidden" name="oe" value="ISO-8859-1" /> <input type="hidden" name="cof" value="GALT:#008000;GL:1;DIV:#336699;VLC:663399;AH:center;BGC:FFFFFF;LBGC:336699;ALC:0000FF;LC:0000FF;T:000000;GFNT:0000FF;GIMP:0000FF;FORID:1;" /> <input type="hidden" name="hl" value="en" /> </form> </div> <div class="center"> <p align="right"><a href="http://skepdic.com/authorpage.html"><strong>Books by R. 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decline effect - The Skeptic's Dictionary - Skepdic.com