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Experimental Studies of the Differential Effect in Life Setting  (Paperback) 
Author(s): P. Sailaja and K. Ramakrishna Rao
78 pp. (1973) ISBN 0-912328-20-7 
Price: $10.00
PE Club Discount Price: $9.00

The authors attempt to answer the question “Why is the differential effect so frequently observed?” (That is why do individuals in psi experiments tend to “hit” on one condition and “miss” on the other, if two conditions are contrasted.) The authors propose that if the differential response is a built-in defense mechanism, then normally every successful psi-operation would be accompanied by a missing response and psi would become unreliable and therefore fall into disuse. This hypothesis assumes that there is something like a psi homeostasis effect, a necessity to balance between hitting and missing. The differential response in laboratory experiments, then, would express itself as both missing and hitting responses that maintain the homeostasis.

An alternate hypothesis also exists; that the differential response is simply a conjunction of hitting and missing prompted by two sets of conditions that favor positive and negative scoring. If this hypothesis is correct, the differential effect would occur only when the subject is working under two contrasting conditions and thus would say nothing specific about the nature of psi, reflecting rather, the structure of the experiments.

The authors conducted experiments, with target materials they hoped would be more analogous to life experiences of psi, and which, they hoped, would, by design, allow them to test which of these two models better explained the data. Unfortunately, the results obtained did not allow them to say conclusively which of the two hypotheses was the better one.




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