This work builds upon Savva and French (2001), undertaken to test the success of applying evolutionary theory to parapsychological research. Although two unsuccessful presentiment experiments did not support the hypothesis, it was felt that adapting another previously successful paradigm might well provide support for the hypothesis that psi is a 'pre-sense'.
It was Thouless and Wiesner (1946) who first proposed a pre-sense theory of psi. It is very easy to imagine the adaptive potential of a precognitive ability, where an organism that could make use of information about a future state would have a survival advantage over an organism that could not. If we suggest that the psi-signal, if it exists at all, only provides correct information part of the time (and research would suggest that this is only very slightly above chance) then it is easy to see why the conventional senses evolved over the initial psi-sense. Even a primitive eye would allow inference about future conditions (for example, locating a predator) to be more accurate than the psi-signal.
Psi-timing research has been conducted by a number of researchers (Lowry, 1981; Schmeidler & Borchardt, 1981; Radin & Bosworth, 1985; May, Radin, Hubbard, Humphrey, & Utts, 1985; Radin & May, 1986 and Braud & Shafer, 1989) and the overall conclusions from the area are positive. Psi-timing experiments generally consist of a behavioural component based on the timing of a key-press, which affects a complex process resulting in a hit or miss.
The current research is an adaptation of the Braud and Shafer (1989) methodology. Braud and Shafer's participants pressed a keyboard button which recorded the current time and used the number to seed a random number generator, which in turn produced a random number between one and six. The participant pressed a keyboard button a second time and produced another random number through the same process. The two numbers were then compared and the trial scored as a hit (if the two numbers matched) or a miss (if they were different).
The current study changed the Braud and Shafer methodology by replacing the second key-press with a simulated key-press (therefore making it a test of precognition). Also different was that a hit resulted in the presentation of a neutral picture, and a miss resulted in the presentation of a spider picture. It was hypothesised that those rating themselves as spider fearful after the experiment (using a fear of spiders questionnaire) would score more hits than the non-spider-fearful, using precognitive information about the threatening stimulus to illicit a behavioural avoidance response by timing the keyboard press correctly.
Fifty participants contributed 1800 trials, consisting of 36 trials per participant. The overall hit rate was 16.1% and did not differ significantly from the mean chance expectation (MCE) of 16.7% (t (49) = -.773; p >.05). The difference in scoring between the spider-fearful and the non-spider- fearful was tested through an independent t-test and was not significant, t (48) = .896; p>.05. The hit rate for the spider fearful group was 15.5% and did not differ significantly from chance (t (25) = -1.088; p>.05) and for the non-spider-fearful group the hit rate was 16.8% which also did not differ significantly from chance (t (23) = .123; p>.05). One thousand control trials were conducted before and after the experimental study (two thousand in total where both key-presses were simulated) and resulted in a combined hit rate of 16.2% which a binomial test found was not significantly different from MCE (p>.05). Binomial tests on the control runs, before and after, were also non-significant and showed that, individually, they did not deviate significantly from MCE.
The conclusions drawn from the results are that despite previous significant results, no evidence for a psi-mediated timing response can be found in the current study. No further psi-timing experiments are planned. However further research is being conducted to test the hypothesis that psi is a pre-sense.