Other Methodology Articles [Letter on Methodology for Presentiment Studies]

The recent article by Dalkvist, Mossbridge, and Westerlund (2014) on expectation bias in presentiment studies discussed an important methodological problem, but included a controversial recommendation and two key comments that are not correct. Presentiment studies investigate whether physiological measures indicate that a person can unconsciously and precognitively anticipate a random stimulus. The most common strategy for analyzing the data has been to compare the average values of the observed physiological measures preceding the different types of random stimuli. This analysis strategy reverses the traditional analysis for a typical ESP experiment, such as a participant pushing a button to predict which light will be randomly selected. The traditional analysis uses the button press or response to predict the random light or target. As described by Burdick and Kelly (1977, p. 93), The response array is taken as fixed (in fact, it is immaterial where it came from, and this underlies the great generality of the method). The statistical problem is to evaluate the probability of obtaining a number of hits as large or larger than that observed, given the response array