I've talked a bit about expectations. So, what happens when you try to manipulate expectations within the context of a psi experiment?
Pitman, J. A., The effect of manipulating expectations both before and during a test of ESP. Journal of Parapsychology, Spring 2004. (here)
This paper begins with a very general overview of expectations as they may relate to psi performance. The thing to note here is that 'expectations' are never precisely defined in terms of their components - mental imagery, representations of time, degree and nature of emotional content, changes in expectations as testing progresses, etc. It's assumed that everyone has the same definition of 'expectation' and that 'expectation' means the same thing in every study that is discussed. This means that 'expectations' are not being manipulated with a level of precision that will easily lead to future testable hypotheses.
Pitman presents two experiments which have basically the same design. The second experiment corrects subtle flaws in 'random' presentation and increases the number of subjects, as compared to the first experiment. Pitman manipulates expectation in two ways - by artificially inflating (or not) the degree of positive feedback the subjects are given about their ESP 'guessing' trials, and by giving them a placebo (or not) that is presented as a substance that enhances ESP. We are largely left to speculate as to what the actual effects of these manipulations might be upon expectations for success. It is assumed that subjects will have greater expectations of success when given the 'ESP-enhancing' placebo and when given artificially inflated positive ('false') feedback about their success. But again, the nature of these expectations is never elaborated upon.
In both experiments, Pitman found a significant interaction between the placebo manipulation and the feedback manipulation.
"When participants were given false feedback, there was a placebo effect... However, when participants were given true feedback, there was no placebo effect... Further, when participants were given a placebo, there was an effect of feedback... However, when participants were not given a placebo, there was no effect of feedback." (Results - Experiment 1; confirmed in Experiment 2)
In other words, unless your expectations were (theoretically) artificially inflated in two different ways at the same time, your performance was no different from that of everyone else in the study.
Pitman acknowledges that this is a problematic result. "Without a significant effect for the placebo manipulation in increasing predicted ESP performance, explanation of the additive performance for placebo and falsely positive feedback is challenging." (Her next sentence brings to light an additional problem with this study - "One must conclude that all participants started the ESP test with similar levels of expectancy...". Yeah, that's a problem for many reasons.)
I think it's a fascinating result. Due to the imprecise definition of 'expectation' and the vague manipulations thereof in this experiment (and pretty much all similar studies), any conclusion that I would attempt to draw from the data would be highly speculative. But go ahead and twist my arm... okay, okay, I'll speculate.
The first thing that comes to my mind is that, with two sources for expectations of success, participants may have been able to shift their attention between two significantly different frameworks. For example, when I am told that I got the answer wrong, I may be able to shift my attention and draw upon my expectations about the placebo, and it may take several trials worth of false positive feedback for my expectations to again center on the outcome/feedback. With only a single source of expectation for success, my expectations will probably begin to be altered in the subtle ways that lead to a pull towards the opposite outcome. (I tried some of this out on slot machines in Las Vegas. I could only be successful for so long before my expectations, by virtue of simple exposure to success, had qualitatively changed to the point where, without a much greater effort, I was pulled towards an unsuccessful outcome.)
Before I digress too far, I should point out that other studies have shown effects of a single manipulation of expectation. Pitman points out that J.B. Rhine was successful in getting a single main effect of placebo upon ESP performance. Other studies have also attempted to manipulate the participants' beliefs about ESP in an (sometimes successful) attempt to improve their performance. So further speculation about the results of this study would probably only be productive if I were able to include the other studies for comparison purposes.
Subjects in this study were also asked to predict their ESP scores prior to testing, but it appears that these predictions were collected after the placebo manipulation. Of course it's possible that asking the subjects to quantify expectations had an effect in and of itself, but there are not enough details about when and how this data was collected to allow for useful speculation.
The author attempts to make further inferences about 'expectation' as it relates to the subjects' scores on the 'sheep-goat' scale of psi belief, but these are not the expectations we are interested in, and therefore they will not be discussed here. The expectations that occur at the time of testing are, IMHO, the ones most likely to influence the outcome. Their nature most closely matches the representations of the outcome and success or failure, therefore these are the expectations that I think need to be more carefully teased apart and manipulated in future testing.
Kudos to Pitman for a simple, elegant experimental design, and a fascinating finding!
