I have had many failures replicating the Hayes et al (1999) pain tolerance study. Over the years I have answered criticisms of reviewers in my attempt to have negative results published. As a result I have begun to video record my interventions for analysis by anyone who is interested. I now take a whole host of adherence measures and subjective reports. I have even examined acceptance over the long run in the lab. But still no effects on pain tolerance for ACT-derived protocols over placebos or alternative treatments (relaxation and education or supression). often no effects for acceptance-based interventions at all.
I would love to offer practical suggestions but as you will see from my list I have five years of research here - so I am trying! I am all out of suggestions. I also think that if the procedure has to be contrived so much that effects are only measureable on such measures as the AAQ (which measures what ACT teaches the client - ipso facto we will see changes in scores) or if the research requires a clincian as experimenter or highly elaborate and exhaustive subjective ratings and statistical techniques - its not a very powerful effect! So I hesitate to contrive procedures much mroe complex than what I have got. (The details of which I hope we will discuss as a community in reposne to these postings).
So here is my list of failures....
Failure 1
Examining the effectiveness of acceptance and control – based interventions on pain tolerance.
This study compared the effectiveness of an acceptance-based and control-based intervention on pain tolerance using a cold pressor task, and is a part-replication and extension of the Hayes et al., (1999) study. Twenty college students were exposed to the cold pressor task before, immediately after, and 20 minutes subsequent, to an 8 minute acceptance-based or control-based therapeutic intervention, including the use of physical and abstract metaphors. Half of the participants were also assigned to a high demand characteristic condition in which the experimenter purposely placed subtle social pressure on them to please the experimenter. The results showed that the most significant factor influencing performance on the cold pressor task was the effect of placing social pressure on participants, with no significant overall effect for Acceptance or Control interventions.
Failure 2
A Systematic Analysis of the Role of Demand Characteristics in an Acceptance Based Approach to Pain Tolerance.
This study compared the role of demand characteristics in an acceptance-based approach to pain tolerance and both the long and short-term effects of the acceptance-based versus the no therapy interventions. Forty participants were exposed to a cold pressor task before and immediately after a short intervention. Twenty-eight participants also completed a follow up task three months later. Half of the participants receiving each intervention were also subject to high levels of demand characteristics. In this high demand condition the experimenter placed subtle social pressure on the participants to perform well on the second cold pressor task. The findings showed that participants in the acceptance condition improved more, but not significantly more, than those in the no therapy condition. Participants in the high demand condition performed significantly better than those in the low demand condition. Interaction effects for therapy x demand were also found between the experimental groups.
Failure 3
Comparing the Effectiveness of Acceptance and Control Strategies for Pain Tolerance with a Sub-clinical Population
This study used an experienced psycho synthesis therapist and cognitive behavior therapy postgraduate as an experimenter who had studied ACT and taken the full ACT weekend workshop. This study was a part replication and extension of the Hayes, Bissett, Korn, Zettle, Rosenfarb, Cooper and Grunt (1999) study. Four sub-clinical volunteers (two smokers, one drinker and a tantrum thrower) were exposed to a cold pressor task before, immediately after, and several weeks subsequent to a 90 minute acceptance-based therapeutic intervention. Baseline rates of idiosyncratic problem behaviours were also recorded prior to, and for several weeks subsequent to, the initial intervention. The acceptance-based intervention was then administered weekly for up to 25 weeks by a qualified cognitive-behavior therapist to asses its impact on pain tolerance and target problem behaviour rates in the longer term. The acceptance-based intervention showed weak effects on pain tolerance during all phases of the study and no discernible effects on problem behaviors were observed (in fact they got worse!).
Failure 4
Examining the effectiveness of an acceptance and relaxation-based intervention on pain tolerance
This study attempted to compare the effectiveness of an acceptance and relaxation-based intervention on pain tolerance to a cold pressor task and is a partial replication and extension of the Hayes et al., (1999) study. Forty college students were exposed to a cold pressor task before and immediately after an eight minute acceptance-based and relaxation-based intervention. Half of the participants in each group were also assigned to a high demand condition, in which subtle social pressure was placed on the participants to please the experimenter and do well in the task. The results confirmed that the most significant factor influencing performance on the cold pressor task was placing social pressure on participants to do well. There was no significant overall effect for either the acceptance or relaxation-based intervention although both produced mild improvements in pain tolerance.
Failure 5
The effectiveness of an acceptance and control-based interventions on pain tolerance at two different levels of pain in a cold pressor task.
This study employed the now standard procedure of using 40 subjects – half get an acceptance protocol and half get a control-based protocol following a baseline cold pressor task and before a post-intervention cold pressor task. Half of each group get cold pressors at 0 degrees centigrade – the remainder at 3 degrees. Acceptance has a mild effect – not significant – and does not interact with temperature on an ANOVA. This dashed our hopes that maybe acceptance was more useful for intense pain over mild pain – no lab data to support that idea yet.
Failure 6
So maybe it’s the subject’s fault! Assessing the effectiveness of acceptance and control based interventions with anxious and non-anxious subjects.
We recruited 20 high and 20 low trait anxiety subjects by screening with the STAI. We defined high and low as one SD above and below the mean score as outlined in the standardized distribution scores. Half of each got a control intervention and half got acceptance. Anxious subjects did not benefit more than non anxious from either the acceptance or the control intervention on a cold pressor task. Overall no effect for acceptance. No effects were found on any subjective reports.