Dr. Johnson's Laboratory Experiment
Problem: The laboratory experiments were designed to isolate the effect of providing sensory information to decrease distress from a threatening event (heath care procedure), in a controlled environment before attempting to measure the reduction of distress in a clinical setting.
Experimental Design and Treatments
The threatening event to which subjects were exposed in the laboratory was ischemic pain of the arm. The pain was induced by inflating a blood pressure cuff on the arm to 250 mm. Hg, and having the subject exercise the cuffed arm by squeezing a hand dynamometer. In the first experiment, 20 male university student volunteers were randomly assigned to hear two messages prior to the experiment. One group heard a description of typical sensations subjects usually experienced – pressure, tingling, aching, numbness, and the sight of paleness or blueness of the fingernails. The other group heard a description of the procedure used to produce the ischemic pain.
Measurement
During the time the arm was ischemic, each subject was asked to rate the intensity of the physical sensation they experienced and how much distress they felt from the sensation. Perhaps from the sensory information subjects anticipated that the pain would be either less intense or less distressing than the others. To rule out this explanation, all the subjects – after they had received their respective information message, but before the cuff was inflated – reported how intense and how distressing they thought the sensations would be. Reports from the two groups did not differ significantly, thus controlling for possible "power of suggestion" impact of sensory information.
The results: The intensity ratings did not differ significantly for the two groups; but, as hypothesized, the subjects who received a description of the typical sensations reported lower distress than the subjects who received a description of the procedure.
Questions Researchers Ask to Critique Their Own Studies:
- What if the sensation information led those subjects to believe that the event was less dangerous…
Subjects in both groups reported that they perceived the experiment to be low in danger whereas surgery and medical examinations will be anxiety or worry provoking.
- The possibility that fear caused certain subjects to develop strategies for coping with the event might explain the results obtained. All subjects reported their moods before.
Johnson's Theory: "Discrepancy between expected and experienced physical sensations (what is felt seen, heard, tasted, and smelled) during a threatening experience will result in distress."
Now read about J. Johnson's first clinical research with Sensation Theory.
