An experimental investigation of the construct validity of the McGill Pain Questionnaire.

In order to circumvent problems with self-report measures of pain we conducted an experimental analysis of MPQ pain descriptors using a Stroop task. In this task subjects are asked to name the colours in which stimulus words are written. Previous research has demonstrated that words with emotional significance interfere (indexed by increased latencies to respond) with a person's ability to name the colour. We predicted that: (1) chronic pain patients, compared with normal controls, would show more interference to words drawn from the MPQ, and (2) affective/evaluative descriptors would produce greater interference than sensory descriptors. There was support for the first hypothesis but not the second. Possible reasons for these findings are discussed.