A new faces scale in pain measurement: a test of bias from current mood, trait affectivity, and scale range.
OBJECTIVE
Faces pain rating scales used among children have been criticized to confound affective states with pain when smiling faces are included. This experimental study is an attempt to examine the possible confounding of affective states with pain when smiling faces are used as part of a faces scale. The meaning of the faces was tested to depend on current mood, current pain, trait affectivity, and inclusion versus exclusion of smiling faces.


METHODS
Sixty-four participants made 6,720 two-categorical pain judgments on faces with different mouth curvature.


RESULTS
In multilevel regression analysis, current level of pain and negative trait affectivity biased faces' meaning only when the smiling faces were excluded from the scale.


CONCLUSIONS
In adults, the new full range faces pain scale including a midpoint neutral face and smiling faces was more robust than the restricted scale. The faces scale that was tested in this study is not applicable for patient measurement but it is an interesting tool for psychological research.
University of Bern, Department of Psychology, Switzerland. achim.elfering@psy.unibe.ch
Achim
A
Elfering
Simone
S
Grebner
D000328:Adult; D000368:Aged; D001008:Anxiety Disorders; D005149:Facial Expression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D000075384:Neuroticism; D009730:Nursing Assessment; D010147:Pain Measurement / Q000379:methods* / Q000523:psychology*