Cultural Differences in Pain Expression

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Cultural Differences in Pain Expression

• Nancy Alvarado
• California State Polytechnic University, Pomona

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Coauthors

• Ralph B. JesterUniversity of California, Irvine
• Christine R. HarrisUniversity of California, San
  Diego
• Julia F. WhitakerUniversity of Utah, Health
  Sciences Center
• Funded by NIH MBRS/SCORE Grant S06 GM053933,
  2006-2009

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Undertreatment for Pain

• Chart review studies suggest routine under
  medication for pain of members of ethnic and
  racial minority groups in the USA.
• This occurs regardless of the type of injury or
  medical condition, for both chronic and acute
  pain.

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Why does this happen?

• Are members of such groups different in their
• Self report
• Expressive behavior (including facial expression)
• Physical reactivity (heart rate, blood pressure)
• Pain tolerance
• Or is the difference with the observers?

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Our Study

• Multiple measures
• FACS coding of videotaped behavior
• Pain attitudes questionnaire assessing cultural
  beliefs about pain and its expression
• Physiological measures
• Self-report using multiple scales
• Acculturation questionnaires
• Only FACS results are presented today.

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Pain Evoked by Cold Pressor

• Subjects immersed left hand up to wrist in
  circulating cold water
• Held at 3 degrees Centigrade (- .2)
• Hand removed when subject could no longer
  tolerate the cold or reached the time limit (3
  min.)
• The colder water temperature was used to minimize
  sex differences.

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Subjects

• Four self-identified groups were tested
• Asian American
• African American
• Hispanic
• European American (dominant culture)
• 50 subjects per group, Cal Poly students
• 25 male, 25 female

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Coding Method

• FACS all AUs except head position and eye
  movements (Ekman Friesen, 1978).
• Frequency of occurrence, presence or absence of
  each AU by subject, duration not coded.
• Events as described by Ekman Rosenberg
  (1997). What the Face Reveals.
• Co-occurrence of AU 14, 47, 12, and 612 was
  also coded.

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Predictions

• We expected to find expressive differences
  related to subculture and sex.
• We expected
• Asian Americans and Hispanics to be more stoic
  (less expressive)
• African Americans to be more expressive.
• Men to be less expressive than women.

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Results

• No strong sex differences in expressivity were
  observed, F(1,173)2.56, p.110.
• No differences in events across cultural groups
  were observed, F(3,173)0.66, p.580.
• Discriminant analysis showed better than chance
  prediction (group45.3, sex71.3), improved with
  segregation by acculturation

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Expected Pain AUs

• The AUs found in previous pain studies were found
  here, equally in all four groups.
• Distress expressions (AU 14) were more frequent
  among African American women.
• Hispanic men showed more frowns (AU 47) and
  fewer smiles (AU 612) than Hispanic women.

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Larger Sex Differences Were Found Among Hispanics
for Smiling
13
Frowning Showed Similar Results
14
Distress Expressions also Varied
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Smiling

• Both Duchenne and non-Duchenne smiles occurred
  during the pain experience with no experimenter
  present.
• Smiling often occurred just before a subject
  signaled to remove the hand from the water.

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Duchenne vs Non-Duchenne Smiles
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Smile Types by Sex and Group
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Conclusions

• Cultural differences occurred in more general AUs
  (frowns, smiles, AU 14) not in pain AUs
  (grimaces, lip presses, AU 9 or 10).
• Culture may influence social interaction more
  than expressivity directly related to pain.
• Because results were stronger for less
  acculturated subjects, members of the wider
  community may show larger differences.
• Our study lacked power more subjects needed.