Cultural Differences in Pain Expression Nancy Alvarado California State Polytechnic University, Pomona

Coauthors  Ralph B. Jester University of California, Irvine  Christine R. Harris University of California, San Diego  Julia F. Whitaker University of Utah, Health Sciences Center  Funded by NIH MBRS/SCORE Grant S06 GM053933,

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.

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?

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.

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.

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

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 1+4, 4+7, 1+2, and 6+12 was also coded.

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.

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 (group=45.3, sex=71.3), improved with segregation by acculturation

Expected Pain AUs  The AUs found in previous pain studies were found here, equally in all four groups.  Distress expressions (AU 1+4) were more frequent among African American women.  Hispanic men showed more frowns (AU 4+7) and fewer smiles (AU 6+12) than Hispanic women.

Larger Sex Differences Were Found Among Hispanics for Smiling

Frowning Showed Similar Results

Distress Expressions also Varied

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.

Duchenne vs Non-Duchenne Smiles

Smile Types by Sex and Group

Conclusions  Cultural differences occurred in more general AUs (frowns, smiles, AU 1+4) 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.