Provided by Cognitive Sciences ePrint Archive
LATERALITY, 2001, б (3), 225-231
Functional asymmetry in the human face: Perception
of health in the left and right sides of the face
V.A. Reis and D.W. Zaidel
University’ of California, USA
The expression of health on the human face, like beauty or emotions, is an
important biological display. Previous findings of left-right functional asymmetry
in facial attractiveness and the linkage of attractiveness and health in evolutionary-
biology notions have prompted the present study. A total of 38 pairs Ofleft-Ieft and
right-right facial composites were viewed by 24 subjects on a computer screen,
and the task was to decide which member of the pair looked healthier or there was
no difference. The results revealed a significant interaction between face side and
sex of face. Right-right composites of women’s faces were judged significantly
healthier than left-left, whereas in men's faces, no significant left-right difference
emerged. As these results parallel previous findings of attractiveness in the
identical set of faces, we propose that evolutionary biology notions linking the
appearance of health and of attractiveness apply to the human face as well.
INTRODUCTION
The human face serves a range of biological functions which facilitate
communication between the observer and the observed. Not only are the
individual's identity and emotional expressions perceived and processed in the
observer’s brain, so is information about beauty and health. Previously, we
found a sex-related left-right asymmetry in facial attractiveness, with higher
ratings for right-right composites of women's faces than for left-left composites
but with no significant difference between right-right and left-left in men's
faces (Chen, German. & Zaidel. 1997; Zaidcl. Chen. & German. 1995). In
addition, we found an asymmetry in smiling saliency, with the smile judged
more pronounced in the left-left composite, in both sexes (Zaidel et al., 1995).
In biological and evolutionary theory, attractiveness and health are nearly
synonymous. Considering this and our previous finding of facial functional
asymmetry, we now wanted to determine whether or not the perception of health
is also asymmetrically organised in the face.
Address correspondence to: Dr Dahlia W. Zaidel. Dept, of Psychology, University of California.
Los Angeles. Box 951563 Los Angeles, CA 90095-1563. USA. Email: dahliaz@ucla edu