230 RElS AND ZAIDEL
neuroanatomical underpinning. Unfortunately, there are no published reports
that we could find that investigated this underpinning. We propose that the
asymmetrical display of perceived facial health is not coincidental, but rather
may be related to functional asymmetry of the brain. This makes sense from an
evolutionary standpoint: if attractiveness is correlated with health (be it honestly
or otherwise), then those who display attractiveness will have a selective
advantage. This will only work well evolutionarily in the long run, however, if
those perceiving these cues have evolved sufficient strategies for reliable
detection of honestly correlated indicators of health.
In both non-human species and humans, accurate perception of health can be
fooled by various factors; parasites, for instance, can mimic normal features
while their very presence indicates disease (Cronin, 1991). However, even if we
assume that in non-humans attractiveness is essentially synonymous with health,
in humans there may be a myriad of non-biological factors that interfere with the
perception ofhealth in people’s faces. We do not yet know the breakdown of all
those possible factors. Cultural, emotional, or psychological factors could
conceivably interfere with accurate estimates. Laboratory experiments involving
the appearance of health thus far have relied on conscious (behavioural)
decisions. By comparison, more insight may be gained if implicit physiological
responses were recorded (say, Galvanic Skin Response). It may be that complex
factors interfere with health assessments when subjects are making conscious
decisions. What does seem to be clear for now is that the appearance of health in
the face is asymmetrically organised and the asymmetry is sex-related. The
reasons for this asymmetry in women’s faces is rooted in the co-evolution of
face and brain in humans, as discussed previously (Zaidel et al., 1995).
Manuscript received 30 May 2000
Revised manuscript received 4 November 2000
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