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Female adornment in humans and animals
Francesco Nardelli 2015
Discussion paper
Abstract
Research on animals behavior leads sometime to evaluate Homo sapiens’ too. Although humans are
not my field of knowledge, during animal observation some questions arise by themselves. This es-
say is mostly a report of interpretations by specialists on the intriguing reasons behind adornments,
particularly in female individuals and it reviews the association between female ornaments in hu-
mans and animals, with some conclusions from a viewpoint of an animals ecologist.
Introduction
1. The evolution and signaling content of female orna-
mentation has remained an enduring challenge to ecol-
ogists.
2. Females usually invest significant amounts of their re-
sources in offspring. The ingenuity allocated to elabo-
rate adornment reduce energy available for other pur-
poses.
I interviewed 43 women to ask this question: When we observe Homo sapiens, we found that males
of so called 'primitive people' adorn themselves with colored make-ups, feathers, etc., alike in the
large majority of animal species. When we examine 'advanced people', virtually only females use
makeup.
The answers, synthesized, were: 'to look nicer' 33 (77%), 'to feel better or self confident' 9 (21%), 1
explanation (0.5%) was (reported in full): "In my opinion, the reason why women use makeup and
believe that it makes them 'more appealing' to both men and their personal tastes, is not a conscious
reason at all. Of course it appeals to us visually, but like you said, "why?" Well, I believe it's be-
cause of our hard-wiring when we were just starting out as a species and had to recognize the
healthiest individuals that possessed the best genes. If you notice, women go out of their way to
make their cheeks appear more flushed using blush, their eyes more defined using eyeliner, and
their lips brighter with lipstick. Well, this might
be done because subconsciously we're trying to
highlight that we are in fact 'healthy specimens' by
showing off good genes which is reflected in our
outward beauty. Women, by making their eyes
Spangled Cotinga (Cotinga cayana) - Trinidad Carnival
more defined, for example, would tell the man that they have good, working eyes and that they,
therefore, would be good mates. Same thing goes for creating red, flushing cheeks - this shows that
they are healthy and able to bare children. So, basically, the reason why women put on makeup is
much the same reason that birds try to attract mates with their beautiful feathers, to make them-
selves more appealing to the opposite sex and to nonverbally display their ability to reproduce suc-
cessfully".
Citations It has been hypothesized that female ornaments signal the genetic quality of indi-
viduals, or direct benefits such as parental care or other non-genetic maternal re-
sources. Thus, a male choosing to fertilize
the eggs from an elaborately ornamented
female might sire fewer or poorer quality
offspring than his rivals choosing to mate
with the drabber female, which has allo-
cated relatively larger proportion of her re-
sources into the eggs.
Spangled Cotinga breast feathers, Nail polish (R)
Two main hypotheses have been proposed to explain the evolution of female ornaments. The 'direct
selection hypothesis' predicts that female ornaments are under direct sexual selection by males or
selection via reproductive competition among females (Amundsen 2000). The alternative hypothe-
sis, the 'genetic correlation hypothesis', in turn suggests that female ornamentation is a genetically
correlated response to selection for male ornamentation. This idea originally gained some support
already from Darwin (1871).
Feathers ornaments - Blue-naped Chlorophonia (Chlorophonia cyanea)
Table 1. Overview of number of studies with negative, non-existing and positive association be-
tween ornament (carotenoids based, and other ornaments than carotenoids-based pooled) and
offspring quality
Taxonomic group Negative None Positive
Birds
5
10
18
Fishes
4
3
2
Lizards
0
1
0
Total
9
14
20
Carotenoids are pigments synthesized only by plants, algae, some bacteria and some fungi, and thus
animals must obtain them through their diets (Goodwin 1984, Moran & Jarvik 2010).
The offspring in different animals face different selective pressures determined by the environment.
At the individual level trade-offs are expected, but in a good, nutrient-rich environment such trade-
offs may not necessarily become apparent (in contrast to low-quality environments).
For example, the great tit chicks of brightly ornamented mothers had lower fledging success
compared with chicks of drabber mothers only during environmental unfavorable conditions
(Mand, Tilgar & Møller 2005).
In general, males are expected to base their mate choice principally on phenotypic indicators that
are associated with female fecundity either directly, e.g. body size, (Sargent, Gross & van den
Berghe 1986; Kraak & Bakker 1998; Bonduriansky 2001; Byrne & Rice 2006) or indirectly e.g. or-
naments (Amundsen & Forsgren 2001; Massironi, Rasotto & Mazzoldi 2005). Even in species
where female ornaments are negatively associated with offspring fitness, elaborately ornamented
females may potentially have higher fitness than non-ornamented females. This may be very un-
likely, but would occur
if higher sexual attrac-
tiveness of daughters
of the bright mother
more than compen-
sates her reduced
number of surviving
offspring.
However, in species
where ornament off-
spring trade-offs have
been demonstrated so
far, males preferring
ornamented relative to
drab females have
been shown in the
large majority of
Doutzen Kroes without and with makeup
animal species.
The most likely and especially interesting explanation is natural-
ly that there is simply no association between the ornament and
offspring quality.
These results have a number of implications. As predicted,
makeup had significant positive effects on ratings of female fa-
cial attractiveness at brief and longer inspection times. Ratings
of competence increased significantly with makeup look tested
on first glance and longer inspection. Effects were weaker and
more variable for ratings of likability and trustworthiness, alt-
hough generally positive.
Social psychologists have suggested that social warmth and so-
cial competence represent two universal dimensions of social
perception by which we
evaluate individuals and
groups (Etcoff 2011),
with warmth capturing "Glamorous makeup" female
traits related to social cooperation, and power/competence
capturing cues relevant to advantage in social competition,
such as status and dominance. Here it is shown a robust and
positive effect of increased beauty on social pow-
er/competence and a generally positive but more nuanced
and variable effect on social warmth.
Past studies have shown that attractive people are expected
to do better on the job, in school, and in life – and are treat-
ed that way – by being agreed with, deferred to, helped, and
Mandrill (Mandrillus sphinx), male
granted larger personal space. In a recent experimental study using a task for which physical attrac-
tiveness did not improve productivity, researchers demonstrated conclusively that employers expect
physically attractive workers to perform better at their jobs and be more competent. But, as sociolo-
gists Webster and Driskell noted when first proposing the idea of beauty as status, there are im-
portant differences between attractiveness and other status characteristics such as race or sex: beau-
ty is a malleable characteristic (Webster et al. 1983).
They predicted that, given the powerful effect of status, 'attractiveness' will assume increasing sig-
nificance as other characteristics such as race and sex fall into disuse.
Latest research (Leeuwen Van et al.
(2014) found that just like humans,
chimpanzees, too, like to spruce up
their style. A recent study published
in the journal Animal Cognition
found that chimpanzees also like to
keep up with the latest fashion trends
going around.
After many fellow chimps saw female
Julie place a piece of grass in her hair
- for no apparent reason - many of the
animals jumped in on the fashion
trend.
"This reflects chimpanzees' proclivity
to actively investigate and learn from
group members' behaviors in order to Female Chimpanzee "Julie" with grass straw
obtain biologically relevant information," said lead study author Edwin van Leeuwen, of the Max
Planck Institute for Psycholinguistics in The Netherlands.
Over 700 hours of video footage documented the trend. Prior to that, van Leeuwen had first noticed
that Julie would repeatedly put a stiff, straw-like blade of grass in one or both of her ears back in
2010. Even while grooming, Julie left the objects in place. Over time, other chimps starting mim-
icking a similar look to Julies'.
In order to find out why this was happening, van Leeuwen conducted a year-long study that exam-
ined 94 chimpanzees living in four different social groups in a sanctuary. The findings revealed that
one of the four groups regularly performed Julie's grass trick, which convinced eight of the 12
chimps in the group to also go for the same look. Even after Julie died, the trend is still going
strong, according to researchers.
"The fact that these behaviors can be arbitrary and outlast the originator speaks to the cultural po-
tential of chimpanzees," van Leeuwen concluded.
Conclusions I would suggest that attractiveness has
implications greater than before, and
the trend will continue in this way as
long as attractiveness remains an often
unconscious proxy for status and abil-
ity.
The beauty halo effect has been called
the 'what is beautiful is good' effect. (I
would add 'what is rare is beautiful' in
case of animals seen through human
eyes). In my opinion, makeup increas-
es inferences of warmth and coopera-
tion (likability and trustworthiness)
when faces are presented very briefly,
but it does not achieve that result on
South American Indios, males
longer inspection. In general, there is less agreement about whether beauty invariably signals social
cooperation, with some studies suggesting that there is a ”dark side” to beauty characterized by van-
ity, immodesty, or greater likelihood to cheat on a partner (Mobius et al. 2006).
My findings suggest that it may be
fruitful to disentangle the effects of
beauty from beauty enhancement.
It may be that natural beauty or natural
appearing beauty leads to positive in-
ferences of social cooperation, where
more obvious beauty enhancement
may lead to neutral or even negative
inferences.
Finally, results provide additional evi-
dence that judgments of facial trust-
worthiness and facial attractiveness are
(at least partially) separable; the high-
est contrast makeup (glamorous)
South American Indios, females.
increases attractiveness significantly while at the same time decreasing judgments of trustworthi-
ness.
One potential source of the cosmetics effect on face perception
is increasing luminance contrast between the features (eyes
and lips) and the surrounding skin. Cosmetics increase lumi-
nance contrast by significantly darkening the eyes and lips.
Skin is neither significantly lightened nor darkened but by sun
tanning. However, luminance contrast effects for our natural
look compared to a face without makeup is only marginally
significant.
It is likely that cosmetics induce image changes other than
changes in luminance contrast contribute to our effects. These
include possible changes in the smoothness of skin tone, in the
redness of skin color or lip color, and in shading that accentu-
ates the cheekbones. Previous research has shown that makeup
can improve skin appearance, evenness and texture to appear
healthier, fertile, and youthful (Fink et al. 2006), and that skin
and lip color can contribute significantly to perception of sex
typicality and attractiveness (Stephen et al. 2009), with lip
redness enhancing femininity and attractiveness of female
Caucasian faces (Stephen et al. 2011). New Guinea indigenous, male
In sum, faces with cosmetics engage both fast, reflexive processes, and more deliberative conscious
processes. The fast, automatic effects are uniformly strong and positive for all outcomes.
In situations where a perceiver is under a high cognitive load or under time pressure, he or she is
more likely to rely on such automatic judgments for decision-making: facial images appear on bal-
lots, job applications, websites and dating sites.
These results underscore the malleability of judgments derived from facial images of a single indi-
vidual, judgments that can be highly consequential. When inferring trustworthiness, likeability, or
competence from an image we are influenced significantly not only by the attractiveness of the in-
herited phenotype but by the effects of the 'extended phenotype,' in this case, makeup.
Questions still remain unanswered: why in present human society females adorn themselves to a
largest extent than males? Have they become dominant or competition is getting tougher? Or...
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