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Evolutionary Psychology 2: 177-194
Original Article
Narcissism guides mate selection: Humans
mate assortatively, as revealed by facial resemblance,
following an algorithm of "self seeking like"
Liliana Alvarez, Universidad Simón
Bolívar, Caracas, Venezuela.
Klaus Jaffe, Universidad Simón Bolívar,
Apartado 89000, Caracas 1080A, Venezuela. (Corresponding
author).
Abstract: Theoretical studies suggest
that mating and pair formation is not likely to be random.
Computer simulations suggested that sex among genetically
complex organisms requires mate choice strategies for its
evolutionary maintenance, to reduce excessive genetic
variance produced by out-crossing. One strategy achieving
this aim efficiently in computer simulations is assortative
mating modeled as "self seeking like". Another one is
selection of "good genes". Assortative mating increases
the probability of finding a genetically similar mate,
without fomenting inbreeding, achieving assortative mating
without hindering the working of other mate selection
strategies which aim to maximize the search for "good genes", optimizing the working of sex in evolutionary
terms. Here we present indirect evidence that in a
significant proportion of human reproductive couples, the
partners show much higher facial resemblances than can be
expected by random pair formation, or as the outcome of "matching
for attractiveness" or the outcome of competition for the
most attractive partner accessible, as had been previously
assumed. The data presented is compatible with the
hypothesis derived from computer simulations, that human
mate selection strategies achieve various aims: "self
seeking like" (including matching for attractiveness) and
mating with the best available genes.
Keywords: mate selection, face recognition,
assortative mating, sex, evolution.
Introduction
What is the adaptive value of love? We
certainly do not know, but we might get closer in answering this
question by understanding the evolutionary mechanisms underlying
mate choice. Although many theoretical studies assume mating to
be random, recent computer simulations showed that random mating
is very unlikely to occur in nature (Kalick and Hamilton 1986,
Jaffe 1996, 1998). Specifically, theoretical studies have
suggested that assortative mating seems to be highly adaptive (Thiessen
and Gregg 1980, Davis 1995), as it reduces excessive allelic
variance induced by recombination and sex, especially among
diploids with a large genome (Jaffe 1998, 1999, 2000).
Assortative mating defined as "self seeking like" has a
strong stabilizing effect on sex, is evolutionary stable, and
has an evolutionary dynamics analogous to kin selection (Jaffe
2000). In addition, assortative mating affects the genetic
structure of populations, influencing the evolutionary dynamics
of sexual organisms significantly (Dieckmann and Doebeli 1999,
Kondrashov and Kondrashov 1999, but see Ochoa and Jaffe 1999)
and thus, is a feature that should be taken into account when
studying the adaptive value of behaviors related to mate
selection. The theoretical works mentioned suggest that
assortative mating in itself is beneficial in evolutionary terms
to the organism practicing it, and thus is likely to be
widespread in nature.
The interpretation of evidence for
assortative mating is controversial (Moore 1992). Data can be
interpreted in the light of incest avoidance mechanisms or in
that of optimizing outbreeding. Living organisms seem to
optimize rather than maximize outbreeding (Bateson 1983). That
is, mate choice mechanisms avoid maximizing outbreeding and
inbreeding at the same time. A complementary theory to an
incest-avoidance-outbreeding equilibrium is the optimization of
the working of sex (Jaffe 1999, 2000, 2002). This theory accepts
that genetic similarity is not only achieved through familiar
proximity, and recognizes that genetic relatedness may exist
among individuals with no familiar relationship between them.
Therefore, assortative mating of the kind "self seeking like"
may achieve reproduction between genetically similar mates,
favoring the stabilization of genes supporting social behavior,
with no kin relationship among them (Jaffe 2001).
Revising the experimental evidence for
assortative pairing at the molecular level, Tregenza and Wedell
(2000) found evidence that suggests that genetic compatibility
limits mate choice. Recent studies with lizards (Dickinson and
Koenig 2003, Sinervo and Clobert 2003) showed that after
removing all spatial surrogates for kinship, lizards still
settle and actively chose to cooperate with phenotypically and
genetically similar lizards.
Evidence for assortative mating among humans
seems well established. Human's mate assortatively regarding
age, IQ, height, weight, nationality, educational and
occupational level, physical and personality characters (Buston
and Emlen 2003, Buss 1989, Epstein and Guttman 1984, Garrison et
al. 1968, Ho 1986, Jaffe and Chacon 1995, Spuhler 1968),
and family relatedness (Rushton 1989, Spuhler 1968, but see
Genin et al. 2000, Isles et al. 2001). Even Homer in his
Odyssey (XVII, 218) wrote that "god always joins those who are
similar". Yet, assortative mating is evidently limited by very
well known mechanisms of inbreeding avoidance among humans (see
for example reviews in van den Berghe 1983, Wolf 1993).
Humans place much weight on the visual aspect
of faces. Leonardo Da Vinci (1452-1519) wrote in his notebook,
when referring to how to select beautiful faces to paint, that
the artist should search for faces regarded as beautiful by the
public rather than by himself, as his own wit might deceive him
as it will lead him to look for faces similar to himself. Thus,
if he has an ugly face, he will paint ugly faces, unless he
searches for the public taste (Da Vinci 1999).
The human face is a complex, unique and
characteristic pattern, most familiar to us when distinguishing
people (Vezjak and Stephancic 1994). For example, studies have
shown that people remember faces of their own race better than
faces of other races; that the recognition memory for same-race
is superior to other-race faces; and that differential
activation in fusiform regions contributes to same-race memory
superiority (Golby et al. 2001). Hauber and Sherman (2001)
showed how mechanisms of self reference have a
neurophysiological basis. Faces seem to be involved in
reproductive behavior among humans. Couples faces resemble each
other much more than random pair formation would suggest
(Griffiths and Kunz 1973, Zajonc et al 1987, Hinsz 1989).
Similarities between faces are not likely to arise as a result
of pair formation or environmental factors (Rice and Borecki
2001), as facial features have a strong genetic basis (Savoye et
al. 1998). Facial resemblance between couples has been
extensively reviewed recently (Penton-Voak and Perrett 2000) and
can certainly be viewed as an adaptive trait, product of
evolutionary forces and not an experimental artefact. Human
faces are even considered as a communication device for the
advertisement of some kind of heritable quality (Thornhill and
Gangestad 1999) and thus should provide reliable signals in the
search for mates with "good genes" (Jaffe 1999).
Imprinting, i.e. memorizing in early age the
visual images of parents and then using these images for mate
choice, as first discovered in birds (Lorenz 1935), also seems
to guide assortative mating in humans (Todd and Miller1993,
Penton-Voak and Perrett 2000, Bereczkei et al 2002, Perrett et
al 2002, Little et al. 2003). Other evidence, pointing to
the existence of parts of the mechanism needed to allow humans "imprint" the faces of their parents, was provided by Le
Grand et al. (2001). They showed the need of "early"
visual input to develop normal face recognitions later. Children
resemble their parents (Nesse et al 1990, Bredart and French
1999, McLain et al 2000, Oda 2002, but see Bressan and Grassi
2004), sometimes even in odd ways: they seem first to resemble
more their fathers (see also Daly and Wilson 1982, Regalski and
Gaulin 1993). Facial child-parent resemblance mechanisms seem to
exist even among chimpanzee (Parr and de Waal 1999). This visual
memory may then be use to establish criteria for beauty, which
in turn are used to select a mate, producing as a consequence
assortative mating. These and other evolutionary effects of
parental imprinting have been discussed by Todd and Miller
(1993).
Yet how is this assortment achieved among
humans? What are the behavioral and psychological processes that
achieve assortment of couples in human society? Mainly three
theories are known to address this question: The matching
hypothesis; assortative mating based on "self seeks like";
and the competition for the most attractive mate which achieves
assortative mating as a kind of Nash equilibrium outcome.
The "self seeking like" hypothesis,
assumes a multidimensional space for individual preferences so
that every "self" is unique. Data on assortative pairing
based on facial visual cues, favoring the "self seeking like"
hypothesis, include the finding by DeBruine (2002) that facial
resemblance enhances trust. That is, inborn psychological
mechanisms originally evolved for kin selection and mate
selection seem to serve as a basis of other more advanced
developments of social behavior. One such behavior in humans
could well be the outcome of cognitive processes underlying
human mate choice, where self-perception seems to modulate mate
preference (Buston and Emlen 2003). Evidence that humans look
for a self, or that they root criteria of beauty on the self,
are also compatible with this hypothesis (Aron. and Aron 1986,
Yela and Sangrador 2002).
More commonly accepted, though, is the competition
hypothesis, where the physical and psychological resemblance
between mates is thought to be the outcome of a competition for
the most attractive partner. Some evidence supports this
assumption as similar degrees of attractiveness have also been
found between partners in reproductive couples (Berscheid and
Walster 1974, Murstaein and Christy 1976). These and other
authors do not regard similar attractiveness between partners of
a couple as a unequivocal sign of assortative mating (Kalick and
Hamilton 1986) but more likely as the outcome of competition,
where more attractive individuals will mate with the most
attractive partner available to him or her (Miller and Todd 1998
for example). Other variables are known to also affect
attractiveness and thus should influence pair formation. These
could be adaptive for basic physiological reasons such as those
suggested by Penton-Voak et al. (1999) who showed that menstrual
cycle alters face preference.
Under the competition hypothesis, assortative
mating is the outcome of a mechanism based on general levels of
attractiveness. That is, highly attractive females have a first
choice for highly attractive males, and/or vice versa (Miller
and Todd 1998). Attractiveness seems to be a rather general and
broad attribute applied to different stimuli, visual or not. A
specific piece of evidence for this was recently provided by
Collins and Missing (2003) who showed that vocal and visual
attractiveness are related in women.
A variant of the competition hypothesis is
provided by the matching
hypothesis, which
proposes that we don't seek the most physically attractive
person but that we are attracted to individuals who match us in
terms of physical attraction (Kalick and Hamilton 1986). This
compromise is thought to be necessary because of a fear of
rejection (a more attractive person might reject your advances)
and/or to achieve a balance between partners (Walster et al.
1966). Murstein (1972) obtained indirect support for the
matching hypothesis. The physical attractiveness of engaged
couples and those going out together was judged from
photographs. There was a definite tendency for the two people in
each couple to be similar in terms of physical attractiveness (Murstein
and Christy1976).
One way to discriminate between the various
theories is to recognize that attractiveness is a
one-dimensional space whereas similarity is a multidimensional
one. That is, if a universal sense of beauty creates a basis for
a universal scale of attractiveness, then pairing would proceed
from the most attractive extreme downwards in an assortative
fashion: the best pair up with the best, then the second-best
pair up, and so on. On the other hand, similarity has no
universal extremes. If assortative mating is based on
similarities (other or in addition to attractiveness), then
paring would not form a hierarchical linear scale of
attractiveness.
Thus, if theoretical predictions about
assortative mating are correct, and physical features of faces
are largely determined by genetic factors, we should detect
assortative mating based on facial visual cues. If assortative
pairing is the outcome of competition for the most attractive
partner, partners in a couple should have similar levels of
attractiveness, and little heterogeneities in level of
attractiveness between partners of couples should be expected.
Here we present evidence that assortative mating based on facial
visual cues occurs in human populations, and that these facial
similarities seem to be the product of "self seeking like"
rather than of the competition for the most attractive
accessible partner.
Methods
We photographed 36 randomly selected couples,
from a list of addresses provided by a local doctor in the city
of Mérida, Venezuela, which either had children and/or were
living for at least 3 years together, and which reported to have
no known family relationship between them. A digital black and
white photograph of each of the partners was taken in or around
their homes (Figure 1). The subjects of these 36 couples were
not used for any of the behavioral tests performed and we will
call them the target subjects.
To assess the existence of resemblance
between the faces of couples among the target subjects, the
photographs of the males were placed on a table and those of the
females were randomly shuffled. The test subjects (over 100
volunteers at the universities in Caracas and Mérida) had to
assign each of the photographs of female target subjects to one
of the males. Test subjects did not know any of the target
subjects photographed. The test was performed double blind, as
neither the experimenter nor the test subject knew who the
correspondence of the photos to the real couples.
The amount of correct guesses, i.e., joining
photographs of male and female partners of the same couple, did
not differ between test subjects asked to "Choose the
female to which the male is most likely to be married" and
test subjects asked to "Choose the female that is most
likely to be a sibling to the male" (p > 0.55, Chi
squared test, df = 19. The questions given in quotations are
rough translations from Spanish). Thus, for further tests, we
asked the test subjects to "Join the photographs of the
putative couples with the closest resemblance and or the more
likely to be married".
In order to simplify the tests and reduce the
rejection of test subjects to participate, we built 6 pools of 6
couples (i.e. 12 target subjects each), so that in each pool,
the target males had the same age in a range of ± 2 years if
less than 35 years old and ± 5 years if 35 years of age or
more. Test subjects were then presented with the 6 photos of the
faces (or parts of faces) of the target males placed on a table,
and they had to assign the randomly shuffled photos of the 6
target females to their partners.
Figure 1: Photographs of the faces (same
background for all faces), and parts of faces, of a selection of
6 couples (Nos. 31, 29, 10, 2, 27 and 4 in Table 4) including
the couple receiving the highest score (No. 29). Photos given to
test subjects were five times larger than the size shown here.
[View
Figure 1]
To test for the effect of cues in the
background of the photo in identifying correctly couples from
photographs of target subjects, we prepared 3 experiments. We
manipulated the digital photos so as to provide: 1- the same
background for each pair in a couple but which differed between
couples; 2- a different background for each of the partners in a
couple; 3- no background for all couples which made all photos
to have the same background (as in Figure 1). As an additional
test to reject a possible effect of background cues in the
photographs, we also presented photos of only the mouth, eyes or
nose of the subjects (see Figure 1). The test subjects were then
asked to pair the photos of the facial features of target
subjects according to their similarity.
As face recognition abilities are dependent
on early visual experience (Le Grand et al. 2001) and are
better between individuals of the same race (Golby et al. 2001),
we correlated the number of correct guesses made by test
subjects with the skin colour difference between the test
subject and the average of the faces of the correctly guessed
couples. The colour was assessed by the experimenter for both
test and target subjects in 3 distinct categories (dark,
slightly dark, white), which were assigned values of 1 to 3 in
order to perform statistical correlations on the results. Not
all test subjects were used for this test as only skin colour
data assessed by one of the experimenters was used
In order to estimate the effect of
attractiveness of faces as a possible confounding factor, we
assessed the attractiveness of a face, through test subjects
from the opposite sex. The attractiveness was registered from
less attractive to very attractive in a scale from 1 to 4.
Twenty one subjects of each sex were presented with the
photographs of 35 members of couples of the opposite sex of the
test subject for this assessment. That is, test males were given
the photos of target females and test females those of target
males to assess the attractiveness. Data was ordered based on
increased attractiveness of either males or females.
The statistical analyses performed on the
data were applied on the scores of test subjects. That is on the
number of correct couples guessed by the test subjects. The
analyses were: Pearson correlation coefficient to assess
correlations between age and scoring, and between attractiveness
and scoring. Chi square test to compare the total number of
scores obtained for a given experimental setting with those
expected for random guessing. The tests involved that each test
subject had to match all photos for all coupes. Random guessing
under this scenario for either 36 pairs or 6 pairs gives in
average one correct guess per test subject. Deviation from one
was assumed to be non-random guessing and its significance was
assessed by the Chi-squared test. The degrees of freedom were
calculated as the number of test subjects used for that given
experimental setting, minus one. Another more sensitive way to
look at the results was to assess the number of times a given
couple was correctly identified as such by test subjects. This
distribution of guesses (see Figure 2) was then compared with an
expected distribution obtained by random guessing. The outcome
of random pair formation plus random guessing was estimated
using a simple Monte Carlo simulation model written in basic.
Figure 2: Number of times a couple was
correctly guessed by test subjects compared to the expected
frequency of correct guesses from a sample of 36 couples,
assessed with a Monte Carlo simulation, assuming random pair
formation and random guessing (line with small dots). [View
Figure 2]
Results
The number of correct guesses, i.e. guessed
pairs of photographs corresponding to actual couples, made by
tests subjects was far larger than expected by random guessing
in most experiments. When females were provided with the photos
of the target faces of 36 couples, they guessed correctly an
average of 2.5 couples (Significantly different from random, n =
25 test females, p < 0.0001, Chi-square = 132). Male test
subjects placed in front of the same task managed to identify
correctly only an average of 0.94 couples (Not different from
random, n= 18 test males, p=0.6, Chi-square = 15). The amount of
correct guesses made by female test subjects was significantly
higher than those made by male test subjects (p < 0.003,
chi-square = 38).
When the test was simplified, so that only
the photos of faces of 6 couples were presented at the same
time, this difference between the number of correctly guessed
couples achieved by female and male test subjects disappeared (p
= 0.11, Chi-square = 21). The average number of correctly
guessed couples was 1.71 and 1.91 for female and male test
subjects respectively (Significantly different from random in
both cases, n = 35 and 21, p < 0.0001 in both cases).
No significant correlation (a
= 0.1) between correct guesses and age of the test subjects was
found (neither for females r = 0.009, mean age = 27, range
19-52, nor for males r = -0.2, mean age = 25, range = 18-70).
We correlated the number of correct guesses
made by test subjects with the skin colour difference (dark,
slightly dark, white) between the test subject and the average
of the faces of the correctly guessed couples, and obtained a
Pearson's correlation coefficient r = 0.5 (p < 0.01, n = 65).
Thus, if test subjects were given same race faces to evaluate,
the number of correct guesses increased.
Table 1: Scores, assessed as number of
correctly guesses target couples, produced by test subjects when
confronted with photographs of faces from partners from 36
couples. [View
Table 1]
When examining the distribution on the number
of correct guesses received by each target couple we found that
many test subjects never guessed correctly any couple (Table 1).
That is, 39 % of males and 16 % of females never scored a single
correct guess, and 28 % of males and 64 % of females scored
above one (random). Of the 36 target couples, 64 % were guessed
more than once (chance) and 44 % more than two times (Fourth
column of Table 4). We compared the number of times each couple
was guessed correctly with that predicted by a Monte Carlo
simulation based on random pair formation and random guessing.
These comparisons, for all the experiments performed, are given
in Table 2, where we compare the distribution of correct guesses
with that produced by Monte Carlo simulations, using a
chi-squared test . The table reads as follows. In the first
line, for example, we present the results of tests using
photographs of faces having all the same background. The number
of photos provided to the test subjects was 72 (36 photos of
females and 36 of males, belonging to 36 couples). The test
subjects for this experiment were both male and females and 43
test subjects were tested. The chi-square value obtained when
comparing the actual data with that from a Monte Carlo
simulation with totally random guessing, as explained in Figure
2, was 352. This value indicates that the actual data differs
from totally random guessing significantly, as the odds of
obtaining the actual data by chance are <<0.0001 for a
distribution function of guesses with 13 degrees of freedom (see
Figure 2).
Table 2: Comparison between a
distribution of guesses achieved randomly (Monte Carlo
simulations) and the distribution of the number of correct
assignments made by test subjects, guessing the partners of
couples, based on photographs of faces or parts of faces. [View
Table 2]
The results presented in Table 2 show that in
all cases studied test subjects were able to correctly identify
a significant proportion of couples with an accuracy that far
exceeded that expected by random guessing or by random pair
formation. With this more sensitive test, even male test subject
which were much less accurate compared to females in guessing
the correct pairs for the couples if the sample of photographs
to choose from was large, showed a score that statistically
differed from random guessing.
The results in Table 2 also show that the
background of the photographs did not affect significantly the
correct guessing of pairs. Independently of how the background
of the photos was presented, test subjects could pick out the
real couples based on facial similarities. Test subjects were
even able to correctly guess the real couples if photos of only
parts of the faces of target subjects (nose, eyes or mouth) were
presented. This recognition was less accurate than if the
complete face was presented, but the large amount of tests
performed provide for a high statistical significance of this
effect.
When ordering couples based on the
attractiveness of the faces of one of the sexes, the average
value of attractiveness of the opposite sex correlated strongly
with the attractiveness of the sex used to order the couples.
That is, more attractive females tended to pair with more
attractive males, or vice-versa. This tendency can be visualized
in Table 3. This table shows that the average attractiveness, as
assessed by 20 test subjects of the opposite sex, was lowest for
female mates of the most unattractive males and highest for the
female mates of the most attractive males, when the couples were
ordered according to the attractiveness of the male partner.
When the data was order according to the attractiveness of the
female partner in the couple, an even stronger result was
obtained. The average attractiveness of male mates of the least
attractive females was much lower than that of male mates of the
most attractive females.
Table 3: Mean attractiveness of the
partner of opposite sex, in couples in a given quartile if
ordered by attractiveness of: [View
Table 3]
Table 4:
Scores obtained by each couple (number of correct guesses), the
average attractiveness index obtained by each individual, and
the difference in attractiveness between the partners of the
couple (absolute difference) as assessed by neutral judges. [View
Table 4]
Discussion
Our results confirm that human couples
resemble each other significantly more than expected for random
pair formation, and that this resemblance can be detected by
neutral judges (test subjects). In the sample used here, a
significant proportion of the couples studied showed to have
conspicuous facial similarities, detectable by judges. This
result confirms that our test was sufficiently sensitive and the
sample examined was adequate, regarding the number of couples
with conspicuous facial similarities between them, for the
assessment of assortative mating.
We wanted to know if this assortment was the
product of "self seeking like" or the outcome of competition
for the most attractive partner available. Assortment based on
attractiveness was certainly at work in our sample as shown with
our experiments assessing the attractiveness of the partners of
the couples, presented in Table 3. That is, there was a general
tendency for more attractive males to pair with more attractive
females and vice versa. Yet, attractiveness by itself could not
explain our results for various reasons:
1- Test subjects correctly guessed the real
couples if photos of only parts of the faces of target subjects
(nose, eyes or mouth) were presented. Even though the criteria
for attractiveness are not applicable or are much more difficult
to apply on only parts of faces, these parts revealed sufficient
information on similarities for test subjects to re-assemble
photographs of real life couples.
2- The lack of correlation between the scores
of correct guesses and the difference in attractiveness between
partners in the couples (Table 4) is not compatible with the
competition hypothesis or the matching hypothesis. If
assortative mating was the outcome of competition for
attractiveness, "similarity" and matching for attractiveness
should correlate positively. In addition, if matching
attractiveness is at work, the assessment of similarity by test
subjects should also be based on levels of attractiveness. This
was certainly not the case in our study as the scores for
similarity and the differences in levels of attractiveness
between the partners of a couple diverged conspicuously. Thus,
the competition hypothesis by itself can not explain our
results.
3- Criteria for attractiveness vary between
races and thus, an absolute scale of attractiveness for humans
is not likely to exist. This fact has been known for quite a
wile as discussed in the introduction. Our data confirmed that
the ability to recognize similarities in faces was related to
race, making it unlikely that assortative mating can be
explained solely on the basis of matching universal
attractiveness criteria or as the outcome of competition for the
most attractive mate available.
The cumulative evidence presented here favors
the hypothesis that humans search for couples based on "self
seeks like", using a narcissistic psychological algorithm in
assessing the appropriate mate. Yet passive assortative mating
could also explain our results. Passive assortative mating
occurs when, due to population viscosity, reproduction occurs
among spatially proximate individuals that are probably close or
distant relatives. In the active sort, individuals choose their
mates based on similar phenotypic traits, which reflect similar
genes. In both cases the result is assortative mating or
breeding among mates that possess similar genes.
Our results showed that females are better
than males in assessing facial resemblance between individuals
when a large number of choices are presented to test subjects.
This phenomenon is congruent with the fact that females have a
much finer discriminatory ability than males (Briceño and
Jaffe1997).
The results of this study are compatible with
the notion that humans develop a sense of beauty through
imprinting-like mechanisms. This sense of beauty must have a
strong narcissistic component, as it is formed through the
images of the parents, as discussed in the introduction. When
this sense of beauty is applied to mate selection, the outcome
is assortative mating in a multidimensional scale, as no
universal scale of beauty can be formed through this mechanism.
Our results can not discard that assortative mating in humans is
at least partially achieved through competition for the most
attractive potential partner, or by matching attractiveness.
Yet, our results strongly suggest that a multitude of other
visual criteria are involved in mate selection. The hypothesis
of "self seeking like" explains the experimental results
rather well. The fact that these narcissistic criteria seem to
be applied also in situation were no pairs for reproductive
purposes are involved, such as in the choice of partners for
business purposes (DeBruine 2002), strongly support the
narcissist hypothesis. A testable prediction to possibly falsify
the 'self seeking like" hypothesis is that narcissistic
criteria should be applied to many other situations in human
every day life involving aesthetic or affective assessments. For
example the choice of pets should also follow narcissistic
criteria. This has been shown to be the case after obtaining our
results (Roy and Christenfeld 2004, Payne and Jaffe 2004).
In the present study we seem to have dealt
just with one envelop of a rather complex set of mate selection
mechanisms. Thus, further research should refine the mechanisms
at work that seem to balance assortative mating with inbreeding
avoidance and selection for 'good genes' (Jaffe 2002). The
results might direct future research in focusing on the still
unknown intricacies of mate selection mechanisms and the origin
of love.
Acknowledgements: We thank Omar Arenas
for advice in the statistical treatment of the data, Peter Todd,
John Hutchinson and Diana Ajami for helpful comments, Oswaldo
Henriquez and Rodolfo Jaffe for help in recruiting test
subjects. L. A. received financial support from CONICIT.
Received 8 May, 2004, Revision received 10
November, 2004, Accepted 19 September, 2004.
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Citation
Alvarez, L. and Jaffe, K. (2004). Narcissism
guides mate selection: Humans mate assortatively, as revealed by
facial resemblance, following an algorithm of "self seeking
like". Evolutionary Psychology, 2:177-194.
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