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The Effect of Eyelash Length on Attractiveness: A Previously Uninvestigated Indicator of Beauty


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Human eyelashes are one of the facial features that contributes to facial attractiveness. While enhancing the appearance of eyelashes has been practiced since antiquity, research investigations that consider the effect of their length on perceived attractiveness are scarce. Length of eyelashes can be an indicator of health, and it has recently been proposed that there is an optimum length for eye protection. In the current article, we investigated if the attractiveness of eyelash length dovetails with these evolutionary and functional proposals. Our results support this proposition, with the preference for eyelash length following an inverted-U function, with the highest ratings peaking at approximately one third of the eyes’ width. Interestingly, there is a difference between male and female faces, suggesting that while in general, eyelashes of an optimum ratio are considered more attractive, this preference is not solely a biologically adaptive phenomenon and is influenced by cultural norms.
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Pazhoohi, F., & Kingstone, A. (2020). The effect of eyelash length on attractiveness: A
previously uninvestigated indicator of beauty. Evolutionary Behavioral Sciences. Advance
online publication.
The effect of eyelash length on attractiveness: A previously uninvestigated indicator of
Farid Pazhoohi & Alan Kingstone
Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, British
Columbia, Canada V6T 1Z4
Human eyelashes are one of the facial features that contributes to facial attractiveness. While
enhancing the appearance of eyelashes has been practiced since antiquity, research investigations
that consider the effect of their length on perceived attractiveness are scarce. Length of eyelashes
can be an indicator of health, and it has recently been proposed that there is an optimum length
for eye protection. In the current paper, we investigated if the attractiveness of eyelash length
dovetails with these evolutionary and functional proposals. Our results support this proposition,
with the preference for eyelash length following an inverted-U function, with the highest ratings
peaking at approximately one third of the eyes’ width. Interestingly, there is a difference between
male and female faces, suggesting that while in general eyelashes of an optimum ratio are
considered more attractive, this preference is not solely a biologically adaptive phenomenon and
is influenced by cultural norms.
Keywords: eyelash length, eyelash attractiveness, facial attractiveness, evolutionary biology,
Public Significance Statements: Eyelashes have evolved to protect eyes from external
contaminations and excessive evaporations, and changes in eyelash length can reflect different
congenitally and noncongenitally diseases. From this evolutionary and biological perspective, we
test, and confirm, that the perceived attractiveness of eyelashes dovetails with their predicted
value to protect the eyes and signal healthiness to others. Contrary to some beliefs that the
attractiveness is increasing with the length of eyelashes on female faces, the preference for
eyelash length follows an inverted-U function. This function is observed for both female and
male faces.
The effect of eyelash length on attractiveness: A previously uninvestigated indicator of
My eyes drown in tears, yet thirst for but one chance,
I'll give away my whole life, for Beloved, but one glance.
Be ashamed of Beloved's beautiful eyes and long lashes,
If you have seen what I have, and still deny me my trance.
– Hafez, 1315-1390 A.D.
Human eyelashes are one of several facial features that contribute to facial attractiveness
(Dang et al., 2016). In many cultures, such as old civilizations in Middle East and North Africa,
eyelashes have been used to enhance and modify facial attractiveness and in particular the beauty
of the eyes. Presently such practices are showcased in the use of mascaras and curlers by women,
as possessing long eyelashes is considered beautiful (Patel, Abdul & Joos, 2019). However, the
perceived length of eyelashes needs to be balanced against the fact that long eyelashes can also
be indicators of different congenitally and noncongenitally diseases (for a review see Paus et al.,
2016). For example, children and adolescents with allergic or immunodeficiency diseases have
longer eyelashes than normal cohorts, potentially as a response to these diseases (Graham &
Sires, 1997; Singh & Pawar, 2018; Patrizi et al., 1998; Sharma, Mahajan, Sharma & Sharma,
2002). Such lengthening of eyelashes is suggested to be due to mast cells release of histamine,
prostaglandins, and leukotrienes in response to allergies (Church & McGill, 2002; Singh &
Pawar, 2018), remodelling hair follicle tissue (Paus et al., 1998). On the other hand, the loss of
eyelashes, or when they are very short, may signal disorders of a dermatological or nutritional
nature, or alternatively, endocrine or systemic diseases (Khong, Casson, Huilgol & Selva, 2006;
Kumar & Karthikeyan, 2012).
Beyond studies examining the relationship between eyelash length and disease, very few
studies have investigated eyelashes from an aesthetic perspective (Shaiek et al., 2018). Recently,
Amador and colleagues (2015) measured eyelashes of twenty-two mammals and showed that the
length of the eyelash is phylogenetically constant and is approximately one-third of the eye
width. They proposed that eyelashes act as air filters for the eyes, and using theoretical models
and simulated eyelashes, they measured the airflow around and through the eyelashes. They
found that the optimum length of eyelashes to width of the eye (L/W ratio) for minimizing
evaporation and contamination at the ocular surface was approximately 0.35 ± 0.15.
The current study reports the first systematic examination of the effect of eyelash length
on perceived facial attractiveness in humans. Assuming the phylogenetically adaptive
functionality of the L/W ratio, we hypothesized that attractiveness would be highest around the
proposed optimum range suggested by Amador et al. (2015). Our hypothesis is based on an
adaptive evolutionary perspective, in which attractiveness is an honest indicator of health and
genetic quality (Gangestad & Scheyd, 2005; Grammar, Fink, Moller & Thornhill, 2003). In other
words, if very short and very long eyelashes are indicators of diseases, such characteristics
should be considered less attractive. Furthermore, our prediction is based on the suggested
evolved functionality of eyelash length, in which shorter than the optimum lengths cannot
effectively protect eye surfaces from contamination, excessive evaporation, and shear stress from
airflow; while longer than optimum lengths impede vision and may signal hyper-sensitivity to
allergic diseases (Amador et al., 2015). Therefore, we asked participants to rank eleven images
of a woman’s face for attractiveness, with the sole manipulation being eyelash length. Lengths
ranged from zero-length to half the width of the eye (L/W of 0.50). We hypothesize that
preference for eyelashes will show an inverted-U relationship with L/W ratios about 0.35 ± 0.15
being considered the most attractive. From a purely evolutionary-biology perspective, this
inverted-U function should hold for both females and males. However, there is the potential that
the relationship may be modulated by gender cultural norms and the most attractive eyelashes for
a man’s face may be different (e.g., shorter) than for a female face (i.e., men might culturally be
associated with less feminized features, such as shorter eyelashes). Therefore, we also tested the
effect of eyelash length on facial attractiveness using a man’s face.
Material and Methods
Experimenters randomly tested university students in the Department of Psychology,
asking for either the female or male faces to be rank-ordered in terms of attractiveness. This
resulted in 81 participants (64 women and 17 men; aged 18 to 30 years; M = 20.42 years, SD =
2.48) being tested with the female face, and 51 individuals (38 women and 13 men; aged 18 to
45 years; M = 21.72 years, SD = 5.18) being tested with the male face. (Note that as the majority
of the individuals participating in the study were undergraduate women, reflecting the enrollment
ratio for the Department of Psychology, sex differences were not analyzed.) A total of 79
individuals (62.2%) reported single as their marital status, 34.6% as being in a relationship, and
3.1% as married. In terms of their highest academic degree, 54.3% had a high school diploma,
6.3% had a post-secondary diploma, and 38.6% of the participants had an undergraduate degree.
All participants consented to taking part in the study. The experiment was approved by the Ethics
Committee of the University of British Columbia and was conducted in accordance with the
Declaration of Helsinki as it pertains to research with human participants.
Stimuli and experiment
The female and male images were each generated using Daz3D software, and using
Photoshop eleven copies of each face varying in eyelash length were created (see Figure 1 for
examples). Eyelash length to eye width ratios were varied by units of .10, with the intervening
value being .04 or .06 (rather than .05) to create some unexpected variation in the different
lengths. Thus, the L/W ratios were: 0, .04, .10, .16, .20, .24, .30, .36, .40, .44, and .50. To avoid
other facial features as potential confounds on the perceived attractiveness, participants were
shown only the female or male face. The eleven female, and male, stimuli were printed
separately in high quality color on US Letter size paper (8" x 11.5") in portrait mode. The female
or male stimuli were stacked randomly and handed to participants. They were asked to order
them on a table from least (1) to most (11) attractive. Then the order of their rating was recorded
by the experimenters.
Figure 1. Examples of stimuli varying in eyelash length to eye width ratio; left image 0, middle
image .24, and right image .50. Upper row shows examples of the female stimuli, and the lower
row shows examples of the male stimuli.
For female faces, a Kruskal-Wallis H (one-way ANOVA) test was conducted to compare
the perceived attractiveness of eyelashes of different lengths. Results showed a significant main
effect for attractiveness ranking, χ2(10) = 374.95, p < .001. Pairwise comparisons indicated that
eyelashes with .20, .24, .30 and .36 eyelash/eye ratios were ranked as the most attractive
compared to the rest, while .16, .40, and .44 ranked highest in the second order. Images with
eyelash/eye ratios of 0 and .04 were ranked as the least attractive (see Figure 2A).
For male faces, a Kruskal-Wallis H test showed a significant main effect for
attractiveness ranking, χ2(10) = 194.61, p < .001. Pairwise comparisons indicated that eyelashes
with .16 and .20 L/W ratios were ranked as the most attractive compared to the rest, and images
with L/W ratios of .44 and .50 ranked as least attractive (see Figure 2B).
Figure 2. A) Attractiveness ranking means for eleven female images differing in eyelash length
to eye width ratios (L/W); B) Attractiveness means for eleven male images differing in L/W
ratios. Means not sharing the same letters are significantly different (p < .01).
To investigate if the perceived attractiveness between female and male faces differed as
eyelash length was altered, we ran a series of Mann-Whitney U tests comparing the sex
differences for each ratio. Results showed that the rankings for the ratios 0, .04, .30, .36, .40 and
.50 were significantly different between male and female faces (all Us > 944.5, all ps < .011 after
Bonferroni correction for multiple comparisons). Specifically, individuals ranked males faces as
higher on attractiveness than females at the smaller eyelash length ratios (0 and .04), and they
ranked female faces as higher on attractiveness than males for the larger eyelash ratios (.30, .36,
.40 and .50). No significant difference was observed for intermediate ratios of .10, .16, .20 and
.24 (all ps > .074).
The current study tests the perceived attractiveness of eyelash length, and the results
provide support for the proposed evolutionary adaptive length of eyelashes. Perceived
attractiveness rating scores were highest for female faces with L/W ratios of .20, .24, .30 and .36,
and for male faces with ratios of .10, .16, .20 and .24. These highest ratings for males are skewed
toward a shorter ratio than the optimum ratio (0.35 ± 0.15) suggested by Amador et al. (2015).
Collectively, our result shows that contrary to some beliefs and a recent study (Adam, 2020)
finding that attractiveness increases with the length of eyelashes on women faces, our results
indicate that the preference for eyelash length follows an inverted-U function. Moreover, our
results show that female faces with L/W ratios of 0 and .04 (no eyelashes or very short
eyelashes) were considered the least attractive, while for the male faces the least attractive faces
were those with .44 and .50 L/W ratios (very long eyelashes). In other words, there is a
difference in attribution of attractiveness to male and female faces as a function of eyelash
length. The skewed ratings’ in attractiveness peak for male faces towards shorter eyelashes
relative to those of female faces, suggesting that the preference for eyelash length may be
modulated by gender cultural norms. That is, while in general eyelashes of an optimum ratio are
considered more attractive, this preference is not solely a biologically adaptive phenomenon, and
is influenced by cultural norms. For example, the present result might be different in cultures
where the practice of eyeliners and/or mascara is not limited to women and could also be applied
to children and men (e.g., West and South Asia). Similarly, future studies may wish to combine
eyelash length with other facial features as well as using different ethnicities than the one used in
the current study. Finally, future studies may choose to use larger sample sizes, use ratings rather
than ordinal rankings to enable a direct test of sex differences, and/or assess 3D images, or
stimuli in motion, rather than 2D static images. In sum, although there is much work still to be
done, the present study adds to previously investigated ocular features in the perception of
attractiveness, such as eye color (Kleisner, Kočnar, Rubešová & Flegr, 2010), limbal ring
(Peshek, Semmaknejad, Hoffman & Foley, 2011), pupil size and scleral color (Gründl, Knoll,
Eisenmann-Klein & Prantl, 2012), and in general, to the field of facial attractiveness.
Declaration of Competing Interest: The authors declare no conflict of interest.
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... A similar example that has recently received empirical attention is eyelash length. Eyelash length may be a visual cue to health, with males expressing a stronger preference for longer lashes on females (Pazhoohi & Kingstone, 2020). Eyelash vigor and length can be modified with eyelash conditioners and serums (e.g., RevitaLash®), curling, extensions, and with mascara. ...
... Collectively, these findings suggest that digital visual appearance enhancement involves culturally unique modern technologies, applications, and websites that appear to be governed by motivations, dynamics, and outcomes that are similar to those observed with traditional face-to-face visual self-presentation modification. It will be fruitful for future researchers to study the motivations and effectiveness of using digital means to augment various aspects of physical appearance often regarded as attractive, such as using virtual makeup apps (e.g., Perfect365©) to increase the prominence of limbal rings (Lewis & Buss, 2021), eyelash length (Pazhoohi & Kingstone, 2020), and youthfulness (Jones et al., 2021). ...
... Since the writing of the target article, research on the diverse ways in which humans alter and modify their appearance from an evolutionary perspective has continued to grow (e.g., Jach & Moroń, 2020;Kellie et al., 2021;Pazhoohi & Kingstone, 2020;Wang et al., 2021). This demonstrates the timely nature of a comprehensive review of human visual selfpresentation modification to provide scholars with insight into the complementarity of sociocultural and evolutionary approaches (i.e., a socioevolutionary framework), pertinent theoretical and methodological considerations, and avenues in need of future empirical attention. ...
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Considerable research has examined human mate preferences across cultures, finding universal sex differences in preferences for attractiveness and resources as well as sources of systematic cultural variation. Two competing perspectives—an evolutionary psychological perspective and a biosocial role perspective—offer alternative explanations for these findings. However, the original data on which each perspective relies are decades old, and the literature is fraught with conflicting methods, analyses, results, and conclusions. Using a new 45-country sample ( N = 14,399), we attempted to replicate classic studies and test both the evolutionary and biosocial role perspectives. Support for universal sex differences in preferences remains robust: Men, more than women, prefer attractive, young mates, and women, more than men, prefer older mates with financial prospects. Cross-culturally, both sexes have mates closer to their own ages as gender equality increases. Beyond age of partner, neither pathogen prevalence nor gender equality robustly predicted sex differences or preferences across countries.
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Conclusion: Thus, long eyelashes may act as surrogate marker of severe AD and serve as a cutaneous marker of IV patients. What is Known: • Among acquired causes, allergic diseases and atopic dermatitis have been found to be associated with eyelash trichomegaly especially in children. What is New: • The severity of atopic dermatitis, i.e., SCORAD of > 50, hyperlinearity of palms and soles, and high IgE levels significantly correlate with the long eyelashes; thus, long eyelashes may act as surrogate marker of severe atopic dermatitis. • It may also serve as a cutaneous marker of ichthyosis vulgaris especially in male patients and patients with palmoplantar hyperlinearity.
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Background: Patient-reported outcome (PRO) measures have been used to assess treatment benefit in a variety of therapeutic areas and are now becoming increasingly important in aesthetic research. Objectives: The objective of the current study was to develop and validate a new PRO measure (Eyelash Satisfaction Questionnaire [ESQ]) to assess satisfaction with eyelash prominence. Methods: The content of the questionnaire (including conceptual framework and questionnaire items) was generated by review of literature, participant interviews, and expert opinion. Cognitive interviews were conducted to pilot test the questionnaire. Psychometric properties of the questionnaire were examined in a combined sample of participants (n = 970) completing Internet- (n = 909) and paper-based (n = 61) versions. Item- and domain-level properties were examined using modern and classical psychometrics. Results: Content-based analysis of qualitative data demonstrated the presence of 3 distinct domains (Length, Fullness, Overall Satisfaction; Confidence, Attractiveness, and Professionalism; and Daily Routine). Initial confirmatory factor analysis (CFA) results of 23 items revealed insufficient model-data fit (comparative fit index [CFI] of 0.86 and a non-normed fit index [NNFI] of 0.82). A revised model using 9 items (3 per domain) achieved appropriate fit (CFI of 0.99 and NNFI of 0.97). Analyses revealed measurement equivalence across the Internet- and paper-based versions. The 3 ESQ domains had strong internal consistency reliability (Cronbach's α [range] = 0.919-0.976) and adequate convergent and discriminant validity. Conclusions: The ESQ was found to be a reliable and valid PRO measure for assessing satisfaction with eyelash prominence. Level of evidence: 3 Therapeutic.
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Eyelashes are ubiquitous, although their function has long remained a mystery. In this study, we elucidate the aerodynamic benefits of eyelashes. Through anatomical measurements, we find that 22 species of mammals possess eyelashes of a length one-third the eye width. Wind tunnel experiments confirm that this optimal eyelash length reduces both deposition of airborne particles and evaporation of the tear film by a factor of two. Using scaling theory, we find this optimum arises because of the incoming flow's interactions with both the eye and eyelashes. Short eyelashes create a stagnation zone above the ocular surface that thickens the boundary layer, causing shear stress to decrease with increasing eyelash length. Long eyelashes channel flow towards the ocular surface, causing shear stress to increase with increasing eyelash length. These competing effects result in a minimum shear stress for intermediate eyelash lengths. This design may be employed in creating eyelash-inspired protection for optical sensors. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
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Everywhere the issue has been examined, people make discriminations about others’ physical attractiveness. Can human standards of physical attractiveness be understood through the lens of evolutionary biology? In the past decade, this question has guided much theoretical and empirical work. In this paper, we (a) outline the basic adaptationist approach that has guided the bulk of this work, (b) describe evolutionary models of signaling that have been applied to understand human physical attractiveness, and (c) discuss and evaluate specific lines of empirical research attempting to address the selective history of human standards of physical attractiveness. We also discuss ways evolutionary scientists have attempted to understand variability in standards of attractiveness across cultures as well as the ways current literature speaks to body modification in modern Western cultures. Though much work has been done, many fundamental questions remain unanswered.
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Madarosis is a terminology that refers to loss of eyebrows or eyelashes. This clinical sign occurs in various diseases ranging from local dermatological disorders to complex systemic diseases. Madarosis can be scarring or non-scarring depending upon the etiology. Appropriate diagnosis is essential for management. Follicular unit transplantation has been found to be a useful method of treating scarring madarosis and the procedure relevant to eyebrow and eyelash reconstruction has been discussed. A useful clinical approach to madarosis has also been included for bedside diagnosis. The literature search was conducted with Pubmed, Medline, and Google scholar using the keywords madarosis, eyebrow loss, and eyelash loss for articles from 1960 to September 2011. Relevant material was also searched in textbooks and used wherever appropriate.
Background: The wide diversity of feminine eyelashes in shape, length, and curvature makes it a complex domain that remains to be quantified in vivo, together with their changes brought by application of mascaras that are visually assessed by women themselves or make-up experts. Methods: A dedicated software was developed to semi-automatically extract and quantify, from digital images (frontal and lateral pictures), the major parameters of feminine eyelashes of Mexican and Caucasian women and to record the changes brought by the applications of various mascaras and their brushes, being self or professionally applied. Results: The diversity of feminine eyelashes appears as a major influencing factor in the application of mascaras and their related results. Eight marketed mascaras and their respective brushes were tested and their quantitative profiles, in terms of coverage, morphology, or curvature were assessed. Standard applications by trained aestheticians led to higher and more homogeneous deposits of mascara, as compared to those resulting from self-applications. Conclusion: The developed software appears a precious tool for both quantifying the major characteristics of eyelashes and assessing the making-up results brought by mascaras and their associated brushes.
Because of their crucial impact on our perception of beauty, eyelashes constitute a prime target for the cosmetic industry. However, when compared to other hair shafts and the mini-organs that produce them (eyelash hair follicles [ELHFs]), knowledge on the biology underlying growth and pigmentation of eyelashes is still rudimentary. This is due in part to the extremely restricted availability of human ELHFs for experimental study, under-appreciation of their important sensory and protective functions and insufficient interest in understanding why they are distinct from scalp HFs (e.g. ELHFs produce shorter hair shafts, do not possess an arrector pili muscle, have a shorter hair cycle and undergo greying significantly later than scalp HFs). Here we synthesize the limited current knowledge on the biology of ELHFs, in humans and other species, their role in health and disease, the known similarities and differences with other HF populations, and their intrinsic inter-ethnic variations. We define major open questions in the biology of these intriguing mini-organs and conclude by proposing future research directions. These include dissecting the molecular and cellular mechanisms that underlie trichomegaly and the development of in vitro models in order to interrogate the molecular controls of ELHF growth, cycling, and pigmentation and to probe novel strategies for the therapeutic and cosmetic manipulation of ELHFs beyond prostaglandin receptor stimulation. This article is protected by copyright. All rights reserved.
The limbal ring of the eye appears as a dark annulus where the iris meets the sclera. Both width and opacity of the limbal ring are influenced by iris pigmentation and optical properties of the region. With age the limbal ring becomes less prominent, making it a probabilistic indicator of youth and health. This raises the question: Are judgments of facial attractiveness sensitive to this signal in a potentially adaptive way? Here we show that the answer is yes. For male and female observers, both male and female faces with a dark and distinct limbal ring are rated as more attractive than otherwise identical faces with no limbal ring. This result is observed not just for upright faces but also for inverted faces, suggesting that the limbal ring is processed primarily as a local feature rather than as a configural feature in the analysis of facial beauty. We also discuss directions for future research that can clarify the role of the limbal ring in the visual perception of facial attractiveness.