Perception of Facial Symmetry and Attractiveness

ORiGiNAL PAPERS

Liwia Minch

_{, Małgorzata Zielińska}

_{, Beata Kawala}

Perception of Facial Symmetry and Attractiveness

Postrzeganie symetrii i atrakcyjności twarzy

1 _{Department of Maxillofacial Orthopedics and Orthodontics, Wroclaw Medical University, Poland} 2 _{Students’ Scientific Association at Department of Maxillofacial Orthopedics and Orthodontics,}

Wroclaw Medical University, Poland

A – koncepcja i projekt badania; B – gromadzenie i/lub zestawianie danych; C – opracowanie statystyczne; D – interpretacja danych; E – przygotowanie tekstu; F – zebranie piśmiennictwa

Abstract

Background. The concept of facial symmetry is very significant from the orthodontic diagnostics point of view,

and also for attractiveness assessment. A shift of the midline leads to disharmony, which negatively affects the sense of esthetics. However, a subjective face assessment by different individuals can make a slight, seemingly indefinable asymmetry acceptable.

Objectives. The assessment of the perception of the female face symmetry, its attractiveness by dentistry students

and by the individuals unrelated to dentistry.

Material and Methods. The test group included 101 dentistry students aged from 22–28 years (50 men and

51 women), 102 students of the University of Technology in Wrocław aged from 20–25 years (52 men and 50 women). The respondents were asked to order, according to their attractiveness, three photos of the face of every individual: one natural and two modified, using graphic software, which were mirror images of the half right and half left face. Additionally, the respondents assessed facial symmetry (6 photos in the scale of 1:1): of one natural (symmetric) and asymmetrical within mandible, with a pogonion point shifted left of 2, 4, 6, 8, and 10 mm.

Results. The respondents have considered as a most attractive the symmetric face, which was the mirror image of

the half left face, less attractive was the natural face, and the least attractive was, according to them, the face that was the mirror image of the half right side. The statistical analysis has confirmed the lack of differences in perception of the attractiveness between both test groups (p < 0.772). Among the dentistry students approximately half of the respondents have considered the natural face and the face with the pogonion point shifted of 2 mm as symmetrical. The other versions were classified by most of the respondents as asymmetric. The assessment performed by the individuals unrelated to dentistry was similar, although they have more often indicated the face with the pogonion point shifted of 4 mm as asymmetric.

Conclusions. The facial symmetry toward the facial midline is extremely important, although it is not a unique

factor affecting the attractiveness. The perception of the asymmetry in the case of the greater deviations from the midline (6–10 mm) was correct in the vast majority of the cases. The greater difficulty was the correct assessment of both symmetrical, as well as slightly asymmetrical face (Dent. Med. Probl. 2012, 49, 4, 550–555).

Key words: facial asymmetry, esthetics, perception.

Streszczenie

Wprowadzenie. Pojęcie symetrii twarzy jest bardzo istotne zarówno z punktu widzenia diagnostyki

ortodontycz-nej, jak i oceny atrakcyjności. Przesunięcie linii pośrodkowej wprowadza dysharmonię, która wpływa negatywnie na poczucie estetyki. Subiektywna ocena twarzy przez różnych ludzi może jednak sprawić, że nieznaczna, pozornie nieuchwytna asymetria będzie akceptowalna.

Cel pracy. Ocena postrzegania symetrii i atrakcyjności twarzy żeńskiej przez studentów stomatologii oraz osoby

niezwiązane ze stomatologią.

Materiał i metody. Badaniem objęto grupę 101 studentów stomatologii (50 mężczyzn i 51 kobiet) w wieku 22–28 lat

oraz grupę 102 osób niezwiązanych ze stomatologią (52 mężczyzn i 50 kobiet) w wieku 20–25 lat. Ankietowanych poproszono o uszeregowanie według atrakcyjności 3 zdjęć tej samej twarzy: naturalnej oraz dwóch zmienionych za pomocą programu graficznego, będących odbiciem lustrzanym prawej i lewej połowy twarzy. Badane osoby

Dent. Med. Probl. 2012, 49, 4, 550–555

Facial symmetry is not only essential from the point of view of the preservation of normal mas-ticatory system function, but also esthetics. The canon of the human face beauty has been formed in ancient times, which may be seen in the pre-served works of the Egyptians. An example of this is a sculpture from the fourteenth century BC de-picting Queen Nefertiti, whose face reflects perfect harmony and symmetry, which even today is con-sidered to be beautiful. Though in nature such ex-tremely idealized beauty does not occur, it is true that symmetrical faces are considered more attrac-tive [1]. This is related to the fact that perfect sym-metry is subconsciously identified with the lack of serious illnesses or genetic mutations, and thus is a synonym for overall health [2]. Faces consid-ered symmetrical may have an asymmetry with-in the bone structures, which suggests a potential soft tissue adaptation to offset the small deviations from generally accepted standard [3]. On the oth-er hand, asymmetry can be limited only to soft-tissue structures [2] and occur by normal occlu-sion [4]. Those facts suggest a question concern-ing which level symmetry has an influence on the esthetics.

The ancients Greeks were the first to have no-ticed the “natural asymmetry” in the form of dif-ferences in the size of the right and left side of the face. Since that time, the canon of beauty has been repeatedly changed; however, the deviation from the midline, considered currently as the standard, still constitutes the individuality and uniqueness of the face [1]. A direct confirmation of the nat-ural asymmetry of the face is also based on ma-nipulating the en face photos using graphic pro-grams. They enable us to create new, ideally sym-metrical faces by replacing the right face part by the mirror image of its left half, and vice versa. in this way we can obtain three different pictures of originally one individual, which, though similar,

are not identical [2]. it should be noted, however, that a slight asymmetry is often poorly observable by the outsiders. Thus, it is difficult to determine the border between still acceptable asymmetry and a significantly observable disharmony [2, 5] the more so, since the perception of the human face beauty has a multifactor (both genetic, as also environmental) base [1].

Accordingly to the above assumptions, the as-pects related to the esthetics and symmetry of the face should be evaluated among different groups, especially among young people, who constitute a significant part of patients treated orthodonti-cally. Therefore, the aim of the following study was to assess the perception of the female face symme-try and attractiveness by dentissymme-try students and by individuals unrelated to dentistry in order to show possible differences between both groups.

Material and Methods

The test group consisted of 101 dentistry stu-dents (50 men and 51 women) aged from 22 to 28 years (mean age: 23.02) and 102 students of the Wro-claw University of Technology (52 men and 50 wom-en) in age from 20 to 25 years (mean age: 21.62).

The en face photos of the female face with a preserved median line and facial symmetry (tak-en according to the Simon’s standard, with an Olympus Digital SLR Camera E-500 camera) were scaled and subjected to graphic processing using Adobe® _Photoshop® _{CS5 12.0 × 32. Then, the}

pho-tos were printed in color in the scale of 1:1. The respondents were asked to order, according to their attractiveness, three photos of the same face: one natural and two modified, made of half of the face completed by its mirror image (Figs. 1A–C).

Secondly, both test groups assessed the facial symmetry (6 photos): of one natural and five

asym-Wyniki. Ankietowani za najatrakcyjniejszą uznali twarz symetryczną, będącą odbiciem lustrzanym lewej połowy

twarzy, za mniej atrakcyjną – twarz naturalną, najmniej atrakcyjna zaś była według nich twarz będąca odbiciem lustrzanym prawej połowy twarzy. Analiza statystyczna potwierdziła brak różnic w postrzeganiu atrakcyjności między badanymi grupami (p < 0,772). Oceniając symetrię względem linii pośrodkowej wśród studentów stoma-tologii, około połowa ankietowanych uznała twarz naturalną oraz z przesuniętym punktem pogonion o 2 mm za symetryczną. Pozostałe wersje większość ankietowanych klasyfikowała jako niesymetryczne. Ocena dokonana przez osoby niezwiązane ze stomatologią była podobna, chociaż częściej wskazywali oni twarz z przesuniętym punktem

pogonion o 4 mm jako symetryczną.

Wnioski. Symetria twarzy względem linii pośrodkowej jest niezmiernie ważnym, choć nie jedynym czynnikiem

wpływającym na atrakcyjność. Postrzeganie asymetrii w przypadku większych odchyleń od linii pośrodkowej (6–10 mm) było w przeważającej liczbie przypadków prawidłowe. Większą trudność stanowiła prawidłowa ocena twarzy zarówno symetrycznej, jak i w niewielkim stopniu niesymetrycznej (Dent. Med. Probl. 2012, 49, 4, 550–555).

metrical faces with a pogonion point shifted left by 2, 4, 6, 8, and 10 mm respectively (Figs. 2A–F) and the asymmetry grade (minimal or significant) was eval-uated. Additionally, both test groups were asked to pay no attention to elements such as earrings, ears or hairline and used no tools that could be helpful in assessing the deviations from the median line. The pictures were shown individually, without compar-ing them with each other and in random order.

The results were subjected to the statistical anal-ysis in STATiSTiCA 10.0 software, using Pearson’s chi-squared test (statistical significance = 0.05).

Results

The attractiveness assessment of the face has shown that the face with the mirror image of its left part was considered the most attractive by 77 dentistry students and by 71 students of the University of Technology. The natural face has been considered second most attractive (respectively 19 and 23 students). The smallest number of respon-dents considered the face with the mirror image of its right part as the most attractive (respectively 5 and 8 students). The statistical analysis has con-firmed a lack of differences in perception of the at-tractiveness between both test groups (p < 0.772).

The results of the facial symmetry assessment are shown in Table 1. it is worth noting that the

natural face assessment by the two groups was sim-ilar. They have also similarly perceived the asym-metry in the case of deviations from the

pogon-ion point, ranging from 6 to 10 mm, where most

of them assessed these faces as asymmetrical. The statistical analysis has confirmed that the differ-ences between the results of both groups in these ranges were not statistically significant (p > 0.05).

Whereas the results of perception of the devi-ations from the median line in case of shifting the

pogonion point by 2 and 4 mm were statistically

significant (p < 0.005) – the tested groups have at-tained different results in this range.

Discussion

Esthetics and symmetry of the face are cur-rently sufficiently important issues and, from the point of view of the orthodontic patients, are one of the overarching goals of the treatment [6]. Al-though there are differences in the perception of the midline by orthodontists and dentists, and people, who are not related to the dentistry [5], the symmetrical face is considered by the general pub-lic as the most attractive. The incidence of facial asymmetry, according to studies of various foreign authors ranges from 34% [7] to even 69.2% [8], and is observed also in individuals considered attrac-tive. Most often it involves the shift of the midline

Fig. 1. Photographs of the same face: one natural (b) and 2 modified, made of half of the face completed by its mirror

image: right (a) and left (c)

Ryc. 1. Zdjęcia tej samej twarzy: naturalnej (b) i 2 zmienionych, będących połową twarzy uzupełnioną jej lustrzanym

odbiciem: prawym (a) i lewym (c)

within the lower face section [7, 9–11]. Some of the researchers have proven that in the population the shift to the right side is seen more often [10], and some of them have proven that it is the shift to the left side [8, 9, 11–13]. Depending on the devia-tion degree, the asymmetry concerning mandible location can be not only an esthetic problem, but also have its implications in the stomatognathic system function. [3, 14]. The symmetry disorders

within the facial portion of the skull can correlate, although they must not do so with the occlusion defects. They are diagnosed predominantly in pa-tients with the transverse defects and also with the anteroposterior defects, where they most often oc-cur along with the 2nd or 3rd, less frequently with the 1st Angle class. The etiology of these changes is various and can be associated with the congen-ital, developmental or acquired during

individu-Fig. 2. Photographs of one natural (a) and 5 asymmetrical faces with a pogonion point shifted left by 2 (b), 4 (c), 6 (d),

8 (e), and 10 mm (f)

Ryc. 2. Zdjęcia twarzy naturalnej (a) i 5 asymetrycznych twarzy z punktem pogonion przesuniętym o 2 (b), 4 (c), 6 (d),

8 (e), and 10 mm (f)

a b c

al development defects (e.g. temporo-mandibular joint disorders, traumas) [15].

in the present study of facial symmetry assess-ment it is worth noting that both test groups simi-larly assessed the natural face, with a preserved me-dian line and symmetry; however, approximately half of the respondents considered it to be asym-metrical. interestingly, the face with the pogonion point shifted of 2 mm was considered symmetrical more often in a group of University of Technology students than the natural face. Not without signif-icance seems to be the influence of the suggestions of respondents that among the images shown was also one with the symmetrical face. Additionally, the photographs were presented in random order, which could enhance the suggestion effect. De-spite these nuances, faces with the pogonion point shifted of 6 mm and more were assessed correctly by most of the respondents as asymmetrical. Thus, the value of 6 mm can be regarded as boundary in the present studies for the undeniable percep-tion by outsiders of the asymmetry within the low-er third part of the face.

The most difficult factor in both test groups was to assess the face with asymmetry in the range of 2 and 4 mm. Although the dentistry students have obtained in these cases better results than individ-uals not related to dentistry (which was statistically significant), this assessment was however not unam-biguous, especially concerning the natural face as-sessment. Therefore, it can be assumed that asymme-try within the limit of 4 mm is not unequivocally vis-ible. The more so, when one considers factors which

under normal conditions distract us from such fa-cial details, as e.g. hairstyle, make-up, head covers, glasses etc. Similar results have been obtained study-ing the perception of the dental midline. For the ac-ceptable, still unobservable by the outsiders, asym-metry was considered deviations ranging from ap-proximately 2 mm [5, 16–18] to even 4 mm [19].

The value of the accepted asymmetry can turn out to be very significant in making a decision about the treatment type. A special case is the lack of symmetry in the bone bases coexisting with the occlusion defect, where surgical intervention is con-sidered [2]. However, when making decisions about the surgery together with the patient, we should take into account not only the end result, but also the possible complications, postoperative rehabili-tation, prolonged treatment and the increase in the cost. if the deviations from the midline are in the range up to 4 mm, which has been shown to be un-observable to the outsiders, the decision about less radical treatment is acceptable.

in the common opinion, an attractive face is symmetrical and there are reports confirming such relationship [20, 21]. On the other hand, scientific studies refuting this assumption can also be found. The studies of Zaidel et al. [22] show that ideal sym-metry is not the only component of beauty, because the natural faces compared to the perfectly sym-metrical faces can be equally attractive [22, 23], or even slightly more attractive [24]. The results of this study partially confirm both of these theses. First of all, one of the most striking results was the dif-ference in the assessment of the symmetrical faces,

Table 1. Results of the facial symmetry assessment Tabela 1. Wyniki oceny symetrii twarzy

Natural face (Twarz naturalna) Shift of 2 mm (Przesunięcie o 2 mm) Shift of 4 mm (Przesunięcie o 4 mm) Shift of 6 mm (Przesunięcie o 6 mm) Shift of 8 mm (Przesunięcie o 8 mm) Shift of 10 mm (Przesunięcie o 10 mm) S AS S AS S AS S AS S AS S AS Dentistry students (Studenci stomatologii) minimally significantly % 50 50 84 16 40 60 77 23 15 85 65 23 9 91 42 58 7 93 45 55 8 92 18 82 Wrocław University of Technology students (Studenci Politechniki Wrocławskiej) minimally significantly % 45 55 84 16 58 42 81 19 35 65 89 11 8 92 67 33 12 88 60 40 14 86 47 53 Statistical analysis (Analiza statystyczna) p = 0.625 p < 0.005 p < 0.005 p = 0.982 p = 0.347 p = 0.269 S – symmetrical, AS – asymmetrical. S – symetryczna, AS – niesymetryczna.

be attractive, than the one with the mirror image of its right half. Most likely, such a perception of beauty was affected by other factors, such as facial proportions in transversal dimension, distance be-tween eyes and nose width. Since there is no indis-putable advantage of symmetry in shaping the con-cept of facial attractiveness, this issue is worth ana-lyzing further in order to study the other elements affecting the perception of esthetics.

though not a unique factor affecting the percep-tion of attractiveness. Facial asymmetry, in the case of greater deviations from the midline, with the

pogonion point shifted of 6 to 10 mm, was distinctly

visible by outsiders. The greatest difficulty was the correct assessment of both symmetrical, as well as slightly asymmetrical (2–4 mm), faces. in the latter case, dentistry students attained only slightly better results than the students unrelated to dentistry.

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Address for correspondence:

Liwia Minch

Department of Maxillofacial Orthopedics and Orthodontics Wroclaw Medical University

Krakowska 26 50-425 Wrocław Poland Tel.: +48 609 179 289 E-mail: liwiaminch@tlen.pl Received: 16.07.2012 Revised: 28.09.2012 Accepted: 24.10.2012

Praca wpłynęła do Redakcji: 16.07.2012 r. Po recenzji: 28.09.2012 r.