Comparative evaluation of facial attractiveness by laypersons in terms of facial proportions and equate it's deviation from divine proportions – A photographic study

Abstract

Introduction

The human face is a unique structure and says a lot about an individual even more than what the body indicates about the overall attractiveness. Facial attractiveness is an important key to social interactions and individual behavior. The human body is made in such a way that it follows a specific mathematical proportion called the Golden Proportion. In order for any two parts to be aesthetically proportionate, the ratio between them should be 1.618. Studies have shown that aesthetically pleasing profiles have facial proportions and ratios that closely resemble the golden proportions.

Aim

To evaluate the perception of esthetic facial photographs by laypersons and compare these with the accepted norms of divine proportions to find for any deviations from those norms.

Methodology

Forty subjects having normal soft tissue profile angle, as evaluated using Burstone's method, were selected to be photographed for the study. All the photographs were taken using DSLR Camera and under a standard photographic setup. All the photographs were edited and compiled into a PowerPoint presentation. The edited photographs on the PowerPoint presentation were displayed to 302 evaluators. These evaluators were asked to score each photograph according to a visual analogue scale with markings from 0 to 10 (with 0 being least attractive and 10 being most attractive) according to their attractiveness. All the scored photos were then grouped into three categories viz. Very attractive, Average attractive and Least attractive. Three horizontal proportions and three vertical proportions were assessed digitally in all the photographs and any deviations from the golden proportion were assessed.

Results

It was found that none of the three groups followed golden proportions accurately. However the Very Attractive group showed closest resemblance to the golden proportion as compared to the other two groups. Amongst all the horizontal and vertical proportions in the Very Attractive group, Interchelion to Interalar proportion (Ch:Ln) was the one that showed maximum deviation from the divine proportion (mean value 1.38 ± 0.15). Rest of the other horizontal and vertical proportions in the Very Attractive group were close enough to the divine proportion. However the difference between the proportions amongst the three groups was not statistically significant. Comparison between the three groups showed that Very Attractive faces showed the least deviations from the golden proportions whereas least attractive faces showed most deviations from the golden proportions.

Conclusion

The findings of this study state that the perception of aesthetically pleasing faces by laypersons do not accurately follow golden proportion but are close enough to it. The faces not showing golden proportions are perceived as less attractive.

1. Introduction

The human face is a unique structure and says a lot about an individual even more than what the body indicates about the overall attractiveness.¹ It is the most important part of the overall physical appearance of an individual. Facial attractiveness is an important key to social interactions and individual behavior. It is also known to influence an individual's self-esteem considerably.² Facial attractiveness plays an important role starting right from childhood with issues like bullying in school; or even choices relating to job positions in the office.^3,4

People today seek orthodontic treatment for either of the two reasons- Esthetic or Functional; the former being more common than the latter. The esthetic reasons include better dentofacial appearance, external influences like input from a third person like the family dentist, friends, parents⁵ and increasing awareness amongst people regarding facial esthetics.⁶ The main factors that contribute to the facial esthetics are averageness, youthfulness, sexual dimorphism and symmetry.⁷

The human body is made in such a way that it follows a specific mathematical proportion called the Divine Proportion, also known as the Golden Proportion. The ratio of two quantities which is the same as the ratio of their sum to the larger of the two quantities is always constant. This is known as the “Divine Proportion” or “Golden Proportion”.⁸ Divine proportion was described geometrically in the 4th century BC by the Greek mathematician, Euclid. Later on Fibonacci, an Italian mathematician in the 12th century gave a more accurate approach to the golden proportion and defined it as Phi (φ) whose value was equal to 1.618. In order for any two parts to be esthetically proportionate, the ratio between them should be 1.618.⁹

The features of an average human face also show golden proportions, because of which it is the most expressive part of the body that is subject to visual evaluation and recognition. It is correctly said that “Beauty lies in the eye of the beholder”.¹⁰ The esthetic perception of different faces differs from individual to individual. Studies have shown that aesthetically pleasing profiles have facial proportions and ratios that closely resemble the golden proportions.¹¹ In the field of orthodontics, Rickets was the first to incorporate the use of golden proportions in the analysis of an aesthetically pleasing facial form.¹⁰ Clinical applications of the golden proportion apart from orthodontics include dental prostheses, esthetic surgeries, etc. In Orthodontics the role played by Divine or Golden proportions is essential in treatment planning process in order to end the treatment in an acceptable facial profile satisfying the patients treatment need and expectations from orthodontic treatment.

2. Aims and objectives

In the existing literature there are several studies similar to the present study that have tried to find the correlation of Divine proportions to normal facial proportions. However the results of all the studies were not uniform. There are certain number of studies that have found a positive correlation between Divine proportions and facial proportions, and there are some other studies that have concluded otherwise. The aim of this study was to evaluate the perception of esthetic facial photographs by laypersons and compare these with the accepted norms of divine proportions to find for any deviations from those norms.

3. Materials and methods

The present study is a Cross-sectional Photographic type of study. Ethical approval for the study was provided by the institutional ethical committee. Subjects for photographs were selected between 18 and 25 years of age. Any of the subjects having a previous history of orthodontic treatment; subjects with gross facial asymmetry, any congenital anomalies; and history of facial trauma; history of previous plastic surgery or orthognathic surgery were excluded from the study. For determining pleasing facial profile, a photograph of the subject was obtained in the profile view and analyzed for the Soft tissue profile angle using Burstone's method.¹² The analysis was done using the soft tissue points: Glabella (G), Sub-nasale (Sn) and soft tissue Pogonion (Pg’). The subjects having values in normal range (165°–175°) were shortlisted as fit for the study. Hence a total of 40 subjects were selected to be photographed.

A standardized frontal profile photograph was obtained in the photographic area of the department under quality lighting. The participants were made to sit erect on a stool. Two Fluid Level Devices were fixed on the face of the subject; one on the forehead and the other one on the zygoma (cheek-bone). This method making use of fluid level devices had been used because it accurately determined the natural head position of the subjects.¹³ The position of camera was fixed on a tripod and positioned such that the distance between camera lens and the subject was 36 inches. The vertical positioning of the tripod was adjusted according to the subject in such a way that the lens of the camera was parallel to their apparent occlusal plane and focused on the entire face. Photographic umbrella was used for adequate illumination. The photographs were taken using Canon EOS 1500 D DSLR with 18–55 lens having 24.2 megapixels, CMOS type image sensor having a size of 22.3 × 14.9 mm with maximum output resolution of 6000 x 4000.

All the images were shot in portrait mode without zoom. The subjects were instructed and educated to hold the head in natural head position and neutral facial expressions. All the standardized photographs captured were transferred to the computer software (Adobe Photoshop, version 8, Adobe system, San Jose, CA, USA). All the photographs obtained were edited to be monochromatic in order to have the same value of facial complexion so as to avoid its influence on the perception of facial attractiveness¹⁴ as shown in Fig. 1.

Fig. 1.

Final edited photograph that was evaluated by laypersons.

The edited photographs were compiled on a Microsoft PowerPoint presentation, with each photograph displayed to the evaluators for a time interval of 5 s. The evaluators (laypersons) rated each photograph on a Visual Analogue Scale15 from 0 to 10, with 0 being least attractive and 10 being most attractive. The PowerPoint presentation was displayed to a total of 302 evaluators who rated each of the forty photographs. The evaluators for the study were not related to the field of dentistry, or medicine as these disciplines happen to deal with facial esthetics directly or indirectly. All evaluators for the study were above the age of 18 years and any evaluators with visual impairment were excluded. Average scores were calculated for each photograph and then they were grouped as very attractive (8–10), average attractive (4–7) and least attractive (0–3) groups.

3.1. Photographic analysis

The anatomic landmarks selected for the photographic analysis were (Fig. 2):

• ⁃Tr = Trichion: Junction of hairline and forehead.
• ⁃Ch = Chelion: Outer canthus of the mouth. Right and Left.
• ⁃Ln = Ala of the nose. Lateral outermost point on the convexity of the nose. Right and Left.
• ⁃Ts = Temporal soft tissue point. Soft tissue point on the temporal bone above the ear at the level of eyebrows. Right and left.
• ⁃Lc = Lateral canthus of the eye. Outermost point on the outer canthus of the eye
• ⁃Me = Menton: Inferior most point on the contour of the skin
• ⁃St = Stomion: Point of intersection of the inter-chelion distance.
• ⁃LN = Point of intersection of midline to inter-alar distance
• ⁃LC = Point of intersection of midline to inter-canthus distance.

Fig. 2.

Anatomic landmarks for photographic analysis.

The various proportions evaluated in the study were:

• ⁃
  Horizontal proportions (Fig. 3)

  • I.
    Ch: Ln = Inter-chelion distance to Inter-alar distance
  • II.
    Lc: Ch = Inter-canthus distance to Inter-chelion distance
  • III.
    Ts: Lc = Temporal soft tissue distance to Inter-canthus distance
• ⁃
  Vertical proportions (Fig. 4)

  • I.
    Tr-LC: LC-Me = Trichion to Inter-canthus midpoint: Inter-canthus midpoint to Menton
  • II.
    LC-LN: LN-Me = Inter-canthus midpoint to Inter-alar midpoint: Inter-alar midpoint to Menton
  • III.
    LN-St: LC-LN = Inter-alar midpoint to Stomion: Inter-canthus midpoint to Inter-alar midpoint

Fig. 3.

Horizontal proportions of the face.

Fig. 4.

Vertical proportions of the face.

All these proportions should ideally be equal to 1.618 i.e. the golden proportion. Photographs from all the three groups i.e. Very attractive, Average attractive and Least attractive groups were evaluated for any deviations from the golden proportions.

4. Results

Comparison of Ch:Ln between the three groups shows that Average Attractive group has the highest value of 1.687667 and Least Attractive has the least value of 1.334. This difference is statistically significant with a test value of 10.097 and p value of <0.001. Posthoc Tukey test comparing the Least Attractive and Average Attractive groups shows a mean difference of −0.3536667 and is statistically significant with a p value of 0.001. Comparison between the Least Attractive and Very Attractive groups shows a mean difference of −0.0478261 and is not statistically significant with a p value of 0.812. Comparison between Average Attractive and Very Attractive groups shows a mean difference of 0.3058406 and is statistically significant with a p value of 0.001.

Comparison of Lc:Ch between the three groups shows that Least Attractive group has the highest value of 1.736875 and Average Attractive has the least value of 1.427667. This difference is not statistically significant with a test value of 3.625* and p value of 0.054. Posthoc Tukey test comparing Least Attractive and Average Attractive groups shows a mean difference of 0.3092083 and is not statistically significant with a p value of 0.114. Comparison between the Least Attractive and Very Attractive groups shows a mean difference of 0.0179185 and is not statistically significant with a p value of 0.989. Comparing Average Attractive and Very Attractive groups shows a mean difference of −0.2912899 and is not statistically significant with a p value of 0.056.

Comparison of Ts:Lc between the three groups shows that Very Attractive group has the highest value of 1.654667 and Least Attractive has the least value of 1.4395. This difference is not statistically significant with a test value of 0.319 and p value of 0.729. Posthoc Tukey test comparing Least Attractive and Average Attractive groups shows a mean difference of −0.1051667 and is not statistically significant with a p value of 0.711. Comparison between the Least Attractive and Very Attractive groups shows a mean difference of −0.0649348 and is not statistically significant with a p value of 0.833. Comparison between the Average Attractive and Very Attractive groups shows a mean difference of 0.0402319 and is not statistically significant with a p value of 0.926.

Comparison of LC-Me:Tr-LC between the three groups shows that Very Attractive group has the highest value of 1.658783 and Average Attractive has the least value of 1.331222. This difference is statistically significant with a test value of 3.611 and p value of 0.037. Posthoc Tukey test comparing the Least Attractive and Average Attractive groups shows a mean difference of 0.0299028 and is not statistically significant with a p value of 0.984. Comparison between the Least Attractive and Very Attractive groups shows a mean difference of −0.2976576 and is not statistically significant with a p value of 0.13. Comparison between the Average Attractive and Very Attractive groups shows a mean difference of −0.3275604 and is not statistically significant with a p value of 0.071.

Comparison of LN-Me:LC-LN between the three groups shows that Average Attractive group has the highest value of 2.175111 and Very Attractive has the least value of 1.615391. This difference is statistically significant with a test value of 7.87 and p value of 0.001. Posthoc Tukey test comparing the Least Attractive and Average Attractive groups shows a mean difference of −0.0118611 and is not statistically significant with a p value of 0.99. Comparison between the Least Attractive and Very Attractive groups shows a mean difference of 0.2278587 and is statistically significant with a p value of 0.013. Comparison between the Average Attractive and Very Attractive groups shows a mean difference of 0.2397198 and is statistically significant with a p value of 0.006.

Comparison of LC-LN:LN-St between the three groups shows that Very Attractive group has the highest value of 1.576174 and Least Attractive has the least value of 1.19775. This difference is statistically significant with a test value of 3.56 and p value of 0.039. Posthoc Tukey test comparing the Least Attractive and Average Attractive groups shows a mean difference of −0.0828056 and is not statistically significant with a p value of 0.732. Comparison between the Least Attractive and Very Attractive groups shows a mean difference of −0.2284239 and is statistically significant with a p value of 0.047. Comparison between the Average Attractive and Very Attractive groups shows a mean difference of −0.1456184 and is not statistically significant with a p value of 0.241 (see Table 1) (see Fig. 5).

Table 1.

Comparison of the attractiveness amongst the ratios using one way ANOVA and Post Hoc Tukey Test.

Proportion	Least Attractive (n = 8)	Average Attractive (n = 9)	Very Attractive (n = 23)	ONE WAY ANOVA		POSTHOC TUKEY TEST
				F value (* = welch test)	p value	Least Attractive vs Average Attractive difference (p value)	Least Attractive vs Very Attractive difference (p value)	Average Attractive vs Very Attractive difference (p value)
Ch:Ln	1.33 ± 0.24	1.69 ± 0.23	1.38 ± 0.15	10.097	0.001	−0.35 (0.001)	−0.05 (0.812)	0.31 (0.001)
Lc:Ch	1.74 ± 0.43	1.43 ± 0.28	1.59 ± 0.28	3.625*	0.054	0.31 (0.114)	0.02 (0.989)	−0.29 (0.056)
Ts:Lc	1.44 ± 0.27	1.54 ± 0.33	1.65 ± 0.25	0.319	0.729	−0.11 (0.711)	−0.06 (0.833)	0.04 (0.926)
LC-Me:Tr-LC	1.36 ± 0.35	1.33 ± 0.42	1.66 ± 0.35	3.611	0.037	0.03 (0.984)	−0.3 (0.13)	−0.33 (0.071)
LN-Me:LC-LN	2.16 ± 0.2	2.18 ± 0.21	1.62 ± 0.17	7.87	0.001	−0.01 (0.99)	0.23 (0.013)	0.24 (0.006)
LC-LN:LN-St	1.2 ± 0.16	1.28 ± 0.2	1.58 ± 0.25	3.56	0.039	−0.08 (0.732)	−0.23 (0.047)	−0.15 (0.241)

Chart 1.

Average values of selected proportions.

Table 2 shows the deviation of all the selected proportions to the golden proportion. Very attractive group shows facial proportions closest to the divine proportion, when compared to Average attractive and the Least attractive groups. Amongst the selected six proportins in the very attractive group, only one proportion, that is Inter-chelion distance to Inter-alar distance (Ch:Ln), showed a mean of 1.38 ± 0.15. Other proportions had mean values close to 1.618. Chart 2 shows the graphical representation of the deviation of all the proportions from the divine proportions, in which it is clear that the very attractive facial proportions show lesser deviations when compared to the average and least attractive groups.

Table 2.

Table showing deviations of the facial proportions of the three groups from the divine proportion.

One-Sample Statistics
Inference		N	Mean	Std. Deviation	Std. Error Mean
Least Attractive facial ratios	Ch:Ln	8	1.334000	0.2446443	0.0864948
	Lc:Ch	8	1.736875	0.4251277	0.1503053
	Ts:Lc	8	1.439500	0.2727044	0.0964156
	LC-Me:Tr-LC	8	1.361125	0.3509735	0.1240879
	LN-Me:LC-LN	8	2.163250	0.1957190	0.0691971
	LC-LN:LN-St	8	1.197750	0.1555284	0.0549876
Average Attractive facial ratios	Ch:Ln	9	1.687667	0.2269014	0.0756338
	Lc:Ch	9	1.427667	0.2760960	0.0920320
	Ts:Lc	9	1.544667	0.3250050	0.1083350
	LC-Me:Tr-LC	9	1.331222	0.4176370	0.1392123
	LN-Me:LC-LN	9	2.175111	0.2068674	0.0689558
	LC-LN:LN-St	9	1.280556	0.2018917	0.0672972
Very Attractive facial ratios	Ch:Ln	23	1.381826	0.1489074	0.0310493
	Lc:Ch	23	1.589572	0.2761532	0.0575819
	Ts:Lc	23	1.650435	0.2526057	0.0526719
	LC-Me:Tr-LC	23	1.658783	0.3492410	0.0728218
	LN-Me:LC-LN	23	1.619353	0.1719740	0.0358591
	LC-LN:LN-St	23	1.584174	0.2510247	0.0523423

Chart 2.

Deviations of each proportion from the Divine Proportion.

5. Discussion

The human body is structured in such a way that it follows the divine proportions. Even the face shows divine proportions. It is a known fact that an attractive face shows facial proportions equal to the divine proportion. This study was aimed at finding out whether the laypersons perception of attractive faces follows the divine proportions or not.

The present study was a photographic study in which the subjects having a pleasing profile were selected for photographic evaluation. The subjects having the soft tissue profile angle within the normal range were selected based on Burstone's soft tissue analysis. Thus a total of forty subjects were selected to be photographed. The photographs of the selected subjects were cropped and edited to be monochromatic. This was done because complexion is known to influence the perception of facial attractiveness.¹⁴ The edited photographs were rated by a total of 302 evaluators over a period of three months who scored each photograph on a scale of 0–10, with zero being the least attractive and ten being the most attractive. The scores thus given for each photograph ensured nullifying of all the factors that may affect the perception of attractive faces. Meaning to say, the photographs were scored by laypersons just based on the facial proportions.

From the results of the present study, it was clear that the faces that laypersons found attractive did not follow the divine proportions exactly but when compared to Least attractive and Average attractive groups, the facial proportions of the Very attractive group were the closest to the divine proportion. It is thus clear that the perception of attractive faces does follow divine proportion.

A similar study conducted by Kiekens et al.¹⁵ showed that only a few proportions matched the divine proportions in attractive faces. They took into consideration 19 facial proportions out of which only 4 proportions showed correlation with the Visual Analogue Scale. This meant that attractive faces show lesser deviations from the divine proportion in these four proportions when compared to the lesser attractive faces.

Another study conducted by Sunilkumar et al.¹⁶ was aimed at finding the correlation between facial esthetics and divine proportions. They used the photographs of 300 subjects to evaluate the relationship between facial esthetics and divine proportions. They found that most of the parameters of a balanced face showed proportionality to the divine proportions. Only a few parameters for the lower facial width and height showed some deviations from the golden proportions.

Pancherz et al.¹⁷ in their study aimed at testing Rickett's hypothesis that facial beauty is quantifiable by using attractive and non-attractive facial photographs and comparing them in terms of divine proportions. They found that the deviations from the divine proportions were greater in the non-attractive faces when compared to the attractive faces. Thus Rickett's hypothesis was held true that facial beauty is quantifiable and measurable.

Angelos Mantelakis et al.¹⁸ conducted a study in African population to assess the facial proportions in professional black models. They compared the proportions to the divine proportions. Facial photographs were taken which were then rated by laypersons on a Visual Analog Scale. Contrary to the results of the present study they found that only one out of all the proportions they considered for the study, showed a positive correlation to the divine proportion. Rest of all the other proportions were not close to the divine proportions.

Marques Peron et al.¹⁹ conducted a similar study in which they compared the perception of esthetically pleasing facial profiles amongst laypersons, Orthodontists and Artists. From their study, they concluded that there was no correlation between the perception of facial attractiveness and divine proportions.

In another similar type of study conducted by Morihisa et al.,²⁰ they used a total of 208 frontal and profile photographs to find the association between attractive faces and golden proportions. These photographs were first rated by the evaluators who were orthodontists and laypersons. When the photographs were analyzed for facial proportions, it was found that there was no correlation between the facial attractiveness and golden proportions.

6. Conclusion

The perception of attractive faces by laypersons is positively correlated to the divine proportion. Visually attractive faces have facial proportions close to the divine or golden proportion as compared to lesser attractive and non-attractive faces. Orthodontic treatment planning should take this into consideration especially while planning for orthognathic surgeries.

Drawbacks

The photographs had the fluid level device stuck on to the face which could affect the scoring of each photograph by laypersons. The measurements of the facial proportions were carried out digitally. Direct anthropometric measurements could have yielded more accurate values of the proportions. Further studies need to be conducted of similar types in populations all over India so as to accurately determine the role of Divine proportions in facial attractiveness.