Face Shape Research Articles

A Novel Hybrid Injectable for Soft-tissue Augmentation: Analysis of Data and Practical Experience

Background: HA/CaHa (HArmonyCa, Allergan Aesthetics, an AbbVie Company) is a hybrid injectable filler developed for aesthetic purposes that contains calcium hydroxyapatite microspheres suspended in a hyaluronic acid gel. This review describes preclinical and clinical data, recommendations for use based on the primary author’s clinical experience, and case studies that illustrate implementation of product use recommendations and patient outcomes. Methods: Preclinical data on the lift capacity and tissue integration of the HA/CaHa hybrid injectable and clinical data on its safety, efficacy, and real-world use were extracted from poster presentations, published literature, manufacturer instructions for use, and proprietary data files. Case studies were presented based on clinical experience. Results: The HA component of HA/CaHa provides an immediate and noticeable filling and lifting effect, whereas CaHa microspheres result in neocollagenesis. In preclinical studies, HA/CaHa demonstrated higher lift capacity (P < 0.05) and faster tissue integration than a CaHa filler and led to collagen I gene and protein expression. Clinical studies showed clinical safety and effectiveness with high patient satisfaction. The most common adverse event was injection-site response. Clinician recommendations for achieving desired aesthetic results while minimizing or preventing adverse events are reviewed, including patient selection and assessment, treatment approaches based on face shape, injection technique, and postprocedure care. Conclusion: The novel hybrid injectable consisting of HA with incorporated CaHa microspheres in a single marketed product may help achieve aesthetic goals by immediately restoring volume and potentially improving skin architecture and soft-tissue quality over time.

The Concept of Ideal Lips of Caucasian Female: An Anthropometric Analysis of the Lower Third of the Face.

The demand for lip-redefining procedures has been rising in recent years, thus creating the need for reliable and detailed reference sources on aesthetic female lips. This study investigates the morphology of the lower third of the face, including the lips and jawline, of attractive young Caucasian females. A semi-automatic photogrammetric analysis of the faces of professional female photograph models (n=400) of the Caucasian race aged 18-39 was performed. Angular, linear, and surface area parameters were evaluated. A graphical summarization of the average facial shape of all analyzed attractive females was generated as an average body contours (ABC) image. The height of the lower third of the face equaled 0.32 ± 0.02 of the total facial height. The average lip width was 48.06 ± 3.34mm. The upper vermilion height was found to be significantly lower than the lower vermilion height (6.47 ± 1.36 vs. 11.64 ± 1.46mm, p < 0.01). The lip obliquity angle was found to be 1.05° ± 0.79°. The area surface of the upper lip vermilion was considerably smaller than the vermilion of the lower lip (p < 0.01). This is one of the largest studies on attractive Caucasian females' lips and lower face morphology. The data it provides, including the graphical presentation of the aesthetic lower face as an ABC image, may provide physicians with valuable guidelines for lips rejuvenation and reconstruction procedures. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Development of a personalized mask design method using three-dimensional scan data

Purpose This study aims to develop a novel design method to make personalized masks for the effective prevention of pandemic respiratory infectious disease.Design/methodology/approachThe changes in facial shape during speaking were analyzed using a three-dimensional (3D) scanning technique. In total, 13 anthropometric items were measured, and mask patterns were generated using a parametric pattern design method. Three sizing methods were proposed to reflect not only static but also dynamic body dimensions on the mask patterns.FindingsA significant increase or decrease was observed in 10 out of 13 measurement items. Based on this, four items were selected to be used in the mask pattern design. The nose and cheek areas of a mask were fixed to protect the respiratory tract against viruses. The lower jaw area was deformed to improve the fit.Social implicationsThis study is expected to provide fundamental data to understand the changes in facial shape during movement. In addition, it is expected that the development of individualized personal protective equipment with movement adaptability will facilitate an effective response to various pandemic respiratory diseases.Originality/valueIn order to develop a personal protective equipment (PPE) that has a good fit and can protect against pandemic respiratory infectious diseases, morphological analysis was attempted using 3D facial data. It would be possible to design various products and equipment to be worn on the face by using the method proposed in this study.

Saudi Graduate Students’ Identities in Relation to Emotion and Agency in Applied Linguistics: A Narrative Multiple Case Study

This qualitative inquiry explores the identity development processes of graduate students in applied linguistics within the higher education context of Saudi Arabia. Through a merged research design of a multiple-case study and narrative inquiry approach, this study examined the narratives of Saudi graduate students’ identity development in applied linguistics, focusing on key experiences across past, present, and future, as well as their emotional and agentive experiences. Despite the growing body of research on identity in applied linguistics and second language acquisition, limited attention has been given to graduate students’ identity formation in this field. The study contributed to several key findings: 1) Early experiences shape Saudi graduate students’ current academic paths and future aspirations, 2) Positive and negative emotional experiences shape Saudi graduate students’ academic self-perception and identity development and 3) Saudi graduate students’ agentive responses to the challenges they face shape their identity development. This study’s outcomes provide insight into the dynamic relationship between the identities, emotions, and agency of Saudi graduate students in applied linguistics, offering practical implications and suggesting future directions for further research.

(Invited) Wearable Flexible Microfluidic Biosensor for Sweat Monitoring

As we enter the post-pandemic era, our lives have certainly become more convenient than before, due to the advancement and elimination of technologies that became practical or widespread during the pandemic. Among these, technologies related to non-invasive bioinstrumentation, which can be used at an individual level to access one's own health information, have become increasingly important. Non-invasive bioinstrumentation can be broadly divided into the measurement of physical information (shape, activity and so on) and the measurement of chemical information, i.e. the components of the body. For example, facial shape is widely used for personal identification, while weight and energy expenditure related to activity are easily managed by smartphones. In contrast, chemical sensing, which is often difficult to sample and requires a wet environment for measurement, still requires breakthroughs to be used by individuals with the same ease as physical sensing.In the research field of non-invasive biomedical measurements, the technology is often developed in the form of wearable systems. Wearable microfluidic devices have been intensively studied for the measurement of body components. We focused on sweat, which contains a variety of biomarkers, and have developed a wearable microfluidic biosensing system that measures sweat components in real-time. Sweat is secreted from sweat glands on the skin of the entire body, making it easily accessible and less mentally demanding to collect. On the other hand, there are problems with sampling methods for reliable measurement, such as large fluctuations in the sweat rate and evaporation from the skin surface during secretion. We overcame this problem by using a wearable microfluidic device to transport the full amount of sweat from the sweat gland to a downstream biosensor by carrier flow, and developed a wristwatch biosensing system to monitor the constituents released as sweat independent of sweat rate.The wristwatch sweat sensor consists of a PDMS sweat sampling device, a biosensor, a fluid controller and a wireless control circuit with Bluetooth Low Energy and external analogue I/O. Communication with the mobile device is via Bluetooth Low Energy. Our method has the advantage that secretions are transported by dissolution in the carrier stream and can therefore be reliably monitored even at very low sweat levels. The pump is controlled by an microcontroller unit, so the flow rate can be controlled in real time according to the sweat rate and target substances, and the sensitivity can be improved at the expense of temporal resolution by running the pump intermittently, i.e. allowing secretions to accumulate in the carrier flow for a certain time before measurement.We monitored changes in sweat lactic acid in response to exercise load using an ergometer. The results showed an increase in sweat lactate with increasing exercise intensity, with a dependence on sweat rate. By measuring sweat at rest, we found that the lactate accumulated in the sweat glands and on the skin's surface were dissolved by the biosensor in the early stages of measurement, while the signals from the sweat glands became dominant after these had been sufficiently decreased. These results suggest that our system appropriately reflects the physiological phenomena associated with sweating. The presentation will also include the behaviour of lactic acid in sweat, which was detected by our system for the first time.

A Comprehensive Assessment of Soft-tissue Sagging after Zygoma Reduction Surgery through Artificial Intelligence Analysis.

Overdevelopment of zygomatic bones often results in protrusion and flaring of the midfacial region. This makes the face appear squarer than the more favorable oval shape. Therefore, zygoma reduction surgery has become a commonly performed procedure in patients seeking to obtain an ideal facial shape. Facial soft-tissue ptosis is one of the main complications of zygoma reduction surgery. Previously, the evaluation of cheek soft-tissue ptosis was subjectively based on patients and surgeons. Our study aimed to provide an objective evaluation of soft-tissue sagging in the cheek region after zygoma reduction surgery using artificial intelligence (AI). We used AI to evaluate cheek sagging in a series of patients who underwent zygoma reduction surgery. We used four methods: tracking facial landmarks, detecting changes in the cheek curvature, and examining changes in the nasolabial fold and marionette lines. Then, the obtained numerical results were assessed for statistically significant differences using statistical validation methods. Use of AI with the four methods demonstrated no statistically significant differences between the pre- and postsurgery evaluations. AI analysis demonstrated that soft-tissue ptosis did not occur in our series of patients. AI offers objective evaluation for both patients and doctors. Future research could build on this application to examine various influencing factors and develop new tools using machine learning to evaluate and predict the extent of cheek sagging in patients before surgery.

SketchMetaFace: A Learning-Based Sketching Interface for High-Fidelity 3D Character Face Modeling.

Modeling 3D avatars benefits various application scenarios such as AR/VR, gaming, and filming. Character faces contribute significant diversity and vividity as a vital component of avatars. However, building 3D character face models usually requires a heavy workload with commercial tools, even for experienced artists. Various existing sketch-based tools fail to support amateurs in modeling diverse facial shapes and rich geometric details. In this article, we present SketchMetaFace - a sketching system targeting amateur users to model high-fidelity 3D faces in minutes. We carefully design both the user interface and the underlying algorithm. First, curvature-aware strokes are adopted to better support the controllability of carving facial details. Second, considering the key problem of mapping a 2D sketch map to a 3D model, we develop a novel learning-based method termed "Implicit and Depth Guided Mesh Modeling" (IDGMM). It fuses the advantages of mesh, implicit, and depth representations to achieve high-quality results with high efficiency. In addition, to further support usability, we present a coarse-to-fine 2D sketching interface design and a data-driven stroke suggestion tool. User studies demonstrate the superiority of our system over existing modeling tools in terms of the ease to use and visual quality of results. Experimental analyses also show that IDGMM reaches a better trade-off between accuracy and efficiency.

FSAMT: Face Shape Adaptive Makeup Transfer

FSAMT: Face Shape Adaptive Makeup Transfer

Realistic Facial Age Transformation with 3D Uplifting

AbstractWhile current facial re‐ageing methods can produce realistic results, they purely focus on the 2D age transformation. In this work, we present an approach to transform the age of a person in both facial appearance and shape across different ages while preserving their identity. We employ an α‐(de)blending diffusion network with an age‐to‐α transformation to generate coarse structure changes, such as wrinkles. Additionally, we edit biophysical skin properties, including melanin and hemoglobin, to simulate skin color changes, producing realistic re‐ageing results from ages 10 to 80 years. We also propose a geometric neural network that alters the coarse scale facial geometry according to age, followed by a lightweight and efficient network that adds appropriate skin displacement on top of the coarse geometry. Both qualitative and quantitative comparisons show that our method outperforms current state‐of‐the‐art approaches.

Super recognizers: Increased sensitivity or reduced biases? Insights from serial dependence.

Super recognizers (SRs) are people that exhibit a naturally occurring superiority for processing facial identity. Despite the increase of SR research, the mechanisms underlying their exceptional abilities remain unclear. Here, we investigated whether the enhanced facial identity processing of SRs could be attributed to the lack of sequential effects, such as serial dependence. In serial dependence, perception of stimulus features is assimilated toward stimuli presented in previous trials. This constant error in visual perception has been proposed as a mechanism that promotes perceptual stability in everyday life. We hypothesized that an absence of this constant source of error in SRs could account for their superior processing-potentially in a domain-general fashion. We tested SRs (n = 17) identified via a recently proposed diagnostic framework (Ramon, 2021) and age-matched controls (n = 20) with two experiments probing serial dependence in the face and shape domains. In each experiment, observers were presented with randomly morphed face identities or shapes and were asked to adjust a face's identity or a shape to match the stimulus they saw. We found serial dependence in controls and SRs alike, with no difference in its magnitude across groups. Interestingly, we found that serial dependence impacted the performance of SRs more than that of controls. Taken together, our results show that enhanced face identity processing skills in SRs cannot be attributed to the lack of serial dependence. Rather, serial dependence, a beneficial nested error in our visual system, may in fact further stabilize the perception of SRs and thus enhance their visual processing proficiency.

High-Intensity Focused Ultrasound Increases Facial Adipogenesis in a Swine Model via Modulation of Adipose-Derived Stem Cell Cilia.

Decreased medial cheek fat volume during aging leads to loss of a youthful facial shape. Increasing facial volume by methods such as adipose-derived stem cell (ASC) injection can produce facial rejuvenation. High-intensity focused ultrasound (HIFU) can increase adipogenesis in subcutaneous fat by modulating cilia on ASCs, which is accompanied by increased HSP70 and decreased NF-κB expression. Thus, we evaluated the effect of HIFU on increasing facial adipogenesis in swine (n = 2) via modulation of ASC cilia. Expression of CD166, an ASC marker, differed by subcutaneous adipose tissue location. CD166 expression in the zygomatic arch (ZA) was significantly higher than that in the subcutaneous adipose tissue in the mandible or lateral temporal areas. HIFU was applied only on the right side of the face, which was compared with the left side, where HIFU was not applied, as a control. HIFU produced a significant increase in HSP70 expression, decreased expression of NF-κB and a cilia disassembly factor (AURKA), and increased expression of a cilia increasing factor (ARL13B) and PPARG and CEBPA, which are the main regulators of adipogenesis. All of these changes were most prominent at the ZA. Facial adipose tissue thickness was also increased by HIFU. Adipose tissue volume, evaluated by magnetic resonance imaging, was increased by HIFU, most prominently in the ZA. In conclusion, HIFU increased ASC marker expression, accompanied by increased HSP70 and decreased NF-κB expression. Additionally, changes in cilia disassembly and length and expression of adipogenesis were observed. These results suggest that HIFU could be used to increase facial volume by modulating adipogenesis.

An Approach to Selection of Face-Lift Techniques for Different Types of Faces: An Analysis of 1000 Asian Patients Over 9 Years.

A face-lift or rhytidectomy is the procedure most directly associated with rejuvenation. There are several surgical techniques for face-lifts, but criteria for the selection of techniques, based on the patient's face shape, are lacking. In this study, we report on our experience with specific indication criteria for each technique and the consequent achievement of good outcomes. From 2015 to 2023, 1 surgeon performed face-lifts on 1000 patients. Three different superficial musculoaponeurotic system (SMAS) techniques (SMAS dissection, SMASectomy, and SMAS plication) were applied depending on the degree of sagging of the patient's lower face, lateral facial profile, and SMAS mobility and condition. Superficial musculoaponeurotic system dissection was considered for the improvement of a square face, sagging jowls, and marionette lines. Superficial musculoaponeurotic system plication was applied with patients with less sagging jowls and prominent zygoma with concave lateral facial profile. SMASectomy was applied with patients with convex lateral facial profiles or when the SMAS was too thin or damaged. Patient postoperative satisfaction was surveyed using the FACE-Q score 1 year post surgery. Most of the patients attained natural-looking and long-lasting aesthetic outcomes and exhibited high satisfaction. The patients indicated that they looked about 11.2 ± 5.2 years younger than their actual age after the surgery. The mean satisfaction scores for each facial feature were as follows: cheeks (91.1 ± 7.8), marionette lines (88.5 ± 13.6), lower face and jawline (92.5 ± 14.2), under chin (87.8 ± 15.1), and neck (86.2 ± 18.5). Complications such as facial nerve injury, infection, hematoma, and flap necrosis were very rare. Establishing criteria for the selection of face-lift surgical techniques based on the degree of lower face sagging, lateral facial profile, and SMAS mobility and condition led to good outcomes. These criteria can be used by physicians to determine the most effective face-lift surgery technique based on a patient's individual features, which may improve surgical outcomes.

Aesthetic Temporal Augmentation with the Pedicled Temporoparietal Fascia Flap.

The contour of the temple area can significantly influence the overall facial shape and proportions. To date, various methods and techniques have been used to augment the deficient temporal fossa; however, each of these approaches has certain inherent limitations. The present study aimed to transfer the temporoparietal fascia flap (TPFF) to the frontotemporal regions for aesthetic temporal augmentation. This was a retrospective study of 13 cases with temporal depression who underwent a TPFF procedure for aesthetic temporal augmentation. These cases were operated for three years, from January 1, 2020, to December 1, 2023, at Nanjing Second Hospital, Nanjing, China. The data of bilateral temple width showed a measurement of 12.20 ± 0.53cm (preoperative) and 14.36 ± 0.41cm (postoperative), with a statistically significant difference (p < 0.001). There were no postoperative complications, including hematomas, infection, or facial nerve injuries. All patients were followed for 6 to 48 months (mean: 18 months) and exhibited cosmetic improvement. Overall, 10 patients were satisfied with the aesthetic results, while 3 were unsatisfied due to undercorrected depression. During the follow-up period, the temple volume was maintained. The frontal temple exhibited a smooth contour, and scalp baldness at the incision site was inconspicuous. Compared with other methods, the pedicled TPFF flap transfer is a safe and effective technique for correcting depressions in the frontotemporal regions. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors. www.springer.com/00266 .

Research on prevention and control tracking system based on 3D face recognition

In order to improve the tracking effect of prevention and control, this paper combines three-dimensional face recognition technology and posture recognition method to build a prevention and control tracking system, and designs a single-stage human target detection and posture estimation network based on thermal infrared images. By using infrared recognition methods, the face and human body shape can be directly recognized, overcoming the problem of traditional visual recognition methods being easily occluded. The network can simultaneously complete two tasks of human target detection and pose estimation in a multi-task manner. Moreover, this paper uses the knowledge distillation strategy to train a lightweight model to further reduce the amount of model parameters to improve the inference speed. In addition, this paper uses a single-stage human target detection and posture estimation network to judge the effect of prevention and control tracking. Through the prevention and control tracking effect test, it can be seen that the prevention and control tracking system based on 3D face recognition proposed in this paper can effectively improve the prevention and control tracking effect.

Chronic paternal alcohol exposures induce dose-dependent changes in offspring craniofacial shape and symmetry.

Although dose-response analyses are a fundamental tool in developmental toxicology, few studies have examined the impacts of toxicant dose on the non-genetic paternal inheritance of offspring disease and dysgenesis. In this study, we used geometric morphometric analyses to examine the impacts of different levels of preconception paternal alcohol exposure on offspring craniofacial shape and symmetry in a mouse model. Procrustes ANOVA followed by canonical variant analysis of geometric facial relationships revealed that Low-, Medium-, and High-dose treatments each induced distinct changes in craniofacial shape and symmetry. Our analyses identified a dose threshold between 1.543 and 2.321g/kg/day. Below this threshold, preconception paternal alcohol exposure induced changes in facial shape, including a right shift in facial features. In contrast, above this threshold, paternal exposures caused shifts in both shape and center, disrupting facial symmetry. Consistent with previous clinical studies, changes in craniofacial shape predominantly mapped to regions in the lower portion of the face, including the mandible (lower jaw) and maxilla (upper jaw). Notably, high-dose exposures also impacted the positioning of the right eye. Our studies reveal that paternal alcohol use may be an unrecognized factor contributing to the incidence and severity of alcohol-related craniofacial defects, complicating diagnostics of fetal alcohol spectrum disorders.

Advanced deep learning for masked individual surveillance

During Covid-19 pandemic, face masks have become a ubiquitous protective measure. This poses new challenges for surveillance systems that heavily rely on facial recognition. To address this critical issue, we present a novel enhanced surveillance system that leverages deep learning techniques to tackle two crucial tasks simultaneously: anomaly detection of masked individuals' activities and masked face completion for accurate recognition. For anomaly detection, we employ a custom-designed deep neural network capable of processing real-time video streams. Finding a dataset of anomaly events of masked individuals is a big challenge for us. We handle this challenge using efficient techniques such as Dlib library and other image processing techniques. The network is trained on a diverse dataset encompassing normal and abnormal activities of masked individuals, enabling it to identify suspicious behaviors effectively. The surveillance cameras will exchange information, using a suitable network protocol, about detected anomalies and share relevant image data to aid in decision-making and choose the best images for further processing. In the context of masked face completion, we present a novel architecture called CCGAN network that is a combination of convolutional neural network (CNN) and conditioned generative adversarial network (CGAN) to generate the hidden parts of the face in a form that is accurate and close to the original face shape, as shown in our results. We conduct extensive experiments on publicly available datasets, demonstrating superior performance in both anomaly detection and masked face completion tasks. We have achieved 90% accuracy for anomaly detection of masked people.

디지털 휴먼 캐릭터의 성격 특성과 안면 디자인의 관계 탐색

Due to the development of AI technology, the use of digital humans and their market value are on the rise. Accordingly, as an alternative approach to communication between digital humans and users and building brand image, the purpose of this study is to suggest design elements by applying the Enneagram, Carl Jung's personality types, and Sasang Constitution's personality characteristics to facial design. To this end, the connection between each personality theory and digital human facial design was identified. Alternative design elements were extracted by finding consistency between the nine personality types of the Enneagram, Carl Jung's four personality types, and the four personality traits of Sasang Constitution. There are four possible facial shapes: rectangular, inverted triangle, oval, and square. These are the criteria for facial proportions and include facial shape and overall facial features, specifically the size and protrusion of eyes, nose, mouth, and forehead, and facial features. The location of the central axis and the degree of sagging were specified. As a result of the study, the significance of this study was that it found consistency between each personality type used as an argument for this study and used this to suggest alternative design guidelines.

얼굴형과 성별에 따른 선글라스 선호도 연구

얼굴형과 성별에 따른 선글라스 선호도 연구

Palatal segment contributions to midfacial anterior-posterior growth.

Anterior-posterior (A-P) elongation of the palate is a critical aspect of integrated midfacial morphogenesis. Reciprocal epithelial-mesenchymal interactions drive secondary palate elongation that is coupled to the periodic formation of signaling centers within the rugae growth zone (RGZ). However, the relationship between RGZ driven morphogenetic processes, the differentiative dynamics of underlying palatal bone mesenchymal precursors, and the segmental organization of the upper jaw has remained enigmatic. A detailed ontogenetic study of these relationships is important, because palatal segment growth is a critical aspect of normal midfacial growth, can be modified to produce dysmorphology, and is a likely basis for evolutionary differences in upper jaw morphology. Variation in palatal-segment specific growth may also underlie known differences in palatal segment proportions between inbred mouse strains. We completed a combined whole mount gene expression and morphometric analysis of normal murine palatal growth dynamics and their association with palatal segment elongation and resulting upper jaw morphology. Our results demonstrated that the first formed palatal ruga (ruga 1), found just posterior to the RGZ, maintained an association with important nasal, neurovascular and palatal structures throughout early midfacial development; suggesting that these features are positioned at a proximal source of embryonic midfacial directional growth. Our detailed characterization of midfacial morphogenesis revealed a one-to-one relationship between palatal segments and upper jaw bones during the earliest stages of palatal elongation. Growth of the maxillary anlage within the anterior secondary palate is uniquely coupled to RGZ-driven morphogenesis that more than doubles the length of this palatal segment prior to palatal shelf fusion. Our results also demonstrate that the future maxillary-palatine suture, approximated by the position ruga 1 and consistently associated with the palatine anlage, forms predominantly via the posterior differentiation of the maxilla within the expanding anterior secondary palate. Our complementary ontogenetic comparison of three inbred mouse strains identified small but significant strain-specific differences in early embryonic palatal segment contributions to the upper jaw. Although early palatal segment specific growth is not primarily responsible for adult differences in upper jaw morphology between these strains, our ontogenetic series of measurements provide a useful foundation for understanding the impact of background genetic effects on facial shape and elongation. In combination, our results provide a novel and particularly detailed picture of the earliest spatiotemporal dynamics of intramembranous midfacial skeletal specification and differentiation within the context of the surrounding palatal segment A-P elongation and associated rugae formation.

Sexual Dimorphism: The Interrelation of Shape and Color

Sex-typicality displayed as sexual dimorphism of the human face is a key feature enabling sex recognition. It is also believed to be a cue for perceiving biological quality and it plays an important role in the perception of attractiveness. Sexual dimorphism of human faces has two main components: sexual shape dimorphism of various facial features and sexual color dimorphism, generally manifested as dimorphism of skin luminance, where men tend to be darker than women. However, very little is known about the mutual relationship of these two facets. We explored the interconnection between the dimorphism of face shape and dimorphism of face color in three visually distinct populations (Cameroonian, Czech, and Vietnamese). Our results indicated that populations which showed a significant dimorphism in skin luminance (Cameroon, Vietnam) had low levels of sexual shape dimorphism, while a population with higher levels of sexual shape dimorphism (Czech Republic) did not exhibit a significant dimorphism of skin luminance. These findings suggest a possible compensatory mechanism between various domains of sexual dimorphism in populations differing in the levels of shape and color dimorphism.