1
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Bencharattanaphakhi R, Wananukul S, Tempark T, Chatproedprai S. A 595 nm pulsed dye laser as an adjuvant intervention for post-comedone extraction erythema and comedone reduction: A randomized, split-face controlled trial. J Cosmet Dermatol 2024; 23:1645-1653. [PMID: 38192163 DOI: 10.1111/jocd.16178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 12/28/2023] [Indexed: 01/10/2024]
Abstract
BACKGROUND Comedone extraction provides greater satisfaction for acne treatment than conventional treatment alone; however, post-comedone extraction erythema (PCEE) remains a concern for patients. OBJECTIVES To evaluate the efficacy of pulsed-dye laser (PDL) in PCEE and comedone reduction. METHODS Mild-to-moderate acne patients were randomly allocated in split-face fashion. Three comedones were extracted on each facial side. On the PDL-treated side, 595-nm PDL was delivered to the entire side with an additional shot on three comedone-extracted sites. Erythema index (EI) and total acne lesion counts (TALC) were evaluated at baseline, week 2 and 4. The comprehensive acne severity scale (CASS) was assessed by three blinded independent pediatric dermatologists. Participant satisfaction surveys were completed at the end of the study. RESULTS Thirty-five participants (age 12.9-24.2 years) showed no differences in the EI and TALC at baseline on both sides. At weeks 2 and 4, the EI on the PDL-treated side was significantly lower (p < 0.001) with a greater EI reduction (p < 0.001) when compared to the control side regardless of gender and menstruation. There was significantly lower TALC on the PDL-treated side at week 2 (p < 0.001) and week 4 (p = 0.02). No complications were noted with high participant satisfaction reported (median 8; IQR 7-9). PDL remained significantly associated with EI improvements after controlling for gender, menstruation cycle, and examination stress. CONCLUSION PDL can be an adjunctive intervention for the treatment of PCEE and comedone reduction due to its effectiveness and high participant satisfaction.
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Affiliation(s)
- Rungrot Bencharattanaphakhi
- Division of Pediatric Dermatology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
- Division of Pediatric Dermatology, Department of Pediatrics, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
| | - Siriwan Wananukul
- Division of Pediatric Dermatology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Therdpong Tempark
- Division of Pediatric Dermatology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
| | - Susheera Chatproedprai
- Division of Pediatric Dermatology, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, and King Chulalongkorn Memorial Hospital, Bangkok, Thailand
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2
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Stern J, Ostermann S, Penke L. Investigating cycle shifts in women's clothing style and grooming. BRITISH JOURNAL OF SOCIAL PSYCHOLOGY 2024; 63:378-402. [PMID: 37646294 DOI: 10.1111/bjso.12681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 07/15/2023] [Indexed: 09/01/2023]
Abstract
In contrast to some non-human primate species, human females do not show overt cues to fertility. Previous research argued that women still show systematic changes in their appearance across their ovulatory cycle to enhance their mating success when fertile. We report five studies investigating whether women's clothing style and grooming behaviour change across the ovulatory cycle. All studies were large (with N = 157 in Study 1, N = 109 in Study 2, N = 257 in Studies 3-5), longitudinal studies with four testing sessions per participant. They involved salivary hormone samples and luteinizing hormone tests to validate conception risk estimates. Across all studies, our results suggest no compelling evidence for cycle shifts in clothing style and grooming. Rather, two studies suggest effects in the opposite direction as hypothesized, as women wore more skin-revealing clothes when non-fertile. One study suggests small effects of wearing necklaces more and eyeglasses less often when fertile. However, these effects were not robust across all studies. Our results are in line with other recent null replications and suggest that, if existent, cues to fertility might be even more subtle than previously assumed. We discuss the need for testing competing theories that explain the evolution of concealed ovulation.
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Affiliation(s)
- Julia Stern
- Department of Psychology, University of Bremen, Bremen, Germany
- Department of Psychology, University of Goettingen, Goettingen, Germany
| | - Sabine Ostermann
- Department of Psychology, University of Goettingen, Goettingen, Germany
| | - Lars Penke
- Department of Psychology, University of Goettingen, Goettingen, Germany
- Leibniz ScienceCampus Primate Cognition, Goettingen, Germany
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3
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Schleifenbaum L, Stern J, Driebe JC, Wieczorek LL, Gerlach TM, Arslan RC, Penke L. Men are not aware of and do not respond to their female partner's fertility status: Evidence from a dyadic diary study of 384 couples. Horm Behav 2022; 143:105202. [PMID: 35661968 DOI: 10.1016/j.yhbeh.2022.105202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 04/18/2022] [Accepted: 05/16/2022] [Indexed: 11/23/2022]
Abstract
Understanding how human mating psychology is affected by changes in female cyclic fertility is informative for comprehending the evolution of human reproductive behavior. Based on differential selection pressures between the sexes, men are assumed to have evolved adaptations to notice women's within-cycle cues to fertility and show corresponding mate retention tactics to secure access to their female partners when fertile. However, previous studies suffered from methodological shortcomings and yielded inconsistent results. In a large, preregistered online dyadic diary study (384 heterosexual couples), we found no compelling evidence that men notice women's fertility status (as potentially reflected in women's attractiveness, sexual desire, or wish for contact with others) or display mid-cycle increases in mate retention tactics (jealousy, attention, wish for contact or sexual desire towards female partners). These results extend our current understanding of the evolution of women's concealed ovulation and oestrus, and suggest that both might have evolved independently.
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Affiliation(s)
- Lara Schleifenbaum
- University of Goettingen, Goettingen, Germany; Leibniz ScienceCampus Primate Cognition, Goettingen, Germany.
| | - Julia Stern
- University of Goettingen, Goettingen, Germany; University of Bremen, Bremen, Germany
| | | | | | - Tanja M Gerlach
- University of Goettingen, Goettingen, Germany; Leibniz ScienceCampus Primate Cognition, Goettingen, Germany; Queen's University Belfast, Northern Ireland, United Kingdom
| | - Ruben C Arslan
- University of Leipzig, Leipzig, Germany; Max Planck Institute for Human Development, Berlin, Germany
| | - Lars Penke
- University of Goettingen, Goettingen, Germany; Leibniz ScienceCampus Primate Cognition, Goettingen, Germany
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4
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Rigaill L, Vaglio S, Setchell JM, Suda-Hashimoto N, Furuichi T, Garcia C. Chemical cues of identity and reproductive status in Japanese macaques. Am J Primatol 2022; 84:e23411. [PMID: 35757843 DOI: 10.1002/ajp.23411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/26/2022] [Accepted: 05/27/2022] [Indexed: 01/30/2023]
Abstract
Olfactory communication plays an important role in the regulation of socio-sexual interactions in mammals. There is growing evidence that both human and nonhuman primates rely on odors to inform their mating decisions. Nevertheless, studies of primate chemical ecology remain scarce due to the difficulty of obtaining and analyzing samples. We analyzed 67 urine samples from five captive female Japanese macaques (Macaca fuscata) and 30 vaginal swabs from three of these females using gas chromatography-mass spectrometry and examined the relationship between odor (compounds identified, richness, intensity, and diversity) and female identity as well as cycle phase. We found a total of 36 urine compounds of which we identified 31, and 68 vaginal compounds of which we identified 37. Our results suggest that urine and vaginal odor varied more between individuals than within cycle phases. However, we found that within a female cycle, urine samples from similar phases may cluster more than samples from different phases. Our results suggest that female odor may encode information about identity (vaginal and urine odor) and reproductive status (urine odor). The question of how conspecifics use female urine and vaginal odor remains open and could be tested using bioassays. Our results and their interpretation are constrained by our limited sample size and our study design. Nonetheless, our study provides insight into the potential signaling role of female odor in sexual communication in Japanese macaques and contributes to our understanding of how odors may influence mating strategies in primates.
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Affiliation(s)
- Lucie Rigaill
- EthoS (Éthologie animale et humaine), CNRS, Université de Rennes 1, Normandie Université, Rennes, France.,Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Japan
| | - Stefano Vaglio
- School of Sciences, University of Wolverhampton, Wolverhampton, UK
| | - Joanna M Setchell
- Department of Anthropology & Behaviour, Ecology and Evolution Research Centre, Durham University, Durham, UK
| | - Naoko Suda-Hashimoto
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Japan
| | - Takeshi Furuichi
- Center for the Evolutionary Origins of Human Behavior, Kyoto University, Inuyama, Japan
| | - Cécile Garcia
- Eco-anthropologie (EA), Muséum national d'Histoire naturelle, CNRS, Université Paris Cité, Paris, France
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5
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Mei M, Grillot RL, Abbey CK, Emery Thompson M, Roney JR. Does scent attractiveness reveal women's ovulatory timing? Evidence from signal detection analyses and endocrine predictors of odour attractiveness. Proc Biol Sci 2022; 289:20220026. [PMID: 35259990 PMCID: PMC8905178 DOI: 10.1098/rspb.2022.0026] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Odour cues associated with shifts in ovarian hormones indicate ovulatory timing in females of many nonhuman species. Although prior evidence supports women's body odours smelling more attractive on days when conception is possible, that research has left ambiguous how diagnostic of ovulatory timing odour cues are, as well as whether shifts in odour attractiveness are correlated with shifts in ovarian hormones. Here, 46 women each provided six overnight scent and corresponding day saliva samples spaced five days apart, and completed luteinizing hormone tests to determine ovulatory timing. Scent samples collected near ovulation were rated more attractive, on average, relative to samples from the same women collected on other days. Importantly, however, signal detection analyses showed that rater discrimination of fertile window timing from odour attractiveness ratings was very poor. Within-women shifts in salivary oestradiol and progesterone were not significantly associated with within-women shifts in odour attractiveness. Between-women, mean oestradiol was positively associated with mean odour attractiveness. Our findings suggest that raters cannot reliably detect women's ovulatory timing from their scent attractiveness. The between-women effect of oestradiol raises the possibility that women's scents provide information about overall cycle fecundity, though further research is necessary to rigorously investigate this possibility.
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Affiliation(s)
- Mei Mei
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA, USA
| | - Rachel L. Grillot
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA, USA
| | - Craig K. Abbey
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA, USA
| | | | - James R. Roney
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA, USA
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6
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Jones BC, Jones AL, Shiramizu V, Anderson C. What Does Women's Facial Attractiveness Signal? Implications for an Evolutionary Perspective on Appearance Enhancement. ARCHIVES OF SEXUAL BEHAVIOR 2022; 51:67-71. [PMID: 33733308 PMCID: PMC8858290 DOI: 10.1007/s10508-021-01955-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/09/2021] [Accepted: 02/11/2021] [Indexed: 05/11/2023]
Affiliation(s)
- Benedict C Jones
- School of Psychological Sciences and Health, University of Strathclyde, Glasgow, G4 0LN, Scotland.
| | - Alex L Jones
- Department of Psychology, Swansea University, Swansea, Wales
| | - Victor Shiramizu
- Institute of Psychology & Neuroscience, University of Glasgow, Glasgow, Scotland
| | - Claire Anderson
- Textile Design Programme, Chelsea College of Arts, University of the Arts London, London, England
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7
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Lu Y, Yang J, Xiao K, Pointer M, Li C, Wuerger S. Skin coloration is a culturally-specific cue for attractiveness, healthiness, and youthfulness in observers of Chinese and western European descent. PLoS One 2021; 16:e0259276. [PMID: 34710190 PMCID: PMC8553160 DOI: 10.1371/journal.pone.0259276] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 10/15/2021] [Indexed: 11/20/2022] Open
Abstract
Facial skin coloration signals information about an individual and plays an important role in social interactions and mate choice, due its putative association with health, attractiveness, and age. Whether skin coloration as an evolutionary significant cue is universal or specific to a particular culture is unclear and current evidence on the universality of skin color as a cue to health and attractiveness are equivocal. The current study used 80 calibrated, high-resolution, non-manipulated images of real human faces, either of Chinese or western European descent, which were rated in terms of attractiveness, healthiness, and perceived age by 44 observers, 22 western European (13 male; mean age ± SD = 24.27 ± 5.30) and 22 Chinese (7 male; mean age ± SD = 26.05 ± 3.96) observers. To elucidate the associations between skin coloration and these perceptual ratings and whether these associations are modulated by observer or image ethnicity, a linear mixed-effect model was setup with skin lightness (L*; CIELAB), redness (a*) and yellowness (b*), observer and image ethnicity as independent variables and perceived attractiveness, healthiness, and estimated age as dependent variables. We found robust positive associations between facial skin lightness (L*) and attractiveness, healthiness, and youthfulness, but only when Chinese observers judge facial images of their own ethnicity. Observers of European descent, on the other hand, associated an increase in yellowness(b*) with greater attractiveness and healthiness in Chinese facial images. We find no evidence that facial redness is positively associated with these attributes; instead, an increase in redness (a*) is associated with an increase in the estimated age of European facial images. We conclude that observers of both ethnicities make use of skin color and lightness to rate attractiveness, healthiness, and perceived age, but to a lesser degree than previously thought. Furthermore, these coloration cues are not universal and are utilized differently within the Chinese and western European ethnic groups. Our study adds to the growing body of work demonstrating the importance of skin color manipulations within an evolutionary meaningful parameter space, ideally using realistic skin models based on physical parameters.
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Affiliation(s)
- Yan Lu
- School of Design, University of Leeds, Leeds, United Kingdom
| | - Jie Yang
- School of Design, University of Leeds, Leeds, United Kingdom
- School of New Media, Beijing Institute of Graphic Communication, Beijing, China
| | - Kaida Xiao
- School of Design, University of Leeds, Leeds, United Kingdom
| | - Michael Pointer
- School of Design, University of Leeds, Leeds, United Kingdom
| | - Changjun Li
- School of Computer Science and Software Engineering, University of Science and Technology Liaoning, Anshan, China
| | - Sophie Wuerger
- Department of Psychology, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
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8
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Schleifenbaum L, Driebe JC, Gerlach TM, Penke L, Arslan RC. Women feel more attractive before ovulation: evidence from a large-scale online diary study. EVOLUTIONARY HUMAN SCIENCES 2021; 3:e47. [PMID: 37588547 PMCID: PMC10427307 DOI: 10.1017/ehs.2021.44] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
How attractive we find ourselves decides who we target as potential partners and influences our reproductive fitness. Self-perceptions on women's fertile days could be particularly important. However, results on how self-perceived attractiveness changes across women's ovulatory cycles are inconsistent and research has seldomly assessed multiple attractiveness-related constructs simultaneously. Here, we give an overview of ovulatory cycle shifts in self-perceived attractiveness, sexual desirability, grooming, self-esteem and positive mood. We addressed previous methodological shortcomings by conducting a large, preregistered online diary study of 872 women (580 naturally cycling) across 70 consecutive days, applying several robustness analyses and comparing naturally cycling women with women using hormonal contraceptives. As expected, we found robust evidence for ovulatory increases in self-perceived attractiveness and sexual desirability in naturally cycling women. Unexpectedly, we found moderately robust evidence for smaller ovulatory increases in self-esteem and positive mood. Although grooming showed an ovulatory increase descriptively, the effect was small, failed to reach our strict significance level of .01 and was not robust to model variations. We discuss how these results could follow an ovulatory increase in sexual motivation while calling for more theoretical and causally informative research to uncover the nature of ovulatory cycle shifts in the future.
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Affiliation(s)
- Lara Schleifenbaum
- Georg August University, Goettingen, Germany
- Leibniz ScienceCampus Primate Cognition, Goettingen, Germany
| | | | - Tanja M. Gerlach
- Georg August University, Goettingen, Germany
- Leibniz ScienceCampus Primate Cognition, Goettingen, Germany
| | - Lars Penke
- Georg August University, Goettingen, Germany
- Leibniz ScienceCampus Primate Cognition, Goettingen, Germany
| | - Ruben C. Arslan
- Leibniz ScienceCampus Primate Cognition, Goettingen, Germany
- University of Leipzig, Leipzig, Germany
- Max Planck Institute for Human Development, Berlin, Germany
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9
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Marcinkowska UM, Jones BC, Cai H, Contreras-Garduno J, Onyishi IE, Orjiakor CT, Prasai K, Pazhoohi F, Taniguchi H, Lee AJ. An exploratory, cross-cultural study on perception of putative cyclical changes in facial fertility cues. Sci Rep 2021; 11:16911. [PMID: 34413430 PMCID: PMC8377019 DOI: 10.1038/s41598-021-96454-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 08/02/2021] [Indexed: 11/09/2022] Open
Abstract
Although many researchers have argued that facial traits evolved as honest cues to women's current fertility (possibly via changes in facial femininity), evidence that women's facial attractiveness is significantly, positively related to probability of conception throughout menstrual cycle is mixed. These mixed results could reflect differences among studies in the methods used to assess facial attractiveness (i.e., forced choice versus rating-scale methods), differences in how fertility was assessed, differences in perceiver characteristics (e.g., their own attractiveness), and facial preferences possibly being moderated by the characteristics of the living environment. Consequently, the current study investigated the putative effect of cyclical changes in fertility on women's facial attractiveness and femininity (1) using forced choice and rating-scale method, (2) conducting both ovulation tests and repeated daily measures of estradiol assessing the conception probability, (3) based on a culturally diverse sample of perceivers, while (4) controlling for inter-individual variation. Although we found some limited evidence that women's faces became more attractive when conception probability increased, these effects differed depending on the methods used to assess both attractiveness and fertility. Moreover, where statistically significant effects were observed, the effect sizes were extremely small. Similarly, there was little robust evidence that perceivers' characteristics reliably predicted preferences for fertility cues. Collectively, these results suggest that mixed results in previous studies examining cyclical fluctuation in women's facial attractiveness are unlikely to reflect inter-cultural differences and are more likely to reflect differences in the methods used to assess facial attractiveness and fertility.
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Affiliation(s)
| | - Benedict C Jones
- School of Psychology, University of Strathclyde, Glasgow, Scotland, UK
| | - Huaijan Cai
- Institute of Psychology, Chinese Academy of Sciences, Beijing, People's Republic of China
| | | | - Ike E Onyishi
- Department of Psychology, University of Nigeria, Nsukka, Nigeria
| | | | | | - Farid Pazhoohi
- Department of Psychology, University of British Columbia, Vancouver, Canada
| | | | - Anthony J Lee
- Division of Psychology, University of Stirling, Stirling, Scotland, UK
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10
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Humphrey S, Manson Brown S, Cross SJ, Mehta R. Defining Skin Quality: Clinical Relevance, Terminology, and Assessment. Dermatol Surg 2021; 47:974-981. [PMID: 34148998 PMCID: PMC8231670 DOI: 10.1097/dss.0000000000003079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Flawless skin is one of the most universally desired features, and demand for improvements in skin quality is growing rapidly. Skin quality has been shown to substantially impact emotional health, quality of life, self-perception, and interactions with others. Although skin quality improvements are a common end point in studies of cosmeceuticals, they are rarely assessed in clinical studies of other aesthetic treatments and products. Descriptive terminology for skin quality parameters also varies considerably within the aesthetic field, relying on a range of redundant and occasionally contradictory descriptors. In short, skin quality has not been clearly defined. OBJECTIVE The goal of this review is to highlight the importance of skin quality to patients and physicians, explore known and unknown factors comprising skin quality, and provide clarity regarding terminology, descriptors, and evaluation tools for assessing skin quality. MATERIALS AND METHODS A review of the literature on skin quality was performed without limitation on publication date. Relevant articles are presented. RESULTS AND CONCLUSION We propose a framework of attributes contributing to skin quality rooted in 3 fundamental categories-visible, mechanical, and topographical-with the aim to provide information to help guide clinicians and inform future clinical studies.
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Affiliation(s)
- Shannon Humphrey
- Humphrey Cosmetic Dermatology, Vancouver, British Columbia, Canada
- Department of Dermatology and Skin Science, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | - Rahul Mehta
- Allergan Aesthetics, an AbbVie Company, Irvine, California
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11
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Abstract
Because of the strong overreliance on p values in the scientific literature, some researchers have argued that we need to move beyond p values and embrace practical alternatives. When proposing alternatives to p values statisticians often commit the “statistician’s fallacy,” whereby they declare which statistic researchers really “want to know.” Instead of telling researchers what they want to know, statisticians should teach researchers which questions they can ask. In some situations, the answer to the question they are most interested in will be the p value. As long as null-hypothesis tests have been criticized, researchers have suggested including minimum-effect tests and equivalence tests in our statistical toolbox, and these tests have the potential to greatly improve the questions researchers ask. If anyone believes p values affect the quality of scientific research, preventing the misinterpretation of p values by developing better evidence-based education and user-centered statistical software should be a top priority. Polarized discussions about which statistic scientists should use has distracted us from examining more important questions, such as asking researchers what they want to know when they conduct scientific research. Before we can improve our statistical inferences, we need to improve our statistical questions.
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Affiliation(s)
- Daniël Lakens
- Department of Industrial Engineering and Innovation Sciences, Eindhoven University of Technology
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12
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Fine-scale variation in lip and cheek colour according to the timing of ovulation in women. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02851-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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13
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Necka EA, Kardan O, Puts DA, Faig KE, Berman MG, Norman GJ. Visual cues to fertility are in the eye (movements) of the beholder. Horm Behav 2019; 115:104562. [PMID: 31356808 DOI: 10.1016/j.yhbeh.2019.104562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 07/20/2019] [Accepted: 07/24/2019] [Indexed: 11/17/2022]
Abstract
Past work demonstrates that humans behave differently towards women across their menstrual cycles, even after exclusively visual exposure to women's faces. People may look at women's faces differently as a function of women's menstrual cycles. Analyses of participants' scanpaths (eye movement patterns) while they looked at women at different phases of their menstrual cycles revealed that observers exhibit more consistent scanpaths when examining women's faces when women are in a menstrual cycle phase that typically corresponds with peak fertility, whereas they exhibit more variable patterns when looking at women's faces when they are in phases that do not correspond with fertility. A multivariate classifier on participants' scanpaths predicted whether they were looking at the face of a woman in a more typically fertile- versus non-fertile-phase of her menstrual cycle with above-chance accuracy. These findings demonstrate that people look at women's faces differently as a function of women's menstrual cycles, and suggest that people are sensitive to fluctuating visual cues associated with women's menstrual cycle phase.
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Affiliation(s)
- Elizabeth A Necka
- Department of Psychology, University of Chicago, United States of America.
| | - Omid Kardan
- Department of Psychology, University of Chicago, United States of America
| | - David A Puts
- Department of Anthropology, Pennsylvania State University, United States of America
| | - Kelly E Faig
- Department of Psychology, University of Chicago, United States of America
| | - Marc G Berman
- Department of Psychology, University of Chicago, United States of America
| | - Greg J Norman
- Department of Psychology, University of Chicago, United States of America
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14
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The redder the better? Information content of red skin coloration in female Japanese macaques. Behav Ecol Sociobiol 2019. [DOI: 10.1007/s00265-019-2712-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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15
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Thorstenson CA, Pazda AD, Elliot AJ. Social Perception of Facial Color Appearance for Human Trichromatic Versus Dichromatic Color Vision. PERSONALITY AND SOCIAL PSYCHOLOGY BULLETIN 2019; 46:51-63. [DOI: 10.1177/0146167219841641] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Typical human color vision is trichromatic, on the basis that we have three distinct classes of photoreceptors. A recent evolutionary account posits that trichromacy facilitates detecting subtle skin color changes to better distinguish important social states related to proceptivity, health, and emotion in others. Across two experiments, we manipulated the facial color appearance of images consistent with a skin blood perfusion response and asked participants to evaluate the perceived attractiveness, health, and anger of the face (trichromatic condition). We additionally simulated what these faces would look like for three dichromatic conditions (protanopia, deuteranopia, tritanopia). The results demonstrated that flushed (relative to baseline) faces were perceived as more attractive, healthy, and angry in the trichromatic and tritanopia conditions, but not in the protanopia and deuteranopia conditions. The results provide empirical support for the social perception account of trichromatic color vision evolution and lead to systematic predictions of social perception based on ecological social perception theory.
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16
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Le Moëne O, Ågmo A. The neuroendocrinology of sexual attraction. Front Neuroendocrinol 2018; 51:46-67. [PMID: 29288076 DOI: 10.1016/j.yfrne.2017.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 12/21/2017] [Accepted: 12/24/2017] [Indexed: 01/23/2023]
Abstract
Sexual attraction has two components: Emission of sexually attractive stimuli and responsiveness to these stimuli. In rodents, olfactory stimuli are necessary but not sufficient for attraction. We argue that body odors are far superior to odors from excreta (urine, feces) as sexual attractants. Body odors are produced by sebaceous glands all over the body surface and in specialized glands. In primates, visual stimuli, for example the sexual skin, are more important than olfactory. The role of gonadal hormones for the production of and responsiveness to odorants is well established. Both the androgen and the estrogen receptor α are important in male as well as in female rodents. Also in primates, gonadal hormones are necessary for the responsiveness to sexual attractants. In males, the androgen receptor is sufficient for sustaining responsiveness. In female non-human primates, estrogens are needed, whereas androgens seem to contribute to responsiveness in women.
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Affiliation(s)
| | - Anders Ågmo
- Department of Psychology, University of Tromsø, Norway.
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17
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Lakens D, Scheel AM, Isager PM. Equivalence Testing for Psychological Research: A Tutorial. ADVANCES IN METHODS AND PRACTICES IN PSYCHOLOGICAL SCIENCE 2018. [DOI: 10.1177/2515245918770963] [Citation(s) in RCA: 502] [Impact Index Per Article: 83.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Psychologists must be able to test both for the presence of an effect and for the absence of an effect. In addition to testing against zero, researchers can use the two one-sided tests (TOST) procedure to test for equivalence and reject the presence of a smallest effect size of interest (SESOI). The TOST procedure can be used to determine if an observed effect is surprisingly small, given that a true effect at least as extreme as the SESOI exists. We explain a range of approaches to determine the SESOI in psychological science and provide detailed examples of how equivalence tests should be performed and reported. Equivalence tests are an important extension of the statistical tools psychologists currently use and enable researchers to falsify predictions about the presence, and declare the absence, of meaningful effects.
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Affiliation(s)
- Daniël Lakens
- Human-Technology Interaction Group, Eindhoven University of Technology
| | - Anne M. Scheel
- Human-Technology Interaction Group, Eindhoven University of Technology
| | - Peder M. Isager
- Human-Technology Interaction Group, Eindhoven University of Technology
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18
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Women’s Attention to and Memory for Fertile- and Non-Fertile Phase Women Across the Menstrual Cycle. ADAPTIVE HUMAN BEHAVIOR AND PHYSIOLOGY 2018. [DOI: 10.1007/s40750-018-0093-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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19
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Thorstenson CA. The Social Psychophysics of Human Face Color: Review and Recommendations. SOCIAL COGNITION 2018. [DOI: 10.1521/soco.2018.36.2.247] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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20
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Rowland HM, Burriss RP. Human colour in mate choice and competition. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0350. [PMID: 28533465 DOI: 10.1098/rstb.2016.0350] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2017] [Indexed: 01/17/2023] Open
Abstract
The colour of our skin and clothing affects how others perceive us and how we behave. Human skin colour varies conspicuously with genetic ancestry, but even subtle changes in skin colour due to diet, blood oxygenation and hormone levels influence social perceptions. In this review, we describe the theoretical and empirical frameworks in which human colour is researched. We explore how subtle skin colour differences relate to judgements of health and attractiveness. Also, because humans are one of the few organisms able to manipulate their apparent colour, we review how cosmetics and clothing are implicated in courtship and competition, both inside the laboratory and in the real world. Research on human colour is in its infancy compared with human psychophysics and colour research in non-human animals, and hence we present best-practice guidelines for methods and reporting, which we hope will improve the validity and reproducibility of studies on human coloration.This article is part of the themed issue 'Animal coloration: production, perception, function and application'.
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Affiliation(s)
- Hannah M Rowland
- Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK .,Institute of Zoology, Zoological Society of London, London NW1 4RY, UK
| | - Robert P Burriss
- Faculty of Psychology, Basel University, Basel 4055, Switzerland
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21
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Marcinkowska UM, Galbarczyk A, Jasienska G. La donna è mobile? Lack of cyclical shifts in facial symmetry, and facial and body masculinity preferences-A hormone based study. Psychoneuroendocrinology 2018; 88:47-53. [PMID: 29161637 DOI: 10.1016/j.psyneuen.2017.11.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 11/13/2017] [Accepted: 11/13/2017] [Indexed: 11/30/2022]
Abstract
Although under investigation for more than two decades, a common agreement on the occurrence of cyclical shifts in women's masculinity and symmetry preferences is still missing. Such shifts are considered to be an important feature of sexual selection as they supposedly direct women's attention towards cues for "good genes" (e.g. masculinity and symmetry) during times when probability of conception is the highest. Multiple studies have, however, failed to find these shifts. We attempt to address this lack of agreement analysing a sample of 110 healthy women, using intra-participant design and repeated measurements of oestradiol and LH during the cycle. To ensure the reliable detection of increased conception probability, both LH- based ovulation tests and multiple oestradiol measurements were used. We found no significant differences between women's preferences during different cycle phases for either body or facial masculinity, or for facial symmetry. Differences remained non-significant after controlling for participants' sexual openness, relationship status, and self-judged attractiveness. We suggest that putative cyclical shifts in preferences for cues for good genes are either very small (impossible to be tracked even with a relatively large sample) or they are far more complex than previously assumed, and further studies accounting for more confounding variables should be undertaken.
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Affiliation(s)
- Urszula M Marcinkowska
- Department of Environmental Health, Faculty of Health Sciences, Jagiellonian University Medical College, 20 Grzegorzecka St., 31-531 Krakow, Poland
| | - Andrzej Galbarczyk
- Department of Environmental Health, Faculty of Health Sciences, Jagiellonian University Medical College, 20 Grzegorzecka St., 31-531 Krakow, Poland.
| | - Grazyna Jasienska
- Department of Environmental Health, Faculty of Health Sciences, Jagiellonian University Medical College, 20 Grzegorzecka St., 31-531 Krakow, Poland
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22
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23
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Hiramatsu C, Melin AD, Allen WL, Dubuc C, Higham JP. Experimental evidence that primate trichromacy is well suited for detecting primate social colour signals. Proc Biol Sci 2018; 284:rspb.2016.2458. [PMID: 28615496 PMCID: PMC5474062 DOI: 10.1098/rspb.2016.2458] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 05/17/2017] [Indexed: 12/14/2022] Open
Abstract
Primate trichromatic colour vision has been hypothesized to be well tuned for detecting variation in facial coloration, which could be due to selection on either signal wavelengths or the sensitivities of the photoreceptors themselves. We provide one of the first empirical tests of this idea by asking whether, when compared with other visual systems, the information obtained through primate trichromatic vision confers an improved ability to detect the changes in facial colour that female macaque monkeys exhibit when they are proceptive. We presented pairs of digital images of faces of the same monkey to human observers and asked them to select the proceptive face. We tested images that simulated what would be seen by common catarrhine trichromatic vision, two additional trichromatic conditions and three dichromatic conditions. Performance under conditions of common catarrhine trichromacy, and trichromacy with narrowly separated LM cone pigments (common in female platyrrhines), was better than for evenly spaced trichromacy or for any of the dichromatic conditions. These results suggest that primate trichromatic colour vision confers excellent ability to detect meaningful variation in primate face colour. This is consistent with the hypothesis that social information detection has acted on either primate signal spectral reflectance or photoreceptor spectral tuning, or both.
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Affiliation(s)
- Chihiro Hiramatsu
- Department of Human Science, Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minamiku, Fukuoka 815-8540, Japan .,Physiological Anthropology Research Center, Kyushu University, 4-9-1 Shiobaru, Minamiku, Fukuoka 815-8540, Japan
| | - Amanda D Melin
- Department of Anthropology and Archaeology, University of Calgary, Calgary, Alberta, Canada.,Department of Medical Genetics, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - William L Allen
- Department of Anthropology, New York University, New York, NY, USA.,Department of Biosciences, Swansea University, Swansea, UK
| | - Constance Dubuc
- Department of Anthropology, New York University, New York, NY, USA.,Department of Zoology, University of Cambridge, Cambridge, UK
| | - James P Higham
- Department of Anthropology, New York University, New York, NY, USA
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24
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Thorstenson CA, Pazda AD, Elliot AJ. Subjective Perception of Color Differences Is Greater for Faces Than Non-Faces. SOCIAL COGNITION 2017. [DOI: 10.1521/soco.2017.35.3.299] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Christopher A. Thorstenson
- Department of Clinical and Social Sciences in Psychology, University of Rochester
- Munsell Color Science Laboratory, Rochester Institute of Technology
| | - Adam D. Pazda
- Department of Psychology, University of South Carolina–Aiken
| | - Andrew J. Elliot
- Department of Clinical and Social Sciences in Psychology, University of Rochester
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25
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Motta-Mena NV, Puts DA. Endocrinology of human female sexuality, mating, and reproductive behavior. Horm Behav 2017; 91:19-35. [PMID: 27866819 DOI: 10.1016/j.yhbeh.2016.11.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 11/02/2016] [Accepted: 11/12/2016] [Indexed: 10/20/2022]
Abstract
Hormones orchestrate and coordinate human female sexual development, sexuality, and reproduction in relation to three types of phenotypic changes: life history transitions such as puberty and childbirth, responses to contextual factors such as caloric intake and stress, and cyclical patterns such as the ovulatory cycle. Here, we review the endocrinology underlying women's reproductive phenotypes, including sexual orientation and gender identity, mate preferences, competition for mates, sex drive, and maternal behavior. We highlight distinctive aspects of women's sexuality such as the possession of sexual ornaments, relatively cryptic fertile windows, extended sexual behavior across the ovulatory cycle, and a period of midlife reproductive senescence-and we focus on how hormonal mechanisms were shaped by selection to produce adaptive outcomes. We conclude with suggestions for future research to elucidate how hormonal mechanisms subserve women's reproductive phenotypes.
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Affiliation(s)
- Natalie V Motta-Mena
- Department of Psychology, Pennsylvania State University, University Park, PA 16802, United States
| | - David A Puts
- Department of Anthropology, Center for Brain, Behavior, and Cognition, Center for Human Evolution and Diversity, Pennsylvania State University, University Park, PA 16802¸ United States.
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26
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Henderson AJ, Lasselin J, Lekander M, Olsson MJ, Powis SJ, Axelsson J, Perrett DI. Skin colour changes during experimentally-induced sickness. Brain Behav Immun 2017; 60:312-318. [PMID: 27847284 DOI: 10.1016/j.bbi.2016.11.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 10/29/2016] [Accepted: 11/08/2016] [Indexed: 12/30/2022] Open
Abstract
Skin colour may be an important cue to detect sickness in humans but how skin colour changes with acute sickness is currently unknown. To determine possible colour changes, 22 healthy Caucasian participants were injected twice, once with lipopolysaccharide (LPS, at a dose of 2ng/kg body weight) and once with placebo (saline), in a randomised cross-over design study. Skin colour across 3 arm and 3 face locations was recorded spectrophotometrically over a period of 8h in terms of lightness (L∗), redness (a∗) and yellowness (b∗) in a manner that is consistent with human colour perception. In addition, carotenoid status was assessed as we predicted that a decrease it skin yellowness would reflect a drop in skin carotenoids. We found an early change in skin colouration 1-3h post LPS injection with facial skin becoming lighter and less red whilst arm skin become darker but also less red and less yellow. The LPS injection also caused a drop in plasma carotenoids from 3h onwards. However, the timing of the carotenoid changes was not consistent with the skin colour changes suggesting that other mechanisms, such as a reduction of blood perfusion, oxygenation or composition. This is the first experimental study characterising skin colour associated with acute illness, and shows that changes occur early in the development of the sickness response. Colour changes may serve as a cue to health, prompting actions from others in terms of care-giving or disease avoidance. Specific mechanisms underlying these colour changes require further investigation.
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Affiliation(s)
- Audrey J Henderson
- School of Psychology and Neuroscience, University of St Andrews, Scotland, United Kingdom.
| | - Julie Lasselin
- Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Stress Research Institute, Stockholm University and Karolinska Institutet, Stockholm, Sweden; Institute of Medical Psychology and Behavioral Immunobiology, Universitätsklinikum, Essen, Germany
| | - Mats Lekander
- Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Stress Research Institute, Stockholm University and Karolinska Institutet, Stockholm, Sweden
| | - Mats J Olsson
- Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Simon J Powis
- School of Medicine, University of St Andrews, Scotland, United Kingdom
| | - John Axelsson
- Division of Psychology, Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Stress Research Institute, Stockholm University and Karolinska Institutet, Stockholm, Sweden
| | - David I Perrett
- School of Psychology and Neuroscience, University of St Andrews, Scotland, United Kingdom
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27
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Thorstenson CA, Pazda AD, Elliot AJ, Perrett DI. Facial Redness Increases Men’s Perceived Healthiness and Attractiveness. Perception 2016; 46:650-664. [DOI: 10.1177/0301006616680124] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Past research has shown that peripheral and facial redness influences perceptions of attractiveness for men viewing women. The current research investigated whether a parallel effect is present when women rate men with varying facial redness. In four experiments, women judged the attractiveness of men’s faces, which were presented with varying degrees of redness. We also examined perceived healthiness and other candidate variables as mediators of the red-attractiveness effect. The results show that facial redness positively influences ratings of men’s attractiveness. Additionally, perceived healthiness was documented as a mediator of this effect, independent of other potential mediator variables. The current research emphasizes facial coloration as an important feature of social judgments.
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Affiliation(s)
- Christopher A. Thorstenson
- Department of Clinical and Social Sciences in Psychology, University of Rochester, NY, USA
- Munsell Color Science Laboratory, Rochester Institute of Technology, NY, USA
| | - Adam D. Pazda
- Department of Psychology, University of South Carolina–Aiken, SC, USA
| | - Andrew J. Elliot
- Department of Clinical and Social Sciences in Psychology, University of Rochester, NY, USA
| | - David I. Perrett
- School of Psychology & Neuroscience, University of St. Andrews, Fife, KY, UK
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28
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Jones AL, Porcheron A, Sweda JR, Morizot F, Russell R. Coloration in different areas of facial skin is a cue to health: The role of cheek redness and periorbital luminance in health perception. Body Image 2016; 17:57-66. [PMID: 26967010 DOI: 10.1016/j.bodyim.2016.02.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 02/05/2016] [Accepted: 02/06/2016] [Indexed: 01/20/2023]
Abstract
Looking healthy is a desirable trait, and facial skin color is a predictor of perceived health. However, skin conditions that cause dissatisfaction with appearance are specific to particular facial areas. We investigated whether color variation in facial skin is related to perceived health. Study 1 defined three areas based on color differences between faces perceived as healthy or unhealthy: the forehead, periorbital areas, and the cheeks. Periorbital luminance and cheek redness predicted perceived health, as did global skin yellowness. In Study 2, increased luminance and redness caused faces to be perceived as healthier, but only when the increase was in the periorbital and cheek areas, respectively. Manipulating each area separately in Study 3 revealed cheek redness and periorbital luminance equally increased perceived health, with low periorbital luminance more negatively affecting perceptions. These findings show that color variation in facial skin is a cue for health perception in female faces.
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Affiliation(s)
- Alex L Jones
- Department of Psychology, Gettysburg College, Gettysburg, PA, USA.
| | - Aurélie Porcheron
- CHANEL Recherche et Technologie, CHANEL PB, Paris, France; LPNC, University of Grenoble-Alpes, Grenoble, France
| | - Jennifer R Sweda
- Department of Psychology, Gettysburg College, Gettysburg, PA, USA
| | | | - Richard Russell
- Department of Psychology, Gettysburg College, Gettysburg, PA, USA.
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29
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Gangestad SW, Haselton MG, Welling LL, Gildersleeve K, Pillsworth EG, Burriss RP, Larson CM, Puts DA. How valid are assessments of conception probability in ovulatory cycle research? Evaluations, recommendations, and theoretical implications. EVOL HUM BEHAV 2016. [DOI: 10.1016/j.evolhumbehav.2015.09.001] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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30
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Focal Length Affects Depicted Shape and Perception of Facial Images. PLoS One 2016; 11:e0149313. [PMID: 26894832 PMCID: PMC4760932 DOI: 10.1371/journal.pone.0149313] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 01/29/2016] [Indexed: 11/19/2022] Open
Abstract
Static photographs are currently the most often employed stimuli in research on social perception. The method of photograph acquisition might affect the depicted subject's facial appearance and thus also the impression of such stimuli. An important factor influencing the resulting photograph is focal length, as different focal lengths produce various levels of image distortion. Here we tested whether different focal lengths (50, 85, 105 mm) affect depicted shape and perception of female and male faces. We collected three portrait photographs of 45 (22 females, 23 males) participants under standardized conditions and camera setting varying only in the focal length. Subsequently, the three photographs from each individual were shown on screen in a randomized order using a 3-alternative forced-choice paradigm. The images were judged for attractiveness, dominance, and femininity/masculinity by 369 raters (193 females, 176 males). Facial width-to-height ratio (fWHR) was measured from each photograph and overall facial shape was analysed employing geometric morphometric methods (GMM). Our results showed that photographs taken with 50 mm focal length were rated as significantly less feminine/masculine, attractive, and dominant compared to the images taken with longer focal lengths. Further, shorter focal lengths produced faces with smaller fWHR. Subsequent GMM revealed focal length significantly affected overall facial shape of the photographed subjects. Thus methodology of photograph acquisition, focal length in this case, can significantly affect results of studies using photographic stimuli perhaps due to different levels of perspective distortion that influence shapes and proportions of morphological traits.
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