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Banyeh M, Mayeem BN, Woli MK, Kolekang AS, Dagungong CB, Bure D, Wemegah RK, Azindow MI, Yakubu S, Seidu M, Baba MM, Essoun E, Owireduwaa N. Exploring Hematological and Biochemical Disparities in Same-Sex and Opposite-Sex Females: A Cross-Sectional Twin Study in a Ghanaian Population. Twin Res Hum Genet 2024; 27:50-55. [PMID: 38444332 DOI: 10.1017/thg.2024.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
There are sex-dependent differences in hematological and biochemical variables in adulthood attributed to the predominant effects of testosterone in males and estrogen in females. The Twin Testosterone Transfer (TTT) hypothesis proposes that opposite-sex females may develop male-typical traits due to exposure to relatively higher levels of prenatal testosterone than same-sex females. Additionally, prenatal testosterone exposure has been suggested as a correlate of current circulating testosterone levels. Consequently, opposite-sex females might exhibit male-typical patterns in their hematological and biochemical variables. Despite this hypothesis, routine laboratory investigations assign the same reference range to all females. Our cross-sectional study, conducted in Tamale from January to September 2022, included 40 twins, comprising 10 opposite-sex (OS) males (25%), 10 OS females (25%), and 20 same-sex (SS) females (50%), all aged between 18 and 27 years. Fasting venous blood samples were collected and analyzed using automated hematology and biochemistry laboratory analyzers. Results indicated that levels of hemoglobin, serum creatinine, gamma-glutamyl transferase, total protein, globulins, and total testosterone were significantly higher in OS males than OS females. Conversely, total cholesterol and low-density lipoprotein cholesterol were significantly higher in OS females than OS males. Unexpectedly, levels of low-density lipoprotein cholesterol and total testosterone were significantly higher in SS females than OS females. Contrary to expectations, opposite-sex females did not exhibit male-typical patterns in their hematological and biochemical variables. This suggests that the TTT effect may not occur or may not be strong enough to markedly affect hematological and biochemical variables in OS females.
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Affiliation(s)
- Moses Banyeh
- Department of Biomedical Laboratory Science, University for Development Studies, Tamale, Ghana
| | - Benjamin N Mayeem
- Department of Medical Laboratory, Living Waters Hospital, Ejisu-krapa, Kumasi, Ghana
| | - Moses Kofi Woli
- Department of Medical Diagnostics, College of Health and Well-Being, Kintampo, Ghana
| | - Augusta S Kolekang
- Department of Epidemiology, Biostatistics and Disease Control, University for Development Studies, Tamale, Ghana
| | | | - David Bure
- Department of Biomedical Laboratory Science, University for Development Studies, Tamale, Ghana
| | - Romarick Kofi Wemegah
- Department of Biomedical Laboratory Science, University for Development Studies, Tamale, Ghana
| | - Mikail Ihsan Azindow
- Department of Biomedical Laboratory Science, University for Development Studies, Tamale, Ghana
| | - Suleman Yakubu
- Department of Biomedical Laboratory Science, University for Development Studies, Tamale, Ghana
| | - Musah Seidu
- Department of Biomedical Laboratory Science, University for Development Studies, Tamale, Ghana
| | - Mohammed Madde Baba
- Department of Biomedical Laboratory Science, University for Development Studies, Tamale, Ghana
| | - Elisha Essoun
- Department of Biomedical Laboratory Science, University for Development Studies, Tamale, Ghana
| | - Nancy Owireduwaa
- Department of Biomedical Laboratory Science, University for Development Studies, Tamale, Ghana
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Peragine DE, Gervais NJ, Simeon-Spezzaferro C, Einstein G. A new angle on mental rotation ability in transgender men: Modulation by ovarian milieu. Psychoneuroendocrinology 2022; 141:105751. [PMID: 35398751 DOI: 10.1016/j.psyneuen.2022.105751] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 10/18/2022]
Abstract
Organizational/activational theory posits that transgender individuals should perform in the direction of their gender, not their sex, on cognitive tasks that show sex differences-the largest of which are observed on visuospatial tasks. Yet, tests of this hypothesis have been mixed for transgender men (TM). One possible reason is that performance shifts associated with the hormonal milieu at testing have not been fully considered in TM. Although "activating" influences, like gender-affirming hormone therapy (GAHT), are well-characterized in this population, endogenous ones, like ovarian cycling, have gone unaddressed. To provide a more complete picture of hormonal activation, we explored an influence of ovarian milieu on visuospatial performance of TM, and its potential contributions toward effects of sex and GAHT. We administered two male-favoring mental rotation tests (MRTs), and a sex-neutral control task to 22 TM naïve to GAHT (TM-), 29 TM receiving GAHT (TM+), and cisgender men (CM; n = 24) and women (CW; n = 43), testing cycling men (TM-) and women (CW) in either early follicular phase (Follicular) or midluteal phase (Luteal). On MRTs, performance of TM- varied across the menstrual cycle, and matched that of menstrual phase-matched CW. Additionally, cycling individuals in Follicular performed as strongly as TM+ and CM, all of whom performed above individuals in Luteal. Effects did not extend to a verbal control task, on which TM+ performed below others. Rather than conforming to static categories that suggest sex- or gender-typical organization of cognitive circuits, our findings support dynamic shifts in visuospatial ability of TM, and illustrate the need to consider activating effects of hormones beyond GAHT.
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Affiliation(s)
- Diana E Peragine
- Department of Psychology, University of Toronto, Toronto, M5S 3G3 Canada.
| | - Nicole J Gervais
- Department of Psychology, University of Toronto, Toronto, M5S 3G3 Canada; Rotman Research Institute, Baycrest Hospital, Toronto, M6A 2E1 Canada
| | | | - Gillian Einstein
- Department of Psychology, University of Toronto, Toronto, M5S 3G3 Canada; Rotman Research Institute, Baycrest Hospital, Toronto, M6A 2E1 Canada; Women's College Research Institute, Women's College Hospital, Toronto, M5G 1N8 Canada; Tema Genus, Linköping University, Linköping SE-581 83, Sweden
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Banyeh M, Amidu N, Quaye L. The relationship between 2D:4D ratio and postpartum adult female variables in a Ghanaian population. Am J Hum Biol 2021; 34:e23680. [PMID: 34523769 DOI: 10.1002/ajhb.23680] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVES Postpartum hematological and anthropometric assessment is a requirement for optimal maternal and child health. The study aimed to determine the relationship between the 2D:4D ratio and postpartum hematological and anthropometric variables in adult females. METHODS The study was cross-sectional from December 2020 to April 2021 involving 272 postpartum adult females, aged between 18 and 36 years. The right (2D:4DR) and the left (2D:4DL) digit ratios were measured using computer-assisted analysis. Fasting venous samples were collected at a median (interquartile range) of 111 (44-210) days postpartum and analyzed for total testosterone (TT), estradiol, sex hormone-binding globulin, and complete blood count. RESULTS The mean ± standard deviation 2D:4DR and 2D:4DL were 0.94 ± 0.04 and 0.93 ± 0.04, respectively. As expected, the TT (r = -0.198, p = .015) and the free androgen index (FAI: r = -0.186, p = .019) were inversely correlated with the 2D:4DL while free testosterone (FT%: r = -0.157, p = .038) was inversely correlated with the 2D:4DR. The absolute basophile count (BASO: r = -0.124, p = .040) and the Platelet-lymphocyte ratio (PLR: r = -0.153, p = .016) were inversely correlated with the 2D:4DL and the 2D:4DR respectively. In addition, the mean cell volume was inversely correlated with the 2D:4DR (r = -0.139, p = .024) and the 2D:4DL (r = -0.122, p = .045). Moreover, the 2D:4DR was inversely correlated with height (r = -0.164, p = .007). Unexpectedly, the red blood cell count (RBC: r = 0.138, p = .025) was positively correlated with the 2D:4DR. CONCLUSION There are significant relationships between the 2D:4D ratio and postpartum female variables. These findings are useful preliminary reference data for postpartum research and subsequent 2D:4D ratio studies.
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Affiliation(s)
- Moses Banyeh
- Department of Biomedical Laboratory Science, School of Allied Health Sciences, University for Development Studies, Tamale, Ghana
| | - Nafiu Amidu
- Department of Biomedical Laboratory Science, School of Allied Health Sciences, University for Development Studies, Tamale, Ghana
| | - Lawrence Quaye
- Department of Biomedical Laboratory Science, School of Allied Health Sciences, University for Development Studies, Tamale, Ghana
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Xu Y, Norton S, Rahman Q. Sexual Orientation and Cognitive Ability: A Multivariate Meta-Analytic Follow-Up. ARCHIVES OF SEXUAL BEHAVIOR 2020; 49:413-420. [PMID: 31975035 PMCID: PMC7031189 DOI: 10.1007/s10508-020-01632-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 01/06/2020] [Accepted: 01/07/2020] [Indexed: 06/10/2023]
Abstract
A cross-sex shift model of human sexual orientation differences predicts that homosexual men should perform or score in the direction of heterosexual women, and homosexual women in the direction of heterosexual men, in behavioral domains such as cognition and personality. In order to test whether homosexual men and women's cognitive performance was closer to that of heterosexual men or that of heterosexual women (i.e., sex-atypical for their sex and closer to that of the opposite-sex), we conducted a multivariate meta-analysis based on data from our previous meta-analysis (Xu, Norton, & Rahman, 2017). A subset of this data was used and comprised 30 articles (and 2 unpublished datasets) and 244,434 participants. The multivariate meta-analysis revealed that homosexual men were sex-atypical in mental rotation (Hedges' g = -0.36) and the water level test (Hedges' g = -0.55). In mental rotation, homosexual men were in-between heterosexual men and women. There was no significant group difference on spatial location memory. Homosexual men were also sex-atypical on male-favoring spatial-related tasks (Hedges' g = -0.54), and female-favoring spatial-related tasks (Hedges' g = 0.38). Homosexual women tended to be sex-typical (similar to heterosexual women). There were no significant group differences on male-favoring "other" tasks or female-favoring verbal-related tasks. Heterosexual men and women differed significantly on female-favoring "other" tasks. These results support the cross-sex shift hypothesis which predicts that homosexual men perform in the direction of heterosexual women in sex differentiated cognitive domains. However, the type of task and cognitive domain tested is critical.
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Affiliation(s)
- Yin Xu
- Department of Psychology, Institute of Psychiatry Psychology and Neuroscience, King's College London, 5th Floor Bermondsey Wing, Guys Hospital Campus, London, SE1 9RT, UK
| | - Sam Norton
- Department of Psychology, Institute of Psychiatry Psychology and Neuroscience, King's College London, 5th Floor Bermondsey Wing, Guys Hospital Campus, London, SE1 9RT, UK
| | - Qazi Rahman
- Department of Psychology, Institute of Psychiatry Psychology and Neuroscience, King's College London, 5th Floor Bermondsey Wing, Guys Hospital Campus, London, SE1 9RT, UK.
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Lombardo MP, Otieno S, Heiss A. College-aged women in the United States that play overhand throwing sports have masculine digit ratios. PLoS One 2018; 13:e0203685. [PMID: 30212523 PMCID: PMC6136748 DOI: 10.1371/journal.pone.0203685] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 08/24/2018] [Indexed: 11/19/2022] Open
Abstract
Athletic prowess in both males and females is negatively correlated with the ratio between the lengths of the second and fourth fingers (2D:4D), a correlate of prenatal testosterone exposure. Because multiple lines of evidence suggest that prenatal testosterone exposure is associated with sports interest, motivation, and athletic performance we measured the digit ratios of 77 non-athletes, 103 varsity athletes, and 78 club sport athletes to test 8 hypotheses about the relationship between digit ratio and the athletic behavior of college-age women in the USA. Using independent samples t-tests, we found no significant differences between the digit ratios of women that (1) were athletes and non-athletes, (2) were varsity or club sport athletes, (3) had played or were currently playing individual or team sports, (4) played contact and non-contact sports, (5) played sports involving a ball and those that do not, (6) played sports where the outcome was determined by a score or the outcome of direct physical competition or subjectively by judges, or (7) were starters or reserves on their teams. However, women that played overhand throwing sports softball and water polo had significantly smaller digit ratios than did women that played other sports. These differences were not due to scaling effects. The independent samples t-test results were supported by subsequent Monte Carlo bootstrap, Bayesian, Random Forest, and multiple linear regression analyses. We suggest that the organizational consequences of prenatal testosterone exposure may influence the anatomy and physiology of women that leads to success playing overhand throwing sports.
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Affiliation(s)
- Michael P. Lombardo
- Biology Department, Grand Valley State University, Allendale, Michigan, United States of America
- * E-mail:
| | - Sango Otieno
- Statistics Department, Grand Valley State University, Allendale, Michigan, United States of America
| | - Adam Heiss
- Statistics Department, Grand Valley State University, Allendale, Michigan, United States of America
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Paipa N, Stephan-Otto C, Cuevas-Esteban J, Núñez-Navarro A, Usall J, Brébion G. Second-to-fourth digit length ratio is associated with negative and affective symptoms in schizophrenia patients. Schizophr Res 2018; 199:297-303. [PMID: 29503231 DOI: 10.1016/j.schres.2018.02.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 02/20/2018] [Accepted: 02/21/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND Higher levels of circulating oestrogens in women and testosterone in men have been shown to have a protective effect against the clinical manifestations of schizophrenia, mostly with respect to negative symptomatology. Certain studies suggest that they also have a protective effect against the neuropsychological impairment observed in the disease. We investigated whether greater prenatal exposure to estrogens in women and to testosterone in men, reflected by the 2D:4D ratio, was similarly associated with decreased negative symptomatology and improved neuropsychological functioning in patients. METHOD 51 schizophrenia patients and 50 healthy participants were administered a neuropsychological battery. The 2D:4D ratio was measured in all participants. Positive, negative, and affective symptoms were assessed in patients. Regression analyses were conducted separately in male and female subgroups. RESULTS No associations with positive symptoms were revealed. In male patients, the 2D:4D ratio was positively associated with avolition and inversely associated with anxiety. In female patients, it was inversely associated with alogia, and tended to be positively associated with depression. No association between higher prenatal concentration of the relevant sex hormone and improved neuropsychological performance emerged in patients. CONCLUSIONS Higher concentrations of prenatal testosterone in male patients, and prenatal oestrogens in female patients, are associated with a decrement in certain aspects of negative symptomatology. In addition, prenatal sex hormone concentration seems to be associated with predisposition to anxiety in male patients, and to depression in female patients.
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Affiliation(s)
- Nataly Paipa
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain; Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain
| | - Christian Stephan-Otto
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain; Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - Jorge Cuevas-Esteban
- Servei de Psiquiatria, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
| | - Araceli Núñez-Navarro
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain; Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain
| | - Judith Usall
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain; Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain
| | - Gildas Brébion
- Institut de Recerca Sant Joan de Déu, Esplugues de Llobregat, Spain; Parc Sanitari Sant Joan de Déu, Sant Boi de Llobregat, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Madrid, Spain.
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Xu Y, Norton S, Rahman Q. Sexual orientation and neurocognitive ability: A meta-analysis in men and women. Neurosci Biobehav Rev 2017; 83:691-696. [DOI: 10.1016/j.neubiorev.2017.06.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/02/2017] [Accepted: 06/28/2017] [Indexed: 12/18/2022]
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Danborno B, Adebisi1 SS, Adelaiye AB, Ojo S. Relationship between Digit Ratio (2D:4D) and Birth Weight in Nigerians. ACTA ACUST UNITED AC 2017. [DOI: 10.1080/09720073.2010.11891142] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
| | | | | | - S.A. Ojo
- Department of Veterinary Anatomy, Faculty of Veterinary Medicine, Ahmadu Bello University , Zaria, Nigeria
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Li C, Jia M, Ma Y, Luo H, Li Q, Wang Y, Li Z, Ding W, Zhang R, Song L, Cao L, Guo M, Wei T, Lu L. The relationship between digit ratio and sexual orientation in a Chinese Yunnan Han population. PERSONALITY AND INDIVIDUAL DIFFERENCES 2016. [DOI: 10.1016/j.paid.2016.05.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Ellis L, Lykins A, Hoskin A, Ratnasingam M. Putative Androgen Exposure and Sexual Orientation: Cross-Cultural Evidence Suggesting a Modified Neurohormonal Theory. J Sex Med 2015; 12:2364-77. [PMID: 26663858 DOI: 10.1111/jsm.13070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION According to neurohormonal theory, prenatal androgens are key determinants of sexual orientation. As a reputed marker for prenatal androgens, the 2D:4D finger length ratio has been used in more than a dozen studies to test the hypothesis that prenatal androgens influence sexual orientation. Findings have been very inconsistent. AIM The present study sought to retest the hypothesis that 2D:4D and sexual orientation are related is a manner consistent with neurohormonal theory. METHODS A 2D:4D measure (of the right hand) along with four additional somatic markers of androgen exposure (height, physical strength, muscularity, and athletic ability) with samples of college students in Malaysia (N = 2,058) and the United States (N = 2,511). The five androgen measures were factor analyzed, resulting in a two-factor solution: Factor 1 consisted of strength, muscularity, and athletic ability (the muscular coordination factor), and Factor 2 was comprised of the r2D:4D and adult height (the bone growth factor). MAIN OUTCOME MEASURES Sexual orientation was measured by asking each respondent the extent to which they were sexually attracted to males and the extent to which they were sexually attracted to females, both on 11-point scales. RESULTS When the countries and sexes were analyzed separately, neither the r2D:4D measure nor Factor 2 correlated with sexual orientation to significant degrees. Instead, it was the muscular coordination factor that correlated the best. Support was found for the hypothesis that prenatal androgens influence sexual orientation, but the nature of these influences was more complex than neurohormonal theory predicted. CONCLUSION A modified theory is needed and presented to accommodate the results from this study.
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Affiliation(s)
- Lee Ellis
- University of Malaya, Kuala Lumpur, Malaysia
| | - Amy Lykins
- University of New England, Armidale, NSW, Australia
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Sen J, Kanchan T, Ghosh A, Mondal N, Krishan K. Estimation of Sex From Index and Ring Finger Lengths in An Indigenous Population of Eastern India. J Clin Diagn Res 2015; 9:HC01-5. [PMID: 26673873 DOI: 10.7860/jcdr/2015/14940.6846] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 09/14/2015] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Forensic anthropology involves the identification of human remains for medico-legal purposes. Estimation of sex is an essential element of medico-legal investigations when identification of unknown dismembered remains is involved. AIM The present study was conducted with an aim to estimate sex from index and ring finger lengths of adult individuals belonging to an indigenous population of eastern India. MATERIALS AND METHODS A total of 500 unrelated adult individuals (18-60 years) from the Rajbanshi population (males: 250, females: 250) took part in the study. A total of 400 (males: 200, 200 female) participants were randomly used to develop sex estimation models using Binary Logistic Regression Analysis (BLR). A separate group of 200 adults (18-60 years) from the Karbi tribal population (males 100, females 100) were included to validate the results obtained on the Rajbanshi population. The univarate and bivariate models derived on the study group (n=400) were tested on hold-out sample of Rajbanshi participants (n=100) and the other test population of the Karbi (n=200) participants. RESULTS The results indicate that Index Finger Length (IFL) and Ring Finger Length (RFL) of both hands were significantly longer in males as compared to females. The ring finger was longer than the index finger in both sexes. The study successfully highlights the existence of sex differences in IFL and RFL (p<0.05). No sex differences were however, observed for the index and ring finger ratio. The predictive accuracy of IFL and RFL in sex estimation ranged between 70%-75% (in the hold out sample from the Rajbanshi population) and 60-66% (in the test sample from the Karbi population). A Receiver Operating Curve (ROC) analysis was performed to test the predictive accuracy after predicting the probability of IFL and RFL in sex estimation. The predicted probabilities using ROC analysis were observed to be higher on the left side and in multivariate analysis. CONCLUSION The study concludes that sex estimation from index and ring finger lengths could be of utility when more reliable means of sex estimation are not available during medico-legal investigations.
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Affiliation(s)
- Jaydip Sen
- Professor, Department of Anthropology, University of North Bengal , Darjeeling, West Bengal, India
| | - Tanuj Kanchan
- Associate Professor, Department of Forensic Medicine, Kasturba Medical College , Mangalore India
| | - Ahana Ghosh
- Research Scholar, Department of Anthropology, University of North Bengal , Darjeeling, West Bengal, India
| | - Nitish Mondal
- Assistant Professor, Department of Anthropology, Assam University Diphu Campus, Karbi Anglong, Assam, India
| | - Kewal Krishan
- Senior Assistant Professor, Department of Anthropology, Panjab University , Chandigarh, India
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Klimek M, Galbarczyk A, Colleran H, Thune I, Ellison PT, Ziomkiewicz A, Jasienska G. Digit ratio (2D:4D) does not correlate with daily 17β-estradiol and progesterone concentrations in healthy women of reproductive age. Am J Hum Biol 2015; 27:667-73. [DOI: 10.1002/ajhb.22717] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 01/29/2015] [Accepted: 03/03/2015] [Indexed: 12/20/2022] Open
Affiliation(s)
- Magdalena Klimek
- Department of Environmental Health; Faculty of Health Sciences; Jagiellonian University Medical College; Krakow Poland
| | - Andrzej Galbarczyk
- Department of Environmental Health; Faculty of Health Sciences; Jagiellonian University Medical College; Krakow Poland
| | - Heidi Colleran
- Institute for Advanced Study in Toulouse; Toulouse School of Economics; Toulouse France
| | - Inger Thune
- Department of Oncology; Oslo University Hospital; Ullevål Oslo Norway
| | - Peter T. Ellison
- Department of Human Evolutionary Biology; Harvard University; Cambridge Massachusetts
| | - Anna Ziomkiewicz
- Polish Academy of Sciences; Unit of Anthropology in Wroclaw; Wroclaw Poland
| | - Grazyna Jasienska
- Department of Environmental Health; Faculty of Health Sciences; Jagiellonian University Medical College; Krakow Poland
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Differences in salivary testosterone, digit ratio and empathy between intellectually gifted and control boys. INTELLIGENCE 2015. [DOI: 10.1016/j.intell.2014.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Saenz J, Yaugher A, Alexander GM. Sleep in infancy predicts gender specific social-emotional problems in toddlers. Front Pediatr 2015; 3:42. [PMID: 26029685 PMCID: PMC4426713 DOI: 10.3389/fped.2015.00042] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 04/25/2015] [Indexed: 11/14/2022] Open
Abstract
Despite strong evidence linking sleep to developmental outcomes, the longitudinal relationship between sleep and emotional well-being remains largely unknown. To address this gap in our knowledge, the current study examined sleep in infancy, measured via actigraphy, as a predictor of social-emotional problems in toddlers. A total of 47 children (29 males) were included in this longitudinal study. At time one, actigraphy measures of sleep were obtained from 3- to 4-month-old infants. At time two, parents rated their 18- to 24-month-old toddler's social-emotional well-being using the Brief Infant Toddler Social Emotional Assessment. Results indicated that boys tended to have higher levels of externalizing behaviors than did girls. Additionally, boys with longer sleep durations also showed lower sleep efficiency. In girls, sleep duration in infancy was a significant predictor of autism spectrum disorder behaviors and approached significance as a predictor of externalizing problems in toddlerhood. Our findings are the first to show a relationship between sleep measured in infancy and autism spectrum disorder symptomatology measured in early childhood. They suggest that the etiology of social-emotional problems may differ between genders and raise the possibility that sleep/wake cycles may be differentially related to autism spectrum disorder symptoms in girls and boys.
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Affiliation(s)
- Janet Saenz
- Department of Psychology, Texas A&M University , College Station, TX , USA ; Division of Adolescent Medicine, Children's Hospital Los Angeles , Los Angeles, CA , USA
| | - Ashley Yaugher
- Department of Psychology, Texas A&M University , College Station, TX , USA
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Dawson SJ, Chivers ML. Gender Differences and Similarities in Sexual Desire. CURRENT SEXUAL HEALTH REPORTS 2014. [DOI: 10.1007/s11930-014-0027-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Winegard BM, Winegard BM, Deaner RO. Misrepresentations of Evolutionary Psychology in Sex and Gender Textbooks. EVOLUTIONARY PSYCHOLOGY 2014. [DOI: 10.1177/147470491401200301] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Evolutionary psychology has provoked controversy, especially when applied to human sex differences. We hypothesize that this is partly due to misunderstandings of evolutionary psychology that are perpetuated by undergraduate sex and gender textbooks. As an initial test of this hypothesis, we develop a catalog of eight types of errors and document their occurrence in 15 widely used sex and gender textbooks. Consistent with our hypothesis, of the 12 textbooks that discussed evolutionary psychology, all contained at least one error, and the median number of errors was five. The most common types of errors were “Straw Man,” “Biological Determinism,” and “Species Selection.” We conclude by suggesting improvements to undergraduate sex and gender textbooks.
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Affiliation(s)
- Benjamin M. Winegard
- Department of Psychological Science, the University of Missouri, Columbia, MO, USA
| | - Bo M. Winegard
- Department of Psychology, Florida State University, Tallahassee, FL, USA
| | - Robert O. Deaner
- Department of Psychology, Grand Valley State University, Allendale, MI, USA
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Hollier LP, Maybery MT, Whitehouse AJ. Chapter 10. Atypical cerebral lateralisation and language impairment in autism. ACTA ACUST UNITED AC 2014. [DOI: 10.1075/tilar.11.11hol] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023]
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18
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Mental rotation in intellectually gifted boys is affected by the androgen receptor CAG repeat polymorphism. Neuropsychologia 2013; 51:1693-8. [DOI: 10.1016/j.neuropsychologia.2013.05.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 05/21/2013] [Accepted: 05/23/2013] [Indexed: 12/11/2022]
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19
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Saenz J, Alexander GM. Postnatal testosterone levels and disorder relevant behavior in the second year of life. Biol Psychol 2013; 94:152-9. [PMID: 23727253 DOI: 10.1016/j.biopsycho.2013.05.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 03/29/2013] [Accepted: 05/14/2013] [Indexed: 11/17/2022]
Abstract
The objective of the current study was to investigate the relationship between testosterone collected at 3-4 months of age and sex-linked disorder-relevant behaviors in the second year of life. Eighty-four children participated at 3-4 (when salivary testosterone levels were obtained and second to fourth digit ratios were measured) and 18-24 months of age (when behavioral ratings of aggression and verbal ability were coded from two 8-min play sessions). Parents also completed the Brief Infant-Toddler Social and Emotional Assessment, and the four subscales (Internalizing, Externalizing, Dysregulation, and Autism Spectrum Disorder) were used to indicate child specific problems. Greater postnatal testosterone levels in early infancy were predictive of more male-typical behaviors in the second year of life (i.e., more autism spectrum behaviors, less time vocalizing, and more Internalizing Problems). These results support the hypothesis that early infancy may be another critical period for the development of gender-linked behavior.
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Affiliation(s)
- Janet Saenz
- Department of Psychology, Texas A&M University, College Station, TX 77843, USA.
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21
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Doyle RA, Voyer D, Cherney ID. The relation between childhood spatial activities and spatial abilities in adulthood. JOURNAL OF APPLIED DEVELOPMENTAL PSYCHOLOGY 2012. [DOI: 10.1016/j.appdev.2012.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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22
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Chai XJ, Jacobs LF. Digit ratio predicts sense of direction in women. PLoS One 2012; 7:e32816. [PMID: 22393451 PMCID: PMC3290629 DOI: 10.1371/journal.pone.0032816] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 02/06/2012] [Indexed: 11/19/2022] Open
Abstract
The relative length of the second-to-fourth digits (2D:4D) has been linked with prenatal androgen in humans. The 2D:4D is sexually dimorphic, with lower values in males than females, and appears to correlate with diverse measures of behavior. However, the relationship between digit ratio and cognition, and spatial cognition in particular, has produced mixed results. In the present study, we hypothesized that spatial tasks separating cue conditions that either favored female or male strategies would examine this structure-function correlation with greater precision. Previous work suggests that males are better in the use of directional cues than females. In the present study, participants learned a target location in a virtual landscape environment, in conditions that contained either all directional (i.e., distant or compass bearing) cues, or all positional (i.e., local, small objects) cues. After a short delay, participants navigated back to the target location from a novel starting location. Males had higher accuracy in initial search direction than females in environments with all directional cues. Lower digit ratio was correlated with higher accuracy of initial search direction in females in environments with all directional cues. Mental rotation scores did not correlate with digit ratio in either males or females. These results demonstrate for the first time that a sex difference in the use of directional cues, i.e., the sense of direction, is associated with more male-like digit ratio.
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Affiliation(s)
- Xiaoqian J Chai
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America.
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23
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Gregory Appelbaum L, Cain MS, Darling EF, Stanton SJ, Nguyen MT, Mitroff SR. What is the identity of a sports spectator? PERSONALITY AND INDIVIDUAL DIFFERENCES 2012. [DOI: 10.1016/j.paid.2011.10.048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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24
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Organizing effects of testosterone and economic behavior: not just risk taking. PLoS One 2011; 6:e29842. [PMID: 22242144 PMCID: PMC3248440 DOI: 10.1371/journal.pone.0029842] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Accepted: 12/05/2011] [Indexed: 11/19/2022] Open
Abstract
Recent literature emphasizes the role that testosterone, as well as markers indicating early exposure to T and its organizing effect on the brain (such as the ratio of second to fourth finger, ), have on performance in financial markets. These results may suggest that the main effect of T, either circulating or in fetal exposure, on economic behavior occurs through the increased willingness to take risks. However, these findings indicate that traders with a low digit ratio are not only more profitable, but more able to survive in the long run, thus the effect might consist of more than just lower risk aversion. In addition, recent literature suggests a positive correlation between abstract reasoning ability and higher willingness to take risks. To test the two hypotheses of testosterone on performance in financial activities (effect on risk attitude versus a complex effect involving risk attitude and reasoning ability), we gather data on the three variables in a sample of 188 ethnically homogeneous college students (Caucasians). We measure a digit ratio, abstract reasoning ability with the Raven Progressive Matrices task, and risk attitude with choice among lotteries. Low digit ratio in men is associated with higher risk taking and higher scores in abstract reasoning ability when a combined measure of risk aversion over different tasks is used. This explains both the higher performance and higher survival rate observed in traders, as well as the observed correlation between abstract reasoning ability and risk taking. We also analyze how much of the total effect of digit ratio on risk attitude is direct, and how much is mediated. Mediation analysis shows that a substantial part of the effect of T on attitude to risk is mediated by abstract reasoning ability.
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Kangassalo K, Pölkki M, Rantala MJ. Prenatal Influences on Sexual Orientation: Digit Ratio (2D:4D) and Number of Older Siblings. EVOLUTIONARY PSYCHOLOGY 2011. [DOI: 10.1177/147470491100900402] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Prenatal androgen levels are suggested to influence sexual orientation in both sexes. The 2D:4D digit ratio has been found to associate with sexual orientation, but published findings have often been contradictory, which may partly be due to the large ethnic diversity between and within studied populations. In men, number of older brothers has been found to correlate positively with homosexuality. This phenomenon has been explained with a maternal immune reaction, which is provoked only by male fetuses and which gets stronger after each pregnancy. Here we assessed the relationship of sexual orientation to 2D:4D ratios and number of older siblings in Finland, where the population is found to be genetically relatively homogeneous. As in many previous studies, heterosexual men had lower 2D:4D than non-heterosexual men, which supports the notion that non-heterosexual men experience higher androgen levels in utero than population norms. Contrary to previous reports, non-heterosexual women had higher 2D:4D than heterosexual women. Non-heterosexual men had more older brothers and older sisters than heterosexual men. The greater number of older sisters in non-heterosexual men indicates that there are other factors that contribute to the higher birth order of homosexual men than the maternal immunization.
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Affiliation(s)
| | - Mari Pölkki
- Department of Biology, University of Turku, Turku, Finland
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Nowak NT, Moffat SD. The relationship between second to fourth digit ratio, spatial cognition, and virtual navigation. ARCHIVES OF SEXUAL BEHAVIOR 2011; 40:575-585. [PMID: 20809371 DOI: 10.1007/s10508-010-9668-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Revised: 07/08/2010] [Accepted: 07/08/2010] [Indexed: 05/29/2023]
Abstract
Studies in human and non-human animals have found that early life exposure to androgens may affect later spatial performance. Recent studies have suggested that the ratio of the second to fourth digit (2D:4D) may serve as an index of prenatal androgen exposure. Some studies have found that the 2D:4D ratio predicts adult spatial performance, although the nature of the relationship is equivocal. This study was designed to quantify the relationships between 2D:4D ratio, spatial cognition, and spatial navigation using a virtual Morris water task (vMWT) in a sample of young adult men and women (N = 140). The results replicated findings from the literature regarding sex differences in 2D:4D ratio, vMWT performance, and spatial cognition. However, 2D:4D ratio was not consistently related to spatial cognition or spatial navigation in men or women. Results were discussed within the framework of androgen influences on spatial cognition and the degree to which 2D:4D ratio serves as a marker for early life androgen exposure.
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Affiliation(s)
- Nicole T Nowak
- Department of Psychology, Wayne State University, Detroit, MI, USA
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Muller DC, Giles GG, Bassett J, Morris HA, Manning JT, Hopper JL, English DR, Severi G. Second to fourth digit ratio (2D:4D) and concentrations of circulating sex hormones in adulthood. Reprod Biol Endocrinol 2011; 9:57. [PMID: 21521531 PMCID: PMC3107785 DOI: 10.1186/1477-7827-9-57] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 04/27/2011] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The second to fourth digit ratio (2D:4D) is used as a marker of prenatal sex hormone exposure. The objective of this study was to examine whether circulating concentrations of sex hormones and SHBG measured in adulthood was associated with 2D:4D. METHODS This analysis was based on a random sample from the Melbourne Collaborative Cohort Study. The sample consisted of of 1036 men and 620 post-menopausal women aged between 39 and 70 at the time of blood draw. Concentrations of circulating sex hormones were measured from plasma collected at baseline (1990-1994), while digit length was measured from hand photocopies taken during a recent follow-up (2003-2009). The outcome measures were circulating concentrations of testosterone, oestradiol, dehydroepiandrosterone sulphate, androstenedione, Sex Hormone Binding Globulin, androstenediol glucoronide for men only and oestrone sulphate for women only. Free testosterone and oestradiol were estimated using standard formulae derived empirically. Predicted geometric mean hormone concentrations (for tertiles of 2D:4D) and conditional correlation coefficients (for continuous 2D:4D) were obtained using mixed effects linear regression models. RESULTS No strong associations were observed between 2D:4D measures and circulating concentrations of hormones for men or women. For males, right 2D:4D was weakly inversely associated with circulating testosterone (predicted geometric mean testosterone was 15.9 and 15.0 nmol/L for the lowest and highest tertiles of male right 2D:4D respectively (P-trend = 0.04). There was a similar weak association between male right 2D:4D and the ratio of testosterone to oestradiol. These associations were not evident in analyses of continuous 2D:4D. CONCLUSIONS There were no strong associations between any adult circulating concentration of sex hormone or SHGB and 2D:4D. These results contribute to the growing body of evidence indicating that 2D:4D is unrelated to adult sex hormone concentrations.
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Affiliation(s)
- David C Muller
- Cancer Epidemiology Centre, The Cancer Council of Victoria, Melbourne, Australia
- Centre for Molecular, Environmental, Genetic, and Analytic Epidemiology, The University of Melbourne, Australia
| | - Graham G Giles
- Cancer Epidemiology Centre, The Cancer Council of Victoria, Melbourne, Australia
- Centre for Molecular, Environmental, Genetic, and Analytic Epidemiology, The University of Melbourne, Australia
| | - Julie Bassett
- Cancer Epidemiology Centre, The Cancer Council of Victoria, Melbourne, Australia
| | - Howard A Morris
- Hanson Institute, Institute of Medical and Veterinary Science, Adelaide, Australia
| | - John T Manning
- MRC Epidemiology Research Centre, University of Southampton, Southampton General Hospital, UK
| | - John L Hopper
- Centre for Molecular, Environmental, Genetic, and Analytic Epidemiology, The University of Melbourne, Australia
| | - Dallas R English
- Cancer Epidemiology Centre, The Cancer Council of Victoria, Melbourne, Australia
- Centre for Molecular, Environmental, Genetic, and Analytic Epidemiology, The University of Melbourne, Australia
| | - Gianluca Severi
- Cancer Epidemiology Centre, The Cancer Council of Victoria, Melbourne, Australia
- Centre for Molecular, Environmental, Genetic, and Analytic Epidemiology, The University of Melbourne, Australia
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28
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Valla J, Ceci SJ. Can Sex Differences in Science Be Tied to the Long Reach of Prenatal Hormones? Brain Organization Theory, Digit Ratio (2D/4D), and Sex Differences in Preferences and Cognition. PERSPECTIVES ON PSYCHOLOGICAL SCIENCE 2011; 6:134-136. [PMID: 22164187 PMCID: PMC3230041 DOI: 10.1177/1745691611400236] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Brain organization theory posits a cascade of physiological and behavioral changes initiated and shaped by prenatal hormones. Recently, this theory has been associated with outcomes including gendered toy preference, 2D/4D digit ratio, personality characteristics, sexual orientation, and cognitive profile (spatial, verbal, and mathematical abilities). We examine the evidence for this claim, focusing on 2D/4D and its putative role as a biomarker for organizational features that influence cognitive abilities/interests predisposing males toward mathematically and spatially intensive careers. Although massive support exists for early brain organization theory overall, there are myriad inconsistencies, alternative explanations, and outright contradictions that must be addressed while still taking the entire theory into account. Like a fractal within the larger theory, the 2D/4D hypothesis mirrors this overall support on a smaller scale while likewise suffering from inconsistencies (positive, negative, and sex-dependent correlations), alternative explanations (2D/4D related to spatial preferences rather than abilities per se), and contradictions (feminine 2D/4D in men associated with higher spatial ability). Using the debate over brain organization theory as the theoretical stage, we focus on 2D/4D evidence as an increasingly important player on this stage, a demonstrative case in point of the evidential complexities of the broader debate, and an increasingly important topic in its own right.
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Affiliation(s)
- Jeffrey Valla
- Department of Human Development, Cornell University, Ithaca, NY
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29
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Hu SH, Wang QD, Xu Y, Liao ZL, Xu LJ, Liao ZL, Xu XJ, Wei EQ, Yan LQ, Hu JB, Wei N, Zhou WH, Huang ML, Zhang MM. Haemodynamic Brain Response to Visual Sexual Stimuli is Different between Homosexual and Heterosexual Men. J Int Med Res 2011; 39:199-211. [PMID: 21672322 DOI: 10.1177/147323001103900121] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The underlying neurobiological factors involved in sexual orientation are largely unknown. This study investigated whether neural circuits or different cognitive processes accounted for differences in brain activation in 14 heterosexual and 14 homosexual males. Brain scans were undertaken in each subject using functional magnetic resonance imaging while they viewed different sexual stimuli, i.e. heterosexual couple stimuli (HCS), gay couple stimuli (GCS), lesbian couple stimuli (LCS) and neutral stimuli (NS). Ratings of sexual attractiveness of the stimuli were assessed. Subjective sexual arousal was induced by HCS and GCS in heterosexual and homosexual men, respectively. Sexual disgust was induced by GCS and LCS in heterosexual and homosexual men, respectively. Compared with viewing NS, viewing sexual stimuli induced significantly different brain activations, most of which had the characteristics of cognitive processes. These observations suggest that different cognitive patterns may be the major cause of different subjective responses to sexual stimuli between heterosexual and homosexual men.
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Affiliation(s)
- S-H Hu
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Q-D Wang
- Department of Radiology, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Y Xu
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Z-L Liao
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - L-J Xu
- National Laboratory of Pattern Recognition, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Z-L Liao
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - X-J Xu
- Department of Radiology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - E-Q Wei
- College of Pharmacology, Zhejiang University, Hangzhou, China
| | - L-Q Yan
- MD Anderson Cancer Center, Virginia Harris Cockrell Cancer Research Center, University of Texas, Austin, Texas, USA
| | - J-B Hu
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - N Wei
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - W-H Zhou
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - M-L Huang
- Department of Mental Health, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - M-M Zhang
- Department of Radiology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
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On relationships between digit ratio (2D:4D) and two fundamental cognitive drives, empathizing and systemizing, in Japanese sample. PERSONALITY AND INDIVIDUAL DIFFERENCES 2010. [DOI: 10.1016/j.paid.2010.07.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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31
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Kanchan T, Pradeep Kumar G. Index and ring finger ratio--a morphologic sex determinant in South-Indian children. Forensic Sci Med Pathol 2010; 6:255-60. [PMID: 20369311 DOI: 10.1007/s12024-010-9156-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2010] [Indexed: 11/28/2022]
Abstract
To investigate the sexual dimorphism of index and ring finger ratio in South Indian children. The index finger length (IFL) and the ring finger length (RFL) were measured in 350 subjects aged between 2 and 12 years using a steel measuring tape. The index and ring finger ratio was computed by dividing index finger length by ring finger length. The data obtained were analyzed statistically using SPSS, version 11.0. Mean RFL was greater than mean IFL in both males and females. The mean ring finger length was longer in males than females and mean index finger length longer in females than males. However, these sex differences observed for index and ring finger length were not significant in both hands. Statistically significant sex differences were observed from the derived index and ring finger ratio. The mean index and ring finger ratio was found to be higher in females than males. Significant correlation was found between age and index and ring finger lengths. Index and ring finger ratio however, did not show any significant correlation with age. This study suggests that among South-Indian children, the index and ring finger ratio of 0.97 and less is indicative of male, and a ratio of more than 0.97 is indicative of female sex. The ratio can be a useful sex indicator irrespective of the age of the individual.
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Affiliation(s)
- Tanuj Kanchan
- Department of Forensic Medicine and Toxicology, Kasturba Medical College (Affiliated to Manipal University), Mangalore, India.
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Voracek M, Loibl LM. Scientometric analysis and bibliography of digit ratio (2D:4D) research, 1998-2008. Psychol Rep 2009; 104:922-56. [PMID: 19708418 DOI: 10.2466/pr0.104.3.922-956] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A scientometric analysis of modern research on the second-to-fourth digit ratio (2D:4D), a widely studied putative marker for prenatal androgen action, is presented. In early 2009, this literature totalled more than 300 publications and, since its initiation in 1998, has grown at a rate slightly faster than linear. Key findings included evidence of publication bias and citation bias, incomplete coverage and outdatedness of existing reviews, and a dearth of meta-analyses in this field. 2D:4D research clusters noticeably in terms of researchers, institutions, countries, and journals involved. Although 2D:4D is an anthropometric trait, most of the research has been conducted at psychology departments, not anthropology departments. However, 2D:4D research has not been predominantly published in core and specialized journals of psychology, but rather in more broadly scoped journals of the behavioral sciences, biomedical social sciences, and neurosciences. Total citation numbers of 2D:4D papers for the most part were not larger than their citation counts within 2D:4D research, indicating that until now, only a few 2D:4D studies have attained broader interest outside this specific field. Comparative citation analyses show that 2D:4D research presently is commensurate in size and importance to evolutionary psychological jealousy research, but has grown faster than the latter field. In contrast, it is much smaller and has spread more slowly than research about the Implicit Association Test Fifteen conjectures about anticipated trends in 2D:4D research are outlined, appendixed by a first-time bibliography of the entirety of the published 2D:4D literature.
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Affiliation(s)
- Martin Voracek
- Department of Basic Psychological Research, School of Psychology, University of Vienna, Liebiggasse 5, Rm 03-46, A-1010 Vienna, Austria.
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Allaway HC, Bloski TG, Pierson RA, Lujan ME. Digit ratios (2D:4D) determined by computer-assisted analysis are more reliable than those using physical measurements, photocopies, and printed scans. Am J Hum Biol 2009; 21:365-70. [PMID: 19263413 DOI: 10.1002/ajhb.20892] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Prenatal androgens influence the second to fourth digit ratio (2D:4D) of hands with men having lower ratios than women. Numerous methods are used to assess 2D:4D including, physical measurements with calipers, and measurements made from photocopies, scanned images, digital photographs, radiographs, and scaled tubes. Although each method appears relatively reliable, agreement upon a gold standard is necessary to better explore the putative effects of prenatal androgens. Our objective was to assess the level of intra and interobserver reliability when evaluating 2D:4D using four techniques: (1) physical measurements, (2) photocopies, (3) printed scanned images, and (4) computer-assisted image analysis. Physical measurements, photocopies, and printed scanned images were measured with Vernier calipers. Scanned images were also measured with computer-based calipers. Measurements were made in 30 men and 30 women at two different time points, by three experienced observers. Intraclass correlation coefficients were used to assess the level of reliability. Intraobserver reliability was best for computer-assisted (0.957), followed by photocopies (0.939), physical measurements (0.925), and printed scans (0.842; P = 0.015). Interobserver reliability was also greatest for computer-assisted (0.892), followed by photocopies (0.858), physical measurements (0.795), and printed scans (0.761; P = 0.001). Mean 2D:4D from physical measurements were higher than all other techniques (P < 0.0001). Digit ratios determined from computer-assisted, physical measurements, and printed scans were more reliable in men than women (P = 0.009, P = 0.017, and P = 0.012, respectively). In summary, 2D:4D determined from computer-assisted analysis yielded the most accurate and consistent measurements among observers. Investigations of 2D:4D should use computer-assisted measurements over alternate methods whenever possible.
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Affiliation(s)
- Heather C Allaway
- Department of Obstetrics, Gynecology and Reproductive Sciences, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Kemper CJ, Schwerdtfeger A. Comparing indirect methods of digit ratio (2D:4D) measurement. Am J Hum Biol 2009; 21:188-91. [PMID: 18988284 DOI: 10.1002/ajhb.20843] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Affiliation(s)
- Christoph J Kemper
- Department of Psychology, Johannes Gutenberg-University Mainz, Mainz, Germany.
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35
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Yang CFJ, Gray PB, Zhang J, Pope HG. Second to fourth digit ratios, sex differences, and behavior in Chinese men and women. Soc Neurosci 2009; 4:49-59. [DOI: 10.1080/17470910801942876] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Witelson SF, Kigar DL, Scamvougeras A, Kideckel DM, Buck B, Stanchev PL, Bronskill M, Black S. Corpus callosum anatomy in right-handed homosexual and heterosexual men. ARCHIVES OF SEXUAL BEHAVIOR 2008; 37:857-63. [PMID: 17975723 DOI: 10.1007/s10508-007-9276-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2007] [Revised: 08/31/2007] [Accepted: 09/15/2007] [Indexed: 05/22/2023]
Abstract
The results of several studies have shown that homosexual men have an increased prevalence of non-right-handedness and atypical patterns of hemispheric functional asymmetry. Non-right-handedness in men has been associated with increased size of the corpus callosum (CC), particularly of the isthmus, which is the posterior region of the callosal body connecting parietotemporal cortical regions. We hypothesized that isthmal area would be greater in homosexual men, even among right handers. Twelve homosexual and ten heterosexual healthy young men, all consistently right-handed, underwent a research-designed magnetic resonance imaging scan. We found that the isthmal area was larger in the homosexual group, adding to the body of findings of structural brain differences between homosexual and heterosexual men. This result suggests that right-handed homosexual men have less marked functional asymmetry compared to right-handed heterosexual men. The results also indicate that callosal anatomy and laterality for motoric functions are dissociated in homosexual men. A logistic regression analysis to predict sexual orientation category correctly classified 21 of the 22 men (96% correct classification) based on area of the callosal isthmus, a left-hand performance measure, water level test score, and a measure of abstraction ability. Our findings indicate that neuroanatomical structure and cognition are associated with sexual orientation in men and support the hypothesis of a neurobiological basis in the origin of sexual orientation.
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Affiliation(s)
- Sandra F Witelson
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, 1200 Main St. W, Hamilton, ON, L8N 3Z5, Canada.
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Puts DA, McDaniel MA, Jordan CL, Breedlove SM. Spatial ability and prenatal androgens: meta-analyses of congenital adrenal hyperplasia and digit ratio (2D:4D) studies. ARCHIVES OF SEXUAL BEHAVIOR 2008; 37:100-11. [PMID: 18074217 PMCID: PMC2883918 DOI: 10.1007/s10508-007-9271-3] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Hormonal manipulations indicate that early androgens organize sex differences in spatial ability in laboratory rats. In humans, spatial ability is also sexually dimorphic, and information about the effects of prenatal androgens on spatial ability can be obtained from studies of congenital adrenal hyperplasia (CAH) and the ratio of the second and fourth finger lengths (2D:4D). CAH is characterized by prenatal overproduction of adrenal androgens and several lines of evidence suggest that 2D:4D reflects prenatal androgen exposure. Some studies have found that these proxy measures of prenatal androgens predict spatial ability, others have found no significant relationship, and yet others have obtained results in the opposite direction. In light of these mixed findings, we conducted meta-analyses of published literature and unpublished results to determine if, across studies, either of these indicators of prenatal androgens predicts performance on spatial tasks that show a male advantage. In addition, we applied a trim and fill analysis to the data in search of asymmetry that might be an indication of publication bias. Results indicated that females with CAH perform better on these spatial tasks, and CAH males perform worse, than do controls. Little or no relationship exists between 2D:4D and spatial ability. Implications for possible hormonal contributions and the developmental timing of sex differences in spatial cognition are discussed.
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Affiliation(s)
- David A Puts
- Neuroscience Program, Department of Psychology, Michigan State University, East Lansing, MI, USA.
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Hampson E, Ellis CL, Tenk CM. On the relation between 2D:4D and sex-dimorphic personality traits. ARCHIVES OF SEXUAL BEHAVIOR 2008; 37:133-144. [PMID: 18075733 DOI: 10.1007/s10508-007-9263-3] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Several personality traits, including aggressiveness and sensation seeking, have been hypothesized to be influenced by prenatal androgen exposure, though evidence for this proposition is limited. We investigated whether individual differences in aggressiveness, sensation seeking, and several prosocial personality traits can be predicted from differences in the 2D:4D digit ratio, a putative marker of prenatal androgen activity. A total of 164 undergraduates (87 men, 77 women) completed self-report measures of physical and verbal aggression, as well as a standardized measure of sensation seeking, and five scales to assess empathy, nurturance, expressivity/femininity, instrumentality/masculinity, and assertiveness. Two sex-dimorphic tests of spatial ability also were included. Men had a lower 2D:4D ratio than women, confirming the typical sex difference in digit proportions. Significant sex differences were observed on 10 of the 11 personality scales purported to show sex differences and on both tests of spatial ability. The 2D:4D ratio was a significant predictor of scores on three of the four aggression subscales, total aggression, thrill and adventure seeking, and total sensation-seeking, in the sample as a whole and in women. In men, correlations with 2D:4D were significant only for total sensation-seeking and verbal aggression. In both sexes, lower 2D:4D ratios were associated with increased aggressiveness and sensation seeking. For the spatial tests, there was no evidence of any association with 2D:4D in either men or women. The 2D:4D digit ratio may be a valid, though weak, predictor of selective sex-dependent traits that are sensitive to testosterone.
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Affiliation(s)
- Elizabeth Hampson
- Department of Psychology, University of Western Ontario, London, Ontario, Canada.
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Lombardo MP, Thorpe PA. Digit Ratios in Green Anolis Lizards (Anolis carolinensis). Anat Rec (Hoboken) 2008; 291:433-40. [DOI: 10.1002/ar.20657] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Ponseti J, Siebner HR, Klöppel S, Wolff S, Granert O, Jansen O, Mehdorn HM, Bosinski HA. Homosexual women have less grey matter in perirhinal cortex than heterosexual women. PLoS One 2007; 2:e762. [PMID: 17712410 PMCID: PMC1942120 DOI: 10.1371/journal.pone.0000762] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 07/23/2007] [Indexed: 11/19/2022] Open
Abstract
Is sexual orientation associated with structural differences in the brain? To address this question, 80 homosexual and heterosexual men and women (16 homosexual men and 15 homosexual women) underwent structural MRI. We used voxel-based morphometry to test for differences in grey matter concentration associated with gender and sexual orientation. Compared with heterosexual women, homosexual women displayed less grey matter bilaterally in the temporo-basal cortex, ventral cerebellum, and left ventral premotor cortex. The relative decrease in grey matter was most prominent in the left perirhinal cortex. The left perirhinal area also showed less grey matter in heterosexual men than in heterosexual women. Thus, in homosexual women, the perirhinal cortex grey matter displayed a more male-like structural pattern. This is in accordance with previous research that revealed signs of sex-atypical prenatal androgenization in homosexual women, but not in homosexual men. The relevance of the perirhinal area for high order multimodal (olfactory and visual) object, social, and sexual processing is discussed.
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Affiliation(s)
- Jorge Ponseti
- Section of Sexual Medicine, Christian-Albrechts University, Kiel, Germany.
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Sandstrom NJ. Sex differences in use of visual cues by rhesus monkeys performing a spatial learning task: comment on "Cognitive performance in rhesus monkeys varies by sex and prenatal androgen exposure" by Herman and Wallen. Horm Behav 2007; 52:139-42. [PMID: 17662744 DOI: 10.1016/j.yhbeh.2007.05.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2007] [Revised: 05/23/2007] [Accepted: 05/24/2007] [Indexed: 10/23/2022]
Affiliation(s)
- Noah J Sandstrom
- Department of Psychology, Williams College, 18 Hoxsey Street, Williamstown, MA 01267, USA.
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Hönekopp J, Bartholdt L, Beier L, Liebert A. Second to fourth digit length ratio (2D:4D) and adult sex hormone levels: new data and a meta-analytic review. Psychoneuroendocrinology 2007; 32:313-21. [PMID: 17400395 DOI: 10.1016/j.psyneuen.2007.01.007] [Citation(s) in RCA: 231] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2006] [Revised: 12/14/2006] [Accepted: 01/29/2007] [Indexed: 10/23/2022]
Abstract
The relative length of the second (index) to the fourth (ring) finger (2D:4D) is a putative negative correlate of prenatal testosterone (T) exposure. Therefore, 2D:4D (and to a lesser extent D(r-l), the difference between 2D:4D in the right hand and in the left hand) has often been used to study effects of prenatal androgenization on human behavior and cognition. However, evidence suggests that 2D:4D may also be related to levels of circulating sex hormones in adults. This would question the validity of 2D:4D as a means of studying the effects of prenatal sex hormones. Here we present new data from two non-clinical samples (64 women and 102 men) regarding the relationships of 2D:4D and D(r-l) with circulating sex hormone levels. We then present a meta-analytic review of all the present evidence regarding this issue. The results suggest that, in the normal population, 2D:4D and D(r-l) are not associated with adult sex hormone levels. The findings from this current study add to the growing body of evidence demonstrating that 2D:4D is a suitable tool to study the effects of prenatal androgenization on human behavior and cognition.
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Affiliation(s)
- Johannes Hönekopp
- Technische Universität Chemnitz, Institut für Psychologie, Wilhelm-Raabe Str. 43, D-09120 Chemnitz, Germany.
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Collaer ML, Reimers S, Manning JT. Visuospatial performance on an internet line judgment task and potential hormonal markers: sex, sexual orientation, and 2D:4D. ARCHIVES OF SEXUAL BEHAVIOR 2007; 36:177-92. [PMID: 17380373 DOI: 10.1007/s10508-006-9152-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2006] [Accepted: 12/11/2006] [Indexed: 05/14/2023]
Abstract
We investigated whether performance on a visuospatial line judgment task, the Judgment of Line Angle and Position-15 test (JLAP-15), showed evidence of sensitivity to early sex steroid exposure by examining how it related to sex, as well as to sexual orientation and 2D:4D digit ratios. Participants were drawn from a large Internet study with over 250,000 participants. In the main sample (ages 12-58 years), males outperformed females on the JLAP-15, showing a moderate effect size for sex. In agreement with a prenatal sex hormone hypothesis, line judgment accuracy in adults related to 2D:4D and sexual orientation, both of which are postulated to be influenced by early steroids. In both sexes, better visuospatial performance was associated with lower (more male-typical) digit ratios. For men, heterosexual participants outperformed homosexual/bisexual participants on the JLAP-15 and, for women, homosexual/bisexual participants outperformed heterosexual participants. In children aged 8-10 years, presumed to be a largely prepubertal group, boys also outperformed girls. These findings are consistent with the hypothesis that visuospatial ability is influenced by early sex steroids, although they do not rule out alternative explanations or additional influences. More broadly, such results support a prenatal sex hormone hypothesis that degree of androgen exposure may influence the neural circuitry underlying cognition (visuospatial ability) and sexual orientation as well as aspects of somatic (digit ratio) development.
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Affiliation(s)
- Marcia L Collaer
- Department of Psychology and Program in Neuroscience, 5605 Middlebury College, Middlebury, Vermont 05753, USA.
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Peters M, Manning JT, Reimers S. The effects of sex, sexual orientation, and digit ratio (2D:4D) on mental rotation performance. ARCHIVES OF SEXUAL BEHAVIOR 2007; 36:251-60. [PMID: 17394056 DOI: 10.1007/s10508-006-9166-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2005] [Accepted: 12/01/2006] [Indexed: 05/14/2023]
Abstract
In spite of the reduced level of experimental control, this large scale study brought some clarity into the relation between mental rotation task (MRT) performance and a number of variables where contradictory associations had previously been reported in the literature. Clear sex differences in MRT were observed for a sample of 134,317 men and 120,783 women, with men outperforming women. There were also MRT differences as a function of sexual orientation: heterosexual men performed better than homosexual men and homosexual women performed better than heterosexual women. Although bisexual men performed better than homosexual men but less well than heterosexual men, no significant differences were observed between bisexual and homosexual women. MRT performance in both men and women peaked in the 20-30 year range, and declined significantly and markedly thereafter. Both men and women showed a significant negative correlation between left and right digit finger ratio and MRT scores, such that individuals with smaller digit ratios (relatively longer ring finger than index finger) performed better than individuals with larger digit ratios.
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Affiliation(s)
- Michael Peters
- Department of Psychology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
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van Anders SM, Watson NV. Testosterone levels in women and men who are single, in long-distance relationships, or same-city relationships. Horm Behav 2007; 51:286-91. [PMID: 17196592 DOI: 10.1016/j.yhbeh.2006.11.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Revised: 11/15/2006] [Accepted: 11/16/2006] [Indexed: 10/23/2022]
Abstract
Research points to an association between testosterone (T) and partnering in some women and men, and this association has been interpreted as an effect of either relationship status (i.e. differences in relationship status lead to differences in T) or relationship orientation (i.e. T is associated with the likelihood of entering relationships). To address whether physical partner presence was associated with decreased T, we examined T levels in people (72 women; 49 men) who were single, in long-distance relationships, or in same-city relationships. No participants were using exogenous hormones, including hormonal contraceptives. Participants provided a saliva sample and responded to questions about their relationship status. Single men had higher T than long-distance and same-city partnered men, which supports the relationship orientation interpretation. In contrast, same-city partnered women had lower T than single women and women in long-distance relationships, which supports the relationship status interpretation. We conclude that physical partner presence is not necessary to see an association between partnering and hormones in men (since same-city and long-distance partnered men had similar T levels), but may be necessary in women (since same-city partnered women had lower T than long-distance partnered women).
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Affiliation(s)
- Sari M van Anders
- Department of Psychology, Simon Fraser University, 8888 University Drive, Burnaby BC, Canada V5A 1S6.
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van Anders SM, Watson NV. Effects of ability- and chance-determined competition outcome on testosterone. Physiol Behav 2007; 90:634-42. [PMID: 17223140 DOI: 10.1016/j.physbeh.2006.11.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 11/06/2006] [Accepted: 11/20/2006] [Indexed: 11/19/2022]
Abstract
Winning competitions has been shown to lead to higher testosterone (T) relative to losing in men and males of other species. In Experiment 1, 38 women and 37 men provided a saliva sample, completed a novel computer-based vocabulary competition task at which they won or lost based on their own ability, provided feedback about the competition via questionnaire, and then produced a second saliva sample. Task outcome and performance was not sexually differentiated, and overall task performance was negatively correlated with T. Male but not female winners had lower baseline and post-competition T, and male losers had a larger decrease in T from baseline to post-competition. In Experiment 2, 31 men and 43 women completed the same as above, but were randomly assigned to win or lose. In this case, competition outcome did not affect T for men but there was an effect such that women who would have had an ability-determined loss showed a larger decrease in T than women who would have had an ability-determined win. Thus, earned wins appear to attenuate a decline in T in men, consistent with past research into the competition effect and T, and perhaps women under complex circumstances.
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Affiliation(s)
- Sari M van Anders
- Department of Psychology, Simon Fraser University, RCB 5246, 8888 University Drive, Burnaby, BC, Canada V5A 1S6
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Brookes H, Neave N, Hamilton C, Fink B. Digit Ratio (2D:4D) and Lateralization for Basic Numerical Quantification. JOURNAL OF INDIVIDUAL DIFFERENCES 2007. [DOI: 10.1027/1614-0001.28.2.55] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract. The ratio between the second and fourth fingers (2D:4D) is supposed to serve as a putative indicator of prenatal testosterone (PT). Significant associations between 2D:4D, children's basic numerical ability, and the Spatial Numerical Associations of Response Codes (SNARC) effect have recently been reported. The present study explored potential relationships between 2D:4D and the basic numerical ability of subitizing (the rapid enumeration of small quantities) in 80 right-handed adult volunteers. Participants completed a short battery of computerized subitizing and color recognition control tasks with both left and right hands, independently (order counterbalanced). Findings revealed a significant interaction between sex and 2D:4D on reaction time differences for right vs. left hand responses to the subitizing task. While 2D:4D in women showed a significant negative association with a right-hand advantage for the task, a nonsignificant trend in the opposite direction was observed for men. Results are discussed with respect to the possible effect of PT on sex differences in lateralization for basic quantification.
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Affiliation(s)
- Helen Brookes
- Human Cognitive Neuroscience Unit, School of Psychology & Sport Sciences, Northumbria University, UK
| | - Nick Neave
- Human Cognitive Neuroscience Unit, School of Psychology & Sport Sciences, Northumbria University, UK
| | - Colin Hamilton
- Human Cognitive Neuroscience Unit, School of Psychology & Sport Sciences, Northumbria University, UK
| | - Bernhard Fink
- Department of Sociobiology/Anthropology, University of Göttingen, Germany
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Abstract
Fink et al. (2006) have reported that men with higher grip strength (GS) have lower digit ratios (2D:4D), interpreting this as evidence for organizational effects of prenatal androgens on strength. In this study, I attempted to replicate their finding with 99 women. I found no evidence that digit ratios were associated with GS, suggesting that 2D:4D is not associated with GS in women. The null findings are discussed in light of gender and statistical considerations.
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Affiliation(s)
- Sari M van Anders
- Department of Psychology, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
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