Development of the external genitalia: Perspectives from the spotted hyena (Crocuta crocuta)

Differentiation. 2014 pii: S0301-4681(13)00087-X
doi: 10.1016/j.diff.2013.12.003
Available online 28 February 2014
[Epub ahead of print]

Gerald R. Cunha [a,b], Gail Risbridger [b], Hong Wang [b], Ned J. Place [c], Mel Grumbach [d], Tristan J. Cunha [a], Mary Weldele [e], Al J. Conley [f], Dale Barcellos [g], Sanjana Agarwal [g], Argun Bhargava [g], Christine Drea [h], Geoffrey L. Hammond [i], Penti Siiteri [j], Elizabeth M. Coscia [k], Michael J. McPhaul [l], Laurence S. Baskin [a], Stephen E. Glickman [e]

[a] Department of Urology, University of California San Francisco, 400 Parnassus Avenue, Box A610, San Francisco, CA 94143, United States
[b] Department of Anatomy & Developmental Biology, Monash University, Clayton Campus, Building 76 Level 3, Wellington Road, Clayton, VIC, Australia
[c] Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, United States
[d] Department of Pediatrics, University of California San Francisco, Box 0434, San Francisco, CA 94143, United States
[e] Departments of Psychology and Integrative Biology, University of California, Berkeley, CA 94720, United States
[f] Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, United States
[g] Monte Vista High School, Cupertino, CA 95014, United States
[h] Departments of Evolutionary Anthropology and Biology, Duke University, Durham, NC 27708, United States
[i] Department of Cellular & Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
[j] Department of Obstetrics and Gynecology, University of California San Francisco, 400 Parnassus Avenue, Box A610, San Francisco, CA 94143, United States
[k] Salesian High School, Richmond, CA 94804, United States
[l] University of Texas Southwestern, Division of Endocrinology and Metabolism, 5323 Harry Hines Blvd., Dallas, TX, 75390-8857 and Quest Diagnostics, Endocrine Division, 33608 Ortega Highway, San Juan Capistrano, CA 92675, United States

Abstract

This review/research paper summarizes data on development of the external genitalia of the spotted hyena, a fascinating mammal noted for extreme masculinization of the female external genitalia. The female spotted hyena is the only extant mammal that mates and gives birth through a pendulous penis-like clitoris. Our studies indicate that early formation of the phallus in both males and females is independent of androgens; indeed the phallus forms before the fetal testes or ovaries are capable of synthesizing androgens. Likewise, pre- and postnatal growth in length of the penis and clitoris is minimally affected by “androgen status”. Nonetheless, several internal morphologies, as well as external surface features of the phallus, are androgen-dependent and thus account for dimorphism between the penis and clitoris. Finally, estrogens play a critical role in penile and clitoral development, specifying the position of the urethral orifice, determining elasticity of the urethral meatus, and facilitating epithelial–epithelial fusion events required for proper formation of the distal urethra/urogenital sinus and prepuce. Accordingly, prenatal inhibition of estrogen synthesis via administration of letrozole (an aromatase inhibitor) leads to malformations of the glans as well as the prepuce (hypospadias). The effects of prenatal androgens, anti-androgens and impaired estrogen synthesis correlated with the tissue expression of androgen and estrogen receptors.

http://www.sciencedirect.com/science/article/pii/S030146811300087X

Shrouded in the Veil of Darkness: Machiavellians but not narcissists and psychopaths profit from darker weather in courtship

Personality and Individual Differences
Available online 7 February 2014
In Press, Corrected Proof
http://dx.doi.org/10.1016/j.paid.2014.01.020

John F. Rauthmann [a], Marlit Kappes [a], Johannes Lanzinger [b]

[a] Humboldt-Universität zu Berlin, Departmernt of Psychology, Rudower Chaussee 18, D-12489 Berlin-Adlershof, Germany
[b] Leopold-Franzens Universität Innsbruck, Department of Psychology, Innrain 52, A-6020 Innsbruck, Austria

Abstract

We proposed in the “Veil of Darkness” hypothesis that dark personalities (narcissists, Machiavellians, psychopaths) profit from conditions of less illumination where they can better manipulate others. As an initial test of this hypothesis in the domain of mating, we predicted that male dark personalities should be more successful in their courtship during dark/cloudy rather than bright/sunny weather. In a large naturalistic field-study, 59 men romantically advanced 1395 women on the street, while they were unobtrusively followed by confederate observers. We thus obtained ratings from men, women, and observers on women’s reactions to men’s advances. Machiavellians, but not narcissists and psychopaths, elicited more positive reactions from women during cloudy weather. This effect was mediated by Machiavellian men’s assuredness. We discuss different mechanisms that may constitute the observed Veil of Darkness effect for Machiavellianism.

Keywords

Dark Triad; Narcissism; Machiavellianism; Psychopathy; Courtship; Mating; Veil of Darkness

Highlights

• Veil of Darkness hypothesis: dark personalities perform well during less illumination.
• Tested in courtship/mating domain for dark/cloudy vs. bright/sunny weather.
• Male Machiavellians (but not narcissists and psychopaths) elicited more positive responses from women during dark weather.

http://www.sciencedirect.com/science/article/pii/S0191886914000403

Self-Portraits: Smartphones Reveal a Side Bias in Non-Artists

PLoS ONE
February 2013 | Volume 8 | Issue 2 | e55141
Published: February 06, 2013
DOI: 10.1371/journal.pone.0055141

Nicola Bruno [1], Marco Bertamini [2]

1 Dipartimento di Neuroscienze, Università di Parma, Parma, Italy
2 Department of Experimental Psychology, University of Liverpool, Liverpool, United Kingdom

Abstract

According to surveys of art books and exhibitions, artists prefer poses showing the left side of the face when composing a portrait and the right side when composing a self-portrait. However, it is presently not known whether similar biases can be observed in individuals that lack formal artistic training. We collected self-portraits by naïve photographers who used the iPhone front camera, and confirmed a right side bias in this non-artist sample and even when biomechanical constraints would have favored the opposite. This result undermines explanations based on posing conventions due to artistic training or biomechanical factors, and is consistent with the hypothesis that side biases in portraiture and self-portraiture are caused by biologically-determined asymmetries in facial expressiveness.

Introduction

When they compose a self-portrait, artists prefer poses showing the right side of their face. This right-side bias is well documented by surveys of art books and exhibitions but its origin has remained controversial. As an alternative to observational data from the history of art, we collected self-portraits by naïve photographers who used the iPhone™ front camera in controlled settings. The right side bias remained observable in this non-artist sample, and even when biomechanical constraints would have favored a left-side bias. These results argue against explanations based on posing constraints and support the hypothesis that side biases in portraiture and self-portraiture are caused by biologically determined asymmetries in facial expressiveness...

http://www.plosone.org/article/info:doi/10.1371/journal.pone.0055141

Half Full or Empty: Cues That Lead Wine Drinkers to Unintentionally Overpour

Substance Use & Misuse
February 2014, Vol. 49, No. 3 , Pages 295-302
doi:10.3109/10826084.2013.832327

Doug Walker [1], Laura Smarandescu [1] and Brian Wansink [2]

1 Iowa State University, Ames, Iowa, USA
2 Cornell University, Ithaca, NY 14850, USA

What might unknowingly bias the amount of wine a person serves themselves? Wine is often self-poured in various settings (e.g., at home, restaurants, receptions, parties). Building on research involving visual illusions and haptic cues, an exploratory field study finds that environmental factors (e.g., glass shape, pouring position, wine color) affect how much wine is poured in different scenarios. When individuals overpoured, they were generally accurate in post hoc perceptions of the relative extent to which the environmental cues affected their pouring. Increasing awareness of pouring biases is a step toward limiting alcohol intake for improved health outcomes and preventing alcohol-related problems.

Keywords
overpouring, overconsuming, environmental cues, wine

http://informahealthcare.com/doi/abs/10.3109/10826084.2013.832327