Height, hands & handwriting:Cues to competition and dominance

Individual differences, contextual- and biological factors play a major role in human behavior. Gathering evidence from different studies, I provide further evidence for the role of well conserved physiological and behavioral mechanisms in human social interactions. I analyzed two different human mechanisms reminiscent of animal body-inflation strategies—height over-report and expanded handwritten signatures—in relation to intrasexual competition, dominance, and narcissism—which can be related to a tendency to impose one’s own interest or aims. Consistent with my hypotheses, I observed a positive correlation between intrasexual competition and inflated-height reports in a sample of male junior soccer players, but not with sociable or aggressive dominance. Similarly, signature size appeared to be positively correlated with sociable dominance and narcissism in a sample of university students, even after controlling for a number of potential confounders, i.e., sex, age, number of characters in printed name, average character size, and signature type. I found a significant association between signature size and sociable dominance, both among males and females, while narcissism was only among females significantly associated with signature size. In addition, I examined the association of prenatal testosterone levels—measured as the second-to-fourth digit ratio (2D:4D)—with actual aggressive behavior and personality traits in adult life. I observed a negative association of 2D:4D ratios—indicative of higher prenatal testosterone levels—and both the severity and frequency of aggressive behavior, as indicated by the type—i.e., none, yellow, or red cards—and number of cards per match awarded to junior soccer players. However, contrary to previous findings, a lower, i.e., more masculine, 2D:4D ratio was associated with less aggressive dominance in the same sample of junior soccer players. With these findings, I hope to have shed light on behavioral cues to competition and dominance, and on the role of prenatal testosterone in competition and aggressive behavior

High intrasexual competition is related to inflated height reports in male junior soccer players

Intrasexual competition refers to the rivalry between same-sex individuals over access to potential mates. Because in many animal species larger males are more likely to defeat smaller opponents over access to potential mates and additional resources, it has been suggested that intrasexual competition was a major driver in the emergence of male-biased sexual size dimorphism. In the same vein, human male height has been related to aggressive behavior, status and dominance. Given the value of body size in agonistic interactions, body inflation strategies are likely to have evolved in many animal species. In this study, we explored the relationship of the bias in reporting one's own height-a phenomenon reminiscent of animal self-inflation mechanisms-with intrasexual competition, and sociable and aggressive dominance, in the highly competitive context of Uruguayan pre-professional soccer. We also considered the bias in reporting additional operationalizations of body size, i.e., weight, and body mass index (BMI). We showed that intrasexual competition is positively correlated with height over-report. To the best of our knowledge, this study is the first to relate intrasexual competition and the bias in reporting one's own height, a putative indicator or power and status. (C) 2017 Elsevier Ltd. All rights reserved

Favoreciendo el aprendizaje de la matemática con la tablet: Juguemos con el tiempo, el espacio y las cantidades

Todo el conocimiento que desarrollamos en nuestra etapa escolar está basado en intuiciones básicas. Por ejemplo, en matemática, incluso los niños más pequeños tienen las habilidades básicas necesarias para representar tamaños de objetos, duraciones de tiempo y para estimar la cantidad aproximada de elementos de un conjunto sin contarlos. Esta última habilidad se relaciona con el ‘Sistema Numérico Aproximado’ que se ha propuesto como base para soportar las operaciones simbólicas y, específicamente, el concepto de número. La mayor parte de las investigaciones sobre este sistema muestran que a mayor precisión en la discriminación no simbólica de cantidades, mayor capacidad para la resolución simbólica de problemas matemáticos. Asimismo, estudios previos muestran que el desarrollo de las habilidades básicas de estimación de magnitudes no simbólicas impacta positivamente en el desempeño de las matemáticas simbólicas. A partir de estos estudios previos, el presente proyecto se propone estudiar el efecto de una serie de mini juegos—diseñados específicamente para potenciar el desarrollo de diferentes dimensiones del sistema de magnitudes no simbólicas—sobre las matemáticas simbólicas. Estos juegos podrán ser distribuidos a la población escolar uruguaya a través de las tablets del Plan Ceibal. El entrenamiento de estas habilidades no simbólicas tempranamente puede construir una base sólida para el aprendizaje de las matemáticas en la escuela.Centro de Estudios Fundacion Ceibal, Agencia Nacional de Investigación e Innovació

Soccer players awarded one or more red cards exhibit lower 2D:4D ratios

Anatomical, cognitive and behavioral sex differences are widely recognized in many species. It has been proposed that some of these differences might result from the organizing effects of prenatal sex steroids. In humans, males usually exhibit higher levels of physical aggression and prowess. In this study, we analyze the relationship between second-to-fourth digit (2D:4D) ratiosa proxy for prenatal androgen levelsand foul play and sporting performance in a sample of junior soccer players from a professional Uruguayan soccer club. Our results show that the most aggressive players (i.e., those awarded one or more red cards) have a more masculine finger pattern (lower 2D:4D ratio), while no relationship could be found between sporting performance and 2D:4D ratios. The results are discussed in the context of previous findings. Aggr. Behav. 42:417-426, 2016. (c) 2015 Wiley Periodicals, Inc

Voice pitch is negatively associated with sociosexual behavior in males but not in females

Acoustic cues play a major role in social interactions in many animal species. In addition to the semantic contents of human speech, voice attributes – e.g., voice pitch, formant position, formant dispersion, etc. – have been proposed to provide critical information for the assessment of potential rivals and mates. However, prior studies exploring the association of acoustic attributes with reproductive success, or some of its proxies, have produced mixed results. Here, we investigate whether the mean fundamental frequency (F0), formant position (Pf), and formant dispersion (Df) – dimorphic attributes of the human voice – are related to sociosexuality, as measured by the Revised Sociosexual Orientation Inventory (SOI-R) – a trait also known to exhibit sex differences – in a sample of native Spanish-speaking students (101 males, 147 females). Analyses showed a significant negative correlation between F0 and sociosexual behavior, and between Pf and sociosexual desire in males but not in females. These correlations remained significant after correcting for false discovery rate (FDR) and controlling for age, a potential confounding variable. Our results are consistent with a role of F0 and Pf serving as cues in the mating domain in males but not in females. Alternatively, the association of voice attributes and sociosexual orientation might stem from the parallel effect of male sex hormones both on the male brain and the anatomical structures involved in voice production

Vocal Cues to Male Physical Formidability

Animal vocalizations convey important information about the emitter, including sex, age, biological quality, and emotional state. Early on, Darwin proposed that sex differences in auditory signals and vocalizations were driven by sexual selection mechanisms. In humans, studies on the association between male voice attributes and physical formidability have thus far reported mixed results. Hence, with a view to furthering our understanding of the role of human voice in advertising physical formidability, we sought to identify acoustic attributes of male voices associated with physical formidability proxies. Mean fundamental frequency (F-0), formant dispersion (D-f), formant position (P-f), and vocal tract length (VTL) data from a sample of 101 male voices was analyzed for potential associations with height, weight, and maximal handgrip strength (HGS). F-0 correlated negatively with HGS; P-f showed negative correlations with HGS, height and weight, whereas VTL positively correlated with HGS, height and weight. All zero-order correlations remained significant after controlling for false discovery rate (FDR) with the Benjamini-Hochberg method. After controlling for height and weight -and controlling for FDR-the correlation between F-0 and HGS remained significant. In addition, to evaluate the ability of human male voices to advertise physical formidability to potential mates, 151 heterosexual female participants rated the voices of the 10 strongest and the 10 weakest males from the original sample for perceived physical strength, and given that physical strength is a desirable attribute in male partners, perceived attractiveness. Generalized linear mixed model analyses-which allow for generalization of inferences to other samples of both raters and targets-failed to support a significant association of perceived strength or attractiveness from voices alone and actual physical strength. These results add to the growing body of work on the role of human voices in conveying relevant biological information

Predictors of Enhancing Human Physical Attractiveness: Data from 93 Countries

People across the world and throughout history have gone to great lengths to enhance their physical appearance. Evolutionary psychologists and ethologists have largely attempted to explain this phenomenon via mating preferences and strategies. Here, we test one of the most popular evolutionary hypotheses for beauty-enhancing behaviors, drawn from mating market and parasite stress perspectives, in a large cross-cultural sample. We also test hypotheses drawn from other influential and non-mutually exclusive theoretical frameworks, from biosocial role theory to a cultural media perspective. Survey data from 93,158 human participants across 93 countries provide evidence that behaviors such as applying makeup or using other cosmetics, hair grooming, clothing style, caring for body hygiene, and exercising or following a specific diet for the specific purpose of improving ones physical attractiveness, are universal. Indeed, 99% of participants reported spending \u3e10 min a day performing beauty-enhancing behaviors. The results largely support evolutionary hypotheses: more time was spent enhancing beauty by women (almost 4 h a day, on average) than by men (3.6 h a day), by the youngest participants (and contrary to predictions, also the oldest), by those with a relatively more severe history of infectious diseases, and by participants currently dating compared to those in established relationships. The strongest predictor of attractiveness-enhancing behaviors was social media usage. Other predictors, in order of effect size, included adhering to traditional gender roles, residing in countries with less gender equality, considering oneself as highly attractive or, conversely, highly unattractive, TV watching time, higher socioeconomic status, right-wing political beliefs, a lower level of education, and personal individualistic attitudes. This study provides novel insight into universal beauty-enhancing behaviors by unifying evolutionary theory with several other complementary perspectives

Reasons for facebook usage: Data from 46 countries

Seventy-nine percent of internet users use Facebook, and on average they access Facebook eight times a day (Greenwood et al., 2016). To put these numbers into perspective, according to Clement (2019), around 30% of the world\u2019s population uses this Online Social Network (OSN) site. Despite the constantly growing body of academic research on Facebook (Chou et al., 2009; Back et al., 2010; Kaplan and Haenlein, 2010; McAndrew and Jeong, 2012; Wilson et al., 2012; Krasnova et al., 2017), there remains limited research regarding the motivation behind Facebook use across different cultures. Our main goal was to collect data from a large cross-cultural sample of Facebook users to examine the roles of sex, age, and, most importantly, cultural differences underlying Facebook use