Risk-taking, fear, dominance, and testosterone

1999 ◽  
Vol 22 (2) ◽  
pp. 214-215 ◽  
Author(s):  
John Archer
Keyword(s):  
Sex Differences ◽  
Sex Difference ◽  
Risk Taking ◽  
Selective Advantage ◽  
Human Sex Differences ◽  
Dominance Hierarchies ◽  
Selection Pressures ◽  
Human Aggression ◽  
Absence Of Evidence ◽  
The Impact

Campbell's analysis of the evolution of human sex differences to include selection pressures on the female is generally welcomed. This commentary raises some specific issues about the evidence cited: the impact of paternal death on survival prospects; a possible mechanism underlying a sex difference in fear; the selective advantage of dominance hierarchies; and the absence of evidence that testosterone causes human aggression.

scholarly journals Sex-Related Differences in the Effects of the Mediterranean Diet on Glucose and Insulin Homeostasis

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Alexandra Bédard ◽  
Louise Corneau ◽  
Benoît Lamarche ◽  
Sylvie Dodin ◽  
Simone Lemieux
Keyword(s):  
Sex Differences ◽  
Insulin Sensitivity ◽  
Mediterranean Diet ◽  
Sex Difference ◽  
Premenopausal Women ◽  
Nonesterified Fatty Acids ◽  
Time Interaction ◽  
Insulin Homeostasis ◽  
The Mediterranean ◽  
The Impact

Objective. To document sex differences in the impact of the Mediterranean diet (MedDiet) on glucose/insulin homeostasis and to verify whether these sex-related effects were associated with changes in nonesterified fatty acids (NEFA).Methods. All foods were provided to 38 men and 32 premenopausal women (24–53 y) during 4 weeks. Variables were measured during a 180 min OGTT before and after the MedDiet.Results. A sex-by-time interaction for plasma insulin iAUC was found (men: −17.8%,P=0.02; women: +9.4%,P=0.63;Pfor sex-by-time interaction = 0.005). A sex-by-time interaction was also observed for insulin sensitivity (Cederholm index,P=0.03), for which only men experienced improvements (men: +8.1%,P=0.047; women: −5.9%,P=0.94). No sex difference was observed for glucose and C-peptide responses. Trends toward a decrease in NEFA AUC (P=0.06) and an increase in NEFA suppression rate (P=0.06) were noted, with no sex difference. Changes in NEFA were not associated with change in insulin sensitivity.Conclusions. Results suggest that the more favorable changes in glucose/insulin homeostasis observed in men compared to women in response to the MedDiet are not explained by sex differences in NEFA response. This clinical trial is registered with clinicaltrials.govNCT01293344.

Gonadal hormone effects on entrained and free-running circadian activity rhythms in the developing diurnal rodent Octodon degus

2007 ◽  
Vol 292 (1) ◽  
pp. R586-R597 ◽  
Author(s):  
Daniel L. Hummer ◽  
Tammy J. Jechura ◽  
Megan M. Mahoney ◽  
Theresa M. Lee
Keyword(s):  
Sex Differences ◽  
Sex Difference ◽  
Sexual Differentiation ◽  
Gonadal Hormones ◽  
Circadian System ◽  
System Structure ◽  
Octodon Degus ◽  
Activity Rhythms ◽  
Free Running ◽  
The Impact

The slowly maturing, long-lived rodent Octodon degus (degu) provides a unique opportunity to examine the development of the circadian system during adolescence. These studies characterize entrained and free-running activity rhythms in gonadally intact and prepubertally gonadectomized male and female degus across the first year of life to clarify the impact of sex and gonadal hormones on the circadian system during adolescence. Gonadally intact degus exhibited a delay in the phase angle of activity onset (Ψon) during puberty, which reversed as animals became reproductively competent. Gonadectomy before puberty prevented this phase delay. However, the effect of gonadal hormones during puberty on Ψon does not result from changes in the period of the underlying circadian pacemaker. A sex difference in Ψon and free-running period (τ) emerged several months after puberty; these developmental changes are not likely to be related, since the sex difference in Ψon emerged before the sex difference in τ. Changes in the levels of circulating hormones cannot explain the emergence of these sex differences, since there is a rather lengthy delay between the age at which degus reach sexual maturity and the age at which Ψon and τ become sexually dimorphic. However, postnatal exposure to gonadal hormones is required for sexual differentiation of Ψon and τ, since these sex differences were absent in prepubertally gonadectomized degus. These data suggest that gonadal hormones modulate the circadian system during adolescent development and provide a new model for postpubertal sexual differentiation of a central nervous system structure.

Relative Cerebellum Size Is Not Sexually Dimorphic across Primates

2020 ◽  
Vol 95 (2) ◽  
pp. 93-101
Author(s):  
Alex R. DeCasien ◽  
James P. Higham
Keyword(s):  
Sex Differences ◽  
Sexual Selection ◽  
Sex Difference ◽  
Cognitive Abilities ◽  
Relative Size ◽  
Brain Evolution ◽  
Primate Species ◽  
Published Data ◽  
Heterogeneous Structure ◽  
Selection Pressures

Background/Aims: Substantive sex differences in behavior and cognition are found in humans and other primates. However, potential sex differences in primate neuroanatomy remain largely unexplored. Here, we investigate sex differences in the relative size of the cerebellum, a region that has played a major role in primate brain evolution and that has been associated with cognitive abilities that may be subject to sexual selection in primates. Methods: We compiled individual volumetric and sex data from published data sources and used MCMC generalized linear mixed models to test for sex effects in relative cerebellar volume while controlling for phylogenetic relationships between species. Given that the cerebellum is a functionally heterogeneous structure involved in multiple complex cognitive processes that may be under selection in males or females within certain species, and that sexual selection pressures vary so greatly across primate species, we predicted there would be no sex difference in the relative size of the cerebellum across primates. Results: Our results support our prediction, suggesting there is no consistent sex difference in relative cerebellum size. Conclusion: This work suggests that the potential for sex differences in relative cerebellum size has been subject to either developmental constraint or lack of consistent selection pressures, and highlights the need for more individual-level primate neuroanatomical data to facilitate intra- and inter-specific study of brain sexual dimorphism.

Staying alive: Evolution, culture, and women's intrasexual aggression

1999 ◽  
Vol 22 (2) ◽  
pp. 203-214 ◽  
Author(s):  
Anne Campbell
Keyword(s):  
Sex Differences ◽  
Reproductive Success ◽  
Risk Taking ◽  
Paternal Care ◽  
Indirect Aggression ◽  
Female Competition ◽  
Dominance Hierarchies ◽  
Scarce Resources ◽  
Bodily Injury ◽  
Hierarchy Formation

Females' tendency to place a high value on protecting their own lives enhanced their reproductive success in the environment of evolutionary adaptation because infant survival depended more upon maternal than on paternal care and defence. The evolved mechanism by which the costs of aggression (and other forms of risk taking) are weighted more heavily for females may be a lower threshold for fear in situations which pose a direct threat of bodily injury. Females' concern with personal survival also has implications for sex differences in dominance hierarchies because the risks associated with hierarchy formation in nonbonded exogamous females are not offset by increased reproductive success. Hence among females, disputes do not carry implications for status with them as they do among males, but are chiefly connected with the acquisition and defence of scarce resources. Consequently, female competition is more likely to take the form of indirect aggression or low-level direct combat than among males. Under patriarchy, men have held the power to propagate images and attributions which are favourable to the continuance of their control. Women's aggression has been viewed as a gender-incongruent aberration or dismissed as evidence of irrationality. These cultural interpretations have “enhanced” evolutionarily based sex differences by a process of imposition which stigmatises the expression of aggression by females and causes women to offer exculpatory (rather than justificatory) accounts of their own aggression.

Some reflections on sex differences in aggression and violence

1999 ◽  
Vol 22 (2) ◽  
pp. 232-233
Author(s):  
Stephen C. Maxson
Keyword(s):  
Sex Differences ◽  
Sex Difference ◽  
Evolutionary Explanation ◽  
Men And Women ◽  
Human Aggression ◽  
Intrasexual Aggression ◽  
Males And Females ◽  
Evolutionary Explanations

Four issues relevant to sex differences in human aggression and violence are considered. (1) The motivation for play and serious aggression in children and juvenile animals is different. Consequently, the evolutionary explanations for each may be different. (2) Sex differences in intrasexual aggression may be due to effects of the attacker or the target. There is evidence that both males and females are more physically aggressive against males and less physically aggressive against females. The evolutionary explanation for each component of the sex difference in intrasexual aggression may be different. (3) Aggression and violence are defined. The former is the attack, and the latter is the consequent injury or death. The evolutionary explanation for each may not be the same. (4) Most men and women are neither physically aggressive nor criminally violent. The evolutionary explanations of sex differences in aggression and violence should take this polymorphism into account.

scholarly journals Is sex a proxy for mechanical variables during an upper limb repetitive movement task? An investigation of the effects of sex and of anthropometric load on muscle fatigue

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Matthew Slopecki ◽  
Karen Messing ◽  
Julie N. Côté
Keyword(s):  
Sex Differences ◽  
Sex Difference ◽  
Future Research ◽  
Repetitive Movement ◽  
Work Related ◽  
Upper Trapezius ◽  
Specific Effects ◽  
Body Parameter ◽  
Anterior Deltoid ◽  
The Impact

Abstract Background Women report more work-related pain and neck/shoulder musculoskeletal disorders than men. For the same absolute workload, due to lower strength, females generally work at a higher relative intensity, which could induce more fatigue. However, the arm’s anthropometric load (AL) of men is higher. Therefore, simply lifting their arm could be more fatiguing. Sex as a variable is formed of many constructs, and analyses can become muddied by their differing responses to fatigue. No studies have considered AL, when comparing how fatigue affects men and women. The purpose was to determine if including the arm’s AL in the statistical analysis would impact findings of sex-specific effects of shoulder fatigue on muscle EMG. Methods Fifty-five (29m/26f) participants completed a repetitive pointing task (RPT) at shoulder height until they reported fatigue of 8+ on the BORG CR-10 scale. Muscle activities were measured using surface electrodes placed over the anterior deltoid (AD) and upper trapezius (UT) muscles. Muscle activity amplitude was quantified using root mean square (RMS). First- and last-minute data were used to assess change from no-fatigue (NF) to fatigue-terminal (FT) conditions. AL was calculated using sex-specific body parameter equations. General estimating equations (GEE) were used to determine the effects of sex and fatigue on RMS values, while including AL in the GEE. Results There was no sex difference in time to reach fatigue. A significant main effect of sex on RMS was observed (χ2(1) = 4.17, p = 0.04) when including AL as a covariate. Females displayed a significantly higher percentage change in AD RMS from NF to FT, compared to males (p = 0.03), when AL was included in the GEE. No sex differences in UT were observed. Conclusions This sex difference emerged when AL was included as a covariate, suggesting that sex-associated anthropometric differences may contribute to sex differences in the fatigue response. Differences in the impact of AL on AD compared to UT could be explained by differences in their respective mechanical roles or muscle fiber content. Anthropometrics may be useful to include as covariates in future research to separate individual anthropometric differences from sex differences.

scholarly journals Sex Differences in Misperceptions of Sexual Interest Can Be Explained by Sociosexual Orientation and Men Projecting Their Own Interest Onto Women

2020 ◽  
Vol 31 (2) ◽  
pp. 184-192 ◽  
Author(s):  
Anthony J. Lee ◽  
Morgan J. Sidari ◽  
Sean C. Murphy ◽  
James M. Sherlock ◽  
Brendan P. Zietsch
Keyword(s):  
Sex Differences ◽  
Sex Difference ◽  
Cognitive Bias ◽  
Sexual Interest ◽  
Selection Pressures ◽  
Men And Women ◽  
Sociosexual Orientation ◽  
Speed Dating

Sex differences in misperceptions of sexual interest have been well documented; however, it is unclear whether this cognitive bias could be explained by other factors. In the current study, 1,226 participants (586 men, 640 women) participated in a speed-dating task in which they rated their sexual interest in each other as well as the sexual interest they perceived from their partners. Consistent with previous findings, results showed that men tended to overperceive sexual interest from their partners, whereas women tended to underperceive sexual interest. However, this sex difference became negligible when we considered potential mediators, such as the raters’ sociosexual orientation and raters’ tendency to project their own levels of sexual interest onto their partners. These findings challenge the popular notion that sex differences in misperceptions of sexual interest have evolved as a specialized adaptation to different selection pressures in men and women.

scholarly journals Factors Effecting on Study Habits

2016 ◽  
Vol 3 (1) ◽  
pp. 145
Author(s):  
Zebun Nisa Khan
Keyword(s):  
Sex Differences ◽  
Sex Difference ◽  
Interaction Effect ◽  
Economic Status ◽  
Psychological Tests ◽  
Study Habits ◽  
Independent Variables ◽  
Socio Economic Status ◽  
The Impact ◽  
Two Independent Variables

<p><em>The present study was undertaken with the objectives to find out the impact of Socio-economic Status as well as sex differences on study habits of class VII students (100) of Government Colleges of Amroha District. The effects of two independent variables on study habits of the aforementioned students were assessed by using two Psychological tests namely Socio-economic Status Scale (Urban); by Dr. Kulshrestha and Rao’s Study Habits Inventory. The findings indicated a significant effect of gender on study habits of the subjects. The effect of Socio-economic Status on study habits was found to be insignificant. Interaction effect of sex difference and Socio-economic Status was also not significant.</em><em></em></p>

scholarly journals The Father-Child Activation Relationship, Sex Differences, and Attachment Disorganization in Toddlerhood

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Daniel Paquette ◽  
Caroline Dumont
Keyword(s):  
Sex Difference ◽  
Risk Taking ◽  
Emotional Support ◽  
Parental Behavior ◽  
Strange Situation ◽  
Attachment Relationship ◽  
Attachment Disorganization ◽  
And Control ◽  
The Impact ◽  
Stimulation Of

The activation relationship theory serves as a complement to Bowlby’s attachment theory to better understand the impact of fathering on child development, focusing primarily on parental stimulation of risk taking and control during children’s exploration. The first aim of this study was to confirm that the activation relationship as assessed with the observational procedure, the Risky Situation, is primarily determined by paternal stimulation of risk taking as assessed by questionnaire. The second aim was to verify the link between the activation relationship and attachment disorganization. The third aim was to verify the existence of a sex difference in father-toddler dyad activation relationships. The Strange Situation procedure and the Risky Situation procedure were conducted with 58 father-toddler dyads. Fathers completed questionnaires on child temperament and parental behavior. Paternal stimulation of risk taking explains activation once child sex and temperament, the attachment relationship, and emotional support are taken into account. Moreover, there is no relation between the father-child activation relationship and attachment disorganization. Finally, data confirm the existence of a sex difference in the activation relationship in toddlers: fathers activate their sons more than their daughters.

scholarly journals Sex differences in associations of fine particulate matter with non-accidental deaths: an ecological time-series study

2021 ◽  
Author(s):  
Tian Xia ◽  
Fang Fang ◽  
Scott Montgomery ◽  
Bo Fang ◽  
Chunfang Wang ◽  
...  
Keyword(s):  
Air Pollution ◽  
Sex Differences ◽  
Particulate Matter ◽  
Sex Difference ◽  
Lower Risk ◽  
Smoking Prevalence ◽  
Fine Particulate Matter ◽  
Men And Women ◽  
Fine Particulate ◽  
The Impact

AbstractSex differences in the impact of exposure to air pollution have been reported previously and epidemiological studies indicate that fine particulate matter (PM2.5) effects on nonaccidental death are modified by sex; however, the results are not conclusive. To introduce a new method incorporating the monotone nonlinear relationship between PM2.5 and deaths to reveal the sex difference in the relationship, we illustrated the use of the constrained generalized additive model (CGAM) to investigate the sex difference in the effects of PM2.5 on nonaccidental deaths in Shanghai, China. Information on daily non-accidental deaths, air pollution, meteorological data, and smoking prevalence between 1 January 2012 and 31 December 2014 was obtained in Shanghai. The CGAM was used to assess the association of interaction between sex and daily PM2.5 concentrations with daily nonaccidental deaths, adjusting for weather type and smoking rate. A 2-week lag analysis was conducted as a sensitivity analysis. During the study period, the total number of non-accidental deaths in Shanghai was 336,379, with a daily mean of 163 deaths and 144 deaths for men and women, respectively. The average daily concentration of PM2.5 in Shanghai was 55.0 μg/m3 during the same time period. Women showed a lower risk for non-accidental death (risk ratio (RR) = 0.892, 95% confidence interval (CI): 0.802–0.993). Compared with men, the risk for nonaccidental death in relation to increasing PM2.5 concentration was smaller in women (RR = 0.998, 95% CI: 0.996–1.000, per 10 μg/m3 increase in PM2.5 concentration. The difference is consistent during the two lag weeks and more obvious when adjusting for the interaction between PM2.5 concentration and smoking prevalence. The effects of PM2.5 on daily nonaccidental death are different between men and women in Shanghai, China, and women tend to have a lower risk. The underlying mechanisms of the sex difference of PM2.5 effects on death need further investigation. The method displayed in the manuscript can be used for other environmental stressors as well.

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