Sex differences in crime

From Wikipedia, the free encyclopedia

Sex differences in crime are differences between men and women as the perpetrators or victims of crime. Such studies may belong to fields such as criminology (the scientific study of criminal behavior), sociobiology (which attempts to demonstrate a causal relationship between biological factors, in this case biological sex and human behaviors), or feminist studies. Despite the difficulty of interpreting them, crime statistics may provide a way to investigate such a relationship from a gender differences perspective. An observable difference in crime rates between men and women might be due to social and cultural factors, crimes going unreported, or to biological factors (for example, testosterone or sociobiological theories). Taking the nature of the crime itself into consideration may also be a factor.

Statistics have been consistent in reporting that men commit more criminal acts than women. Self-reported delinquent acts are also higher for men than women across many different actions. Burton, et al. (1998) found that low levels of self control are associated with criminal activity. Many professionals have offered explanations for this sex difference. Some differing explanations include men's evolutionary tendency toward risk and violent behavior, sex differences in activity, social support, or gender inequality.

General theory of crime

Burton et al. (1998) assessed Gottfredson and Hirschi's (1990) "general theory of crime," which stated that individuals with lower levels of self-control are more likely to be involved in criminal behavior, in a gender-sensitive context. The purpose of their study was to account for the gender gap in crime rates. By using a self-reporting questionnaire, Burton et al. (1998) retrieved data from 555 people aged eighteen and older in the Cincinnati, Ohio, area. Early results from the study indicated that low self-control was highly positively correlated to criminal behavior in both genders, but was especially significant for males. For females, the relationship became significant when opportunity was introduced and considered with level of self-control. Opportunity was not a significant indicator of male criminal behavior, which the authors attribute to the assumption that opportunity for criminal behavior is ubiquitous for men. In this study, opportunity was measured by the number of nights per week individuals go out for recreation purposes. Similarly, the authors conclude that women are less likely to be exposed to opportunities for criminal behavior, speculating that "constraints often placed on females, and that accompany their lifestyles" contribute to less opportunity for crime. With self-control being significant for males but not for females, the conclusions of this study pointed toward the notion that men and women commit crimes for different reasons. The notion that self-control was only significant for women when combined with opportunity helps account for the gender gap seen in crime rates.

David Rowe, Alexander Vazsonyi, and Daniel Flannery, authors of Sex Differences in Crime: Do Means and Within-Sex Variation Have Similar Causes?, focus on the widely acknowledged fact that there is a large sex difference in crime: more men than women commit crimes. This fact has been true over time and across cultures. Also, there are a more equal number of men that commit serious crimes resulting in injury or death than women. In a study that looked at self-reports of delinquent acts, researchers identified several sex differences by looking at sex ratios. For every woman, 1.28 men drink alcohol, which is a large influencer in deviant behavior. For every woman, 2.7 men committed the crime of stealing up to $50. Lastly, for every woman, 3.7 men steal more than $50. Also, more males are involved in homicides, as both the perpetrators and victims, than females. Furthermore, one male is more delinquent than another for mainly the same reasons that men typically engage in criminal acts more than women.

Nature, nurture, and life course

Onset

Terrie Moffitt and Avshalom Caspi compare childhood risk factors of males and females portraying childhood-onset and adolescent-onset antisocial behavior, which influences deviant behavior in individuals. Childhood-onset delinquency is attributed to lack of parenting, neurocognitive problems, and temperament and behavior problems. On the other hand, adolescent-onset delinquents did not encounter similar childhood problems. This study showed a male-to-female ratio of 10:1 for those experiencing childhood-onset delinquency and 15:1 for adolescent-onset delinquency. Moffitt and Caspi hypothesized that "'life-course-persistent' antisocial behavior originates early in life, when the difficult behavior of a high-risk young child is exacerbated by a high-risk social environment". Also, "'adolescent-limited' antisocial behavior emerges alongside puberty, where otherwise healthy youngsters experience dysphoria during the relatively role-less years between biological maturation and access to mature privileges and responsibilities", called the maturity gap. They look at the taxonomy theory, which states that the gender difference in crime are based on sex differences in the risk factors for life-course-persistent antisocial behavior. Based on research, girls are less likely than boys to have nervous system dysfunctions, difficult temperament, late maturity in verbal and motor development, learning disabilities, and childhood behavioral problems.

Sociology

Considerations of gender in regard to crime have been considered to be largely ignored and pushed aside in criminological and sociological study, until recent years, to the extent of female deviance having been marginalized. In the past fifty years of sociological research into crime and deviance, sex differences were understood and quite often mentioned within works, such as Merton's theory of anomie; however, they were not critically discussed, and often any mention of female delinquency was only as comparative to males, to explain male behaviors, or through defining the girl as taking on the role of a boy, namely, conducting their behavior and appearance as that of a tomboy and by rejecting the female gender role, adopting stereotypical masculine traits.

Eagly and Steffen suggested in their meta-analysis of data on sex and aggression that beliefs about the negative consequences of violating gender expectations affect how both genders behave regarding aggression. Psychologist Anne Campbell argued that "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."

One key reason contended for this lack of attention to females in crime and deviance is due to the view that female crime has almost exclusively been dealt with by men, from policing through to legislators, and that this has continued through into the theoretical approaches, quite often portraying what could be considered as a one-sided view, as Mannheim suggested.

However, other contentions have been made as explanations for the invisibility of women in regard to theoretical approaches, such as: females have an '...apparently low level of offending'); that they pose less of a social threat than their male counterparts; that their 'delinquencies tend to be of a relatively minor kind', but also due to the fear that including women in research could threaten or undermine theories, as Thrasher and Sutherland feared would happen with their research.

Further theories have been contended, with many debates surrounding the involvement and ignoring of women within theoretical studies of crime; however, with new approaches and advances in feminist studies and masculinity studies, and the claims of increases in recent years in female crime, especially that of violent crime.

Past studies explained gender and crime through psychological and biological aspects. However, now specific sociological theories analyze the gender differences when it comes to committing crime. Brezina's research focuses on the "general strain theory," specifically, on why males and females have a gap rate in crime. One view is that the gender gap of crime is associated with different strains and various types of experiences males and females go through. For instance, their socialization, life events, home life, and relationships differ from one another. Because of this, research suggests that boys and men are more closely related to crime and delinquency. Brezina argues that because boys are more exposed to harsh punishment from their parents while growing up, negative experiences at school, no support system, and homelessness, they have more freedom to commit a crime. Brezina states that some boys and men tend to see crime as acceptable because they favor their "internalized 'masculine' values."

Brezina argues that girls and women have limited opportunities to commit crime. They, for example, are more dedicated to family and friends, have higher parental supervision, and are less likely to link themselves to delinquent peers. Therefore, their strains would be high family demands and lose of friendship. This leads to them reacting to strain differently than males do. Instead of coping their strain with crime, they express it with their emotions to eliminate the stress. The emotional response females receive, are fear, guilt, anxiety, or shame, which decreases their chances of committing a crime. In addition, girls and women have a great amount of social support, which also leads to lower rate of crime. The types of strain that males and females experience can be an understanding of why there is a gender gap in crime.

Sociobiological and evolutionary psychology perspective

Evolutionary psychology has proposed several evolutionary explanations for gender differences in aggressiveness. Males can increase their reproductive success by polygyny which will lead the competition with other males over females. If the mother died, this may have had more serious consequences for a child than if the father died in the ancestral environment since there is a tendency for greater parental investments and caring for children by females than by males. Greater caring for children also leads to difficulty leaving them in order to either fight or flee. Anne Campbell writes that females may thus avoid direct physical aggressiveness and instead use strategies such as "friendship termination, gossiping, ostracism, and stigmatization".

Psychologist and professor Mark van Vugt, from VU University at Amsterdam, Netherlands, has argued that males have evolved more aggressive and group-oriented in order to gain access to resources, territories, mates and higher status. His theory the Male Warrior hypothesis explains that males throughout hominid history have evolved to form coalitions or groups in order to engage in inter-group aggression and increase their chances of acquiring resources, mates and territory. Vugt argues that this evolved male social dynamic explains the human history of war to modern day gang rivalry which is under a process of male on male competition in order to gain resources and potential mates.

There are two theories on the role of testosterone in aggression and competition among males. The first one is the Challenge hypothesis which states that testosterone would increase during puberty thus facilitating reproductive and competitive behaviour which would include aggression as a result of evolution. Thus it is the challenge of competition in relation to testosterone among males of the species that facilitates aggression and violence. Studies conducted have found direct correlation between testosterone and dominance especially among the most violent criminals in prison who had the highest testosterone levels. The same research also found fathers (those outside competitive environments) had the lowest testosterone levels compared to other males. The second theory is also similar and is known as the evolutionary neuroandrogenic (ENA) theory of male aggression. Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even as far as being a risk to harming others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible. Thus, crime can be seen as an extreme form of adaptation to gain status and acquire more resources. Many other researchers have agreed with this and have stated that criminal behavior is an expression of inter-male competition in mating efforts and resource seeking since there is a huge correlation between criminals and fathering children at younger ages.

Aggression and violence among peers and in relationships

Women are more likely to use direct aggression in private, where other people cannot see them, and are more likely to use indirect aggression (such as passive-aggressive behavior) in public. Men are more likely to be the targets of displays of aggression and provocation than women. Studies by Bettencourt and Miller show that when provocation is controlled for, sex differences in aggression are greatly reduced. They argue that this shows that gender-role norms play a large part in the differences in aggressive behavior between men and women.

According to the 2015 International Encyclopedia of the Social & Behavioral Sciences, sex differences in aggression is one of the most robust and oldest findings in psychology. Past meta-analyses in the encyclopedia found males regardless of age engaged in more physical and verbal aggression while small effect for females engaging in more indirect aggression such as rumor spreading or gossiping. It also found males tend to engage in more unprovoked aggression at higher frequency than females. This replicated another 2007 meta-analysis of 148 studies in the journal Child Development which found greater male aggression in childhood and adolescence. This analysis also conforms with the Oxford Handbook of Evolutionary Psychology which reviewed past analysis and found greater male use in verbal and physical aggression with the difference being greater in the physical type. A meta-analysis of 122 studies published in the journal of Aggressive Behavior found males are more likely to cyberbully than females. Difference also showed that females reported more cyberbullying behavior during mid-adolescence while males showed more cyberbullying behavior at late adolescence.

While the literature generally finds that women are more commonly the victims of domestic violence, some research suggests that rates of physical aggression within the context of dating and marriage tend to be similar for men and women, or that women are more likely to commit domestic violence against a partner; this is known as gender symmetry. However, such data generally shows that men tend to inflict the greater share of injuries and incite significantly more fear in domestic violence. Critics have used studies such as Dekeseredy et al. to argue that "studies finding about equal rates of violence by women in relationships are misleading because they fail to place the violence in context; in other words, there is a difference between someone who uses violence to fight back or defend oneself and someone who initiates an unprovoked assault."

One study argued that it was the above-cited Dekeseredy et al. that in fact improperly contextualized partner violence; Dekeseredy's campus study was based around asking women and only women if their violence was in self-defense, and not permitting the same for men. This results in counting men who had defended themselves as perpetrators, and counting women who may have engaged in ex post facto justification of their violence, a noted trait of psychological abuse, as victims. The study further found that studies from the US Department of Justice did not contextualize violence simply by not counting women perpetrators until forced to by the US Center for Disease Control (CDC). Other studies that decontextualized partner violence included labeling aggregate findings of motivations for violence that included the desire to coerce or control the partner or being angry with the partner as "striking back" when such questions revealed that women scored equal to or higher than men in desires to use violence out of simple anger or to coerce and control the partner. This, however, is contradicted by other reviews which found women's primary motivation were triggered by anger or self-defense while men's motivation was more about control. Some studies have also postulated that when other factors such as allowing both or neither gender to claim self-defense, or simply including male victims and female perpetrators in the sample, the results were at or near parity for perpetrators and victims, with the results near parity sometimes favoring females and sometimes favoring males. Another large study reveals that women are between two and three times as likely to be the offender in non-reciprocal partner violence. The study suggests that while women are far more prone to be the sole offender, reciprocal violence where both partners use violence has higher frequency of serious injuries, and that these injuries more often have female victims than male.

A 2008 review published in the journal Violence and Victims found that although less serious situation violence or altercation was equal for both genders, more serious and violent abuse was perpetrated by men. It was also found that women's physical violence was more likely motivated by self-defense or fear while men's was motivated by control. A 2011 systematic review from the journal of Trauma Violence Abuse also found that the common motives for female on male domestic violence were anger, a need for attention, or as a response to their partner's own violence. Another 2011 review published in the journal of Aggression and Violent Behavior also found that although minor domestic violence was equal, more severe violence was perpetrated by men. It was also found that men were more likely to beat up, choke or strangle their partners, while women were more likely to throw something at their partner, slap, kick, bite, punch, or hit with an object.

Court system

One study has noted substantial differences in the treatment and behavior of defendants in the courts on the basis of gender; female criminologist Frances Heidensohn postulates that for judges and juries it is often "impossible to isolate the circumstances that the defendant is a woman from the circumstances that she can also be a widow, a mother, attractive, or may cry on the stand." Furthermore, male and female defendants in court have reported being advised to conduct themselves differently in accordance with their gender; women in particular recall being advised to express "mute passivity," whereas men are encouraged to "assert themselves" in cross-examinations and testimony.

Statistics

In the United States

In the United States, men are much more likely to be incarcerated than women. More than 9 times as many men (5,037,000) as women (581,000) had ever at one time been incarcerated in a State or Federal prison at year end 2001.

In 2014, more than 73% of those arrested in the US were males. Men accounted for 80.4 percent of persons arrested for violent crime and 62.9 percent of those arrested for property crime. In 2011, the United States Department of Justice compiled homicide statistics in the United States between 1980 and 2008. That study showed the following:

• Males were convicted of the vast majority of homicides in the United States, representing 89.5% of the total number of offenders.
• Young adult black males had the highest homicide conviction rate compared to offenders in other racial and sex categories.
• White females of all ages had the lowest conviction rates of any racial or age groups.
• Of children under age 5 killed by a parent, the rate for biological father conviction was slightly higher than for biological mothers.
• However, of children under 5 killed by someone other than their parent, 80% of the people that were convicted were males.
• Victimization rates for both males and females have been relatively stable since 2000.
• Males were more likely to be murder victims (76.8%).
• Females were most likely to be victims of domestic homicides (63.7%) and sex-related homicides (81.7%)
• Males were most likely to be victims of drug-related (90.5%) and gang-related homicides (94.6%).

2011 arrest data from the FBI:

• Males constituted 98.9% of those arrested for forcible rape
• Males constituted 87.9% of those arrested for robbery
• Males constituted 85.0% of those arrested for burglary
• Males constituted 83.0% of those arrested for arson.
• Males constituted 81.7% of those arrested for vandalism.
• Males constituted 81.5% of those arrested for motor-vehicle theft.
• Males constituted 79.7% of those arrested for offenses against family and children.
• Males constituted 77.8% of those arrested for aggravated assault
• Males constituted 58.7% of those arrested for fraud.
• Males constituted 57.3% of those arrested for larceny-theft.
• Males constituted 51.3% of those arrested for embezzlement.

From 2003 to 2012, there was a decrease in the rate of crime overall, but an increase in crimes committed by women. There was an increase in arrest rate for women of 2.9% but a decrease in arrest rate for men of 12.7%. This demonstrates an increase in arrests for women which only slightly offsets the decrease in arrest for men resulting in a decrease overall in arrest rate in the United States. Arrests rates for women had a sizable increase in the following crimes: robbery (+20.2%), larceny-theft (+29.6%), and arson – property crime (+24.7%). The trend results from 2003-2012 showed the vast majority of crimes were still committed by men with around 88% of homicides and 75% of all legal felonies. According to government statistics from the US Department of Justice, male perpetrators constituted 96% of federal prosecution on domestic violence. Another report by the US department of Justice on non-fatal domestic violence from 2003-2012 found that 76 percent of domestic violence was committed against women and 24 percent were committed against men.

In Canada

According to a Canadian Public Health Agency report, the rate of violent crime doubled among male youth during the late 1980s and 1990s, while it almost tripled among female youth. It rose for the latter from 2.2 per 1,000 in 1988 to a peak of 5.6 per 1,000 in 1996, and began to decline in 1999. Some researchers have suggested that the increase on crime statistics could be partly explained by the stricter approach to schoolyard fights and bullying, leading to a criminalization of behaviors now defined as "assault" behaviors (while they were simply negatively perceived before). The increase in the proportion of female violent crime would thus be explained more by a change in law enforcement policies than by effective behavior of the population itself. According to the report aforementioned, "Evidence suggests that aggressive and violent behavior in children is linked to family and social factors, such as social and financial deprivation; harsh and inconsistent parenting; parents' marital problems; family violence, whether between parents, by parents toward children or between siblings; poor parental mental health; physical and sexual abuse; and alcoholism, drug dependency or other substance misuse by parents or other family members."

Gender statistics Canada by total charged annual crimes (2002):

• Adult males – 326,536
• Adult females – 71, 058
• Young males (12-17) – 74,513
• Youth females (12-17) – 24, 487

Victims of Person Crimes in Canada by Gender, per 100,000 residents (2008)
Crime	Female	Male	Result
Aggravated assault	119	233	Males are 2 times more likely
Forcible confinement	22	7	Females are 3.1 times more likely
Homicide & attempted murder	2	7	Males are 3.5 times more likely
Robbery	62	114	Males are 1.8 times more likely
Sexual assault	68	6	Females are 11.3 times more likely
Simple assault	576	484	Females are 1.2 times more likely
Uttering threats	156	184	Males are 1.2 times more likely
Criminal harassment	135	51	Females are 2.6 times more likely
Other assaults	16	62	Males are 3.9 times more likely
Other "person" crimes	1	2	Males are 2 times more likely

In 2013 and 2014, males accounted for 85% of those that have committed legal offenses and sent to provincial and territorial correctional services in Canada. Females account for 15 percent of overall committed legal offenses.

Worldwide homicide statistics by gender

According to the data given by the United Nations Office on Drugs and Crime, worldwide, 78.7% of homicide victims are male, and in 193 of the 202 listed countries or regions, males were more likely to be killed than females. In two, the ratio was 50:50 (Switzerland and British Virgin Islands), and in the remaining 7; Tonga, Iceland, Japan, New Zealand, Republic of Korea, Latvia and Hong Kong, females were more likely to be victims of homicides compared to males. A 2013 global study on homicide by the United Nations Office on Drugs and Crime found that males accounted for about 96 percent of all homicide perpetrators worldwide. Also, according to the United Nations Office on Drugs and Crime, the percent of victims killed by their spouses or ex-spouses in 2011 were 77.4 percent women and 22.6 percent men in selected countries across Europe.

Sex differences in cognition

From Wikipedia, the free encyclopedia

 

Sex differences in cognition, or mental abilities, are widely studied in the current scientific literature. Biological and genetic differences in combination with environment and culture have resulted in the cognitive differences among men and women. Among biological factors, hormones such as testosterone and estrogen may play some role mediating these differences. Among differences of diverse mental and cognitive abilities, the largest or most well known are those relating to spatial abilities, social cognition and verbal skills and abilities.

Cognitive abilities

Cognitive abilities are mental abilities that a person uses in everyday life, as well as specific demand tasks. The most basic of these abilities are memory, executive function, processing speed and perception, which combine to form a larger perceptual umbrella relating to different social, affective, verbal and spatial information. Memory, which is one of the primary core of cognitive abilities can be broken down into short-term memory, working memory and long-term memory. There are also other abilities relating to perceptual information such as mental rotation, spatial visualization ability, verbal fluency and reading comprehension. Other larger perceptual umbrellas include social cognition, empathy, spatial perception and verbal abilities.

Sex differences in memory

Short term memory

Various researchers have conducted studies to determine the differences between men and women and their abilities within their short-term memory. For example, a study conducted by Lowe, Mayfield, and Reynolds (2003) examined gender differences among children and adolescents on various short-term memory measures. This study included 1,279 children and adolescents, 637 males and 642 females, between the ages of 5 and 19. They found that females scored higher on two verbal subtests: Word Selective Reminding and Object Recall, and males scored higher on the Memory for Location and Abstract Visual Memory subtests, the key spatial memory tasks. In two different studies researchers have found that women perform higher on verbal tasks and men perform higher on spatial tasks (Voyer, Voyer, & Saint-Aubin, 2016). These findings are consistent with studies of intelligence with regards to pattern, females performing higher on certain verbal tasks and males performing higher on certain spatial tasks (Voyer, Voyer, & Saint-Aubin, 2016). Same results have been also found cross culturally. Sex differences in verbal short term memory have been found regardless of age even among adults, for example a review published in the journal Neuropsychologia which evaluated studies from 1990–2013 found greater female verbal memory from ages 11–89 years old.

Working memory

There are usually no sex differences in overall working memory except those involving spatial information such as space and object. A 2004 study published in the journal of Applied Cognitive Psychology found significantly higher male performance on four visuo-spatial working memory. Another 2010 study published in the journal Brain and Cognition found a male advantage in spatial and object working memory on an n-back test but not for verbal working memory. Similarly another study published in the journal Human Brain Mapping found no sex differences in a verbal n-back working memory task among adults from ages 18–58 years old. There was also no sex differences in verbal working memory among a study of university students published in the Journal of Dental and Medical Sciences. However, they still found greater male spatial working memory in studies published in the journals Brain Cognition and Intelligence. Also, even though they found no sex differences in verbal working memory, researchers have found lower brain activity or hermodynamics in the prefrontal cortex of women which suggested greater neural efficiency and less effort for the same performance. Researchers indicate women might have greater working memory on tasks that only relies on the prefrontal cortex. A 2013 study published in the journal Current Research in Psychology also found a female advantage in one visual-working memory task among university students. A 2006 review and study on working memory published in the journal European Journal of Cognitive Psychology also found no gender differences in working memory processes except in a double-span task where women outperformed men. There have also been no sex differences found in a popular working memory task known as n-back among a large number of studies.

Long term memory

Studies have found a greater female ability in episodic memory involving verbal or both verbal and visual-spatial tasks while a higher male ability that only involves complex visual-spatial episodic memory. For example, a study published in the journal Neuropsychology found that women perform at a higher level on most verbal episodic tasks and tasks involving some or little visual-spatial episodic memory. Another study published the following year found that women perform at a higher level in verbal and non-verbal (non-spatial visual) episodic memory but men performed at a higher level in complex visual-spatial episodic memory. A review published in the journal Current Directions in Psychological Science by researcher Agneta Herlitz also conclude that higher ability in women on episodic-memory tasks requiring both verbal and visuospatial episodic memory and on face-recognition tasks.

Sex differences in semantic memory have also been found with a higher female ability which can be explained by a female advantage in verbal fluency. One other study also found greater female free-recall and long term retrieval among the ages 5–17.

Sex differences in executive functions

There has not been enough literature or studies assessing sex difference in executive functioning, especially since executive functions are not a unitary concept. However, in the ones that have been done, there have been differences found in attention and inhibition.

Attention

A 2002 study published in the Journal of Vision found that males were faster at shifting attention from one object to another as well as shifting attention within objects. 2012–2014 studies published in the Journal of Neuropsychology with a sample size ranging from 3500–9138 participants by researcher Ruben C Gur found higher female attention accuracy in a neurocognitive battery assessing individuals from ages 8–21. A 2013 study published in the Chinese Medical Journal found no sex differences in executive and alerting of attention networks but faster orientation of attention among females. A 2010 study published in Neuropsychologia also found greater female responsiveness in attention to processing overall sensory stimulation.

Inhibition and self-regulation

A 2008 study published in the journal Psychophysiology found faster reaction time to deviant stimuli in women. The study also analyzed past literature and found higher female performance in withholding social behavior such as aggressive responses and improper sexual arousal. Furthermore, they found evidence that women were better at resisting temptation in tasks, delaying gratification and controlling emotional expressions. They also found lower female effort in response inhibition in equal performance for the same tasks implying an advantage for females in response inhibition based on neural efficiency. In another study published in 2011 in the journal Brain and Cognition, it was found that females outperformed males on the Sustained Attention to Response Task which is a test that measures inhibitory control. Researchers have hypothesized that any female advantage in inhibition or self-regulation may have evolved as a response to greater parenting responsibilities in ancestral settings.

Sex differences in processing speed

Sex differences in processing speed has been largely noted in literature. Studies published in the journal Intelligence have found faster processing speed in women. For example, a 2006 study published in Intelligence by researcher Stephen Camarata and Richard Woodcock found faster processing speed in females across all age groups in a sample of 4,213 participants. This was followed by another study published in 2008 by researchers Timothy Z Keith and Matthew R. Reynolds who found faster processing speed in females from ages 6 to 89 years old. The sample also had a number of 8,818 participants. Other studies by Keith have also found faster processing speed in females from ages 5 to 17.

Sex differences in semantic perception

Studies of sex differences in semantic perception (attribution of meaning) of words reported that males conceptualize items in terms of physical or observable attributes whereas females use more evaluative concepts. Another study of young adults in three cultures showed significant sex differences in semantic perception (attribution of meaning) of most common and abstract words. Contrary to common beliefs, women gave more negative scores to the concepts describing sensational objects, social and physical attractors but more positive estimations to work- and reality-related words, in comparison to men  This suggests that men favour concepts related to extreme experience and women favour concepts related to predictable and controllable routines. In a light of the higher rates of sensation seeking and deviancy in males, in comparison to females, these sex differences in meaning attribution were interpreted as support for the Evolutionary theory of sex.

Sex differences in spatial abilities

Rubik's cube puzzle involving mental rotation

 

Sex differences in spatial abilities are widely established in literature. Males have much higher level of performance in three major spatial tasks which include spatial visualization, spatial perception and mental rotation. Spatial visualization elicits the smallest difference with a deviation of 0.13, perception a deviation of 0.44 and mental rotation the largest with a deviation of 0.73. Another 2013 meta-analysis published in the journal Educational Review found greater male mental rotation in a deviation of 0.57 which only grew larger as time limits were added. These male advantages manifests themselves in math and mechanical tasks for example significantly higher male performance on tests of geometry, measurement, probability, statistics and especially mechanical reasoning. It also manifests and largely mediates higher male performance in arithmetic and computational fluency. All of these math and technical fields involve spatial abilities such as rotation and manipulation of imagined space, symbols and objects. Mental rotation has also been linked to higher success in fields of engineering, physics and chemistry regardless of gender. Spatial visualization on the other hand also correlate with higher math achievement in a range of 0.30 to 0.60. Furthermore, male advantage in spatial abilities can be accounted for by their greater ability in spatial working memory. Sex differences in mental rotation also reaches almost a single deviation (1.0) when the tasks require navigation, as found in one study with participants who used Oculus Rift in a virtual environment.

Even though most spatial abilities are higher in men, object location memory or the ability to memorize spatial cues involving categorical relations are higher in women. Higher female ability in visual recognition of objects and shapes have also been found.

Sex differences in verbal abilities

Like spatial ability, sex differences in verbal abilities have been widely established in literature. There is a clear higher female performance on a number of verbal tasks prominently a higher level of performance in speech production which reaches a deviation of 0.33 and also a higher performance in writing. Studies have also found greater female performance in phonological processing, identifying alphabetical sequences, and word fluency tasks. Studies have also females outperforming males in verbal learning especially on tests such as Rey Auditory Verbal Learning Test and Verbal Paired Associates. and A 2010 study published in the Journal of Advanced Prosthodentics found women showed significantly higher speech intelligibility scores than men and differences in acoustic (sound) parameters. Meanwhile, in another studies, a female advantage in generating synonyms and solving anagrams have also been found. Furthermore, a 2009 study published in the Archive of Clinical Neuropsychology found better female performance in writing that reached about 8 points in a sample of 22–80 year old adults, in relation to better male performance in math which reached about 4 points. It has also been found that the hormone estrogen increases ability of speech production and phonological processing in women, which could be tied to their advantages in these areas. Overall better female performance have also been found in verbal fluency which include a trivial advantage in vocabulary and reading comprehension while a significantly higher performance in speech production and essay writing. This manifests in higher female international PISA scores in reading and higher female Grade 12 scores in national reading, writing and study skills. Researchers Joseph M. Andreano and Larry Cahill have also found that the female verbal advantage extends into numerous tasks, including tests of spatial and autobiographical abilities. Another 2008 study published in the journal Act Psychologica found no sex differences in remembering phonologically-unfamiliar novel words but higher female ability to remember phonologically-familiar novel words. Meanwhile, higher depth of processing in semantic analysis among females compared to males have also been found in brain imaging studies, while greater female performance in many verbal abilities might be linked to their higher verbal memory. A 2013 study published in the International Journal of Psychology also found an adult female advantage in time for performing a verbal lexical task and temperament scale of social-verbal tempo.

Sex differences in social cognition

Current literature suggests women have higher level of social cognition. A 2012 review published in the journal Neuropsychologia found that women are better at recognizing facial effects, expression processing and emotions in general. Men were only better at recognizing specific behaviour which includes anger, aggression and threatening cues. A 2012 study published in the journal Neuropsychology with a sample of 3,500 individuals from ages 8–21, found that females outperformed males on face memory and all social cognition tests. In 2014, another study published in the journal Cerebral Cortex found that females had larger activity in the right temporal cortex, an essential core of the social brain connected to perception and understanding the social behaviour of others such as intentions, emotions, and expectations. In 2014, a meta-analysis of 215 study sample by researcher A.E. Johnson and D Voyeur in the journal Cognition and Emotion found overall female advantage in emotional recognition. Other studies have also indicated greater female superiority to discriminate vocal and facial expression regardless of valence, and also being able to accurately process emotional speech. Studies have also found males to be slower in making social judgments than females. Structural studies with MRI neuroimaging has also shown that women have bigger regional grey matter volumes in a number of regions related to social information processing including the Inferior frontal cortex and bigger cortical folding in the Inferior frontal cortex and parietal cortex  Researchers suppose that these sex differences in social cognition predisposes males to high rates of autism spectrum disorders which is characterized by lower social cognition.

Empathy

Empathy is a large part of social cognition and facilitates its cognitive components known as theory of mind. Current literature suggests a higher level of empathy in woman compared to men. Reviews, meta-analysis and studies of physiological measures, behavioral tests, and brain neuroimaging, however, revealed mixed findings. Whereas experimental and neuropsychological measures show no reliable sex effect, self-report data consistently indicates greater empathy in females. The research from Developmental Cognitive Neuroscience compared age-related sex differences in both self-report and neurophysiological measures of empathic arousal in sixty-five 4–17-year-old children. Self-report indicated greater responsivity by females, which increased with age, while implicit hemodynamic and physiological measures did not demonstrate any gender-related patterns.

Sex differences in humans

From Wikipedia, the free encyclopedia

Sex differences in humans have been studied in a variety of fields. In humans, biological sex is determined by five factors present at birth: the presence or absence of a Y chromosome, the type of gonads, the sex hormones, the internal reproductive anatomy (such as the uterus), and the external genitalia. Genetic sex is determined solely by the presence or absence of a Y chromosome. Phenotypic sex refers to an individual's sex as determined by their internal and external genitalia, expression of secondary sex characteristics, and behavior.

The sex of the individual can be defined in different ways, giving rise to different conceptual frameworks about what determines sex. Sex differences generally refer to traits that are sexually dimorphic. A subset of such differences is hypothesized to be the product of the evolutionary process of sexual selection.

Medicine

Sex differences in medicine include sex-specific diseases, which are diseases that occur only in people of one sex; and sex-related diseases, which are diseases that are more usual to one sex, or which manifest differently in each sex. For example, certain autoimmune diseases may occur predominantly in one sex, for unknown reasons. 90% of primary biliary cirrhosis cases are women, whereas primary sclerosing cholangitis is more common in men. Gender-based medicine, also called "gender medicine", is the field of medicine that studies the biological and physiological differences between the human sexes and how that affects differences in disease. Traditionally, medical research has mostly been conducted using the male body as the basis for clinical studies. Similar findings are also reported in the sport medicine literature where males typically account for >60% of the individuals studied. The findings of these studies have often been applied across the sexes and healthcare providers have assumed a uniform approach in treating both male and female patients. More recently, medical research has started to understand the importance of taking the sex into account as the symptoms and responses to medical treatment may be very different between sexes.

Neither concept should be confused with sexually transmitted diseases, which are diseases that have a significant probability of transmission through sexual contact.

Sex-related illnesses have various causes:

• Sex-linked genetic illnesses
• Parts of the reproductive system that are specific to one sex
• Social causes that relate to the gender role expected of that sex in a particular society.
• Different levels of prevention, reporting, diagnosis or treatment in each gender.

Research has found that female doctors may be providing better care than male doctors in the U.S. and also in Canada.

Physiology

Sex differences in human physiology are distinctions of physiological characteristics associated with either male or female humans. These can be of several types, including direct and indirect, direct being the direct result of differences prescribed by the Y-chromosome, and indirect being characteristics influenced indirectly (e.g., hormonally) by the Y-chromosome. Sexual dimorphism is a term for the phenotypic difference between males and females of the same species.

Direct sex differences follow a bimodal distribution. Through the process of meiosis and fertilization (with rare exceptions), each individual is created with zero or one Y-chromosome. The complementary result for the X-chromosome follows, either a double or a single X. Therefore, direct sex differences are usually binary in expression (although the deviations in complex biological processes produce a menagerie of exceptions). These include, most conspicuously, male (vs female) gonads.

Indirect sex differences are general differences as quantified by empirical data and statistical analysis. Most differing characteristics will conform to a bell-curve (i.e., normal) distribution which can be broadly described by the mean (peak distribution) and standard deviation (indicator of size of range). Often only the mean or mean difference between sexes is given. This may or may not preclude overlap in distributions. For example, most males are taller and stronger than females, but an individual female could be taller and stronger than an individual male. The extents of these differences vary across societies.

The most obvious differences between males and females include all the features related to reproductive role, notably the endocrine (hormonal) systems and their physiological and behavioral effects, including gonadal differentiation, internal and external genital and breast differentiation, and differentiation of muscle mass, height, and hair distribution. There are also differences in the structure of specific areas of the brain. For example, on average, the SDN (INAH3 in humans) has been repeatedly found to be considerably larger in males than in females.

Psychology

Research on biological sex differences in human psychology investigates cognitive and behavioral differences between men and women. This research employs experimental tests of cognition, which take a variety of forms. Tests focus on possible differences in areas such as IQ, spatial reasoning, aggression, emotion, and brain structure and function. 

Chromosomal make up is important in human psychology. Women have two X chromosomes while males have an X and Y chromosomal structure. The X chromosome is much more active than Y and it affects behavior. Genetic researchers theorize that the X chromosome may contain a gene responsible for sociability.

Most IQ tests are constructed so that there are no overall score differences between females and males. Areas where differences have been found include verbal and mathematical ability. IQ tests that measure fluid g and have not been constructed to eliminate sex differences also tend to show that sex differences are either non-existent or negligible. 2008 research found that, for grades 2 to 11, there were no significant gender differences in math skills among the general population. Differences in variability of IQ scores have been observed in studies, with more men falling at the extremes of the spectrum.

Because social and environmental factors affect brain activity and behavior, where differences are found, it can be difficult for researchers to assess whether or not the differences are innate. Studies on this topic explore the possibility of social influences on how both sexes perform in cognitive and behavioral tests. Stereotypes about differences between men and women have been shown to affect a person's behavior (this is called stereotype threat).

In his book titled Gender, Nature, and Nurture, psychologist Richard Lippa found that there were large differences in women's and men's preferences for realistic occupations (for example, mechanic or carpenters) and moderate differences in their preferences for social and artistic occupations. His results also found that women tend to be more people-oriented and men more thing-oriented.

Hartung & Widiger (1998) found that many kinds of mental illnesses and behavioral problems show gender differences in prevalence and incidence. "Of the 80 disorders diagnosed in adulthood for which sex ratios are provided, 35 are said to be more common in men than in women (17 of which are substance related or a paraphilia), 31 are said to be more common in women than men, and 14 are said to be equally common in both sexes."

Differences in male and female jealousy can also be observed. While female jealousy is more likely to be inspired by emotional infidelity, male jealousy is most likely to be brought on by sexual infidelity. A clear majority of approximately 62% to 86% of women reported that they would be more bothered by emotional infidelity and 47% to 60% of men reported that they would be more bothered by sexual infidelity.

In 2005, Janet Shibley Hyde from the University of Wisconsin-Madison introduced the gender similarities hypothesis, which suggests that males and females are similar on most, but not all, psychological variables. The research focused on cognitive variables (for example, reading comprehension, mathematics), communication (for example, talkativeness, facial expressions), social and personality (for example, aggression, sexuality), psychological well-being, and motor behaviors. Using results from a review of 46 meta-analyses, she found that 78% of gender differences were small or close to zero. A few exceptions were some motor behaviors (such as throwing distance) and some aspects of sexuality (such as attitudes about casual sex), which show the largest gender differences. She concludes her article by stating: "It is time to consider the costs of overinflated claims of gender differences. Arguably, they cause harm in numerous realms, including women’s opportunities in the workplace, couple conflict and communication, and analyses of self-esteem problems among adolescents." Hyde also stated elsewhere that "variations within genders are greater than variations between genders."

In 2011 Irina Trofimova found a significant female advantage in time on the lexical task and on the temperament scale of social-verbal tempo, and a male advantage on the temperament scale of physical endurance which were more pronounced in young age groups and faded in older groups. She suggested that there is a "middle age - middle sex" effect: sex differences in these two types of abilities observed in younger groups might be entangled with age and hormonal changes. The study concluded that a one-dimensional approach to sex differences (common in meta-analytic studies) therefore overlooks a possible interaction of sex differences with age. This hormones-based "middle age-middle sex effect", and also specifics of the few psychological sex differences (verbal and physical) were analysed in terms of the systemic evolutional tendencies driving sex dimorphism. 

Sociology

Crime

Statistics have been consistent in reporting that men commit more criminal acts than women. Self-reported delinquent acts are also higher for men than women across many different actions. Many professionals have offered explanations for this sex difference. Some differing explanations include men's evolutionary tendency toward risk and violent behavior, sex differences in activity, social support, and gender inequality. 

Despite the difficulty of interpreting them, crime statistics may provide a way to investigate such a relationship from a gender differences perspective. An observable difference in crime rates between men and women might be due to social and cultural factors, crimes going unreported, or to biological factors (for example, testosterone or sociobiological theories). Taking the nature of the crime itself into consideration may also be a factor. Crime can be measured by such data as arrest records, imprisonment rates, and surveys. However, not all crimes are reported or investigated. Moreover, some studies show that men can have an overwhelming bias against reporting themselves to be the victims of a crime (particularly when victimized by a woman), and some studies have argued that men reporting intimate partner violence find disadvantageous biases in law enforcement. Burton et al. (1998) found that low levels of self control are associated with criminal activity.

Education

A world map showing countries by gender education disparity, 2010.

 

Sometimes and in some places, there are sex differences in educational achievement. This may be caused by sex discrimination in law or culture, or may reflect natural differences in the interests of the sexes.

Leadership

Research has been undertaken to examine whether or not there are sex differences in leadership. Until recently, leadership positions have predominantly been held by men. Women were rarely seen in senior leadership positions leading to a lack of data on how they behave in such positions. The two main lines of research contradict one another, the first being that there are significant sex differences in leadership and the second being that gender does not have an effect on leadership.

Women and men have been surveyed by Gallup each year concerning workplace topics, and when questioned about preferences of a female boss or a male boss, women chose a preference for a male boss 39% of the time, compared to 26% of men displaying preference for a male boss. Only 27% of females would prefer a boss of the same gender. This preference, among both sexes, for male leadership in the workplace has continued unabated for sixty years, according to the survey results.

Religion

Sex differences in religion can be classified as either "internal" or "external." Internal religious issues are studied from the perspective of a given religion, and might include religious beliefs and practices about the roles and rights of men and women in government, education and worship; beliefs about the sex or gender of deities and religious figures; and beliefs about the origin and meaning of human gender. External religious issues can be broadly defined as an examination of a given religion from an outsider's perspective, including possible clashes between religious leaders and laity; and the influence of, and differences between, religious perspectives on social issues. For example, various religious perspectives have either endorsed or condemned alternative family structures, homosexual relationships, and abortion. External religious issues can also be examined from the "lens of gender" perspective embraced by some in feminism or critical theory and its offshoots.

Social capital

Sex differences in social capital are differences between men and women in their ability to coordinate actions and achieve their aims through trust, norms and networks. Social capital is often seen as the missing link in development; as social networks facilitate access to resources and protect the commons, while cooperation makes markets work more efficiently. Social capital has been thought of as women's capital as whereas there are gendered barriers to accessing economic capital, women's role in family, and community ensures that they have strong networks. There is potential that the concept can help to bring women's unpaid 'community and household labor', vital to survival and development, to the attention of economists. However, research analyzing social capital from a gendered perspective is rare, and the notable exceptions are very critical.

Suicide

Sex differences in suicide have been shown to be significant; there are highly asymmetric rates of attempted and completed suicide between males and females. The gap, also called the gender paradox of suicidal behavior, can vary significantly between different countries. Statistics indicate that males die much more often by means of suicide than do females, however reported suicide attempts are 3 times more common among females than males. This paradox is partially explained by the methodology, with females more often choosing medication-induced overdosage, and males more often turning to weapons such as firearms or knives.

Financial risk-taking

Sex differences in financial decision making are relevant and significant. Numerous studies have found that women tend to be financially more risk-averse than men and hold safer portfolios. A May 3, 2015 article in the Wall Street Journal by Georgette Jasen reported that "when it comes to investing, men sometimes have their way of doing things, and women have different ways." Scholarly research has documented systematic differences in financial decisions such as buying investments versus insurance, donating to ingroups versus outgroups (such as terrorism victims in Iraq versus USA), spending in stores, and the endowment effect-or asking price for goods people have. The majority of these studies are based on the theory of agency-communion developed by David Bakan in 1966; according to this theory, due to factors such as socialization, males are typically more agentic (focus on self, upside potential, aggressiveness) and females typically more communal (focus on others, downside potential, and nurturing). This framework robustly explains many financial decision making outcomes.

Sex differences in intelligence

From Wikipedia, the free encyclopedia

 

Differences in human intelligence have long been a topic of debate among researchers and scholars. With the advent of the concept of g or general intelligence, many researchers have argued for no significant sex differences in g factor or general intelligence, while others have argued for greater intelligence for males, and others for females. These results depend on the methodology, tests researchers used for their claims, and the personal performances of the participants.

 

Some research indicates male advantages on some cognitive tests are minimized when controlling for socioeconomic factors. Other research has concluded that there is larger variability in male scores compared to female scores, which results in more males than females in the top and bottom of the IQ distribution. Additionally, there are differences in the capacity of males and females in performing certain tasks, such as rotation of objects in space, often categorized as spatial ability.

Historical perspectives

Prior to the 20th century, it was a commonly held view that men were intellectually superior to women. In 1801, Thomas Gisborne said that women were naturally suited to domestic work and not spheres suited to men such as politics, science, or business. He stated that this was because women did not possess the same level of rational thinking that men did and had naturally superior abilities in skills related to family support. 

In 1875, Herbert Spencer said that women were incapable of abstract thought and could not understand issues of justice and had only the ability to understand issues of care. In 1925, Sigmund Freud also stated that women were less morally developed in the concept of justice and, unlike men, were more influenced by feeling than rational thought. Early brain studies comparing mass and volumes between the sexes concluded that women were intellectually inferior because they have smaller and lighter brains. Many believed that the size difference caused women to be excitable, emotional, sensitive, and therefore not suited for political participation.

In the nineteenth century, whether men and women had equal intelligence was seen by many as a prerequisite for the granting of suffrage. Leta Hollingworth argued that women were not permitted to realize their full potential, as they were confined to the roles of child-rearing and housekeeping. 

During the early twentieth century, the scientific consensus shifted to the view that gender plays no role in intelligence, but men consistently overestimated their IQs and women consistently underestimated their IQs.

In his 1916 study of children's IQs, psychologist Lewis Terman concluded that "the intelligence of girls, at least up to 14 years, does not differ materially from that of boys". He did, however, find "rather marked" differences on a minority of tests. For example, he found boys were "decidedly better" in arithmetical reasoning, while girls were "superior" at answering comprehension questions. He also proposed that discrimination, lack of opportunity, women's responsibilities in motherhood, or emotional factors may have accounted for the fact that few women had careers in intellectual fields.

Research on general intelligence

Background

Chamorro-Premuzic et al. stated, "The g factor, which is often used synonymously with general intelligence, is a latent variable which emerges in a factor analysis of various cognitive ('IQ') tests. They are not exactly the same thing. g is an indicator or measure of general intelligence; it's not general intelligence itself."

All or most of the major tests commonly used to measure intelligence have been constructed so that there are no overall score differences between males and females. Thus, there is little difference between the average IQ scores of men and women. Differences have been reported, however, in specific areas such as mathematics and verbal measures. Also, studies have found the variability of male scores is greater than that of female scores, resulting in more males than females in the top and bottom of the IQ distribution.

In favor of males or females in g factor

Research, using the Wechsler Adult Intelligence Scale (WAIS III and WAIS-R), that finds general intelligence in favor of males indicates a very small difference. This is consistent across countries. In the United States and Canada, the IQ points range from two to three points in favor of males, while the points rise to four points in favor of males in China and Japan. By contast, some research finds greater advantage for adult females. For children in the United States and the Netherlands, there are one to two IQ point differences in favor of boys. Other research has found a slight advantage for girls on the residual verbal factor.

A 2004 meta-analysis by Richard Lynn and Paul Irwing published in 2005 found that the mean IQ of men exceeded that of women by up to 5 points on the Raven's Progressive Matrices test. Lynn's findings were debated in a series of articles for Nature. He argued that there is a greater male advantage than most tests indicate, stating that because girls mature faster than boys, and that cognitive competence increases with physiological age, rather than with calender age, the male-female difference is small or negative prior to puberty, but males have an advantage after adolescence and this advantage continues into adulthood.

In favor of no sex differences or inconclusive consensus

Most studies find either a very small difference in favor of males or no sex difference with regard to general intelligence. In 2000, researchers Roberto Colom and Francisco J. Abad conducted a large study of 10,475 adults on five IQ tests taken from the Primary Mental Abilities and found negligible or no significant sex differences. The tests conducted were on vocabulary, spatial rotation, verbal fluency and inductive reasoning.

The literature on sex differences in intelligence has produced inconsistent results due to the type of testing used, and this has resulted in debate among researchers. The issue remains unresolved if one uses standardized tests as Jensen (1998) and Colom did. Garcia (2002) agrees that there might be a small insignificant sex difference in intelligence in general (IQ) but this may not necessarily reflect a sex difference in general intelligence or g factor. The difference between the two concepts is that IQ is a psychometric scoring system measured with standardized testing, while g factor is a latent scientific construct that correlates with all cognitive tests and achievements in life. Although most researchers distinguish between g and IQ, those that argue for greater male intelligence assert that IQ and g are synonymous (Lynn & Irwing 2004) and so the real division comes from defining IQ in relation to g factor. However, in 2008 Lynn and Irwing proposed that since working memory ability correlates highest with g factor, researchers would have no choice but to accept greater male intelligence if differences on working memory tasks are found. As a result, a neuroimaging study published by Schmidt (2009) conducted an investigation into this proposal by measuring sex differences on an n-back working memory task. The results found no sex difference in working memory capacity, thus contradicting the position put forward by Lynn and Irwing (2008) and more in line with those arguing for no sex differences in intelligence.

A 2012 review by researchers Richard E. Nisbett, Joshua Aronson, Clancy Blair, William Dickens, James Flynn, Diane F. Halpern and Eric Turkheimer discussed Arthur Jensen's 1998 studies on sex differences in intelligence. Jensen's tests were significantly g-loaded but were not set up to get rid of any sex differences. They summarized his conclusions as he quoted, "No evidence was found for sex differences in the mean level of g or in the variability of g. Males, on average, excel on some factors; females on others." Jensen's conclusion that no overall sex differences existed for g has been reinforced by researchers who analyzed this issue with a battery of 42 mental ability tests and found no overall sex difference.

Although most of the tests showed no difference, there were some that did. For example, they found female subjects performed better on verbal abilities while males performed better on visuospatial abilities. For verbal fluency, females have been specifically found to perform slightly better in vocabulary and reading comprehension but significantly higher in speech production and essay writing. Males have been specifically found to perform better on spatial visualization, spatial perception, and mental rotation. Researchers had then recommended that general models such as fluid and crystallized intelligence be divided into verbal, perceptual and visuospatial domains of g; this is because, as this model is applied, females excel at verbal and perceptual tasks while males on visuospatial tasks, thus evening out the sex differences on IQ tests.

Variability

Some studies have identified the degree of IQ variance as a difference between males and females. Males tend to show greater variability on many traits; for example having both highest and lowest scores on tests of cognitive abilities.

Feingold (1992b) and Hedges and Nowell (1995) have reported that, despite average sex differences being small and relatively stable over time, test score variances of males were generally larger than those of females." Feingold "found that males were more variable than females on tests of quantitative reasoning, spatial visualisation, spelling, and general knowledge. ... Hedges and Nowell go one step further and demonstrate that, with the exception of performance on tests of reading comprehension, perceptual speed, and associative memory, more males than females were observed among high-scoring individuals."

Brain and intelligence

Differences in brain physiology between sexes do not necessarily relate to differences in intellect. Although men have larger brains, men and women typically achieve similar IQ results. For men, the gray matter volume in the frontal and parietal lobes correlates with IQ; for women, the gray matter volume in the frontal lobe and Broca's area (which is used in language processing) correlates with IQ.

Women have greater cortical thickness, cortical complexity and cortical surface area (controlling for body size) which compensates for smaller brain size. Meta-analysis and studies have found that brain size explains 6–12% of variance among individual intelligence and cortical thickness explains 5%.

Mathematics performance

Girl scouts compete in the USS California Science Experience at Naval Surface Warfare. In 2008, the National Science Foundation reported that, on average, girls perform as well as boys on standardized math tests, while boys are overrepresented on both ends of the spectrum.

 

A performance difference in mathematics on the SAT and international PISA exists in favor of males, though differences in mathematics course performance measures favor females. In 1983, Benbow concluded that the study showed a large sex difference by age 13 and that it was especially pronounced at the high end of the distribution. However, Gallagher and Kaufman criticized Benbow's and others' reports, which found that males were over-represented in the highest percentages, on the grounds that they had not ensured representative sampling.

In nearly every study on the subject, males have out-performed females on mathematics in high school, but the size of the male-female difference, across countries, is related to gender inequality in social roles. In a 2008 study paid for by the National Science Foundation in the United States, however, researchers stated that "girls perform as well as boys on standardized math tests. Although 20 years ago, high school boys performed better than girls in math, the researchers found that is no longer the case. The reason, they said, is simple: Girls used to take fewer advanced math courses than boys, but now they are taking just as many." However, the study indicated that, while boys and girls performed similarly on average, boys were over-represented among the very best performers as well as among the very worst.

A 2011 meta-analysis with 242 studies from 1990 to 2007 involving 1,286,350 people found no overall sex difference of performance in mathematics. The meta-analysis also found that although there were no overall differences, a small sex difference that favored males in complex problem solving is still present in high school.

With regard to gender inequality, some psychologists believe that many historical and current sex differences in mathematics performance may be related to boys' higher likelihood of receiving math encouragement than girls. Parents were, and sometimes still are, more likely to consider a son's mathematical achievement as being a natural skill while a daughter's mathematical achievement is more likely to be seen as something she studied hard for. This difference in attitude may contribute to girls and women being discouraged from further involvement in mathematics-related subjects and careers.

Stereotype threat has been shown to affect performance and confidence in mathematics of both males and females.

Spatial ability

Examples of figures from mental rotation tests.

 

A man playing a video game at the Japan Media Arts Festival. Spatial abilities can be affected by experiences such as playing video games, complicating research on sex differences in spatial abilities.

 

Metastudies show a male advantage in mental rotation and assessing horizontality and verticality and a female advantage in spatial memory. A proposed hypothesis is that men and women evolved different mental abilities to adapt to their different roles in society. This explanation suggests that men may have evolved greater spatial abilities as a result of certain behaviors, such as navigating during a hunt.

A number of studies have shown that women tend to rely more on visual information than men in a number of spatial tasks related to perceived orientation.

Results from studies conducted in the physical environment are not conclusive about sex differences, with various studies on the same task showing no differences. For example, there are studies that show no difference in finding one's way between two places.

Performance in mental rotation and similar spatial tasks is affected by gender expectations. For example, studies show that being told before the test that men typically perform better, or that the task is linked with jobs like aviation engineering typically associated with men versus jobs like fashion design typically associated with women, will negatively affect female performance on spatial rotation and positively influence it when subjects are told the opposite. Experiences such as playing video games also increase a person's mental rotation ability.

The possibility of testosterone and other androgens as a cause of sex differences in psychology has been a subject of study. Adult women who were exposed to unusually high levels of androgens in the womb due to congenital adrenal hyperplasia score significantly higher on tests of spatial ability. Some research has found positive correlations between testosterone levels in healthy males and measures of spatial ability. However, the relationship is complex.

Sex differences in academics

A 2014 meta-analysis of sex differences in scholastic achievement published in the journal of Psychological Bulletin found females outperformed males in teacher-assigned school marks throughout elementary, junior/middle, high school and at both undergraduate and graduate university level. The meta-analysis, done by researchers Daniel Voyer and Susan D. Voyer from the University of New Brunswick, drew from 97 years of 502 effect sizes and 369 samples stemming from the year 1914 to 2011.

Beyond sex differences in academic ability, recent research has also been focusing on women's underrepresentation in higher education, especially in the fields of natural science, technology, engineering and mathematics (STEM).