Concealed ovulation

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https://en.wikipedia.org/wiki/Concealed_ovulation 

Concealed ovulation or hidden estrus in a species is the lack of any perceptible change in an adult female (for instance, a change in appearance or scent) when she is fertile and near ovulation. Some examples of perceptible changes are swelling and redness of the genitalia in baboons and bonobos, and pheromone release in the feline family. In contrast, the females of humans and a few other species that undergo hidden estrus have few external signs of fecundity, making it difficult for a mate to consciously deduce, by means of external signs only, whether or not a female is near ovulation.

Human females

In humans, an adult woman's fertility peaks for a few days during each roughly monthly cycle. The frequency and length of fertility (the time when a woman can become pregnant) is highly variable between women, and can slightly change for each woman over the course of her lifespan. Humans are considered to have concealed ovulation because there is no outward physiological sign, either to a woman herself or to others, that ovulation, or biological fertility, is occurring. Knowledge of the fertility cycle, learned through experience or from educational sources, can allow a woman to estimate her own level of fertility at a given time (fertility awareness). Whether other humans, potential reproductive partners in particular, can detect fertility in women through behavioral or invisible biological cues is highly debated. Scientists and laypersons are interested in this question because it has implications for human social behavior, and could theoretically offer biological explanations for some human sexual behavior. However, the science here is weak, due to a relatively small number of studies.

Several small studies have found that fertile women appear more attractive to men than women during infertile portions of her menstrual cycle, or women using hormonal contraception. It has also been suggested that a woman's voice may become more attractive to men during this time. Two small studies of monogamous human couples found that women initiated sex significantly more frequently when fertile, but male-initiated sex occurred at a constant rate, without regard to the woman's phase of menstrual cycle. It may be that a woman's awareness of men's courtship signals increases during her highly fertile phase due to an enhanced olfactory awareness of chemicals specifically found in men's body odor.

Analyses of data provided by the post-1998 U.S. Demographic and Health Surveys found no variation in the occurrence of coitus in the menstrual phases (except during menstruation itself). This is contrary to other studies, which have found female sexual desire and extra-pair copulations (EPCs) to increase during the midfollicular to ovulatory phases (that is, the highly fertile phase). These findings of differences in woman-initiated versus man-initiated sex are likely caused by the woman's subconscious awareness of her ovulation cycle (because of hormonal changes causing her to feel increased sexual desire), contrasting with the man's inability to detect ovulation because of its being "hidden".

In 2008, researchers announced the discovery in human semen of hormones usually found in ovulating women. They theorized that follicle stimulating hormone, luteinising hormone, and estradiol may encourage ovulation in women exposed to semen. These hormones are not found in the semen of chimpanzees, suggesting this phenomenon may be a human male counter-strategy to concealed ovulation in human females. Other researchers are skeptical that the low levels of hormones found in semen could have any effect on ovulation. One group of authors has theorized that concealed ovulation and menstruation were key factors in the development of symbolic culture in early human society.

Evolutionary hypotheses

Evolutionary psychologists have advanced a number of different possible explanations for concealed ovulation. Some posit that the lack of signaling in some species is a trait retained from evolutionary ancestors, not something that existed previously and later disappeared. If signaling is supposed to have existed and was lost, then it could have been merely due to reduced adaptive importance and lessened selection, or due to direct adaptive advantages for the concealment of ovulation. Yet another possibility (regarding humans specifically) is that while highly specific signaling of ovulation is absent, human female anatomy evolved to mimic permanent signaling of fertility.

Paternal investment hypothesis

The paternal investment hypothesis is strongly supported by many evolutionary biologists. Several hypotheses regarding human evolution integrate the idea that women increasingly required supplemental paternal investment in their offspring. The shared reliance on this idea across several hypotheses concerning human evolution increases its significance in terms of this specific phenomenon.

This hypothesis suggests that women concealed ovulation to obtain men's aid in rearing offspring. Schröder summarizes this hypothesis outlined in Alexander and Noonan's 1979 paper: if women no longer signaled the time of ovulation, men would be unable to detect the exact period in which they were fecund. This led to a change in men's mating strategy: rather than mating with multiple women in the hope that some of them, at least, were fecund during that period, men instead chose to mate with a particular woman repeatedly throughout her menstrual cycle. A mating would be successful in resulting in conception when it occurred during ovulation, and thus, frequent matings, necessitated by the effects of concealed ovulation, would be most evolutionarily successful. A similar hypothesis was proposed by Lovejoy in 1981 that argued that concealed ovulation, reduced canines and bipedalism evolved from a reproductive strategy where males provisioned food resources to his paired female and dependent offspring.

Continuous female sexual receptivity suggests human sexuality is not solely defined by reproduction; a large part of it revolves around conjugal love and communication between partners. Copulations between partners while the woman is pregnant or in the infertile period of her menstrual cycle do not achieve conception, but do strengthen the bond between these partners. Therefore, the increased frequency of copulations due to concealed ovulation are thought to have played a role in fostering pair bonds in humans.

The pair bond would be very advantageous to the reproductive fitness of both partners throughout the period of pregnancy, lactation, and rearing of offspring. Pregnancy, lactation and caring for post-lactation offspring require vast amounts of energy and time on the part of the woman. She must at first consume more food, then provide food to her offspring, while her ability to forage is reduced throughout. Supplemental male investment in the mother and her offspring is advantageous to all parties. While the man supplements the woman's limited gathered food, the woman is enabled to devote the necessary time and energy to the care of their offspring. The offspring benefits from the supplemental investment, in the form of food and defense from the father, and receives the full attention and resources of the mother. Through this shared parental investment, both man and woman would increase their offspring's chances for survival, thereby increasing their reproductive fitness. In this way, natural selection would favor the establishment of pair bonds in humans. To the extent that concealed ovulation strengthened pair bonding, selective pressure would favor concealed ovulation as well.

Another, more recent, hypothesis is that concealed ovulation is an adaptation in response to a promiscuous mating system, similar to that of our closest evolutionary relatives, bonobos and chimpanzees. The theory is that concealed ovulation evolved in women to lessen paternity certainty, which would both lessen the chances of infanticide (as a father is less likely to kill offspring that might be his), and potentially increase the number of men motivated to assist her in caring for her offspring (partible paternity). This is supported by the fact that all other mammals with concealed ovulation, such as dolphins and gray langurs, are promiscuous, and that the only other ape species that have multi-male communities, as humans do, are promiscuous. It is argued that evidence such as the Coolidge effect, showing that a man does not seem to be naturally geared towards sexual mate-guarding behavior (that is, preventing other males from having access to his sexual partner), supports the conclusion that sexual monogamy (though perhaps not social monogamy and/or pair bonding) was rare in early modern humans.

Reduced infanticide hypothesis

This hypothesis suggests the adaptive advantage for women who had hidden estrus would be a reduction in the possibility of infanticide by men, as they would be unable to reliably identify, and kill, their rivals' offspring. This hypothesis is supported by recent studies of wild Hanuman langurs, documenting concealed ovulation, and frequent matings with males outside their fertile ovulatory period. Heistermann et al. hypothesize that concealed ovulation is used by women to confuse paternity and thus reduce infanticide in primates. He explains that as ovulation is always concealed in women, men can only determine paternity (and thus decide on whether to kill the woman's child) probabilistically, based on his previous mating frequency with her, and so he would be unable to escape the possibility that the child might be his own, even if he were aware of promiscuous matings on the woman's part.

Sex and reward hypothesis

Schröder reviews a hypothesis by Symons and Hill, that after hunting, men exchanged meat for sex with women. Women who continuously mimicked estrus may have benefited from more meat than those that did not. If this occurred with enough frequency, then a definite period of estrus would have been lost, and with it sexual signaling specific to ovulation would have disappeared.

Social-bonding hypothesis

Schröder presents the idea of a "gradual diminution of mid-cycle estrus and concomitant continuous sexual receptivity in human women" because it facilitated orderly social relationships throughout the menstrual cycle by eliminating the periodic intensification of male–male aggressiveness in competition for mates. The extended estrous period of the bonobo (reproductive-age females are in heat for 75% of their menstrual cycle) has been said to have a similar effect to the lack of a "heat" in women. While concealed human ovulation may have evolved in this fashion, extending estrus until it was no longer a distinct period, as paralleled in the bonobo, this theory of why concealed ovulation evolved has frequently been rejected. Schröder outlines the two objections to this hypothesis: (1) natural selection would need to work at a level above the individual, which is difficult to prove; and (2) selection, because it acts on the individuals with the most reproductive success, would thus favor greater reproductive success over social integration at the expense of reproductive success.

However, since 1993 when that was written, group selection models have seen a resurgence. (See group selection, reciprocal altruism, and kin selection.)

Cuckoldry hypothesis

Schröder in his review writes that Benshoof and Thornhill hypothesized that estrus became hidden after monogamous relationships became the norm in Homo erectus. Concealed ovulation allowed the woman to mate secretly at times with a genetically superior man, and thus gain the benefit of his genes for her offspring, while still retaining the benefits of the pair bond with her usual sexual partner. Her usual sexual partner would have little reason to doubt her fidelity, because of the concealed ovulation, and would have high, albeit unfounded, paternity confidence in her offspring. His confidence would encourage him to invest his time and energy in assisting her to care for the child, even though it was not his own. Again, the idea of a man's investment being vital to the child's survival is a central fixture of a hypothesis regarding concealed ovulation, even as the evolutionary benefits accrue to the child, the woman, and her clandestine partner, and not to her regular sexual partner.

As a side effect of bipedalism

Pawlowski presents the importance of bipedalism to the mechanics and necessity of ovulation signaling. The more open savannah environment inhabited by early humans brought greater danger from predators. This would have caused humans to live in denser groups, and, in such a scenario, the long-distance sexual signaling provided by female genital swellings would have lost its function. Concealed ovulation is thus argued to be a loss of function evolutionary change rather than an adaptation. Thermoregulatory systems were also modified in humans with the move to the savannah to conserve water. It is thought that female genital swellings would have incurred added cost because of ineffective evaporation of water from the area. Pawlowski continues by saying the change to bipedalism in early hominins changed both the position of female genitals and the line of vision of males. Since males could no longer constantly see the female genitals, swelling of them during estrus as a mode of signaling would have become useless. Also, anogenital swelling at each ovulatory period may have interfered with the mechanics of bipedal locomotion, and selection may have favored females who were less hindered by this occurrence. This hypothesis ultimately concludes that bipedalism, which was strongly selected for, caused the physiological changes and a loss of function of sexual signaling through female genital swelling, leading to the concealed ovulation we now observe.

Pawlowski's paper offers views that differ from the other hypotheses regarding concealed ovulation in that it pinpoints physiological changes in early humans as the cause of concealed ovulation rather than social or behavioral ones. One of the strengths of this is derived from the other hypotheses' weaknesses – it is difficult to track the evolution of a behavior as it leaves no verifiable evidence in the form of bone or DNA. However, the fact that the Hanuman langurs also display some concealed ovulation and that it is not directly caused by a physiological change to bipedalism may suggest bipedalism was not, at least, the sole cause of concealed ovulation in humans. As stated earlier, it is possible for many elements of different hypotheses to be true regarding the selective pressures for concealed ovulation in humans.

Evolutionary approaches to postpartum depression

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Evolutionary_approaches_to_postpartum_depression 

Evolutionary approaches to postpartum depression examine the syndrome from the framework of evolutionary theory.

Postpartum (or postnatal) depression refers to major and minor episodes of depression within the first 12 months after delivery. Depression during pregnancy is referred to as prenatal (or antenatal) depression. Symptoms of postpartum depression include sad or depressed mood, feelings of worry, anxiety, guilt, or worthlessness, hypersomnia or insomnia, difficulty concentrating, anhedonia, somatic pain, changes in appetite, weight loss or weight gain, moodiness, irritability, restlessness, and fatigue.

Women may also have doubts about their ability to care for a new infant, difficulty bonding with the infant, or thoughts of harming themselves or their infants. In the DSM-V, diagnosis is made under major depressive disorder, with the added specifier “With peripartum onset” if the episode occurs during pregnancy or the first four weeks postpartum. Postpartum depression is not to be conflated with postpartum psychosis, which is qualitatively different.

A meta-analysis found that up to 12.7% of pregnant women experience an episode of major depression, while as many as 18.4% experience depression at some point in their pregnancy. However, they did not find a significant difference between these and rates of depression in women at nonchildbearing times. Similarly, one meta-analysis found rates of depression of up to 12.9% within the first year postpartum, and other studies have found similar rates.

There is also growing evidence that PPD is under-reported and under-diagnosed, raising concerns that a number of women suffer untreated. Cross-cultural research is often difficult to replicate and synthesize. For instance, one meta-analysis found rates of PPD from 0% to 60% across 40 countries. It is likely that a number of cultural factors likely lead to under- and over-diagnosis in some countries.

Postpartum depression in men

There is growing evidence that new fathers are also at risk of experiencing pre- and postpartum depression, although this remains understudied. Goodman found that during the first postpartum year, the incidence of paternal depression ranged from 1% to 25% in community samples, and from 24% to 50% among men whose partners were experiencing postpartum depression. Others have replicated the association between partner depression and paternal postpartum depression.

Another review found rates of postpartum depression in about 10% of sampled men, with higher rates at 3 to 6 months postpartum. Another review found that along with depression in their partners, low relationship satisfaction was also correlated with paternal postpartum depression. It may also be that adoptive fathers can be at risk of developing postadoption depression, although this requires further study.

Risk factors for postpartum depression

Many studies have examined risk factors in peripartum depression. Although results are sometimes mixed, the factors listed in the table below have been associated with peripartum depression. A comprehensive meta-analysis found that the most strongly associated risk factors for postpartum depression to be stressful life events, previous history of depression, anxiety during pregnancy, low levels of social support, and low socioeconomic status.

One study found that the stress hormone placental corticotropin-releasing hormone (pCRH) mediated the relationship between prenatal family support and fewer depression symptoms postpartum. Studies have also shown that infant health issues represent a suite of risk factors for maternal depression, including preterm birth, low birthweight, birth complications, and infant illness. Another review have found additional risk factors including marital status, relationship quality, infant temperament, and self-esteem.

Some researchers have examined diet as a primary risk factor for depression. According to one review, the typical western diet often leads to inadequacies in n-3, folate, B vitamins, iron, and calcium. Depletion of these nutrients during pregnancy may increase a woman's risk for postpartum depression. Cultural factors may also pose risks for postpartum depression. For instance, in cultures with gender preferences for children, unmet preferences are a risk factor.

Risk factors for postpartum depression
low SES
low social support
birth complications
low infant birth weight
preterm birth
unplanned pregnancy
previous depressive episodes
bottle feeding
anxiety
stressful life events
domestic violence
nutrient deficiency
negative attitude toward pregnancy
poor relationship satisfaction
difficult infant temperament
low self-esteem
preference of infant's gender

Evolutionary approaches to postpartum depression

For evolutionary scientists, postpartum depression is of interest due to its relatively high rates and seemingly universal expression, which may provide evidence of functionality. However, postpartum depression is also detrimental to mothers, their infants, and decreases future reproductive success.

Mismatch hypothesis

Another [In addition to?] evolutionary approach to postpartum depression is framed by the changes in human lifestyles in recent history. Hahn-Holbrook and Haselton review a number of lifestyle shifts that have affected humans since the development of agriculture. First, most people today consume grain-fed domesticated animal products rather than wild-caught animals. Unlike wild animals, domesticated animals have much lower levels of omega-3 fatty acids, which are essential to brain development and to fetal health. In support of the theory that postpartum depression may be related to modern diets, the authors find that rates of postpartum depression are lower in countries that consume higher amounts of seafood, which contain high levels of omega-3 fatty acids.

This hypothesis is weakened by the known poor reliability of measures of PPD in Asian samples, which often return low rates of postpartum depression in countries including Japan. Emerging evidence suggests that postpartum depression may be just as common in these samples, but is experienced differently and is not detected by measures including the Edinburgh Postnatal Depression Scale. Furthermore, a direct randomized control trial found no effect of supplementary omega-3 fatty acids in women with postpartum depression.

The authors also review the relationship between breastfeeding and postpartum depression. They do not specifically explore the child loss hypothesis, discussed above [Discussed where?], but instead examine evidence that breastfeeding is related to stress regulation and reduces negative affect, offering a buffer against the risk of postpartum depression. However, since most studies are cross-sectional the direction of this effect is yet to be determined as it may be that depressed women are less likely to breastfeed than non-depressed women.

Finally, the authors review evidence that lower rates of exercise and sun-exposure, common in Western lifestyles, have also been found to be related to postpartum depression. However, evidence is mixed. These hypotheses would be easy to test in randomized controlled trials, in which supplementary exercise and Vitamin D could be administered to test samples. However, evidence from direct trials is also mixed.

One of the more commonly cited mismatch hypotheses relates to changes in family networks and childcare routines. Hunter-gatherer families often live with their extended families and regularly share childcare duties, whereas Western families may live very far from their relatives and therefore must meet the demands of childcare themselves. This likely causes additional stress and anxiety in new parents, who do not have access to assistance from their family members. This aspect of the hypothesis is more difficult to test, as the relationship between family assistance and postpartum depression is likely more complicated.

Psychological pain hypothesis

Others have focused on the crux of reproductive decision-making in humans, which is twofold. First there exists a tradeoff between present and future offspring. In life-history theory, organisms have limited reproductive energy which requires that trade-offs be made when choosing to invest in one infant over another or over additional mating opportunities. Secondly, there is a tradeoff between the quantity and quality of offspring.

Because women’s reproduction is more constrained than men’s by obligate energetic demands, women experience higher risks relative to decisions to invest or not invest. As such, a mechanism which served to signal to women that they faced a bad investment opportunity, would be evolutionarily adaptive. For instance, in modern, industrialized societies where mortality is low, parents are incentivized to invest more per child than parents who live in less stable environments or utilizing riskier subsistence strategies. See life history theory.

For example, Bereczkei et al. found that women in Hungary with higher rates of low birth-weight infants had shorter inter-birth intervals, corresponding to an additional 2–4 years of potential reproduction. These women had significantly more children by the end of their reproductive careers than women who did not have low birth-weight children, pointing to a tradeoff between offspring quantity and quality.

In this vein, some researchers hypothesized that postpartum depression is more likely to occur in mothers who are suffering a fitness cost, in order to inform them that they should reduce or withdraw investment in their infants. Support for this hypothesis was found in a population of hunter-horticulturalists, the Shuar, located in the Ecuadorian Amazon. Reasons for this could include lack of paternal or other social support, poor infant health, or birth complications, all of which are commonly associated with postpartum depression. Hagen also found support that postpartum depression could function as a bargaining strategy, in which parents who were not receiving adequate support from their partners withdrew their investment in order to elicit additional support. In support of this, Hagen found that postpartum depression in one spouse was related to increased levels of child investment in the other spouse. Furthermore, support was also found for a reduction in rates of postpartum depression for older women with few future reproductive opportunities. Another study reported similar findings.

Can PPD be adaptive and related to reduced fertility?

There is undoubtedly a reproductive cost to experiencing postpartum depression which likely affects future reproductive strategies and child-spacing decisions. Specifically, Myers et al. found that women who experienced postpartum depression with their first or second birth had reduced likelihood of parity progression to a third birth, and lower completed fertility overall. Given this, how do adaptationist hypotheses explain postpartum depression? Hagen and Thornhill, for one, argue that limiting complete family size is one method of reducing parental investment in poor circumstances. Furthermore, they found evidence that poor maternal condition at birth one was highly correlated with poor condition at subsequent births, as such it could be the poor condition, not postpartum depression that drives lower fertility.

Cross-cultural variation in postpartum depression

Cross-cultural rates of peri- and postpartum depression are difficult to interpret, as differences in cultural expressions of depression may lead to inaccurate diagnosis. The majority of screening instruments that test for peri- and postpartum depression were designed in Western contexts and as such emphasize symptoms that are common in Western countries. Studies have found that women in Asia tend to report more somatic symptoms during depressive episodes, including feeling head numbness. Affective symptoms, such as feelings of sadness and guilt, are more commonly reported in Western samples than in Hispanic, Asian, and African cultures. One of the most commonly used screening instruments for postpartum depression, the Edinburgh Postnatal Depression Scale, does not detect depression in Japanese women.

Early research returned mixed evidence regarding cross-cultural rates of postpartum depression. One review found similar rates of postpartum mental disorders across countries. In a more recent meta-analysis including 143 studies with data from samples around the world, rates of PPD varied between 0 and 60%. Another meta-analysis found rates of postpartum depression returned from self-reported questionnaires to vary from 1.9% to 82.1% in developing countries and from 5.2% to 74.0% in developed countries. Rates were much lower when structured clinical interviews used, yet still varied from 0.1% in Finland to 26.3% in India.

The reasons for these discrepancies are not fully understood, however, it may be that the often reported rates of postpartum depression of around 15% do not reflect true rates of postpartum depression experienced by women around the world. Variation may be due to differences in measurement techniques, socio-economic factors, symptom expression, or cultural factors relating to pregnancy and childbirth.

There is some evidence that cultures which designate an explicit postpartum period, in which new mothers are expected to rest and receive assistance from family and friends, have lower rates of postpartum depression. However, other studies have not found this effect.

Evolutionary approaches to postpartum depression offer frameworks that can be informative, even given these variations in rates of postpartum depression. Because evolutionary medicine explores causality and treatment from the perspective of universal human biology and psychology, these approaches may bring to light new perspectives on causes and treatments.

Ovulatory shift hypothesis

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Ovulatory_shift_hypothesis

The ovulatory shift hypothesis holds that women experience evolutionarily adaptive changes in subconscious thoughts and behaviors related to mating during different parts of the ovulatory cycle. It suggests that what women want, in terms of men, changes throughout the menstrual cycle. Two meta-analyses published in 2014 reached opposing conclusions on whether the existing evidence was robust enough to support the prediction that women's mate preferences change across the cycle. A newer 2018 review does not show women changing the type of men they desire at different times in their fertility cycle.

Overview

The theory proposes that women's behavior may change during the most fertile time in their ovulatory cycle. At high fertility, the theory holds that women may become more physically active and avoid male relatives.

The hypothesis separately proposes that hormonal changes across the cycle cause women, when they are most likely to get pregnant, to be more attracted to traits in potential short-term male sexual partners that indicate high genetic quality, leading to greater reproductive success. It has been proposed that genetic traits like compatible major histocompatibility complex gene profiles are considered more attractive. Newer studies do not support female changes in desired reproductive partners when more fertile.

Estrus in humans

Female baboons and many other primates experience sexual swellings that advertise their fertility during estrus. Humans do not display any such obvious physical signals of fertility, but may still experience a subtle estrus-like state.

Most female mammals experience reproductive fertility cycles. They typically consist of a long period of low fertility, and a brief period of high fertility just prior to and including ovulation. In humans, this is called the ovulatory cycle, or menstrual cycle. The period of high fertility is also called the fertile window, and is the only time during the cycle when sex can result in conception.

Females of most mammalian species display hormonally-induced physical and behavioral signals of their fertility during the fertile window, such as sexual swellings and increased motivation to mate. Some species will not—or cannot—engage in sex at all outside of this window. This phase of sexual receptivity and proceptivity, estrus, is often referred to as being "in heat".

Human females, however, engage in sex throughout their ovulatory cycles, and even beyond their reproductive years. Additionally, they do not show obvious physical signals of high fertility. This has led many researchers to conclude that humans lost their estrus through evolution. It has been hypothesized that this could be due to the adaptive benefits of concealed ovulation and extended sexuality.

However, research has shown that human females may in fact experience subtle but distinct physiological, behavioral, and cognitive changes during the high-fertility phase of their ovulatory cycle, and that both men and other women can detect signals that indicate high-fertility in a woman, which may indicate that humans have retained an estrus-like state.

Evolution of ovulatory cycle shifts

Estrus evolved to facilitate reproduction and maximize reproductive success, or the success of passing on one's genes by producing offspring that are most likely to survive and reproduce themselves. The ovulatory shift hypothesis proposes that motivation and desire to mate should increase during the fertile window, and that females should seek and attract the best possible mate at their highest fertility. An ideal mate could have many qualities: resources to care for offspring, the physical ability and social status to protect a mate and offspring, a compatible personality for a long-term pair bond, etc. Evolutionary theory and sexual selection theory suggest that an organism’s top priority should be to maximize survival and reproductive success. Thus, the ovulatory shift hypothesis proposes that women possess a dual sexuality, where during the fertile window, a woman should prioritize attracting and choosing a mate with the best genetic quality, or “good genes”, since this is the only time she can become pregnant and pass on heritable genetic qualities to her offspring. However, at low-fertility, a woman should prioritize a mate with "good parenting" traits, such as willingness and ability to invest in parenting, resources to devote to offspring, and compatibility for a long-term partnership. These differing traits are sometimes referred to as the "sexy cad" vs. the "good dad".

It has also been hypothesized that high-fertility preferences should be strongest when evaluating a short-term sexual partner, but low-fertility preferences should be strongest when evaluating a long-term relationship partner. A woman can gain the benefits of good genes through only a single sexual encounter, and good dad traits are only relevant for a long-term pair bond.

Some researchers have suggested that over evolutionary time, women may have maximized reproductive success by seeking good genes from an extra-pair copulation—cheating on their partner—at high fertility, while also maintaining a long-term pair bond with a partner who provides parenting resources for the offspring, sometimes called the dual strategy hypothesis. Of course, an optimal partner is one with both sexy cad and good dad traits, but such a man is statistically unlikely to be common. Thus, natural selection may have designed ancestral women to be opportunistic. If successful, a woman could gain the benefits of both high-quality genetics and high-quality parenting to give her offspring the best chance of survival. However, natural selection would not have favored men who desire to provide for offspring that do not share their genes, so this would have been a risky strategy.

Mechanisms

Hormonal changes across the ovulatory cycle. Researchers hypothesize that changes in estradiol (blue) and progesterone (black) primarily drive changes in mating-related thoughts and behaviors.

Ovulatory cycle shifts are hypothesized to be regulated by sex hormones, primarily estradiol and progesterone, which become elevated at different times across the cycle. In particular, high levels of estradiol and low levels of progesterone, which peak at high fertility just prior to ovulation, have been shown to be correlated with several mating-related psychological changes. However, some studies have only found correlations with changes in estradiol. It is well-established that estradiol can act in the brain to produce other psychological and behavioral changes, and animal studies tend to show a link between sexual behavior and estrogen concentrations. Other hormones such as testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin have been studied as possible correlates, but most have produced little to no effect.

Changes in cognition and behavior across the ovulatory cycle

Numerous studies have demonstrated ovulatory cycle shifts in women’s mating-related motivations, preferences, thoughts, and behaviors. The ovulatory shift hypothesis proposes that these shifts are designed by natural selection as evolutionary adaptations for selecting and attracting specific types of mates with high genetic quality when a woman is most likely to get pregnant.

Sexual desire

Some of the earliest studies on human ovulatory shifts explored whether women engage in more instances of sexual activity during high fertility, as this could indicate a human estrus-like state. While some studies have found increases in frequency of sexual activity at high fertility, larger studies have concluded that there is generally no difference in frequency of sexual activity across the ovulatory cycle, possibly due to the multitude of factors that affect the ability to engage in sex (e.g., access to a partner, partner’s desire, time for engaging, etc.).

Researchers have subsequently explored whether sexual desire, rather than frequency of sexual activity, changes across the ovulatory cycle, as this would not be affected by practical barriers to engaging in sex. Several studies in this area have shown that women’s sexual desire and masturbation behaviors do increase during the fertile window, although results have been mixed and depend on the type of sexual desire measured. For example, desire for uncommitted sex does not appear to track fertility.

Relationship satisfaction

While some studies have shown that fertile-phase women might be more attracted to, flirt more, and initiate sex more often with men who are not their partner, newer studies do not support the hypothesis that females change who they consider desirable reproductive partners when more fertile.

Women in relationships may tend to be more assertive and independent during the fertile phase.

Attraction and mate preferences

The ovulatory shift hypothesis proposes that women at high fertility should be most attracted to short-term sexual partners with physical and behavioral features that likely signal genetic fitness, or good genes.

Symmetry

Female humans and other primates find faces with high levels of symmetry and masculinity more attractive, especially at high fertility.

Having symmetrical features may indicate that an individual possesses high-quality genes related to health, and that they developed in a stable environment with little disease or trauma. Studies have found that women rate faces of more symmetrical men as more attractive during high fertility, especially when evaluating them as short-term partners. It has also been demonstrated that women at high fertility are more attracted to the body odors of men with more facial and bodily symmetry. Although many studies and one meta-analysis have shown that fertility-moderated shifts in attraction to facial and bodily symmetry occur robustly, other reviews have concluded that the effect is small or non-existent.

Masculinity

In many species, more masculine and dominant males experience greater reproductive success. Masculine traits are produced during puberty by increasing amounts of testosterone. Testosterone is a known immunosuppressant, thus traits that reflect high levels of testosterone may indicate that a man possesses high-quality genes which allowed him to develop masculine features without experiencing any deleterious effects of high testosterone levels. Masculine traits include facial features like a strong jawline, bodily features like height, muscularity, and body hair, and vocal features like a deeper voice. While many studies have shown that women tend to be attracted to more masculine characteristics at high fertility, results have been mixed, and two meta-analyses have concluded that the effect is not robust.

Creativity

Charles Darwin first proposed that music, lacking a functional evolutionary explanation by natural selection, may be an instrument of sexual selection, just like a male peacock's extravagant feathers, which serve to attract a female. Similarly, humans may use artistic expressions as a display of good genetic qualities like creativity and intelligence.

Compatible genes

The major histocompatibility complex (MHC) is a suite of genes responsible for adaptive immune response and histocompatibility in an organism's cells. In animals, including mammals and other primates, MHC has been shown to play a role in MHC sexual selection, where organisms mate selectively with individuals who possess MHC alleles that are more dissimilar from their own. MHC has been shown to be responsible for changing the pheromone compositions of mice, causing mice with dissimilar MHC genes to have more attractive body odors. It has been hypothesized that this is a mechanism for creating genetic diversity, avoiding inbreeding, and creating offspring that are more resistant to pathogens. Some studies have shown that humans tend to form long-term partnerships with individuals who have more dissimilar MHC, and find the scent of MHC-dissimilar individuals more attractive, especially at high fertility. However, other studies have found little or no effect of MHC on mate preferences, and some have even shown a reverse effect, that people prefer partners with more similar MHC to their own. Several reviews and one meta-analysis on the human and primate literature regarding MHC have concluded that the effects of MHC similarity on attraction are not robust, but that humans are reliably attracted to individuals with more heterozygous, or diverse, MHC genotypes, regardless of whether they are similar to their own. However, it is unclear whether attraction to MHC heterozygosity changes across the ovulatory cycle.

Clothing and grooming

The ovulatory shift hypothesis proposes that women's behavior during the fertile phase should also reflect evolutionary adaptations for reproductive success. Fertile-phase women also spend more time on their appearance and tend to wear accessories like jewelry, makeup, or hairstyles that are perceived as trying to look more attractive. Additionally, several studies have demonstrated that women tend to purchase more products related to enhancing their appearance, attractive clothing, shoes, or accessories, during the fertile window.

Activity and food consumption

One of the earliest studies on ovulatory shifts found that female lab rats tend to run on their exercise wheels more during their fertile window. Subsequent research showed that a variety of species experience an increase in the frequency of spontaneous activity and motor behavior during estrus. Some studies on humans have shown a similar pattern: women walk more steps, as counted by a pedometer, during the high-fertility phase of their cycle. However, other research has found no difference in locomotion patterns across the ovulatory cycle, and many studies on activity across the cycle have small sample sizes and substantially differing methodologies, making it difficult to draw definitive conclusions. Despite a possible increase in activity, many studies have found that women consume fewer calories during their fertile phase. Some researchers have suggested that these changes in activity and food consumption may indicate that during estrus, women are motivated to focus more of their energy on mating-related behaviors like going out to meet new potential mates, instead of survival-related behaviors like seeking food.

Competitiveness with other women

Parental investment theory posits the idea that natural selection designed each sex to have different mating strategies based on how much investment the sex is required to devote to offspring for their survival. The sex that invests more in offspring should be more intersexually selective, or picky when choosing a sexual partner, because they have more time and resources to lose if they make a poor choice. The other sex should be more intrasexually competitive, or competitive with members of their same sex, in order to access and attract the more selective sex. In humans, as in all mammals, females are the sex that invests more in parenting, simply through the lengthy and taxing process of pregnancy and lactation, whereas males need only to contribute one act of sexual intercourse to pass on their genes. Thus, females are expected to be the more selective sex, and males are expected to be more competitive. However, unlike many species where males do not contribute to parenting at all, humans have highly dependent offspring, and a complex social structure that allows males to make significant and important investments in parenting effort. According to parental investment theory, this indicates that natural selection may have designed women to be somewhat competitive with other women for access to the best mates and potential fathers for their offspring.

Some studies have indicated that women engage in more competitive behaviors with other women when they are at high fertility. During the fertile window, women not using hormonal contraceptives self-report increased feelings of intrasexual competitiveness, describe other women as less attractive, and use more dehumanizing terms when talking about women, but not men. Women's choices to purchase more attractive or revealing clothing at high fertility are also increased when they are first shown a photograph of an attractive woman, but not photographs of men or unattractive women, suggesting clothing may not be chosen to attract men, but rather as a competitive display for other women. Additionally, some studies have used economic games to show that women are less likely to share resources or engage in cooperative bargaining with other women during the fertile window. Some researchers have noted that the reason why women should be more competitive during the fertile window is unclear.

The ovulatory shift hypothesis proposes that women should be seeking short-term sexual partners at peak fertility, but men can effectively have multiple sexual partners, so competition over one high-quality man should not be necessary. If women were competing for a long-term partner, there is no reason why they should be more competitive during the fertile window than any other time in their cycle.

Ovulatory cycle shifts

Hassleton and Gildersleeve (2011) wrote that both men and women can subconsciously detect cues to women's fertility that change across the ovulatory cycle. Some researchers have suggested that natural selection designed women to signal their fertility in order to attract a mate. Other researchers have proposed that women evolved to have concealed ovulation but they still "leak" subtle cues of their fertility, and men have evolved to detect these cues.

Body odor

During estrus, many species produce pheromones, or body odors that indicate to potential mates that one is in the fertile phase. While no specific human pheromones have been identified, humans may exhibit similar scent changes at high fertility. Body odors of high-fertility women not using hormonal contraceptives are rated in some studies as more attractive by both men and women. Vaginal odors from high-fertility women are also rated as more attractive than odors from the same women at low-fertility. Some studies have shown that men exposed to high-fertility body odors of women exhibit increases in testosterone, a feature associated with mating motivation and behavior, although other studies have failed to replicate this effect.

Physical attractiveness

Studies using facial photographs found that both men and women rate physical features of women at high fertility more attractive than when they are at low fertility and that facial attractiveness increases in fertile phase women. It has been hypothesized that this shift may be due to subtle changes in soft tissue symmetry that increase during high-fertility.

Vocal pitch

Studies have found that fertile phase women speak with a slightly higher vocal pitch. One study reported that recordings of women's voices in the fertile phase are rated, by both men and women, as more attractive than recordings by the same women during low fertility. However, these effect sizes are relatively small compared to other cues of ovulation.

Partner jealousy

Several studies have found that men in a relationship tend to be more protective and possessive of their partner when she is at peak fertility, as well as more jealous of any advances their partner might make on other men. One study found that after interacting with their partner during the fertile phase, men shown a photograph of an attractive man exhibit increased testosterone, which may be a competitive response.

Effects of hormonal contraception

Since it has been proposed that changes in hormone levels across the ovulatory cycle are the primary mechanisms that causes cycle shifts, some studies have explored the effects of hormonal contraception, like the pill, on both women's cycle shifts and other people's ability to detect cycle shifts.

Studies have reported that hormonal contraceptives weaken or eliminate cycle shifts entirely. It has been proposed that the synthetic hormones present in hormonal contraception that suppress ovulation also suppress the subsequent cognitive and behavioral changes found in naturally-cycling women. Other studies have stated that changes in synthetic hormones produce cycle shifts similar to effects produced by the real hormonal changes in naturally-cycling women.

Alternative hypotheses

Within-cycle vs. between-cycle shifts

While the ovulatory shift hypothesis proposes that adaptive changes in mating-related cognition and behavior occur within each ovulatory cycle, some researchers have posited a between-cycle shift theory. Many women experience regular anovulatory cycles, or non-fertile cycles where ovulation does not occur, therefore hormonal changes between ovulatory cycles may be a more reliable indicator of true fertility, as higher levels of estradiol are more likely to produce a fertile ovulatory cycle. Thus, some researchers have proposed that hormonal changes between cycles, primarily in elevated estradiol levels, are responsible for changes in mating-related cognition and behavior. Within-cycle shifts may be simply a byproduct of between-cycle shifts caused by elevated estradiol.

Meta-analyses and reviews

One meta-analysis and a review of the literature have been conducted on both published and unpublished data that support the claim of the ovulatory shift hypothesis that women experience changes in attraction preferences at high fertility. However, another meta-analysis and subsequent commentary concluded that the effect is not actually significant and may be a result of some studies using imprecise measurements of when women are in the fertile window, as well as publication bias. A review subsequently published also does not show women changing the type of men they desire at different times in their fertility cycle. Another study found no correlation between current fertility status and sociosexual attitudes and desires.

Evolutionary psychology of parenting

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Evolutionary_psychology_of_parenting 

Parenting, through the lens of evolutionary psychology, is largely based on traditional gender roles. It suggests that children are more attached to their mothers than fathers due to the effects of familial roles. Women have been expected to be the direct caregivers in a parent-offspring relationship, whereas men are expected to be material resource providers, possibly involved only with their own reproductive success. Females are attributed with the "maternal instinct" to aid, assist, embrace and invest in their offspring given their role as the womb. Due to not carrying the child, the male is suggested to experience paternal uncertainty, causing the individual to seek sexual partners to increase their genes amongst society.

However, males also have a role in securing a connection with the offspring by taking part in making an offspring's decisions when involved in a household. The vast evolutionary differences between direct and indirect care provided by mothers and fathers, respectively, are therefore overlooked and both parents influence the life decisions of the offspring. Different parenting styles across cultures also influence the temperament of an offspring. Additionally, varying attachment styles can influence the development of an offspring, impacting their future choices on their own mates and parenting skills.

Such parental influences lead to the theories of inclusive fitness as well as parental investment in illustrating the roots of parenting styles relayed upon offspring, such as to ensure the parents' reproductive success as well as their fitness through resources that which offspring obtain when making mating choices.

Gender differences

Female/maternal role

According to the parental investment theory, mothers are inclined to provide optimal care for their offspring due to the certainty of a genetic relationship. In regards to this, polyandry is rare in most societies as women will not take more than one husband in order to ensure the father with knowledge of the child's paternity and assistance with future care of their child from the father. Brain circuitry also evolved to favor monogamous attachment around the same time that our ancestors developed upright bipedal abilities. The development of upright movement led to the development of females caring for their children by carrying infants in their arms instead of on their backs.

Holding their infants in their arms led to greater bonds between mother and child. Upright bipedal abilities also developed stronger pairing-bonds between males and females as it became easier for males to protect just one female on the land instead of multiple females as they had done while living in trees. Natural selection favored males and females who had genes regulated towards forming pair-bonds because their young were more likely to survive, and brain circuitry gradually evolved to include attachment in parenting styles.

Women have adapted the ability to recognize infant facial expression of emotion, most especially negative emotion. This adaptation allows for the primary caretaker to develop a bond with their child leading to secure attachment during development. The "tend-and-befriend" hypothesis, which allows for the mother to care for and protect the child during detrimental situations, ensures offspring survival. Women are also able to create and maintain social networks that offer social protection for their offspring.

Grandmothers have evolved mechanisms that allow them to invest in their grandchildren. Menopause might be an adaptation for older women to invest in care of their offspring and their children's offspring. A desire to improve inclusive fitness allows grandmothers, especially maternal grandmothers, to invest the most since they are guaranteed that the child carries their genes. Aunts will also invest more than uncles. Specifically maternal aunts will invest more than paternal aunts.

Male/paternal role

Males have less investment in potential offspring and are generally less adept in their nurturing skills due to a greater emphasis on genetic reproduction, because any children that their mate births may or may not be their own. This phenomenon is termed paternal insecurity. However, "Human males do spend a lot of time investing in their kids and they invest quite heavily...That is a sharp contrast with other mammals, including our closest primate kin." Research has shown that for this reason, fathers tend to invest more resources in children that look and smell like them. Studies have demonstrated that when an infant is first born, males will experience decreased testosterone levels, making them less likely to be abusive, to commit infidelity, or seek divorce. Increased levels of investment when a child is first born may be due to the fact that males want to protect their genes and assure the reproductive success of their offspring in order for their genes to be spread.

Human fathers are involved with their family life as social connections are beneficial and alleviate access to resources. Long term monogamous relationships between parental units are necessary for children's improved development. From an evolutionary perspective, the well-being of children during their development improves the probability of reproduction for the child, and therefore the continuation of the father's genes. Evolutionary perspectives do not see the behavior of fathers who abandon their families, solely based on passing down genetic information, but also through a social perspective as father involvement is an adaptation that has been shaped by the environment and experiences.

In the modern case of divorce, fathers may feel less obliged to care for their children if guardianship of the child or children is granted to the mother, leading men to feel as if they do not need to be involved in the upbringing of their child. Remarrying, entering new romantic relationships, and having children with other women may also lead to fathers detracting from their parental investment towards their first born children. Divorced men finding new reproductive partners overrides their parental investment, as they focus on spreading their genes as widely as possible.

Parenting styles

Authoritative, authoritarian, indulgent, or neglectful parenting influences the development of children's attachment styles and their adjustment ability in order to survive and reproduce.

Authoritative parenting style is associated with the highest level of adjustment in children and is characterized by three factors. First, the parent makes age appropriate demands by insisting that the child behave in an appropriate intellectual and emotional manner. Second, the parent is rational and communicative by giving limits of appropriate behavior and communicating these underlying values to the child. Third, when the child is behaving according to the limits that are set, positive reinforcement and praise are used. Children whose parents raised them with authoritative style will have greater secure attachment leading them to be more successful in both romantic and social relationships.

Authoritarian parenting style is associated with moderately well-adjusted children. The parent lacks the communicative skills of an authoritative parent and does not convey value to the child or give proper attention when necessary. Children who were raised by parents who had authoritarian parenting skills may have greater tendency towards avoidant or insecure attachment issues. This leads them to experience decreased success in relationships and a decreased chance of reproduction.

There are two types of permissive parenting styles; indulgent and neglectful. Indulgent parents do not create proper boundaries for their children and provide them with positive reinforcement even though it is not applicable. Neglectful parents create no boundaries for their child and ignore their needs. Both indulgent and neglectful parenting styles can lead children to develop insecure attachment issues as they may feel that they cannot trust those who are around them to be loyal.

Influence on offspring in mate selection

See also: Mate selection and Reproductive success

Mating adaptations, such as competition for females, can be rooted in evolution, due to them being receivers of "scarce reproductive resources". Therefore, males' nature to involve themselves in competition can be traced to their desire to have genes passed down while using the females resources. The parent who willfully invests in their offspring, is then in control of an offspring's mating choices, specifically those of their daughters. According to Robert Triver's theory of parental investment, the parent which commits to greater investment in an offspring will have greater investment in the mate choices of their children, in order to assure that their engaged parenting will not be wasted on a mate who will not lead to successful reproduction and a loss of their genes being passed down.

Parents play a significant role in determining the offspring's future mates, with greater influence on daughters.

In the ancestral environment, parents of young women recognized the power they possessed in assisting the selection of their daughter's mate and utilizing that power (either as main resource provider or through physical intimidation) to benefit and enhance their own inclusive fitness. Not only do parents have an influence on their offspring's mating choices, they also have an influence on the sexual strategies they adopt.

According to David Buss, a father's absence in early childhood directly affects the sexual strategy that a person will adopt later on. Those who experience a lack of a fatherly role during development may develop insecure attachment expectations that parental resources are not reliable and develop the idea that adult pair bonds do not last, leading them to develop sexual strategies that involve early sexual maturation, early sexual initiation, and frequent partner switching. Those who grew up with the presence of a father or fatherly role in their life have greater secure attachment and view people as reliable and trustworthy. They believe that relationships are expected to last, therefore developing a long-term mating strategy. These people delay in sexual maturation, later onset of sexual activity, search for securely attached long-term adult relationships, and heavy investment in a small number of children.

Self-concept

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Self-concept

In the psychology of self, one's self-concept (also called self-construction, self-identity, self-perspective or self-structure) is a collection of beliefs about oneself. Generally, self-concept embodies the answer to the question "Who am I?".

The self-concept is distinguishable from self-awareness, which is the extent to which self-knowledge is defined, consistent, and currently applicable to one's attitudes and dispositions. Self-concept also differs from self-esteem: self-concept is a cognitive or descriptive component of one's self (e.g. "I am a fast runner"), while self-esteem is evaluative and opinionated (e.g. "I feel good about being a fast runner").

Self-concept is made up of one's self-schemas, and interacts with self-esteem, self-knowledge, and the social self to form the self as a whole. It includes the past, present, and future selves, where future selves (or possible selves) represent individuals' ideas of what they might become, what they would like to become, or what they are afraid of becoming. Possible selves may function as incentives for certain behaviour.

The perception people have about their past or future selves relates to their perception of their current selves. The temporal self-appraisal theory argues that people have a tendency to maintain a positive self-evaluation by distancing themselves from their negative self and paying more attention to their positive one. In addition, people have a tendency to perceive the past self less favourably (e.g. "I'm better than I used to be") and the future self more positively (e.g. "I will be better than I am now").

History

Psychologists Carl Rogers and Abraham Maslow had major influence in popularizing the idea of self-concept in the west. According to Rogers, everyone strives to reach an "ideal self." He believed that a person gets to self-actualize when they prove to themself that they are capable enough to achieve their goals and desires, but in order to attain their fullest potential, the person must have been raised in healthy surroundings which consist of "genuineness, acceptance, and empathy", however, the lack of relationships with people that have healthy personalities will stop the person from growing "like a tree without sunlight and water" and affect the individual's process to accomplish self- actualization. Rogers also hypothesized that psychologically healthy people actively move away from roles created by others' expectations, and instead look within themselves for validation. On the other hand, neurotic people have "self-concepts that do not match their experiences. They are afraid to accept their own experiences as valid, so they distort them, either to protect themselves or to win approval from others."

According to Carl Rogers, the self-concept has three different components:

• The view one has of oneself (self-image)
• How much value one places on oneself (self-esteem or self-worth)
• What one wishes one were really like (ideal self)

Abraham Maslow applied his concept of self-actualization in his hierarchy of needs theory. In this theory, he explained the process it takes for a person to achieve self-actualization. He argues that for an individual to get to the "higher level growth needs", he must first accomplish "lower deficit needs". Once the "deficiency needs" have been achieved, the person's goal is to accomplish the next step, which is the "being needs". Maslow noticed that once individuals reach this level, they tend to "grow as a person" and reach self-actualization. However, individuals who experienced negative events while being in the lower deficit needs level prevents them from ascending in the hierarchy of needs.

The self-categorization theory developed by John Turner states that the self-concept consists of at least two "levels": a personal identity and a social one. In other words, one's self-evaluation relies on self-perceptions and how others perceive them. Self-concept can alternate rapidly between one's personal and social identity. Children and adolescents begin integrating social identity into their own self-concept in elementary school by assessing their position among peers. By age five, acceptance from peers significantly affects children's self-concept, affecting their behaviour and academic success.

Model

One's self-perception is defined by one's self-concept, self-knowledge, self-esteem, and social self.

The self-concept is an internal model that uses self-assessments in order to define one's self-schemas. Changes in self-concept can be measured by spontaneous self-report where a person is prompted by a question like "Who are you?". Often when measuring changes to the self self-evaluation, whether a person has a positive or negative opinion of oneself, is measured instead of self-concept.

Features such as personality, skills and abilities, occupation and hobbies, physical characteristics, gender, etc. are assessed and applied to self-schemas, which are ideas of oneself in a particular dimension (e.g., someone that considers themselves a geek will associate "geek-like" qualities to themselves). A collection of self-schemas makes up one's overall self-concept. For example, the statement "I am lazy" is a self-assessment that contributes to self-concept. Statements such as "I am tired", however, would not be part of someone's self-concept, since being tired is a temporary state and therefore cannot become a part of a self-schema. A person's self-concept may change with time as reassessment occurs, which in extreme cases can lead to identity crises.

Parts

Various theories identify different parts of the self include:

• Self-image The view one has of oneself
• Self-esteem How much you value yourself
• Ideal self What you wish to be
• Social identity The part of the self that is determined by members in social groups

Development

See also: Social emotional development

Researchers debate over when self-concept development begins. Some assert that gender stereotypes and expectations set by parents for their children affect children's understanding of themselves by approximately age three. However, at this developmental stage, children have a very broad sense of self; typically, they use words such as big or nice to describe themselves to others. While this represents the beginnings of self-concept, others suggest that self-concept develops later, in middle childhood, alongside the development of self-control. At this point, children are developmentally prepared to interpret their own feelings and abilities, as well as receive and consider feedback from peers, teachers, and family. In adolescence, the self-concept undergoes a significant time of change. Generally, self-concept changes more gradually, and instead, existing concepts are refined and solidified. However, the development of self-concept during adolescence shows a "U"-shaped curve, in which general self-concept decreases in early adolescence, followed by an increase in later adolescence.

Romantic relationships can affect people's self-concept throughout a relationship. Self-expansion describes the addition of information to an individual's concept of self. Self-expansion can occur during relationships. Expansion of self-concept can occur during relationships, during new challenging experiences.

Additionally, teens begin to evaluate their abilities on a continuum, as opposed to the "yes/no" evaluation of children. For example, while children might evaluate themselves "smart", teens might evaluate themselves as "not the smartest, but smarter than average." Despite differing opinions about the onset of self-concept development, researchers agree on the importance of one's self-concept, which influences people's behaviors and cognitive and emotional outcomes including (but not limited to) academic achievement, levels of happiness, anxiety, social integration, self-esteem, and life-satisfaction.

Academic

Academic self-concept refers to the personal beliefs about their academic abilities or skills. Some research suggests that it begins developing from ages three to five due to influence from parents and early educators. By age ten or eleven, children assess their academic abilities by comparing themselves to their peers. These social comparisons are also referred to as self-estimates. Self-estimates of cognitive ability are most accurate when evaluating subjects that deal with numbers, such as math. Self-estimates were more likely to be poor in other areas, such as reasoning speed.

Some researchers suggest that to raise academic self-concept, parents and teachers need to provide children with specific feedback that focuses on their particular skills or abilities. Others also state that learning opportunities should be conducted in groups (both mixed-ability and like-ability) that downplay social comparison, as too much of either type of grouping can have adverse effects on children's academic self-concept and the way they view themselves in relation to their peers.

Physical

Physical self-concept is the individual's perception of themselves in areas of physical ability and appearance. Physical ability includes concepts such as physical strength and endurance, while appearance refers to attractiveness and body image. Adolescents experience significant changes in general physical self-concept at the onset of puberty, about eleven years old for girls and about 15 years old for boys. The bodily changes during puberty, in conjunction with the various psychological of this period, makes adolescence especially significant for the development of physical self-concept. An important factor of physical self-concept development is participation in physical activities. It has even been suggested that adolescent involvement in competitive sports increases physical self-concept.

Gender identity

Main article: Gender self-identification

A person's gender identity is a sense of one's own gender. These ideas typically form in young children. According to the International Encyclopedia of Marriage and Family, gender identity is developed at an early age when the child starts to communicate; by the age of eighteen months to two years is when the child begins to identify as a girl or a boy. After this stage, some consider gender identity already formed, although some consider non-gendered identities more salient during that young of an age. Kohlberg noted gender constancy occurs by the ages of five to six, a child becomes well-aware of their gender identity. Both biological and social factors may influence identities such as a sense of individuality, identities of place as well as gendered identities. As part of environmental attitudes, some suggest women more than men care about the environment. Forms of gender stereotyping is also important to consider in clinical settings. For example, a study at Kuwait University with a small sample of 102 men with gender dysphoria examined self-concept, masculinity and femininity. Findings were that children who grew up on lower family bonds had lower self-concept. Clearly, it is important to consider the context of social and political attitudes and beliefs before drawing any conclusions about gender identities in relation to personality, particularly about mental health and issues around acceptable behaviours.

Measures

Motivational properties

Self-concept can have motivational properties. There are four types of motives in particular that are most related to self-concept:

• Self-assessment: desire to receive information about the self that is accurate
• Self-enhancement: desire to receive feedback that informs the self of positive or desirable characteristics
• Self-verification: desire to confirm what one already knows about the self
• Self-improvement: desire to learn things that will help to improve the self

Some of these motives may be more prominent depending on the situation. In Western societies, the most automatic is the self-enhancement motive, and may be dominant in some situations where motives contradict one another. For example, the self-enhancement motive may contradict and dominate the self-assessment motive if one seeks out inaccurate compliments rather than honest feedback. Additionally, self-concept can motivate behavior because people tend to act in ways that reaffirm their self-concept, which is consistent with the idea of the self-verification motive. In particular, if people perceive the self a certain way and receive feedback contrary to this perception, a tension is produced that motivates them to reestablish consistency between environmental feedback and self-concept. For example, if someone believes herself to be outgoing, but someone tells her she is shy, she may be motivated to avoid that person or the environment in which she met that person because it is inconsistent with her self-concept of being an outgoing person. Further, another major motivational property of self-concept comes from the desire to eliminate the discrepancy between one's current self-concept and his or her ideal possible self. This is parallel with the idea of the self-improvement motive. For example, if one's current self-concept is that she is a novice at piano playing, though she wants to become a concert pianist, this discrepancy will generate motivation to engage in behaviors (like practicing playing piano) that will bring her closer to her ideal possible self (being a concert pianist).

Cultural differences

Worldviews about one's self in relation to others differ across and within cultures. Western cultures place particular importance on personal independence and on the expression of one's own attributes (i.e. the self is more important than the group). This is not to say those in an independent culture do not identify and support their society or culture, there is simply a different type of relationship. Non-Western cultures favor an interdependent view of the self: Interpersonal relationships are more important than one's individual accomplishments, and individuals experience a sense of oneness with the group. Such identity fusion can have positive and negative consequences. Identity fusion can give people the sense that their existence is meaningful provided the person feels included within the society (for example, in Japan, the definition of the word for self (jibun) roughly translates to "one's share of the shared life space"). Identity fusion can also harm one's self-concept because one's behaviors and thoughts must be able to change to continue to align with those of the overall group. Non-interdependent self-concepts can also differ between cultural traditions.

Additionally, one's social norms and cultural identities have a large effect on self-concept and mental well-being. When a person can clearly define their culture's norms and how those play a part in their life, that person is more likely to have a positive self-identity, leading to better self-concept and psychological welfare. One example of this is in regards to consistency. One of the social norms within a Western, independent culture is consistency, which allows each person to maintain their self-concept over time. The social norm in a non-Western, interdependent culture has a larger focus on one's ability to be flexible and to change as the group and environment change. If this social norm is not followed in either culture, this can lead to a disconnection with one's social identity, which affects personality, behavior, and overall self-concept. Buddhists emphasize the impermanence of any self-concept.

Anit Somech, an organizational psychologist and professor, who carried a small study in Israel showed that the divide between independent and interdependent self-concepts exists within cultures as well. Researchers compared mid-level merchants in an urban community with those in a kibbutz (collective community). The managers from the urban community followed the independent culture. When asked to describe themselves, they primarily used descriptions of their own personal traits without comparison to others within their group. When the independent, urban managers gave interdependent-type responses, most were focused on work or school, due to these being the two biggest groups identified within an independent culture. The kibbutz managers followed the interdependent culture. They used hobbies and preferences to describe their traits, which is more frequently seen in interdependent cultures as these serve as a means of comparison with others in their society. There was also a large focus on residence, lending to the fact they share resources and living space with the others from the kibbutz. These types of differences were also seen in a study done with Swedish and Japanese adolescents. Typically, these would both be considered non-Western cultures, but the Swedish showed more independent traits, while the Japanese followed the expected interdependent traits.

Along with viewing one's identity as part of a group, another factor that coincides with self-concept is stereotype threat. Many working names have been used for this term: stigmatization, stigma pressure, stigma vulnerability and stereotype vulnerability. The terminology that was settled upon Claude Steele and Joshua Aronson to describe this "situational predicament was 'stereotype threat.' This term captures the idea of a situational predicament as a contingency of their [marginalized] group identity, a real threat of judgment or treatment in the person's environment that went beyond any limitations within." Steele and Aronson described the idea of stereotype threat in their study of how this socio‐psychological notion affected the intellectual performance of African Americans. Steele and Aronson tested a hypothesis by administering a diagnostic exam between two different groups: African American and White students. For one group a stereotype threat was introduced while the other served as a control. The findings were that academic performance of the African American students was significantly lower than their White counterparts when a stereotype threat was perceived after controlling for intellectual ability. Since the inception by Steele and Aronson of stereotype threat, other research has demonstrated the applicability of this idea to other groups.

When one's actions could negatively influence general assumptions of a stereotype, those actions are consciously emphasized. Instead of one's individual characteristics, one's categorization into a social group is what society views objectively - which could be perceived as a negative stereotype, thus creating a threat. "The notion that stereotypes held about a particular group may create psychologically threatening situations associated with fears of confirming judgment about one's group, and in turn, inhibit learning and performance."

The presence of stereotype threat perpetuates a "hidden curriculum" that further marginalized minority groups. Hidden curriculum refers to a covert expression of prejudice where one standard is accepted as the "set and right way to do things". More specifically, the hidden curriculum is an unintended transmission of social constructs that operate in the social environment of an educational setting or classroom. In the United States' educational system, this caters to dominant culture groups in American society. "A primary source of stereotyping is often the teachers education program itself. It is in these programs that teachers learn that poor students and students of color should be expected to achieve less than their 'mainstream' counterparts." These child-deficit assumptions that are built into the program that instructs teachers and lead to inadvertently testing all students on a "mainstream" standard that is not necessarily academic and that does not account for the social values and norms of non-"mainstream" students.

For example, the model of "teacher as the formal authority" is the orthodox teaching role that has been perpetuated for many years until the 21st-century teaching model landed on the scene. As part of the 5 main teaching style proposed by Anthony Grasha, a cognitive and social psychologist until his death in 2003, the authoritarian style is described as believing that there are "correct, acceptable, and standard ways to do things".

Gender issues

Some say, girls tend to prefer one-on-one (dyadic) interaction, forming tight, intimate bonds, while boys prefer group activities. One study in particular found that boys performed almost twice as well in groups than in pairs, whereas girls did not show such a difference. In early adolescence, the variations in physical self-concepts appear slightly stronger for boys than girls. This includes self-concepts about movement, body, appearance and other physical attributes. Yet during periods of physical change such as infancy, adolescence and ageing, it is particularly useful to compare these self-concepts with measured skills before drawing broad conclusions. 

Some studies suggest self-concept of social behaviours are substantially similar with specific variations for girls and boys. For instance, girls are more likely than boys to wait their turn to speak, agree with others, and acknowledge the contributions of others. It seems boys see themselves as building larger group relationships based on shared interests, threaten, boast, and call names. In mixed-sex pairs of children aged 33 months, girls were more likely to passively watch a boy play, and boys were more likely to be unresponsive to what the girls were saying. In some cultures, such stereotypical traits are sustained from childhood to adulthood suggesting a strong influence of expectations by other people in these cultures. The key impacts of social self-concepts on social behaviours and of social behaviours on social self-concepts is a vital area of ongoing research.

In contrast, research suggest overall similarities for gender groups in self-concepts about academic work. In general, any variations are systematically gender-based yet small in terms of effect sizes. Any variations suggest overall academic self-concept are slightly stronger for men than women in mathematics, science and technology and slightly stronger for women than men about language related skills. It is important to observe there is no link between self concepts and skills [i.e., correlations about r = 0.19 are rather weak if statistically significant with large samples]. Clearly, even small variations in perceived self-concepts tend to reflect gender stereotypes evident in some cultures . In recent years, more women have been entering into the STEM field, working in predominantly mathematics, technology and science related careers. Many factors play a role in variations in gender effects on self-concept to accumulate as attitudes to mathematics and science; in particular, the impact other people's expectations rather than role-models on our self-concepts .

Media

A commonly-asked question is "why do people choose one form of media over another?" According to the Galileo Model, there are different forms of media spread throughout three-dimensional space. The closer one form of media is to another the more similar the source of media is to each other. The farther away from each form of media is in space, the least similar the source of media is. For example, mobile and cell phone are located closest in space where as newspaper and texting are farthest apart in space. The study further explained the relationship between self-concept and the use of different forms of media. The more hours per day an individual uses a form of media, the closer that form of media is to their self-concept.

Self-concept is related to the form of media most used. If one considers oneself tech savvy, then one will use mobile phones more often than one would use a newspaper. If one considers oneself old fashioned, then one will use a magazine more often than one would instant message.

In this day and age, social media is where people experience most of their communication. With developing a sense of self on a psychological level, feeling as part of a greater body such as social, emotional, political bodies can affect how one feels about themselves. If a person is included or excluded from a group, that can affect how they form their identities. Growing social media is a place for not only expressing an already formed identity, but to explore and experiment with developing identities. In the United Kingdom, a study about changing identities revealed that some people believe that partaking in online social media is the first time they have felt like themselves, and they have achieved their true identities. They also revealed that these online identities transferred to their offline identities.

A 2007 study was done on adolescents aged 12 to 18 to view the ways in which social media affects the formation of an identity. The study found that it affected the formation in three different ways: risk taking, communication of personal views, and perceptions of influences. In this particular study, risk taking behavior was engaging with strangers. When it came to communication about personal views, half of the participants reported that it was easier to express these opinions online, because they felt an enhanced ability to be creative and meaningful. When it came to other's opinions, one subject reported finding out more about themselves, like openness to experience, because of receiving differing opinions on things such as relationships.