I will be drawing from different psychological literature, especially focusing on the research areas of sexual election and parental care and investment, Evolutionary theory assumes that every living organism is a commodity of random natural selection and variation and that faith each generation, natural selection selects the adaptations that are ideal for sustaining life and reproducing. Hellishly (2011) defined Evolutionary psychology “as an approach to the study of the mind that is founded on Drawing’s theory of evolution by natural selection.
It assumes that our mental abilities, emotions and preferences are adapted specifically for solving problems Of survival and reproduction in humanity ancestral environment, and derives stable predictions from this assumption Evolutionary theory believes that living organisms change over a long period of time’. Despite Evolutionary psychology being a relatively new branch Of psychology, it has become increasingly popular over the last decade and a half.
Evolutionary mechanisms form an important part of Evolutionary theory’s argument for its explanation of human behavior as these mechanisms can be explored, studied and tested to provide evidence for its explanations of human behavior. An evolutionary mechanisms can be described as the processes that determine whether an adaptation occurs to elf an organism survive or reproduce (Commodes & Toby, 1987) Examples of evolutionary mechanisms are natural selection, migration, mutation and gene flow.
Natural selection is a key mechanism to Evolutionary theory and was originally proposed by Darwin, This mechanism is a slow process of evolution by which biological characteristics in a population become more or less prominent depending on an organisms differential reproduction success at adapting to their environment (Darwin, 1861).
For Example Drawing’s finches (Grant et al, 1 976) shows how each different finch had passed on an adaptive biological harmonistic to aid in the long term survival of their future descendants, the beaks of the finches had evolved over a long period of time to gain an selective advantage of access to their limited food sources in their unique environments. Furthermore, Buss et al (1998) proposed 3 important components of natural selection that need to be present to impact biological characteristics, these are variation, inheritance and selection.
Variation (genetic) occurs within an population even individuals are genetically different, this is due to natural random genetic mutations that happen over time or as a result Of are environmental effects. Furthermore it’s important that the biological characteristic in question is inheritable, so to allow the genetic component to be transmitted from ancestor to offspring. The final component is Selection.
Buss et al (1998) identified that the individuals that were more desirable, would inevitably lead to producing more offspring than other individuals who were less desirable. Another mechanism of evolution is gene flow, this refers to the random movement of genes of a population from one pool of genes to another. This in turn boosts the biodiversity and increases the genetic similarity of both populations. An example of this is the gene flow between spring salamanders and cave salamanders resulting in a more homogeneous gene pool (Nosily, 2008).
Migration is linked to gene flow as the migration of a species can lead to gene flow occurring, for example it all of the individuals with red hair in Scotland were to leave Scotland it would be plausible to believe that future generations would have a very small amount of people with this biological trait. The population of Scotland would have evolved accordingly, A good way to measure whether evolutionary theory provides a satisfactory explanation for human behavior s to compare the theory to other explanations such as the Social roles theory.
Specifically focusing on drawing from psychological literature of sexual selection, it can be established Vichy theory provides the more superior explanation. Before critically evaluating and comparing the two theories, its important to briefly outline the theories beliefs on the origins Of sexual differences of human behavior. Evolutionary psychologists state that both males and females had to deal With different evolutionary pressures in prehistoric environments (Eagle and Wood, 1999). This resulted in different sex evolved mechanisms that evolutionary psychologist’s believe is the root reason for gender differentiated behavior.
Although the explanation believes that conditions of the environment can affect the development of sex-differentiated behavior, it fails to acknowledge the situational and cultural conditions that might also affect sex difference behavior (Buss & Generic, 1998; Archer, 1996). The Social roles theory believes that the circumstances faced by men and women vary across different periods of history and societies according to ecological and technological changes in social organizations (Eagle and Wood, 1999).
The theory also believes that sex differentiated behavior is caused by the labor divisions of society and because both women and men usually have contrasting social roles, that may have led to both genders to develop deterrent psychological traits to help them to adjust these contrasting roles (Eagle & Wood, 1999) The explanation also states that sex differences are effected by several cultural, individual and situational conditions (Addax &Larance, 1998).
However the Social roles theory does acknowledge the significance of genetic differences in gender, as men’s greater physicality and trench and a women’s ability to give birth and feed offspring are in alignment with universal cultural beliefs and social groups which in turn influence, psychological gender differences (Eagle & Wood Gigs)_ When focusing on the origins of sex differences its important to look at the theory of sexual selection as it’s one of the area that evolutionary theory has most been applied to.
The sexual selection theory proposes that gender typed traits developed through female selection Of men and men’s competition for women (Darwin, 1871). The theory (in accordance with human behavior) believes that because women ere limited by the amount Of children they can give birth to in their lifetimes due to their expenditure through carrying children, giving birth to children and nursing their children.
Hence Why female parental investment is usually more than male parental investment (Background & Skip, 1996) This in turn could have caused women to develop a unique evolved psychological mechanism to help them select men who were better equipped to provide the necessary resources such as food, shelter and protection from other males to support her and her offspring (Drivers, 1992), There seems to be strong evidence to support his notion from research from more than 50 researchers across 6 continents, 33 countries and several thousand participants (Buss, 1989), For example, the research study created by Buss (1989) looked to find out which characteristics people tended to find important when choosing a prospective partner. The S chosen characteristics were earning capability, celibacy, physical attractiveness, youth and ambition- industriousness. The results of the study found that women viewed resource acquisition more important in prospective mates than males did from a sample size over 10,000 participants. Another example to support his notion is the research study ran by Townsend & Levy (1390).
They were investigating the comparative importance of attractiveness and prestige across multiple conditions of romantic involvement. Students were shown pictures of individuals of low, medium and high levels of attractiveness along With three conditions of job status and earnings. Participants were told to reveal their willingness to get into relationships Of various levels Of sexual affection. Townsend & Lieu (1990) found that the economic and social status of an individual was a big factor for female participants across every level Of intimacy ND the preeminent status was able to compensate for unattractiveness. Research into sexual jealousy also provides evidence for a women’s sex specific preferences.
Sexual infidelity causes sexual jealousy but does not threaten the security of motherhood for the women as the child would definitely be hers, so sexual jealousy for women was thought to be an evolved psychological mechanism to stop her partner becoming responsive to other women (De Wreath & Kalmia, 1993) The study by Buss, Larsen, Western and Sommeliers (1996) reported that women selected emotional infidelity as upsetting them ore than sexual infidelity supporting the idea that women employ sexual jealousy to avoid her mate investing his time, resources, protection, and loyalty to other women and to increases the chances of hi, focusing these resources on her children.
However the social role theory disagrees with the evolutionary explanation for female mate selection and instead proposed that female mate selection was a reflection of a woman’s effort to enhance their chances of mating with a desirable potential partner within the bounds of societal and martial roles (Eagle & Wood, 1999). The social theory suggest that woman’s mate selection is to exclusively focused on reproducing but also to further their social status and move up society social ladder (Traversal, 1998), this is due to women often being restricted in social status, so they would look to improve this through their mate (Capable, 1989). The theory proposes that oven have a preference for a partner with the characteristics Of Strong earning ability, high social status and a good education to further their social standing.
The problem with this explanation from the social roles theory perspective is that although both theories have evidence to support the idea the women have a preference for en With a high earning capacity, there is evidence that shows that women With high earning capacity still prefer men with high earning capacity (Waterman & Algeria, 1992) which is unexplained by the social roles theory. However the evolutionary sexual selection theory shows how a women’s preference for a man with high earning capacity regardless of the woman’s earning capacity. This gives the evolutionary explanation an advantage over the social role theory, which weakens the credibility of the social roles theory and strengthens the credibility of evolutionary psychology. The sexual selection theory suggests that men were put under sexual evolutionary pressures to quality/ for the criteria of a woman’s preference for men that could provide the necessary resources (Wood & Eagle, 1999).
It was predicted to be more beneficial for males to have several different sexual partners in the short-term because of the males’ relatively smaller parental investment which is in keeping with 95 percent of mammalian species (Clubfoot- Brock, 19891 The theory also predicts that although both women and men prefer more sexually attractive partners, men tended to place more importance n selecting the more physical attractive females (Buss, 1989; IL et al. , 2002), this preference coupled with other specific preferences of physical attractiveness such as waist-to-hip ratio Of 0. 7, youth, age, a symmetrical face (Miller, Soles & Thrills, 1395: Cunningham, 1386) along with leaner women (Hum & Montgomery, 2001) was thought to be an indication Of fertility. This assumption is supported by evidence from the research study by Sings and Broadband (2001) who found that women were found to be more symmetrical during ovulation and also produce an aromatic hint to signal the start of ovulation.
Further evidence can be provided by Buss and Barnes (1986) who reported that men significantly rated physical attractiveness as a more desirable characteristic than women and concluded that you can look to conventional societal applications such as women focusing some much effort on physical beauty and men looking to advance their social status and earning potential as extra evidence for the both genders wanting to become more appealing to the opposite sex. All this evidence suggests that a male’s preference tort more physically attractive tamales is used to increases the chances of mating with a female with high fertility, This threatens the credibility of the theory of sexual selection. However not all evidence supports the evolutionary perspective of human male mate selection.
In an extension of the study carried out by Buss and Barnes (1986), Howard, Bluntness, & Schwartz ( 1 987) found that the majority of predictions of both the evolutionary and social perspectives was supported by evidence from heterosexual pair studies but also concluded that their results were better explained by the social perspective of mate selection. They found that men also preferred an expressive partner. This holds no advantage from an evolutionary respective, however Howard et al (1987) suggested that being an expressive mate can help to be a better mother which would make a male have a stronger preference for a more expressive mate. The social roles theory states that women have been socialized to conduct themselves in a more expressive manner than men therefore making them more desirable.
This weakens the credibility Of the evolutionary perspective as it cannot explain the preference. On the other hand, the social role theory proposed that male mate selection was a reflection of a man’s effort to enhance their chances of mating with a desirable attention partner within the bounds of martial and societal gender roles. Social roles theory suggests that men will have a preferences for a partner who has characteristics of being a good mother, a good cooker, and the capabilities to carry out domestic work (Howard, Bluntness, & Schwartz, 1987) which is in accordance with martial and society’s perception of gender roles with men providing and women managing the house and the children.
Another important feature of the theory of sexual selection is that men weren’t able to fully establish whether their child was conceived trot their sperm or not, because a woman’s retaliation period is hidden, This may have led to an evolved psychological mechanism such as sexual jealousy to counter the uncertainty of whether they were the biological father of the child and limit the advances of other males (Buss, 2013). This idea is the supported by evidence from the study Sugaring et al (2003), who found that there was a sex difference between opposite ?gender infidelity as men had reported greater discomfort in reaction to sexual infidelity than women.
Interestingly Sugaring et al (2003)it was also reported that the sex difference from opposite-sex infidelity vanished when the infidelity involved name-sex lovers and that males and females felt less jealousy towards same- sex infidelity or in other words infidelity where conception is impossible, these findings substantiate these claims as a males greater distress to infidelity than women disappears when the possibility of cuckoldry is impossible, therefore indicating that the evolved psychological mechanism of sexual jealousy for males may indeed be used as a function to protect and improve their chance of fertilizing their mate. This increases the reliability of the theory of sexual selection and evolutionary theory. Parental care and investment is also an important topic area for evolutionary theory.
More often than not, females invest much more into their offspring, males usually supply a small direct investment into the health and protection of their outstripping although humans are the exception (Cotton-rock, 1989). Parents will usually devote an enormous amount of their resources, attention and time to the look after their children, as well as potentially suffering life-threatening risks to protect them (Daly & Wilson, 2005), Prom an evolutionary standpoint this could be a result of natural selection as the parents that invested more time and are into their offspring would have given them an advantage and therefore had a better chance of surviving, reproducing and passing on their genes. For this reason it would make sense for parents to favor their own genetic offspring, this idea is explained in theory of Inclusive fitness (Hamilton, 1964).
The theoretical concept of inclusive fitness is that main purpose of a species is to pass on its genes and that a species will exhibit altruistic behavior to those with the same or similar genes to help ensure that they survive to reproduce and pass on their genes to other generations (Hamilton, 1964). The concept of inclusive fitness is supported by the study by Leverage, gauzier, & Raymond (2009) Who reported that paternal investment was related to similarities in facial features and Dour. Paternal investment was also related to children’s wellbeing and health, this suggests that fathers would invest more in children that resembled them more and this in turn would benefit the child’s nourishment and growth.
Correspondingly, if you looked at the theory of inclusive fitness from a different angle it could be suggested that children with non-biological parent would e at risk from less parental investment and even harm due to them being of no relation. This notion was derived trot the Cinderella effect (Daly & Wilson, 2005), the concept behind this idea was that stepparents living with children of no relation were more likely to abuse their step children than genetic parents. Evidence for this statement comes from the study by Daly and Wilson (1994). They found that from Evidence taken from the Canadian and British national archives of homicides, that children under the age of five were more likely to have been killed by a stepfather than their Genetic fathers.
Other similar studies found that young children were OIC times more likely to be lethally abused by step-fathers than genetic fathers (from IIS Data) (Daley & Wilson, 1388). This suggests that step-fathers might not hue the parental love, evolutionary motivation to invest and be patient with step children, leading them to be aggressive or even violent. This strengthens the credibility of the evolutionary approach. In conclusion, evidence from evolutionary psychological literature suggests that evolutionary theory does provide a fairly satisfactory explanation or human behavior but the theory is not without its flaws. For example Evolutionary psychology provides a solid explanation for sexual selection, mate preference and parental care and investment.