Preventing Incest, The Evolved Psychological Aversion Technique - Essay Example

? Preventing Incest: The Evolved Psychological Aversion Technique College Introduction One of the most important causes of genetic disorders in humans occurs when mating pairs are blood relations. It can lead to congenital birth defects, some of which can be extremely harmful or even fatal to the child born of an incestuous coupling (Potts & Wakeland, 1993). Socially, however, incest is one of the most common taboos found in a multitude of cultures, suggesting that there may have been a psychological-based evolutionary adaptation designed to prevent incest and the genetic deformities that come alongside it. The purpose of this paper is to explore the problem of incest with respect to sex and mating and the effects that it has on children born to this type of couple. It will explore the adaptive problem to outline why an evolutionary mechanism may have evolved to prevent this problem by weighing up the benefits and costs of developing such a mechanism. The paper will then move on to explore the ways in which the psychological reflex response to incest could have evolved and why this would solve the problem outlined above. Finally, the paper will explore options for testing the hypothesis that there has been an evolutionary ‘disgust’ or inbuilt taboo mechanism designed to prevent incestuous couplings. The Problem of Incest Although incest is commonly seen as being one of the biggest taboos in many societies, incestuous couplings do occur and produce children. It produces children who are scientifically closely inbred, which can lead to a wide number of genetic deformities. The reason for this is that a child will inherit one allele of a gene from each parent. If the parents are related, the likelihood is much increased that they will both share an allele and therefore pass on the same allele to the child. This is scientifically termed being homozygous for a particular gene (Bittles, 2012). This would not normally be a problem for genes such as eye colour, but the problem occurs when both parents pass on a deleterious recessive allele (Speicher, Antonarakis & Motulsky, 2010). In this scenario, one ‘healthy’ copy of the gene is needed to outweigh the ‘bad’ allele, but if both copies are the same the child will inherit a disease (Speicher et al, 2010). Many disease or deformity-causing alleles are rare in the population, so it is less likely to occur through random mating (Speicher et al, 2010). Additionally, there are suggestions that a child will have a less varied set of genes for their immune system, making it weaker over their lifespan (Bittles, 2012). Children born to a culture where the practice is illegal or immoral may also be victim of abuse and their parents may be put into prison, giving them a less than perfect childhood (Bittles, 2012). Indeed, it has been shown that children born to this type of couple are more likely to commit suicide than the general population (Ahmad & Nasir, 2010), again putting some form of selection pressure on preventing incestuous relationships. These facts combined mean that close relation parents are more likely to have ill or less-viable children, which would put a selection pressure against inbreeding. This leaves the problem open to having a psychological aversion to inbreeding which has evolved alongside incestuous relationships. It is evidently extremely important to avoid passing on such mutations to children to ensure their health. It is interesting to look at the facts and figures of incest to see how important it may be as an evolutionary mechanism. In one study of Czechoslovakian children born to parents who were also first-degree relatives, it was found that less than half of them could be considered healthy (Seemanov, 1971). A full 42% of these children had severe birth defects or suffered an early death and an additional 11% of these children had some kind of mental impairment (Seemanov, 1971). In this type of circumstance, there is a selective pressure against incestuous relationships. This is because if 42% of children born to incestuous parents will die before reproductive age, their genetic material cannot be passed on to the next generation (Antfolk, Karlsson, Backstrom & Santtila, 2012). This means that any psychological or physiological tendency towards incest will not be passed onto the next generation if it is a genetic trait. Additionally, these children will not be able to pass on any social trait for incest because they are not creating their own family unit. If 11% of the children also have mental impairments, this may also limit their ability to pass on genetic or social information onto the next generation. One interesting part of incestuous relationships is that sexual relationships between cousins are often not illegal or even encouraged in many parts of the world (Crawford, 2011). This may be due to cultural preferences, but there may also be a genetic or evolutionary mechanism as to why this is not taboo or does not incite the same feelings of disgust. One study found that there was only a 4% increase in the number of birth defects found in children born to cousin parents (Bennett et al, 2002), which is a surprisingly small increase. This would mean that there is a relatively small selection pressure genetically on these children as they would likely be able to pass on genetic and social traits linked with cousin incest onto their own children. This means that there may be a lower psychological evolutionary feeling of “disgust” towards cousin-cousin incest. Solving the Problem of Incest Having identified the problem of incest, it is necessary to explore the ways in which psychological adaptations may have evolved to prevent the problem of genetically disabled children. One of the most obvious targets for this lies in the fact that incest is considered taboo in almost every culture, although the degree to which relations are classified as “too close” can vary amongst different areas (Bittles, 2012). This fact suggests that there may be some evolved "aversion” to incestuous relations which has become the most beneficial approach to have, psychologically, when it comes to sex and mating. This theory has been explored before, although there are a multitude of different theories exploring how humans know their close blood relations and how this can help prevent incest. Although many humans will feel some level of disgust when considering an incestuous relationship, it is important to know why humans feel this way and how they identify close kin as something to avoid during mating. One obvious suggestion is that they identify a sibling or parent as someone they have had a lot of close contact with during their formative years (Gilbert, 1989). For example, a standard family unit in the Western world could have at least one parent present in the home with the siblings and half-siblings also being present in the environment. One of the easiest ways of judging who not to mate with, then, is avoiding those who have grown up in the family unit. This does not solve the problem of how to avoid incestuous mating in situations where the family unit is not comprised simply of close relations, or when siblings grow up in separate home environments. In this case, there is evidence that incest may be prevented by a psychological ability to know close relations which are known as “kin detection mechanisms” (Bittles, 2012). This could occur through smelling pheromones or through an inbuilt aversion to those who look similar to us (Bittles, 2012). This is a much more complex mechanism which has yet to be explored, although it does bring up some interesting questions about incest and kinship aversion during sexual mating. How Aversion to Incest Prevents Genetic Defects My proposed mechanism for avoiding incest is a psychological-based knowledge of who we are related to based on some of the theories outlined above. This includes knowing who we have grown up with (those who live in the same family unit, for example) using visual cues like seeing your mother nurse another infant, or living with another individual for a long period of time. Additionally, I am suggesting that there may be some other visual cues in the mechanism which mean that incest aversion still plays a part in non-traditional family units, such as recognizing face types that are similar to our own and avoiding these individuals when it comes to sexual mating. These visual cues would then develop into a psychological negative emotion when considering sex and mating with this individual as a way of preventing incestuous relationships and the subsequent evolutionary and genetic problems. Evolving this psychological avoidance mechanism would be a major benefit to any individual as their offspring would be less likely to develop any rare genetic disease which occurs more often in offspring of incestuous relationships, as well as potentially having a more varied and therefore stronger immune system. These individuals would therefore be able to go on to breed, passing on the psychological avoidance mechanism to their offspring and continuing the beneficial chain of events. This would help prevent incest because we would feel disgust when thinking about sexual relations with an individual that has triggered the above visual cues. The input information here is purely visual, and involves noticing those who inhabit our home environment, who our own mother seems to also mother, and those who look similar to us. By psychologically associating these visual cues with feelings of disgust (when thinking about sex and mating), this would prevent incest. The decision rule is therefore seeing someone who triggers one of these visual observations, and having this mean the individual does not want to have a sexual relationship with the individual that triggers this rule. For example, an individual would see their own mother nurse a baby, and then from this cue would avoid mating with this individual for life due to a feeling of “disgust” associated with thoughts of sexual relationships with the individual. The output is therefore the feeling of disgust or avoidance that accompanies the temptation or thought of having sex with this individual. Testing the Hypothesis As incest is illegal in most parts of the world (Sebo, 2010), it would be very difficult to ethically collect data about incestuous practices. However, one way of gaining data about the problem of incest and potential psychological adaptations towards its prevention would be to gauge people’s aversion to incest. This could be done using a questionnaire. The first part of the questionnaire would collect demographic data that could be useful for the results, including age, gender and location. Additionally, the questions should also get information about the participant’s home life present and current. This would mean collecting data about their family unit (such as how many biological parents were present in their home, how many biological siblings were present in their home, as well as information about step-siblings and step-parents). The second part of the questionnaire should be more complex. Firstly, a series of questions about the participant’s feelings towards their siblings and parents could be collected, ascertaining whether they have a “typical” or “healthy” relationship with their family. This data could include how much contact that the individual has with their family unit, as well as their emotional connections and feelings towards their parents and siblings. Additionally, some data could be collected about “issues” that they may have had growing up, such as feelings of abandonment (perhaps due to the presence of siblings and step-siblings) as well as previous histories of abuse or neglect. A second section could ask questions about the individual’s feelings about incest. It would be useful to gauge these results using a sliding scale from “extremely disgusting” to “does not bother me”. The questions could ask about various kinds of contact, such as hugging, kissing and sexual behaviours. This would allow the research to find any links between home life and feelings about incest. It may also be useful to collect information about cousin-cousin incest and relationships to test to see if the psychological aversion is less strong when considering this type of incest, as suggested by the biology of incestuous relationships. Another part of the study could invite these participants into a controlled laboratory area where their brain waves could be monitored. During this process, the individual could be shown pictures of their mother, father or siblings with other individuals (children and adults). If these are not available, then these could be digitally rendered. Their brain activity could then be monitored to see which areas of the brain were active when being shown these pictures and to see if they have any feelings of disgust, love or other emotion. The patient could then be asked a series of questions about their feelings towards that individual pictured with their family members, and their brain activity could be monitored to see which areas of the brain were active during this time. In the same setting, the participants could also be shown pictures that had been created of individuals that look similar to themselves, of the opposite and the same sex. Whilst being shown these photographs, the patients could be asked to rate the photograph’s attractiveness on a scale of 1 to 10. Whilst this is occurring, the brain activity should still be monitored to see if there are any psychological feelings of sexual desire or disgust when being asked this question. Additionally, the participant could be asked to imagine sexual relations with the individual pictured to see if there is any psychological mechanism at play. Evidently, this type of study does pose some ethical problems. Due to the sexual nature of the questioning and the invasive nature of the testing, the participants should be over 18 to take part. This would help to avoid psychologically damaging any minors as part of the process. Additionally, as with many psychological studies, the participants would have to be informed of the nature of the testing and that it was about incestuous relationships. Having been given this information, the participants would then be able to give their informed consent to take part in the study. This type of precaution would mean that any participant would be fully prepared for the nature of the test, although it could introduce some bias (Gray, 2006). Additionally, it would be beneficial to some people to provide follow-up counselling or psychological treatment if they feel as though the questions asked were particularly invasive or have brought up any unresolved issues relating to family or incestuous relationships. This should help prevent any psychological or moral damage to the participants. Conclusions There are many different ways in which humans have evolved to avoid sexual and mating problems, but avoiding incest is one of the most important. Incestuous relationships can cause inbred children who have a higher risk of congenital genetic defects, which means that there is a selection pressure acting on the avoidance of incestuous relationships. I propose that there is an inbuilt “disgust” or “taboo” mechanism which is present psychologically which has evolved in response to the dangers of incestuous relationships. The input here is recognizing who we are related to, and the output is feeling “disgust” when thinking about sexual relationships with these individuals. There are many ways of testing this theory, but one way could be to ascertain the history of the individual, and seeing if they have a reflex when thinking about sexual relationships with their families. This could be done by questionnaire and brain scanning techniques, as outlined above, to see which areas of the brain are active when thinking about mating with a relative. References Ahmad, N. S., & Nasir, R. (2010). Emotional Reactions and Behavior of Incest Victims. Procedia-Social and Behavioral Sciences, 5, 1023–1027. Antfolk, J., Karlsson, M., Backstrom, A., & Santtila, P. (2012). Disgust elicited by third-party incest: the roles of biological relatedness, co-residence, and family relationship. Evolution and Human Behavior, 33(3), 217–223. Bennett, R. L., Motulsky, A. G., Bittles, A., Hudgins, L., Uhrich, S., Doyle, D. L., … McGillivray, B. (2002). Genetic counseling and screening of consanguineous couples and their offspring: recommendations of the National Society of Genetic Counselors. Journal of Genetic Counseling, 11(2), 97–119. Bittles, A. H. (2012). Consanguinity in Context. Cambridge University Press. Retrieved from http://www.lavoisier.fr/livre/notice.asp?ouvrage=1436430 Crawford, B. (2011). Authentic Reproductive Regulation. Minnesota Law Review. Retrieved from http://papers.ssrn.com/sol3/Delivery.cfm?abstractid=1960590 Gilbert, C. M. (1989). Sibling incest. Journal of Child and Adolescent Psychiatric Nursing, 2(2), 70–73. Gray, P. O. (2006). Psychology. Worth Publishers. Potts, W. K., & Wakeland, E. K. (1993). Evolution of MHC genetic diversity: a tale of incest, pestilence and sexual preference. Trends in Genetics, 9(12), 408–412. Sebo, J. (2006). The Ethics of Incest. Philosophy in the Contemporary World, 13(1). Seemanov, E. (1971). A Study of Children of Incestuous Matings. Human Heredity, 21(2), 108–128. doi:10.1159/000152391 Speicher, M., Antonarakis, S. E., & Motulsky, A. G. (2010). Vogel and Motulsky’s Human Genetics: Problems and Approaches. Springer. Read More