Understanding Genetic Relatedness, Parental Care and Kin Altruism in Psychology through 3 Important Approaches
Introduction
Genetic relatedness is a term which has been connotated and referenced in the context of evolutionary psychology by many scientists and evolutionary psychologists. One of the most sought after and common-phrase explanation to genetic relatedness has been that of correlating and signifying the primordial role of parental care and kin altruism, or by understanding the amount of attachment, intimacy, care, protectiveness being reflected by the care-givers to that of the child, on the basis of the child’s relation to them in regard to gene expression, i.e. the child being their biological descendant and/or being under their care and supervision by means of adopting it. Most evolutionary psychologists defend this position by stating that parents display greater affiliation and attachment towards those children to whom they give birth biologically, as opposed to those they adopt and pursue as their own after their birth.
An increased investment of resources, personal attention, intimacy is also displayed in higher prominence by the care-givers and the close family members of the child such as uncle, aunt, grandparents and cousins if the child is assumed to be the direct descendant of his/her parents and is born via the direct gene expression of his parents’ genes.
Under circumstances in which there is an inherent doubt or skepticism involved in terms of accepting the parents’ claim of the child being biologically related to them, then the amount of parental care and the degree of kin altruism might vary drastically as opposed to in a situation where there is conviction in terms of evidence that the child is a biological descendant of his parents and all of his kin members.
Kin altruism as a necessary characteristic attribute arising as a consequence of genetic relatedness of the child to its biological parents, is considered to be present in prominence in those species which perceive their genetic inheritance to be highly probable to be passed on to their biological child, and in instances of not bearing a child of their own, they consider the probability of their genes being likely to be passed on to the next of their kin or the offspring of their blood relatives such as sons/daughters of their brothers and sisters. Such humans display greater affiliation towards their blood relatives such as nephew, nieces, granddaughters and grandsons since they are the direct biological descendants of them after their own children, therefore it would be fruitful to see their genes getting expressed in their nephews and nieces’ potential offspring rather than that of their stepchildren or adopted children. Kin altruism is observed to have a direct relation to genetic relatedness, since the attribute of altruism is increasingly observed as being passed on from one generation of species to another by means of reproduction and evolution. Those humans who cannot bear their own children invest highly in kin altruism of their blood relatives since it shall ensure retention of their genes for future generations and a healthy passing on of their inheritance to the future generations of their own kin.
But at the same time, it is necessary to pose a contradiction to the existing hypothesis of deriving a direct correlation between genetic relatedness and kin altruism as well as parental care. According to the existing hypothesis, as posed by the evolutionary scientist William Hamilton, there exists a positive correlation between kin altruism and genetic relatedness, since the carriers of the gene or the care-givers, are more likely to pass on their genes to members of their immediate kin by direct transmission through sexual intercourse or by investment of resources, care and affiliation towards members of the immediate kin, such as nieces, nephews, etc. This attribute of investing heavily in one’s own children and those of the kin members, results in the decreased survival and fitness of the parents and increased survival and probabilities of carrying of the passed genes in the subsequent generations of their kin.
But, is it necessarily apparent to state that all human species display greater affiliation towards their biological children and blood relatives and invest all of their resources, love and care towards them? There might be several instances of portrayal of contrasting behavior of displaying equal affection towards adopted children, stepchildren and distant relatives which might lead to greater investment of their resources, care, love and affiliation ensuring their survival. Let us understand the relevance and validity of the kin altruism and genetic relatedness theories by analyzing alternative explanations to genetic relatedness being a signifier of kin altruism and parental care.
Alternative explanations to Genetic Relatedness, Kin Altruism and Parental Care
In a recently published research study titled “The evolution of altruism and the serial rediscovery of the role of relatedness”, co-authored by Tomas Kay, Laurent Keller and Laurent Lehmann, there is an indicated critical analysis and evidence-based conclusion provided on the basis of reviewing 200 of the most impactful research papers exploring alternative or differently suggestive models/approaches to evolution of kin altruism other than being related to genetic relatedness. Kay, Keller and Lehmann discovered almost 43 different evolutionary models suggesting the evolution of kin altruism not being directly related to kin selection or genetic relatedness.
In a summed-up approach to the analysis of the 200 significantly researched papers, there was a generalized observation that could be derived from all of them alike, which proved the subjective rediscovery of Hamilton’s model of kin altruism as being reflected as a result of genetic relatedness, as being indicated through local interactions amongst individuals of a significantly remote population as in an island, viscous locality, etc. which eventually reiterated and emphasized upon the increased transmission of the alleles of altruism as observed in the ancestral population to that of the descendant populations, which retained those altruistic genes over a period of several other generations ahead. Hamilton had suggested that “in order to analyze the roots of the genetic evolution of the characteristic attribute of altruism in individual populations of human species, it is crucial to consider the average fitness of all individuals bearing that specific allele responsible for making a change or transition in the passed-on trait/characteristic.”
According to Hamilton, “in a typical homogenous population of individuals, the allele which induces the attribute of altruism will increase in frequency when rb-c> 0. -c refers to the average affect of the allele inducing altruism on the fitness of the bearer, b refers to the average affect on the fitness of the recipient population and r refers to the relation between the actor population and the recipient population.”
Therefore, in the above given context, the coefficient r which indicates the relatedness between the actor and the recipient populations of human species, it can also be understood as being representative of understanding the likelihood of a random individual of a population inheriting the altruism attribute from his/her ancestor in contrast to the direct recipient of altruism (kin member, biological child). This is the typical understanding which is an attempt to make the close relation of genetic relatedness and kin altruism evident by Hamilton. Since the coefficient r indicates the direct relation between the recipient population and the actor population, there is an indication of preference of genetic transmission over kin members, since according to Mendelian evolutionary theory of independent assortment, “there is a 50 percent of probability of the child inheriting the genes of either of the parent and the probability of the child inheriting the genes of their aunt or uncle is 25 percent.” Therefore, it shows a typical family structure in which the genetic relatedness of the recipient population is prominently with the actor population of its own ancestral kin members, but at the same time it rules out the possibility of considering instances of local individual populations inheriting closely related genes of altruism from their ancestors apart from sole family members.
This is not the case most of the times since kin selection is likely to be observed in limited populations observed in remote habitats such as islands, etc. due to limited genetic transmission and intermixing of parental genes as observed otherwise in a large population of that of a city, state, etc. According to the mechanism of the “green-beard effect”, the same altruistic allele responsible for causing change in the traits of the individual is observed as frequently mutating in a local population and thereby can be observed as being reflected in multiple individuals due to production of multiple replicate copies of the same allele. Therefore, an individual might possess a similar genotype allele in its genetic material even if it is not related to the ancestor by means of kinship or biological descent. Similar explanations have also been posed by alternative evolutionary models of altruism such as the “stepping stones” model of spatial population structure, viscous model of spatial population structure and island model of spatial population structure. Therefore, there are an increasing proportion of individuals who exhibit altruistic traits of the ancestor who shared the same spatial neighborhood as was inhabited by them. This is an alternative explanation to the kin selection theory, “since in an environment which allows limited genetic mixing of altruistic alleles in a population, there is local interaction of existing individuals which in a way implies that there is rising competitiveness among individuals in order to ensure their fitness and their survival and therefore there is an indication of the phenomenon of ‘kin competition’ opposed to ‘kin selection’ in which the survival is enhanced for those individuals onto whom the genotype is transmitted. In a state of kin competition, there is increased survival of neighbors as well, and similar phenotypical altruistic alleles are observed in almost all of the members of the population.”
Yet, as per Kay, Keller and Lehmann’s analysis, “even under conditions of kin competition, altruism is displayed through kin selection.”
Hamilton’s model of kin selection being positively correlated to genetic relatedness enjoys combined validity and significance from several of the contemporary evolutionary scientists, biologists, psychologists alike. But at the same time there have been several alternative models claiming the kin competitiveness approach to be resulting of limited genetic mixing in a local population, thereby allowing most individuals to possess altruistic alleles regardless of their relation to the ancestor from whose spatial presence they adopted the particular phenotype. Several empirical and mathematical evidences prove the relevance of the positive correlational efficiency of the kin selection theory to that of genetic relatedness from ancestors.
Yet there is an increasing debate amongst evolutionary psychologists regarding alternative explanations such as spatial selections being favored over kin selection theories. The spatial selection mechanism was initially proposed by Martin Nowak who claimed kin selection and group selection to be uniquely differential in nature to spatial selection. Most of the scientific papers revolving around explanations relating to spatial selection are concerned with the dynamic interaction of individuals acquiring the altruistic allele from their relatives or parents thereby reiterating and emphasizing the validity of kin selection over kin competitiveness.
Which is the correct approach to understand the explanation of parental care and kin altruism?
Although it is evidently correct to state that altruism gets affected and significantly influenced under circumstances of local interaction and limited genetic mixing, but it is only true as long as kin competitiveness is not prominent among the population. Moreover, the spatial selection theory is not reliable as a valid contradiction to the kin selection theory since it uses space as a defining factor to determine the relatedness of the individual from its ancestors. There is no mention of the correlational coefficients of relatedness as r, b as the benefit the individual is conferred as a part of acquiring altruism through genetic transmission as influencing kin selection and passing over of altruism to the subsequent generations.
Therefore, the models which consider approaches contrasting to that of kin selection by including factors such as “competitiveness, ‘social diversity’, ‘spatial reciprocity’, ‘spatial structure’, etc. are incorrect in their conclusions of ascribing prominence to kin competitiveness as the key determinant of altruism through evolution.” There is a significant revision and reaffirmation of the kin selection theory as there is increased interaction observed between the individual with their close relatives as opposed to interactions of individuals with complete strangers.
Although, it cannot be stated with complete conviction that the kin selection theory is the sole basis of understanding kin altruism and genetic relatedness in evolutionary psychology, it has to be considered that it is one of the most reliable explanations to understand genetic relatedness being observed as a signifier of kin altruism.
Therefore, in conclusion, it can be stated that kin altruism and genetic relatedness might be positively correlated to each other since they display increased probabilities of individuals bearing 50 percent of the parental genes and 25 percent of the genes of close blood relatives in their inheritance. There are empirical evidences to explain the above hypothesis, which is why it is an acceptable explanation to altruism rather than esoteric claims proposed by kin competitiveness and spatial selection theories. Such alternative approaches are partially correct, since they operate on domain-specific and not domain general mechanisms.
