Evolutionary Psychologists' View on the Human Brain - Essay Example

? Is it possible for evolutionary psychologists to make a convincining case to explain the size of the human brain Introduction The development of human characteristics through the centuries has been explained using different criteria. In certain cases, efforts are made in order to show the close dependency of humans on their environment, claiming even the existence of common ancestors for both human and non-human primates, meaning the relevant theory of Darwin on natural selection. In practice, it has been proved that all these theories can be strongly criticizes as not being sufficiently justified. A particular issue related to human evolution is examined in this paper: the size of the human brain. Effort is made to evaluate whether the size of the human brain can be explained using the principles of evolutionary psychology. The review of the literature published in this field has revealed that the views of evolutionary psychologists regarding the size of the human brain cannot be convincing, a fact highlighted also in the findings of the empirical research developed in this subject, as presented analytically below. 2. Evolutionary psychology and the size of human brain In order to understand the potential use of evolutionary psychology in explaining the size of the human brain it would be necessary to refer primarily to its key characteristics. Most commonly, evolutionary psychology is considered as closely related to the Darwin’s view on natural selection and evolution (Hull et al. 2007). However, evolutionary psychology seems to be differentiated from the Darwinian theory, mostly at the following point: Darwin has emphasized on the role of emotions on psychological and biological processes while evolutionary psychology claims that these processes are mostly cognitive (Badcock 2000, p.123). Of course, the alteration in the size of human brain through the centuries cannot be doubted. In the study of Hampton (2010) reference is made to the increase of the size of human brain as a result, as the above researcher notes, of the socialization of humans, i.e. of their need to live within communities, thus their obligation to change their thinking and their response to their social environment (Hampton 2010); it is noted that the above phenomenon is commonly ‘known as encephalisation’ (Hampton 2010, p.198). The above view can be used for justifying the existence of relationship between the size of human brain and the evolutionary psychology. Since the size of human brain is affected by socialization, this means that it is necessarily related to evolution – under the terms that social ethics and norms change continuously and rapidly (Hampton 2010). However, the above fact cannot lead to the assumption that the interaction between the human brain size and the evolutionary psychology is continuous and critical. On the other hand, evolutionary psychology is often used for explaining the changes in psychological processes, as these ones can also affect the biological processes. From this point of view, evolutionary psychology could be used for explaining the size of the human brain. However, the potential use of evolutionary psychology in giving such explanations would be strongly doubted because of the following reason: evolutionary psychology does not refer to all ‘aspects of mind and behaviour’ (Holcomb 2001, p.294) but only to those which are ‘evolutionary significant’ (Holcomb 2001, p.204). This means that functions and elements of human behaviour, which do not trend to change on a continuous basis cannot be explained using the views of evolutionary psychology. From the same point of view, the size of the human brain, which shows an extremely slow rate of change, cannot be explained or evaluated using the evolutionary psychology, an issue analysed further in the section that follows. 2.1 Are the arguments of evolutionary psychologists regarding the size of human brain convincing? Is it possible for such arguments to be developed? In the context of evolutionary psychology, human body is continuously developed but these changes are rather difficult to be clearly distinguished, especially if they are examined and evaluated in the short term. The evolution related to the human body can be clearer when its structure and functions are studied in a quite long-term period, like for example the first ancestors and modern humans (Morss et al. 2001). In the literature, various approaches have been used for explaining the changes in human body through the centuries. Referring to the human brain, the changes of which are under examination in this paper, different arguments have been developed for explaining its evolution, which seems, in any case, to be rather marginal as explained below. In accordance with Richardson (2007) evolutionary psychology highlights the evolution in human brain, but it does not explain the causes of these changes. It is also noted that evolutionary psychology refers mostly to the size of the human brain and not its functions. From this point of view, the contribution of evolutionary psychology to the explanation of the changes in the size of the human brain is characterized as quite low, taking into consideration the fact that they are the functional characteristics of the human brain, and not its size, that are most related to the evolutionary psychology (Zilmer et al. 2008). The evolution of the human brain is reviewed in the study of Badcock (2000). Reference is made to the size of the human brain, as ‘a ratio of actual brain size’ (Badcock 2000, p.29); for early humans, this ratio has been estimated to 3.1 (Badcock 2000, p.30), a ratio that has not been particularly differentiated in modern humans. Indeed, the research developed in the particular field proved that the size of the brain of modern humans has been increased by approximately 450cc, being expressed rather as ‘compound interest’ (Badcock 2000, p.30) rather than actual increase in the size of human brain. From this point of view also, the role of evolutionary psychology in the explanation of the size of the human brain seems to be unclear. Moreover, the claim of evolutionary psychologists that the human brain is adaptive cannot be considered, by itself, as a convincing argument since adaptation is a process the level of which cannot be precisely estimated (Badcock 2000, p.29); thus, its evaluation is problematic and cannot be used for supporting evolution mostly because the existence and the level of evolution, as described above, cannot be clearly proved. On the other hand, Crawford et al. (1998) note that ‘during the last 2 million years, the size of the human brain has been almost doubled’ (Crawford 1998, p.134), a change which is, however, characterized as rather limited, taking into consideration the claim of the continuous development of biological processes. On the other hand, psychological processes seem to be differentiated quite rapidly in opposition to the biological processes and functions that tend to change quite slow. Thus, evolutionary psychologists could not, at least not easily, develop a convincing argument regarding the increase of the size of human brain. This fact is also revealed in the following case: in the study of Cartwright (2001) reference is made to the view of ‘Geoffrey Miller (2000), a well known evolutionary psychologist at London University’ (Cartwright 2001, p.144). Miller supported that the size of the human brain has been increased as humans have been trying to analyse not just ‘the health, age and social status of their partners but also their cognitive skills’ (Miller 2000, in Cartwright 2001, p.144). In accordance with Miller it is this reason that the size of brain of humans has been increased while that of other ‘hominids’ (Cartwright 2001, p.144) has remained stable, at least as of its size. However, such assumption would be criticized as non-convincing at the following point: why during all these centuries, since the appearance of humans in earth, the size of the brain and the rest biological characteristics of apes (as representatives of hominids) have remained almost intact? And which were the criteria on which a process of change in the size of human brain started? In other words, there are questions that cannot be answered using existing principles of evolutionary psychology and it is for this reason that the arguments of evolutionary psychologists regarding the size of the human brain cannot be considered as convincing. Similar issues appear in regard to the findings of the research of Terrence Deacon; the research of Deacon (as reflected in his studies in 1997 and 1998) is based on the following principle: the brain of the humans and the brain of apes has been increased through the centuries, but this increase has been different; it is explained that the increase of the size of human brain can be characterized as ‘more selective’ (Terrence Deacon in Scher et al. 2003, p.223). Reference is made to certain characteristics of this change, for instance ‘the disproportionate increase of cerebral and cerebellar cortexes’ (Deacon in Scher et al. 2003, p.223-224), a process that has led to the increase of neurons in the brain and the following differentiation of brain functions (Scher et al. 2003, p.224). However, there is no explanation of the exact effects of the increase of the brain size on the brain functions, or of the rate at which these changes have taken place through the centuries. On the other hand, as noted above, evolutionary psychology is mostly related to the functions of the brain and not so much on its organizational characteristics. As a result, the explanation of the increase of the size of the brain cannot justify, without further analysis, the existence of relationship between the size of human brain and the evolutionary psychology. In accordance with French et al. (2001) the inability of evolutionary psychology to explain the size of the human brain is proved through the following fact: evolutionary psychology emphasizes on the importance of social interaction for the increase of the brain (French et al. 2001). This means that in order to understand the rate and the criteria of the increase of the size of human brain, it would be necessary to explore also the criteria under which ‘the size of non-human primates, the apes has been increased’ (French et al. 2001). However, these criteria would be examined by referring to the socialization of humans and apes; in the case of humans, this would be achieved through interviews and similar research tools. In the case of apes, such task would be extremely difficult, living the specific issue unresolved (French et al. 2001). Under these terms, how the evolution regarding the brain size could be evaluated since it would require the examination of the socialization of humans and apes? Any assumptions would refer only to the evolution of the human brain size, a fact that would lead to the rejection of any argument that there is a relationship between humans and non-humans as of their evolution. Moreover, because of the lack of full information in regard to the size of the human brain in terms of its initial forms and origins, any explanation given by evolutionary psychologists regarding the size of human brain would be invalid. At the same time, the empirical research has revealed the existence of differences in the rate of growth of humans compared to chimpanzees (Buss 2005), a fact that justifies the doubt regarding the effectiveness of the evolutionary psychology for explaining the changes in key humans functions and characteristics, such as the size of the human brain. The weakness of the evolutionary psychology to explain the size of the human brain is also reflected at the following fact: in accordance with the evolutionary psychology, ‘our cognitive organization is modular’ (Holcomb 2001, p.357). However, the differences in the human cognitive abilities are important, as noted in the study of Holcomb (2001). In this context, evolutionary psychology cannot offer a clear explanation of all these changes (Holcomb 2001); only estimations can be made regarding the average rate of change of psychological and biological processes. Regarding the size of human brain, no explanations could be given as of its phases of development, especially regarding its functional capacities; this view is in accordance with those of Badcock (2000) and Richardson (2007), as presented above. A different approach for justifying the non-potential of evolutionary psychology to explain the size of human brain is the following one: when tested for its relationship with human behaviour, the human brain is proved to be rather irrelevant. Such example exists in the case of the Williams Syndrome, ‘a genetic disorder that is usually followed by a series of symptoms, including smaller brain’ (Koppl 2005, p.115). It has been proved that the development of this Syndrome is not combined necessarily with changes in human behaviour. In other words, differentiations in the size of human brain, compared to the common size of human brain, are not necessarily related to human behaviour and from this point of view the size of human brain cannot be evaluated using the views of evolutionary psychology (Workman et al. 2004), or at least the explanations given by evolutionary psychologists regarding the size of the human brain cannot be satisfactory. The response of human brain to Williams Syndrome can be further used in order to oppose the view of Miller (2000) as presented above and which is based on the assumption that human behaviour has gradually led to the differentiation of the size of human brain. 3. Conclusion The review of the literature focusing on the use of evolutionary psychology for explaining the size of human brain has led to the following assumption: evolutionary psychology could be possibly used for explaining the changes in the size of human brain but only under the following term: that the relevant views are supported by appropriate explanations on human behaviour. In other words, the biological characteristics of humans, included the size of human brain, cannot be explained without referring to the criteria of human behaviour. In fact, ‘behaviour should be primarily explained and then the biological characteristics could be described’ (Bradley 2005, p.121). The explanation of human characteristics using the evolutionary psychology is biological; for instance when having to answer the question, why the size of the human brain has been increased, the response expected (using the principles of the evolutionary psychology) would be: because of the evolution (Bradley 2005, p.121). However, the explanations given above would be incomplete unless reference is made primary to human behaviour. Moreover, in accordance with the literature, evolutionary psychology focuses rather on the functions of the brain and not so much on its organizational structure. Also, the lack of coherence in the views of evolutionary psychologists regarding the size of the human brain, as reflected in the literature presented above, also proves that the explanations of these psychologists regarding the size of the human brain cannot be convincing; the potential use of additional theories for supporting such explanations cannot be rejected but these theories would have to be evaluated as of their relevance to the specific subject. References Badcock, C. (2000). Evolutionary psychology: a critical introduction. Oxford: Wiley-Blackwell. Bradley, B. (2005). Psychology and experience. Cambridge: Cambridge University Press. Buss, D. (2005). The handbook of evolutionary psychology. Hoboken: John Wiley and Sons. Cartwright, J. (2001). Evolutionary explanations of human behavior. London: Routledge. Crawford, C., Krebs, D. (1998). Handbook of evolutionary psychology: ideas, issues, and applications. London: Routledge. French, J., Kamil, A., Leger, D., Daly, M. (2001). Evolutionary psychology and motivation. Lincoln: University of Nebraska Press. Hampton, S. (2010). Essential Evolutionary Psychology. London: SAGE Publications. Holcomb, H. (2001). Conceptual challenges in evolutionary psychology: innovative research strategies. New York: Springer. Hull, D., Ruse, M. (2007). The Cambridge companion to the philosophy of biology. Cambridge: Cambridge University Press. Koppl, r. (2005). Evolutionary psychology and economic theory. London: Emerald Group Publishing. Morss, J., Stephenson, N., Rappard, J. (2001). Theoretical issues in psychology: proceedings of the International Society for Theoretical Psychology 1999 Conference ????? 8 ??? Biennial Conference of the International Society for Theoretical Psychology Series. New York: Springer. Richardson, R. (2007). Evolutionary psychology as maladapted psychology. Cambridge: MIT Press. Scher, S., Rauscher, F. (2003). Evolutionary psychology: alternative approaches. New York: Springer. Workman, L., Reader, W. (2004). Evolutionary psychology: an introduction. Cambridge: Cambridge University Press. Zilmer, E., Spiers, M., Culbertson, W. (2008). Principles of neuropsychology. Cengage Learning. Read More