Evolutionary Psychology

Evolutionary Psychology
1. Introduction
How do we explain, predict and control human behavior? This question remains a central underlying theme within psychology as a whole. Few specific branches of psychology have attempted to integrate multiple perspectives within their fields of research. Evolutionary psychology appears to be unique in this endeavor, and as the following researchers point out, ?Evolutionary psychology is the long-forestalled scientific attempt to assemble out of the disjointed, fragmentary, and mutually contradictory human disciplines a single, logically integrated research framework for the psychological, social, and behavioural sciences?a framework that not only incorporates the evolutionary sciences on a full and equal basis, but that systematically works out all of the revisions in existing belief and research practice that such a synthesis requires? (Tooby &ump; Cosmides, 2005)
A unification of this type is unquestionably an enormous undertaking, but as the following review ventures, it is likely to be a worthwhile contribution to a number of existing disciplines. 2. Goals and Theoretical Framework
In order to reach any type of conclusion with regard to how much of human behaviour can be explained by an evolutionary psychology framework, it is necessary to understand what the goals of such a subject area are: ?The goal of evolutionary psychology is to study human behaviour as the product of evolved psychological mechanisms that depend on internal and environmental input for their development, activation, and expression in manifest behaviour.? (Buss, et al., 2010)
Like physiology, anatomy and biology, evolutionary psychology examines human behaviour from a Darwinian perspective. That is, like physical traits, psychological traits can be transmitted genetically from parent to offspring. As Darwin proposed, those adaptations and variants that contributed most beneficially to both survival and reproduction of an organism within a given environment would occur in greater frequency in following generations than those that did not, thus resulting in species-typical characteristics (Rossano 2003).
As put forth by researchers Tooby and Cosmides (2005), natural selection of psychological processes occurs through three outcomes: 1) Adaptations, as demonstrated in traits which function to consistently solve specific adaptive problems of survival and reproduction, 2) Byproducts: or those non-functional characteristics which endure as a result of coupling with existing adaptations, and finally 3) Noise, consisting of variability within a particular characteristic which may be the result of a genetic mutation or other random environmental factors.
With this in mind, it appears that evolutionary psychology endeavours to explain the vast majority of human behaviour. However, that is not to say that it is without its limitations in that respect. In the following analysis, I will attempt and overview of some generally established behaviours seen across both human and non-human animals that can explained by evolutionary psychology as having adaptive value, by-product characteristics and noise while also addressing some aspects of human behaviour that evolutionary psychology has difficulty explaining under the current theoretical framework.
3. Adaptations for Survival and Reproduction
One of the main criticisms levelled at evolutionary psychologists is that knowledge of human history is limited, and unknowable. As Tooby and Cosmides (2005) state, ?we can know nothing about the past that is relevant to psychology because behaviour doesn?t fossilize?. This, as the researchers counter, is categorically false. In knowing basic principles of the environment of evolutionary adaptedness, such as a world governed by principles of physics, and through knowledge of necessities for reproductive success (eg., that successful sexual reproduction requires two separate and distinct sexes to occur), behaviour research from an evolutionary psychological point of view certainly has a reasonable and plausible foundation. As pointed out by Tooby and Comsides (2005), knowledge of ancestral hominids abounds. It is known that hominids were sexually dimorphic, omnivorous hunter-gatherers, producing altricial young. They also lived in small cooperative, nomadic, kin-based groups of individuals. Even from this basic information, evolutionary psychologists are able to cultivate and enhance theories of behaviour within these environments.
For instance, an established emotion seen in both human and non-human animals such as fear provides an example of evidence that evolutionary psychology can explain not only the emotion itself, but also those by-product and noise emotions connected to fear that may not be immediately identified as the result of natural selection. Mineka and Ohman (2003) propose a fear module based on research into fear conditioning in humans of snakes and spiders. They found that humans were conditioned much quicker to fear snakes and spiders than other stimuli that would have been in an evolutionary sense, non-threatening. This suggests a certain type of pre-existing adaptive module for fear and survival. In an evolutionary environment, snakes and spiders presented a very real threat to hominids, and to be able to fear these organisms without previous knowledge of their lethal capabilities would be highly adaptive.
In turn, through examination of this single emotion, fear by-products or noise can also be accounted for. For example, those individuals who might acquire a fear of non-poisonous snakes demonstrate an adaptive by-product of fear and individuals who acquire maladaptive fears, or phobias in which they are somehow hindered by otherwise unusual or generally non-threatening stimuli can be said to have acquired noise as a variant of fear because of genetic or developmental factors (Buss, et al., 2010).
This research and analysis provides a large space with which to categorize the emotion fear, and also accounts for those fears we might not directly link to a specific adaptive process, but which are undoubtedly related.
Subsequently, we can see that a large number of adaptive behaviours are classified in this way. Mate selection made by both males and females is also a widely studied behaviour by evolutionary psychologists. Certain regularities with regard to perceived attractiveness of females by males have demonstrated that a woman with a hip-to-waist ratio of roughly 0.7 is the most attractive to males (Rossano 2003). This particular adaptation has been found to positively correlate with female fertility and exposure to estrogen at puberty (Rossano 2003). Consequently, mate selection on the part of males challenged the adaptive problem of reproduction and fertility.
These adaptations are also often coupled with other modules to produce more complex or appropriate responses. As Buss et. al (2005) argue, ?Psychological adaptations are not separate ?modules? in the ... sense of informational encapsulation; rather, they often share components and interact with each other to produce adaptive behaviour?. This contends that mate selection in males is not singularly affected by attractiveness, but also influenced by perceived eagerness on the part of the female, paternity certainty and also the female?s willingness to participate in pair bonding (Rossano 2003). Again, we see that the behaviour encompassed by even something as relatively straightforward as sexual reproduction is highly complex and connected on different levels by multiple selective adaptations. This is seen even without analysis of the other two factors within these adaptations that Tooby and Cosmides (2005) proposed.
Additionally, it is important to note that the above examples continue to fall within Darwin?s theory of natural selection. Both fear and mate selection solve the adaptive problems of survival and reproduction respectively. But how do evolutionary psychologists account for those behaviours which appear to contradict the successful endurance of a species?
4. Limitations in Evolutionary Explanations of Behaviour
While evolutionary psychology appears to explain an abundance of human behaviour, those activities that baffle and mystify evolutionary psychologists are primarily behaviours in which reproductive success or survivability are significantly reduced, and also cannot be explained simply by ?environmentally novel inputs? to produce behaviour (Buss, et al., 2010)
Homosexuality is one example in which reproductive success is completely and utterly negated. The engagement in homosexual activities successfully renders one?s reproductive fitness null so long as the behaviour is practiced. While evolutionary psychology does not shy away from this topic in general, explanations for the persistence of homosexuality seen both historically and currently and are conflicting (Buss, et al., 2010).
Another particularly perplexing behaviour that occurs in humans with alarming frequency is suicide. Survival is most obviously affected in this instance but suicide also indirectly affects future reproductive value. While some evolutionary theorists have formulated basic theories with regard to suicide, such as lack of mating prospects or burdensomeness to kin as a result of age or ill-health (Wakefield, 2005) others argue that it can hardly be stated to be beneficial at any time for an individual to remove both future survival benefits as well as reproductive success for any reason (Buss, et al., 2010). With these two examples, behaviour theories in evolutionary psychology are greatly challenged. However, with a unifying Darwinian foundation, it is much more difficult to see how suicide and homosexuality would solve the adaptive problems of survival and reproduction, or that they could possible solve adaptive problems more important than them. That being said, while current explanations fall short of explaining the evolutionary significance of these two puzzling behaviours, it does not entirely rule out possible future accounts of their evolution.
5. Conclusion
Armed with the above information, it appears as though a large quantity of human behaviour can be explained and analyzed through the lens of evolutionary psychology. In this respect we see that basic emotions such as fear can solve specific survival-related adaptive problems (Mineka &ump; Ohman, 2002), while mate selection coupled with a multitude of other factors can resolve reproductive challenges (Rossano 2003). While both general and over-arching in their nature, they are exemplars in their specific categories, and much research has been devoted studying them. In contrast, those behaviours evolutionary psychology has more difficulty explaining often are those that seem to contradict Darwinian Theory and either significantly reduce or eliminate an organism?s fitness. However, that is not to say such an explanation within evolutionary psychology cannot exist, it merely means a sufficient one does not currently exist.
Undoubtedly, the claim that all human behaviour can be explained by evolutionary psychology in some way is an ambitious one, but that is perhaps because evolutionary psychology attempts an ambitious goal: to unify not only psychological disciplines, but also the anthropological, sociological and biological. With this in mind, it is easier to see how the foregoing conclusion might be possible, probable even. At the very least, it is undeniable that evolutionary psychology provides a foundation with which to explore and interpret human behaviour even in spite of those subjects with which it says little about.

Evolutionary Psychology 7.5 of 10 on the basis of 2315 Review.