Evolutionary Psychology is the study of characteristics and behaviours, in order ot examine their original function, and understand the processes that caused them to change and develop throughout evolutionary history.
Tooby and Cosmides (1992) define evolutionary psychology as psychology informed by the fact that the inherited structure of the human mind is the product of evolutionary processes. 107
In 1859, Charles Darwin in his book 'On the Origin of the Species.' first proposed the idea of Natural Selection. Darwin espoused that the main mechanism of evolution, involved a process through which those heritable traits passed from parent to child, that increase the likelihood of an animal to survive and reach reproductive age, increase within the population over subsequent generations.
Whilst there is natural variation amongst individuals, and many heritable traits do not affect an individual's ability to survive, there are differences that improve the chances of surviving childhood, reaching adulthood and reproducing. Within any given population, those individuals that possess traits which allow them to successfully compete for resources within their environment, have a greater likelihood of passing those genes through reproduction to the next generation. Similarly, those individuals within a population that do not possess favourable genetic traits, have reduced survival and reproductive success.
Modern Evolutionary theory defines fitness not by how long an organism lives but by how successful it is at reproducing, and through this process, passing on favourable genes, that are more likely to increase their progenies reproductive success. In evolutionary terms the individual alone is of little consequence, as it is not the individual that persists over time but rather the genes (Barrett et al., 2002).
Evolutionary psychologists consider that modern human behaviour has evolved through the process of adaptations. Natural selection has, for millions of years, shaped the human brain, improving human's abilities to cooperate with others, negotiate, understand the needs and emotions of others, and identify healthier mates.
Generation after generation, for millions of years, the process of natural selection has slowly shaped the human brain, favouring abilities that are good at solving the day-to-day problems of our hunter-gatherer ancestors. Problems of finding mates, hunting animals, gathering food, negotiating with friends, defending ourselves against aggression, raising children and choosing a good environment in which to live have all been factors in shaping the evolutionary brain and those individuals who were more successful in this process, who were better at solving these problems were more likely to produce children with similar abilities who would, in turn, produce children with similar traits. It is from these ancestors that modern humans have descended.
In 1871 Darwin published 'The Descent of Man and Selection in Relation to Sex' It applied the concept of natural selection to human evolution and explained the concept of sexual selection and mate choice.
Put simply, the greater the number of mates that an individual has, the greater the number of offspring it produces. However, in humans, where there is a greater parental investment in the offspring, a nine month gestation period and monogamous pair bonding, a higher quality of mate, one who will invest time in caring for the young is advantageous in passing on individual genes.
It is these requirements which humans fundamentally differ from other apes. Whilst males can have a virtually unlimited number of mates, females are limited in the number of offspring they can produce. Female humans can therefore be much more 'choosy' about potential partners, a higher quality of mate will ensure that desirable heritable traits will increase the chances that any offspring survive to reproductive age, and that these traits are passed on, via the genes, to the next generation. Sexual selection in humans takes the form of female mate choice and as such characteristics that females find attractive, are those that are selected for.
Evolutionary psychologists consider that modern human behaviour has evolved through the process of adaptations; these include our abilities to cooperate with others, understand the needs and emotions of others, and inform our preference for healthier mates.
Sexual selection works by the individual differences in physical and psychological traits affecting access to the quantity and quality of mate's available (Gangestad and Thornhill, 1997)
Barrett et al 2002 proposed that that the brain increased in size as it solved more complex social problems and In the 1970's Richard Alexander suggested that the evolutionary reason for the increase in intelligence in human beings was that of sexual competition of humans of the same sex requiring individuals to use increasingly Machiavellian strategies in order to find suitable mates.
It is this 'theory of mind' the ability to anticipate other thoughts, to act deceptively and to empathise which lead to improved reproductive success and that by being able to predict one another's behaviour, two individuals can work together more effectively thereby improving survival chances (Baron-Cohen, 1999). 132.
An individual that has the ability to understand what makes another person 'tick' and can use this ability to modify their behaviour and actions will automatically be in stronger position to obtain scarce resources, to find a high quality mate and help their offspring survive to adulthood. Research carried out on children, those with autistic spectrum disorders and primates have helped evolutionary psychologists develop a greater understanding of what it means to have 'theory of mind' whilst studies in remote communities have found that theory of mind is a common human trait, which suggests that it is an evolved characteristic.
In humans, females choose their mates for all kinds of different heritable traits, not only physical appearance but behavioural traits, intellect and abilities, empathy, creativity and kindness. These particular traits give an indication of a potential mate's ability to get along with others, their health and reproductive potential and their ability to share a productive relationship in order to pass on better genes to their offspring.
In contrast men value physical attractiveness more highly than women and that this is found across cultures (Buss, 1989; Buss and Barnes, 1986; Hatfield and Sprecher, 1995; Li et al., 2002 as cited in TKTK).
In the late 1980's David Buss, a leading evolutionary psychologist, studied mate choice, in throughout different world cultures with different histories, and traditions. In his study the top two most desired traits in every culture was kindness and intelligence. Wealth, status, power and physical appearance were less important. It is these traits of kindness and intelligence that are as valued today as they were in our ancestor's time and it is these traits that attract higher quality mates.
Evolutionary psychology and its emphasis on the function of genes in the evolutionary process is seen by some as reductionist, placing emphasisis on the biology of characteristics and not on the impact that environment and culture can have on an individual's personal choices. Although the theory of natural and sexual selection places an emphasis on the genetic predisposition of individuals to make certain choices, humans do not always act in such a predictable way. Evolutionary psychology charts the changes that have taken place throughout human history in relation to the species as a whole, not at an individual or generational level. It is only by considering these adaptive changes over large periods of time that we may consider how individual behaviours and characteristics have evolved in modern humans.