User:R.E.Flanagan/sandbox

= Human Mate Choice =

In humans, males and females differ in their strategies to acquire mates and focus on certain qualities. The strategies that each gender uses differs in regards to whether they are long-term or short-term. Human mate choice depends on a variety of factors, such as genes, negative traits, and pathogen stress.

Parasite-Stress on Human Mate Choice
The Parasite-Stress Theory, otherwise known as pathogen stress, is where a parasite or disease stress's the development of organisms, in this case, people, leading to a change in their mate preference and choice. In societies with a high prevalence of parasites or pathogens greater emphasis is placed by the members of that society, on the physical attractiveness/good looks of their mates or potential mates, compared to members of societies with a lower prevalence of parasites or diseases who put less emphasis on physical attractiveness. It indicates that physical attractiveness is a way in which humans can determine resistance to parasites, as it's believed that parasites and diseases would worsen the look of those who are suffering or have suffered from a disease, and would also limit the number of high-quality pathogen-resistant mates.

Hamilton-Zuk Hypothesis
The Hamilton-Zuk hypothesis (see Indicator Traits) has greatly influenced research into human mate choice. It has been found that males of all cultures have been found to rate female attractiveness very highly, but when the risk of parasitic infection was high, males rated female attractiveness as much higher. Cultures where parasitic infection is especially high, members of that society use every cue available to them to determine the physical health status of the potential mate. Regardless of the wealth or ideology, the areas of a society i.e. that are more at risk or have higher rates of parasites and diseases, the females will rate masculinity as higher.

Scarification
Body markings, such as tattoos or scarification, have also been suggested as a way in which can bring the attention of potential mates to the reproductive quality of a person. However, Singh and Bronstad (1997) only found increased pathogen prevalence to predict female stomach scarification and no other anatomical area, with no evidence for males.

Masculinity
In societies where there are high levels of parasites or diseases, the females of that society, as the overall health of its members decreases, increasingly start to place more emphasis on masculinity in their mate preference. In particular, women look for increasing signs of masculinity in areas such as the voice, face and body shape of males. The face, in particular, may hold several cues for parasitic resistance and has been the subject of most attractiveness research.

Polygamy
It was originally believed that polygynous societies were associated with tropical areas and was down to those environments being ecologically richer and homogenous. However, pathogen stress is positively correlated Polygamy, and areas of high parasite-stress in human evolutionary history may have shifted the polygamy threshold and as a result increased polygamy, and certain types of polygamy.

Criticisms
Gangested and Buss (2009) say that whilst research indicates that parasite stress may have only influenced mate choice, females searching for "good genes" which show parasite resistance,in areas which have high prevalence of parasites. John Cartwright also points out that females may be simply avoiding the transmission of parasites to themselves rather than it being them choosing males with good genes and that females look for more than just parasite-resistant genes.

MHC-Correlated with Mate Choice
Major Histocompatibility Complex (MHC) or in humans, Human Leukocyte Antigen (HLA), produce protein products that are essential for the functioning of the immune system. The genes of MHC have extremely high variability, assumed to be a result of frequency-dependent parasite-driven selection and mate choice. This is believed to be so it promotes heterozygosity improving the chances of survival for the offspring and avoid inbreeding.

Odour Preferences
In experiments using rats, MHC-associated mate choice indicated that odour cues played a role. In humans, it has generally been shown that a correlation men and women will rate the opposite genders odour as more pleasant, if the human has MHC-dissimilar antigens to them. However, women on contraceptive pills rate the odour of MHC-similar men as being more pleasant, it is unknown why women on contraceptive pills rate smell in this way. It was found that when processing MHC-similar smells were processed faster.

Facial Preferences
The face preference of humans has shown some correlates with both MHC-similarity and MHC-heterozygosity.

MHC-similarity
Research into MHC-similarity with regards to facial attractiveness is limited, but research so far suggests that women when thinking of long-term relationships will choose males who are MHC-similar.

MHC-heterozygosity
Whilst, facial asymmetry hasn't been correlated with MHC-heterozygosity, the perceived healthiness of skin appears to be. It appears to be that only MHC-heterozygosity, and only MHC-heterozygosity and no other genetic markers are correlated with facial attractiveness in males. as studies show that no correlation has been found in females.