Genetics+and+Behavior

With reference to relevant research studies, to what extent does genetic inheritance influence behavior? media type="custom" key="23972592" The main techniques used in relation to genetic influences on behaviour are generally twi studies, adoption studies, family studies. Twin studies are the most effective way to demonstrate to what extent genetics are influential in certain aspects of behaviour. Adoption studies take a different approach, they look at how the environment effects behaviour. This is the way to that researchers have used to explain aspects of nature vs nurture.
 * Twin studies
 * Used in genetic research to study the correlation between genetic inheritance and behaviour due to the common genetics shared by twins.
 * Monozygotic twins (MZT) identical - share 100% genetic material.
 * Dizygotic twins (DZT) fraternal - share 50% genetic material.

>> media type="custom" key="24018108" Study 2: Bouchard et al. (1990) - Minnesota Twin Study >>> Strengths:
 * Adoption studies
 * Allow researchers to study the comparison between genetic and environmental influence on behaviour.
 * Adopted children share no genes with their adoptive parents but 50% of genes with their biological parents.
 * Family studies
 * Study behaviour between family members who have similar genetics to different degrees. Inherited factors.
 * Bouchard and McGue (1981)
 * Method:
 * Conducted a meta-analysis – getting data from multiple studies pre-performed.
 * Reviewed 111 studies of intelligence correlations between siblings.
 * Results:
 * The closer the kinship, the higher the correlation for IQ, which supports the influence of genetics on intelligence.
 * 1) Aim: To determine how much of intelligence is attributed to genetics and environment.
 * 2) Method:
 * 3) Longitudinal study
 * 4) Over 100 sets of MZT (monozygotic – identical twins raised together) and DZT (dizygotic – fraternal twins raised together) from around the world who were reared/raised together and apart.
 * 5) Researchers gave them approximately 50 hours of psychological and physiological testing.
 * 6) Results:
 * 7) Similarity rates between MZTs reared apart was approximately 76%
 * 8) Bouchard determined a heritability estimate of 70% of intelligence attributed to genetics, and 30% to other factors.
 * 9) This study relates to the effect of genetics on behaviour as the concordance rate between twins shows that their behaviour was affected mostly (70%) by genetics, rather than the environment, where the other 30% may be attributed to other factors in the surrounding environment
 * 10) Evaluation:

media type="custom" key="24018080"
 * 1) much research has supported his findings, making them more reliable
 * 2) large sample of participants, making the study more externally valid than most twin studies
 * 3) Limitations:
 * 4) Bouchard used media coverage to recruit the sample
 * 5) No control over the frequency of contact between twins before the study
 * 6) Bouchard assumed that the twins reared together experienced the same environment – equal environment assumption

Examine one evolutionary explanation of behaviour. Darwins theory that we all descend from a common ancestor is the basis of evolution. That parent pass down train that give the children the highest possible chance of survival until they are able to reproduce. This is called natural selection, or survival of the fittest. One theory is that disgust is a heritable trait.

__Fessler (2006)__ 
 * Investigated women's experiences of nausea in first trimester of pregnancy (resulting in morning sickness).
 * During the first trimester, hormones suppress the immune system in order to accustom the body to the foreign genetic material growing in the womb.
 * He hypothesised that the heightened sense of disgust experienced by women during this time was the body's way of compensating for the lacking immune system.
 * Participants: 496 healthy pregnant women, ages 18-50.
 * Asked them to consider 32 disgusting scenarios, and rank disgustingness.
 * Women in their first trimester consistently ranked higher than their counterparts in second and third trimesters in terms of disgust-sensitiveness.
 * As many of the most harmful diseases are food-borne, Fessler concluded that a heightened sense of disgust was advantageous to our ancestors and allowed them to survive long enough to produce offspring, who passed on the same sensitivities.
 * It would have helped prevent disease during early pregnancy, which is a risky period due to the suppressed immune system, by increasing the urge to be picky about food.
 * This would diminish the risk of food-borne disease during pregnancy, which is according to the view of disgust as a form of protection against disease.

__Curtis et al. (2004)__ 
 * Investigated whether there were patterns in people's disgust responses.
 * Participants: 77 000 altogether, from 165 different countries.
 * Conducted an Internet based survey in which participants were shown series of 20 photographs, an asked to rank each image for how disgusting it was.
 * There were seven pairs in which one was infectious and a matching image was not (e.g. body fluids, coloured liquid).
 * Those images containing substances that would most strongly harm the immune system were rated highest on disgustingness.
 * Disgust decreased with age and female were more disgusted than males, which supports the idea that disgust is a form of protection to enhance chances of successful reproduction.

There are some points to consider when using evolution-based explanations for behaviour: 
 * 1) It is difficult to test evolution-based theories empirically, so researchers may be susceptible to confirmation bias (finding results that they expect).
 * 2) Very little is known about the behaviour of early //Homo sapiens//, so hypotheses about this are just that - purely hypothetical.
 * 3) Evolutionary arguments can easily underestimate the role of culture and cultural evolution as a factor in the development of human behaviour.

= Discuss ethical considerations in research into genetic influences on behaviour. =

During study participants have the right to know that their confidentiality will be protected, any genetic information obtained throughout the study should be explained to the participant. The aim and the proceedure should be explained and participants need to give their informed connect befer undergoing the study.

Confidentiality and Privacy need to be respected when undergoing any psychological investigation. This protects confidentiality from insurance companies, employers, police but limits ability for follow up investigation.

Genetic research itself can reveal unknown or unexpected information that could be mentally harmfull to participants,like discovery of a genetic disorder, knowledge of misattributed parents or unrevealed adoption.

1. IB, Guides. "With reference to relevant to research studies, to what extent does genetic inheritance influence behaviour.." 2012. .