Unit 2 Short Answers

Describe how molecular genetics affect ONE behavior with reference to ONE research study.

Molecular genetics studies the structure and function of genes at a molecular level. One behavior that molecular genetics affects is alcoholism. To dive deeper, having excess dopamine overall or too much dopamine in some parts of the brain and less in others can affect someone's competitiveness, aggression, and impulse control. This can lead to mental disorders such as ADHD or OCD but it can also lead to addiction. This addiction could be towards anything such as food, alchol, drugs, etc. To conclude, the release of too much dopamine can cause a loss or impulse in control, which can lead to addiction, more specifically alcoholism. One research study that references this is Phillips et al. (1998). The aim of the study was to identify genetic risk factors to alcoholism in mice. The methodology was the studying of the DRD2 gene. The DRD2 gene is related to dopamine. Dopamine is a neurotransmitter that regulates the pleasure and reward system. Knockout mice that were genetically engineered to lack the expression of the DRD2 gene, were compared to normal litter mates, mice who did have the gene. The mice were given the opportunity to drink alcohol. Through this study it was found that the knockout mice showed a natural aversion to alcohol and they drank a very little amount of alchol compared to their littermates. This study shows how molecular genetics affect the behavior of alcholism. Since the mice that lacked the DRD2 gene had a dislike for the alcohol compared to the mice with the gene we can infer that dopamine is the cause for addiction. Since these other mice are finding pleasure in the alcohol dopamine is being released. Which causes an exhilerating effect that rewards and reinforces the mices' behavior.

Evaluate (give the strengths and limitations) the use of animal research in genetics with reference to ONE research study.

The use of animal research in genetics can have many strengths and limitations. Some strengths are that since animals and humans have quite a few genetic similarities, animals can be used in genetic research. ANother strength is that techniques that are considered unethical to use on humans can be used on animals, like brain lesioning, placing them under stress, or genetically engineering them to lack a certain gene, also known as knockouts. The last strength of animal research is that animal research increases the researchers control and it is usually more inexpensive and manageable. One limitation is that it is not guaranteed that findings generalize between animals and humans and there are ethical implications. But it seems like many of the strengths outweigh the limitations so people continue to use animal research. One study that references this is Xu et al. (2015). The aim of this study was to see how depression developed in monkeys in a natural setting. The method consisted of adult female monkeys, some showed depressive symptoms, some socially isolated, and some healthy. Over the course of eight days they were observed. The researcher focused on depressive behaviors such as slumped posture and lessened social interaction. Through this study it was found that depression develops similarly genetically in both macaque monkeys and humans. When the monkeys were stressed they had depressive episodes where they competed for scarce resources and social hierarchy. Through the understanding that animals and humans have a number of genetic similarities, the researcher was able to use monkeys, which are known to be our closest relatives, to further this idea. Since we have the closest common ancestor with monkeys out of every animal they are the most ideal as humans share 90% of their DNA with them. All in all this study showed that the use of animal research can be cruel but it is very beneficial to the understanding of humans' relationship to other species

Describe the use of adoption studies in investigating ONE behavior with the use of ONE research study.

Adoption studies is a tool used to evaluate the genetic and environmental factors in bringing about human characteristics. One behavior that can be investigated through adoption studies is cognitive ability or intelligence. Most existing studies support that IQ is increased by adoption into more prosperous families. But at the same time the same studies show that adopted child-biological parent correlations are always higher than adopted child-adoptive parent correlations, suggesting that the genetic component in cognitive abilities is strong. These two effects suggest the additive influence of genetics and environment in the development ofintelligence. Adopting into a higher SES family results in an increase in IQ, but this increase will be higher or lower depending on the genetic inheritance of the child. Finally researchers use adoption studies to investigate the malleability of cognitive ability. One research study that references this is Kendler et al. The aim of this study was to investigate the additive influence of nurture in relation to IQ. The method consisted of a sample of 436 male sibling pairs aged 18-20 in which one of the siblings was home reared and the other one was adopted away. The IQ scores of the sample was taken from the Military Conscription Register. The data avalable included the educational achievements of both biological and adoptive parents. Once this data was obtained the IQ scores of the home reared and the adoptive siblings were compared. Through this study it was found that the adoptive children had a mean average IQ of 96.9 and shared a 0.20 correlation with their biological parents and a 0.18 correlation with their adoptive eparents. Home reared siblings had an average IQ of 92 and had a correlation of 0.34 with their biological parents. The findings of this study suggest that there is a genetic similarity between sibling pairs but their cognitive ability is environmentally malleable. This study showed that the adoptive sibling had a greater intelligence correlation with their biological parents rather than their adoptive parents despite the fact that they were raised by them, resulting in them developing their daily habits. From this it is easy to conclude that intelligence is genetic despite how a person may be raised.

Describe how evolutionary psychology explains ONE behavior besides mating differences with reference to ONE research study.

Evolutionary psychology is the assumption that the frequencies of genes in a certain species changes over time as generations pass. Genes that are needed to survive are maintained or passed onto the next generation while genes that are not die out. This process is known as natural selection. An example is levels of disgust in humans. The behavior for disgust is evolutionary because at one point in time long ago our ancestors needed to find a way to protect themselves from disease. Due to natural selection the need for humans to protect themselves against the risk of disease passed on through generations. As a result, today humans use disgust as a warning to signal themselves that something they see could be diseased or cause disease to protect themselves from ever interacting with whatever they saw or smelt. One research study that references this is Curtis, Auger and Rabie (2004) The aim of this study was to reason if disgust evolved as a protection from risk to disease according to the criterias that disgust is more strongly felt when faced with a disease-salient stimulus as opposed to a similar stimulus with less salience, disgust operates in a similar way across cultures, disgust is more pronounced in females since they have to protect their babies in addition to themselves, disgust becomesweaker as the individual's reprodouctive potential declines with age, and disgust is stronger in contact with strangers than with close relatives because strangers potentially can carry novel pathogens.The method consisted of a survey placed on the BBC Science website. The survey was advertised in a BBC documentary. Over 77,000 people from 165 countries completed the survey. After this was done the sample size was narrowed down to 40,000 people as all of the participants who had watched the BBC documentary were excluded because they could have been exposed to the hypothesis of the study. First the respondents were asked asked a set of demographic questions on their age, sex, country, and so on. Then they were asked to rate 20 photographs for disgust on a scale from 1 (not disgusting) to 5 (very disgusting). 14 of the photographs comprised 7 pairs of disease-sailent versus less salient stimuli. From this study it was found that first, disease sailent stimuli were rated as more disgusting than less salient ones. For the towel pictures, the organic looking substance produced much higher ratings of disgust than the blue chemical. Second, the results were consistent across cultures. Third, females rated the disease sailent pictures as more disgusting than men. Fourth, there was an age based decline in sensitivity to disease sailent stimuli. Finally, there was a question in the survey that asked participants to choose who they would be least likely to share a toothbrush with. The average responses ranged from the postman (least likely), the boss, the weatherman, a sibling, a best friend, the spouse or partner. This shows that disgust is felt more strongly in contact with strangers than with strangers. All in all the purpose of the study was to find how true the evolutionary explanation of disgust as a response that reduces risk of disease. And the study met all the criteria required for this reasong to be true. So we can conclude that in the past humans needed a way to protect themselves from something that could be diseased. And as many people know humans are prone to curiosity. With the trait is disgust the curiosity to touch or smell something that could be diseased is automatically allimated. So in order for our ancestors to survive they evolved the trait of disgust to protect themselves from the risk of disease.

Describe how evolutionary psychology explains differences in mating behavior between males and females with reference to ONE research study.

Evolutionary psychology is the assumption that the frequencies of genes in a certain species changes over time as generations pass. Genes that are needed to survive are maintained or passed onto the next generation while genes that are not die out. This process is known as natural selection. An example of this is what women and men value in a mate. Both men and women tend to value the same attributes in a mate. Like mutual attraction, dependable character, and emotional stability. But men tend to value physical attractiveness and youth overall as in past generations looking for a mate who had a good physical appearance and were in their prime reproductive age guaranteed the production of a healthy child. While women tend to value ambition and social status above all else as in the past, women who had a mate who was able to support them overall would give the woman confirmation that the child that they produced would grow to be healthy as they are being supported by a man with high social standing and or a man with power.. Due to the selectiveness of evolution (natural selection) this practice of finding a mate passed on through generations. Which is why today men tend to care more about what their partner looks like than their personality or level of smartness and women tend to care less about what their partner looks like and more about their social/financial status. Furthermore rsearchers observe how men and women tend to look for a mate to link it to this evolutionary reasoning. One research study that references how evolutionary psychology explains differences in mating behavior between males and females is Buss et al. (1989) The aim of this study was to investigate the mate preferences of males and females through culture. The method consisted of 10,047 participants from 33 countries from ages 16-28. The participants were asked to rate 18 specific traits from zero to three. Zero being undesirable and three being desirable. They were also asked to rank 13 characteristics from 1-13. Preferences on marriage and biographical information was collected from the participants. The material went through three translations. First in the language of that participant's relevant culture, back into English, and then one last time to fix the differences between the two translations. From this study it was found that in 36 out of the 37 cultures women valued a good financial standing. Males preferred mates who were younger and females preferred mates who were older. Males from 62% of cultures valued chastity. Men from collectivist cultures valued chastity and domestic skills more than men from individualistic cultures. Women from collectivist cultures valued ambition, social status and financial prospects more than women from individualistic cultures. Since it was found that the participants across all of the cultures had similar preferences it can be inferred that the preferences were more biological than cultural. All in all, men and women tend to find particular qualities attractive in a mate because it gives their offspring the highest chance of survival or success in the future.

Describe the extent to which genetics influences intelligence with reference to ONE research study.

Genetics is the study of genes and heredity. Heredity is the transmission of certain traits from parents to their offspring through physical structures called genes. Genes are located on chromosomes. Each sperm and egg contain 23 chromosomes and combine to form pairs. Chromosomes contain DNA and serve as blueprints for building the body and brain. All traits can be seen as a complex interaction between many genes, rather than the product of just one. Being that genes transmit from parents to their offspring it would be easy to assume that genetics influence intelligence. One research study that references this is Scarr & Weinberg (1977). The aim of this study was to determine the contribution of environmental genetic factors to the poor performance of black children on IQ tests as compared to white children. The method consisted of 265 black, white, Asian, indigenous American, and mixed-race children who were adopted by upper-middle-class white families in Minnesota. After being recruited through a newsletter, the IQ of the parents, adopted children, and their biological children was assessed. Through this study it was found that there was no significant difference in IQ scores between the adopted and biological children. The race and age of the children was significant as children who were adopted younger had higher IQ's and black children adopeted into white families had higher IQ's than black children who were home reared. This study shows that intelligence has less to do with genes and more with the race they were and the race of the family that they were being adopted into and the age that they were adopted. This is relevant as children who were adopted at a later age proved to have a lower IQ compared to children who were adopted as babies. When we look at race from the study we can understand that black children who were adopted by white families developed a higher IQ and academic achiechievement compared to black children who were home reared. To further explain, most black people tend to live in smaller, closer communities where there is less oppourtunity for academic excellence. From this we can understand that the black children adopted into white families had more room to grow as they were being exposed to more opportunities here than if they were reared at home. All in all it is easy to assume that genetics influence intelligence but the factor of a change in environment outweighs the idea that genetics influences intelligence completely.

Describe heritability and the use of twin studies with reference to ONE research study.

Heritability is the proportion of total variance in a trait that can be assigned to genetic factors, it tells us how large of an impact nature has in comparison to nurture. Heritability can be determined through twin studies as twin studies evaluate the genetic and environmental influence on a trait using MZ and DZ twin pairs. Monozygotic twins, or identical twins share 100% of the same genes. Dizygotic twins, or fraternal twins share 50% of the same genes. Twin studies usually compare the concordance rates of the two groups. Back on the topic of nature vs nurture, nature attempts to establish whether human behavior is determined primarily by biological factors such as genetics and brain structure. And there are many terms that support this. One is niche-picking. Niche picking is the phenomenon when genetic predisposition causes individuals to select environments that, in turn, start to affect their behavior. This term hints at the fact that what humans' environment is like growing has less to do with their behavior but their genetics do. One research study that references this is Bouchard and McGue (1981). The aim of this study was to investigate between IQ differences and shared gene differences. The method consisted of a meta analysis of 111 studies on IQ correlaitions between relatives. It was found that the median IQ correlations between MZ twins reared together was 0.85 and 0.67 for MZ twins reared apart. DZ twins reared together had a median correlation of 0.58 and siblings reared together had a median correlation of 0.45. In this case MZ twins have a perfect correlation of 1, DZ twins, siblings, and parents with their biological children have the second largest correlation, and adopting parents and offspring have a correlation of zero. All in all the results of the study demonstrate that intelligence is to a large extent (54%) genetically inherited. This supports the idea that yes the way humans grow up can affect their behavior but genetics overrides this. Through this meta-analysis the researcher was able to compare the IQ of relatives and use this data to determine how similar or how different the relatives' IQ's are. Being that the MZ twins were reared together, raised together and they share 100% of genes they had a higher median IQ. Compared to DZ twis, siblings, and parents with their biological siblings only share 50% of their genes. But when we focus on the MZ and DZ twins we can see that they had a higher correlation between twins reared together compared to twins reared apart. All in all twin studies help to determine the heritability of many factors but more specifically intelligence as according to this study intelligence is genetic.

Describe pheromones and their effect on ONE human behavior with reference to ONE research study.

Pheromones are chemicals that carry stimulation. It is a broad term for the chemical communication between the members of a species. It is generally accepted to occur in animals but does it affect humans? This is unknown as humans accessory olfactory bulb regresses after birth and some people do have VNO while others dont. Either way it is still non functional. This is relevant because the accessory olfactory bulb and the VNO is present in animals which allows them to process pheromonal information in the brain. Since most humans lack both, pheromonal information must be processed somewhere else. Although evidence for the influence of pheromones on human behavior is inconclusive, there are still many intriguing findings. Like the finding of human sex pheromones through the release of androstadienone which is the chemical compund found in human sweat. One study that references this is Lundstron and Olsson where the aim was to study the mood of women after being exposed to androstadienone or control solution. In the presence of either a male or female experimenter. The method consisted of 37 heterosexual women with a mean age of twenty five. A male or female experimenter placed cotton wool under the female participant's noses with pheromone (water) or control solution (oil). After being exposed to andistradienone or a control solution in the presence of a male or female experimenter they were assessed. They then answered several questionnaires. Including rating the attractiveness of the males faces, rating their mood, their attention, and their arousal. From this study it was found that androstandienone increased woman's mood in the presence of a male experimenter but had no effect when the experimenter was female. This study supports the idea that the sex pheromones, androstandienone affects womens reaction to men. Furthermore when exposed to androstadienone, estrogen and testosterone is released, affecting sexual attractiveness. This supports the idea that androstadienone serves to signal sexual attractiveness.