Topic 6: Biological Approach {by 12/2}
There is one reading due this week – Text Ch. 5 – Heredity and Personality. Address the following two discussion points: (1) Twin studies are often used to understand the role of nature/nurture on certain personality types. What was one particular twin study you found especially interesting? Explain. (2) Share your thoughts on the concept of gene-environment interaction. Your original post should be posted by the beginning of class 12/2. Have your two replies no later than 12/4. *Please remember to click the “reply” button when posting a reply. This makes it easier for the reader to follow the blog postings.
Dr. Adam M Volungis 
Nov 30, 2015 @ 13:40:08
1. The twin study that I found the most interesting was the one on temperament. Growing up, I had best friends who were identical twins and it was always so strange to me how eerily similar they seemed to be when it came to their emotions. Mischel, Shoda, and Ayduk (2008) define temperament as dispositions that involve your emotionality, sociability, and activity. When they did this study on small children, they used parental reports, and when they did the study on adults they conducted self reports on the individuals themselves. What they found was that temperament was highly correlated in identical twins, which shows that it has a great deal to do with one’s genetic makeup (Mischel et al., 2008). However, they went on to explain that much of the similarity may have to do with the testing itself. Mothers may report that their twins are similar simply because they treat them similar. Mischel et al. (2008) also explained that the set of identical twins may also be treated similar by others in the environment as well. Nevertheless, this twin study helps to show how genes do play a major role in personality development. Going back to my real-life example, I do remember my friends always being dressed the same, having the same things, and also being treated very similar. This could have a lot to do with why their temperament seemed to be very similar as they were growing up.
2. I found the gene-environment interaction section of this chapter very interesting. The controversy of nature vs. nurture is one that has been going on for a very long time, and it makes sense that it is even considered when looking at one’s personality. What I found most interesting about this section, was that even when identical twins, who have the same genetic makeup, grow up in the same shared environment, they still have differences (Mischel et al., 2008). I believe that this just shows that nature and nurture are equally important, and one is not more influential than the other. It was also interesting when they looked at twins who were separated and they found that their personality was only a little less similar to each other (Mischel et al., 2008). This does show that genes play an important role, especially in identical twins, but it also provides evidence for the environment playing a role as well. Other environmental factors play a role in personality development as well, not just the family unit (Mischel et al., 2008). Some examples are peer influences, romantic partners, and even your relationships at your work. It is very important to take into account all aspects of one’s life when you are trying to gain a better understanding of their personality, but it is equally important to remember that their genes do play a role in it as well.
Mischel, W., Shoda, Y., & Ayduk, O. (2008). Introduction to personality: Toward an integrative science of the person (8th ed.). Hoboken, NJ: John Wiley & Sons.
Dec 02, 2015 @ 11:52:00
Marisa,
Your anecdote about your friends who were twins reminded me of my own. I also had two friends that were twins in high school. They were not identical, but the two of them looked very, very similar. People who did not know them well could barely tell them apart. This was also because they talked, laughed, moved, and acted almost identically. They had the same interests, played the same sports, did and said things at the same time. They even went to the same college and majored in the same field. Everything about them was identical, except for the fact that they were fraternal twins. I liked that you brought up the point that it could have been because the mother treated them exactly the same, which now I can reflect back on and see that she did, and that they spent every moment together, making it easy to feel deeply connected to another person. It was clear that many of those instances were biological, from the way they looked to the their athletic and intellectual ability, but much of it was also environmentally based too.
Dec 02, 2015 @ 12:38:14
Another interesting example of how environment is a strong influence, is lack of socialization. In rare case examples are “feral children” .Sometimes, parents don’t want to take care of their children, and instead of giving it up for adoption, or seeking alternative care, the parents will lock up their child in a room and feed it like an animal in a cage. It’s horrific, but it does happen. These children aren’t exposed to any subjected sort of everyday influence. Feral children don’t develop language and are typically malnourished. Without the social interactions that all humans receive, these children are prime examples of how important society can be on humans. This example is also very supportive of the theory of socialization.
Dec 02, 2015 @ 13:18:19
Marisa,
You make an interesting point about the fact that twins that are brought up in the same environment may be treated very similarly by their parents. This is something I would not have really thought about as I often just think about how parents treat each child a little differently. I wonder what it must be like for parents of identical twins. I know that they normally notice differences between the two that people outside the family wouldn’t pick up on. But I also wonder if there would even be any larger differences if they made a concerted effort to treat them differently—the twin reared apart studies seem to suggest that they might still end up pretty similar. I also sometimes think about what it must be like to be the sibling to twins. They usually have a pretty close emotional connection, and if treated so similarly, perhaps another sibling would feel very different or left out?
Dec 04, 2015 @ 12:08:53
Marissa, I think you make a great distinction when you point out the limitations that the researchers indicated in the twin study of temperament. It is difficult to distinguish in the temperament study if the similarities truly had a hereditary link or due to the environmental factor of the mothers treating them similarly. Although you might also consider heredity factors outside of the twin studies. Anecdotally, there are similarities between parent temperament and child temperament.
Dec 04, 2015 @ 18:15:17
Marisa,
I also found the study that you’d mentioned to be interesting, as well. I’ve also been friends with identical twins, but they appeared to be almost complete opposites of each other. I hadn’t met them until they were around 17 years old, and I wonder what environmental changes they each had gone through to turn out so different. One particular twin mentioned that her mother favored her sister more, so I wonder if familial aspects like parental attention played a role in each twin’s personalities.
Dec 04, 2015 @ 22:29:30
Marisa,
Your discussion of that twin study makes me wonder how much one’s appearance affects personality. What I mean is, there is a portion of our personality that is going to have developed based on how people have treated us simply because of the way that we look. In infancy, a child that has bigger eyes, for example, may get more attention, which would help form personality. That being said, I wonder if twins often have similar temperaments because they would have been treated similarly due to having the same appearance. I am sure that this factor influences personality to some degree, I would just be curious to learn how much.
Dec 01, 2015 @ 19:07:32
1. I found the studies of twins that are reared apart very interesting. Twins who grow up in different environments show dramatic similarities in personality and related features (i.e., mannerisms, postures, attitudes, interests, and life histories). The resemblance within identical twin pairs is strongest for general abilities and is less strong for special abilities (Mischel, 2008). Resemblance is somewhat lower for personality inventory scales and lowest for interests, goals, and self-concepts. Bouchard, and Tellegen’s research sampled identical twin pairs reared apart, separated early in life. Many felt close emotional connection even though they spent their entire life apart. Bouchard and his colleague (1990) researched how nature (genetics) and nurture (environment) interplay in developing personality. Our textbook further discusses how personality is partly influenced by genetics, and interacts with and to some degree selects and shapes the situations in his/her psychological life. Mischel described how casual relations go in both directions because those situations over time, in turn, exert their impact on what the person becomes. Identical twins even reared apart may be more alike in how they perceive and interpret their experiences. I find it even more intriguing that they may have been treated more similarly due to their genetically influenced shared characteristics such as their more similar physical appearance, ability skills, and temperaments. Researchers suggest that the environment affects personality when twins are raised apart, but not when they were raise together. Their closeness is partly a strong genetic component bond. Twins separated at birth continued to share not only thoughts, but physical sensations (i.e., personal choice, expressive social behavior (shyness, facial expressions, posture).
2. Heredity is well studied, scientifically proved, personality theories. However, without the help of nurture, it is not accurate. We become who we are, and we act the way we do because we are taught to do so. We are partly what we inherited from our parents, and the environment in which we live in. Personality has been found to have strong biological correlates, and it’s been found that personality traits of the parents can sometimes determine the personality traits of the offspring. For example, there are people with Type A and Type B personalities. Type A is aggressive, outgoing, and stubborn, and Type B is passive, easy-going, and agreeable. If two Type A personalities procreate together, there is a high likelihood that the resulting offspring will also have a Type A personality (supported by numerous twin studies). These studies as we know find two identical twins and place the twins in two completely different environments and study their growth. These twins have been found to be very similar in many aspects that I have discussed above in ques. 1. Socializing factors have completely been taken out of these studies, so the similarities must be biological. Twin studies are by far the best case for nature in the debate of nature versus nurture, because of this complete lack of social factors.
Dec 04, 2015 @ 17:46:18
Heather, the first part of your post got me thinking of the way genetics present themselves in identical twins. You made a point to say how they appear alike, so may be treated in their environment similarly. We learned that people have an effect on the environments (deciding which to enter, behaving within, changing the environment). I think it may be likely that, due to their similar genetics, they effect the environment in a similar way, leading their individual environments to treat them in a (somewhat) similar manner.
Dec 04, 2015 @ 23:48:11
Jason,
I agree that mono-zygote twins are potentially genetically predispose to effect their environment in similar ways, which might compel their environments to respond to them in similar ways. For example some mono-zygote twins raised in different environments can sometimes exhibit genetically determined behaviors that influence their innate selection and attitude to their environment. I attended high school with a set of identical twins and both were aggressive in their interaction with fellow school mates as such they were labelled the “bully twins” and classmates kept limited interaction with them due to their aggressiveness.
Dec 01, 2015 @ 22:39:44
The twin studies on attitudes and beliefs was interesting to me because on a general level I would think that those are aspects of an individual that would be primarily influenced by the environment. It was surprising to note that these studies actually found significant genetic correlations. Personal preferences and beliefs are thought to primarily result from learning and the environment or exposure. It would be interesting to note exactly how genetics plays a role in developing attitudes and beliefs of the heritable type such as music and death. Although, it is important to note that the high heritability rates may not necessarily be attributed to genes but rather similarities that arise between the twins studied (population, geographical sample, racial or ethical sample, cultural sample).
The gene-environment interaction is one of great historical debate and great importance. Previously, it was an either/or issue, which of the two ends influenced an individual. We have gotten to the point where we realize that it is an interaction of the two and you cannot truly have one without the other. Each, genes and environment, play a role in influencing an individual. We are at a point where the search is focused on how they work, the mechanisms by which they influence and how strongly does each end influence.
Dec 02, 2015 @ 11:57:15
Ana,
I enjoyed your point about the gene-environment interaction and how it is a combination of both that makes a person who they are. You cannot have one without the other. For example, if a child is placed in a room with no environmental stimulation, they will not develop the personality characteristics that they would had they been placed in an appropriate environment. That is why I think the study of feral children is so interesting, although tragic in many regards, we have seen how the environment in which the child is placed and grows up in effects the manifestation of their personality and the characteristics that make them who they are.
Dec 02, 2015 @ 12:15:00
I agree,many theorists have believed that either humans are a product of only biology, or that humans are a product of society alone. In my opinion, it seems to me that humans are influenced by society and biology as a combination. Some people may be less influenced by one or the other, but both will have an effect on everyone’s life. One example of socialization is parenting. When two new parents are coming home from the hospital, they have just received a “block of clay” that they will be able to mold. The child will learn many things from its parents through experiences. Family values are influenced by what culture the family is a part of. A child born into a traditional Hmong family will have different values than a child born into a Swedish family. Also, parents help influence what gender roles are “normal”. Parents who paint their daughter’s room pink and buy her dolls are socializing her to be more feminine. Parents who sign their son up for every sport available to them are socializing him to be a manly, sport-playing man. These things are examples of what some parents consider to be gender-appropriate behavior. The research of Albert Bandura illustrated how impactful the example of adults can be on a child by the Bobo Doll experiment. The child is imitating almost exactly what the adult was doing. This experiment illustrates Bandura’s social learning theory, which states that children learn behaviors and language as they are taught by parents, schools, and the media.
Dec 05, 2015 @ 12:55:49
Ana,
I completely agree on your point about the correlation in twins in regards to their attitudes and beliefs. I found it very interesting how such simple things that we don’t even tend to think about on a daily basis can be influenced by our genes. It’s also interesting to note how these correlations may not be because of genetics alone but because of all the other points that you mentioned above. Gene and environment do both play a very important role in the development of one’s personality and I think it’s great that we are finally at a point where it’s not really one or the other. The main focus is now on which one plays a bigger role, and in what aspects it does. Like we discussed in class, even if it seems that there should be similarities between siblings because they grew up in the “same environment” there can be major differences in their individual experiences. I know that this is true in my own family and how we had different experiences within our own family growing up.
Dec 02, 2015 @ 08:19:43
(1) Twin studies are often used to understand the role of nature/nurture on certain personality types. What was one particular twin study you found especially interesting?
I found the study on emotional similarity in twins especially interesting. This is because my personal experience with identical twins as I have two sets in my family lead me to think that there personalities would be different. When looking that the text and seeing that the data suggested different, I was forced to really reset my preconceived notions. It makes sense that those that are raised with the same family and preset biological dispositions would have similar personalities. Especially since their lives are so enmeshed. When looking at the twins in my family, It has always been emphasized that they are individual people and their parents have always tried to promote them exploring different interests and activities.
(2) Share your thoughts on the concept of gene-environment interaction.
This is really in interesting theory. It reminds me of theories like the diathiatsis stress model and the ideas of multifinality. The idea that there are people that are predisposed to certain mental health conditions has been proven over and over again in research. I feel that through environmental influence there is a chance to prevent and minimize effects of biological predispositions. When looking at mental health though, it is important that early intervention takes place. This is due to the fact that individual’s brain development really starts to form major developments in the early childhood. If a person really aims to make the greatest impact the earlier the intervention the better to offset the biological predisposition.
Dec 04, 2015 @ 22:38:52
Brie,
You make a good point that gene-environment interactions that cause maladaptive behaviors and cognitions should be intervened as early as possible, especially for children. I currently work with children in a residential setting, many of which have suffered from abuse and neglect, and every day I wonder how the abuse is going to affect them later in life. It is difficult to imagine experiencing trauma at a time in your life when you may not even be able to put into words what had happened. At that age, gene-environment interactions are going to have a much different effect than at a later age, which is an important thing to note.
Dec 05, 2015 @ 12:56:15
Brie,
I also found the similarity between emotions and temperament to be the most interesting twin study. I also had twins in my life when I was growing up and it was so interesting to see the many things that were so similar about them, right down to some of their mannerisms. The twins that I was close to, were treated very similar, right down to the clothes that they wore. I would be interested to find out if this is why so many of their qualities were the same or if it is influenced more by their genetic makeup. I also really liked how you compared the gene-environment interaction to the diathesis stress model. Being predisposed to certain things because of your gene makeup is such an interesting concept to me. The fact that you could have the predispositions for certain things and then only have these aspects come to the service when you are in a certain environment is something that I found so fascinating. The earlier the intervention in some of these cases the better, as you stated above.
Dec 02, 2015 @ 10:06:10
The twin study I found most interesting was the study examing the differences between children in temperament. These studies observed children in the home and in the laboratory which allowed it to be more accurately generalized. These studies demonstrated the genetic influence of a range of characteristics such as the degree to which a child’s behavior is inhibited, shyness, activity level, and empathy (Mischel, Shoda, & Ayduk, 2008). Additionally, many of these studies were unable to utilize self report because of the young age of the children. Seeings these distinct characteristics at such a young age better demonstrates the genetic influence on certain characteristics.
Just as the environment affects our behavior, our behavior affects the environment. Due to the complexity of the interaction between the expressions of genetic influences and the situations and events an individual experiences it is very difficult to isolate the role genetics versus environmental influences (Mishel et al., 2008). Eventually, their interplay because impossible to separate. While a number of twin studies have demonstrated the integral role genes play in many of an individual’s characteristics it is difficult to ignore the environment when studies have shown twins who were reared apart still show similarities but not as many had they been reared together (Mischel et al., 2008).
An individual’s genetic make-up influences their environment. An individual’s genetic make up influences how people react to and with them. A friendly child is most likely going to be reinforced for their friendliness by having a lot of friends. This will help maintain the genetic factor that makes that individual friendly. Additionally, individuals seek out environments and situations that are congruent to their genetically influenced dispositions. Seeking out and being in these selected environments maintain the already establish genes (Mischel et al., 2008).
Mischel, W., Shoda, Y., & Ayduk, O. (2008). Introduction to personality: Toward an integrative science of the person (8th ed.). Hoboken, NJ: John Wiley & Sons.
Dec 04, 2015 @ 12:20:46
Salome, your response to the gene-environment interaction is very similar to the way I conceptualize reciprocal determinism in social learning theory. Our biological composition does influence our behaviors which do have an effect on the environment and in a feedback loop, the consequences that are elicited from the environment provide us information on our behaviors and we adjust them based on this information loop. Another aspect that you indicated that was interesting is how the environmental consequences can actually influence the genetic makeup of an individual. Your example is good in clarifying the way environment may affect not only our overt behaviors but by reinforcing and these behaviors it may affect he neuronal pathways and reaching another level. The genetic makeup of these pathways may be strengthened by constant use (because the environment strengthens and increases the frequency of the behavior).
Dec 04, 2015 @ 18:21:03
Salome,
I definitely agree that noticing differences among children at a young age does show the genetic influence. Observing differences among children appears to be a more objective way to measure differences among individuals other than self-reports, which have a subjective aspect. I am curious to see how different the findings would be if such children who were observed ended up taking self reports as adults. This may show how their environments changed them in ways, as well.
Dec 02, 2015 @ 11:45:39
Studying twins in terms of personality is one of the best indicators of whether personality characteristics are influenced by genetics or environment. The twin study I enjoyed the most was the one conducted regarding Romantic Love and Marriage. Varying from other results indicating that personality is heavily influenced by genetics, romantic love was found to be more influenced by the environment. As researchers pointed out, the family domain and environment in which the participants grew up in played an important role in love styles and romantic relationships they chose and engaged in. Marriage, however, was found to be more influenced by genetics than the environment. This is interesting because of the many instances where people believed that the sole purpose of finding a partner and being in love was to procreate. Clearly this notion has been given yet another piece of scientific evidence that proves that love and companionship has nothing to do with procreation, but rather, environmental influences that determine what kind of relationship you are looking for.
The gene-environment interaction, or the nature vs nurture debate, has been a long-standing issue in the realm of psychology. The interactions between genetics and the environment that an individual is exposed to from birth are complex and ever changing. However, research has found that the causal relationship goes in both directions. This is to say that genetics has an influence over the environment, and the environment has an influence over genetics; at this time, there is little way to tell which is more prominent, or even if there is a more prominent factor. I believe that there are particular traits and characteristics that people are predetermined to have based upon genetics. Biologically, some individuals may be more susceptible to developing depression or anxiety based upon their chemical and organic make up. This influences how people respond in given situations in their environment. This also works conversely, saying that someone who has the genetic make up to be a strong, ambitious, successful person, may be born into poverty, be given little to no opportunities in life, and not fulfill that true potential based upon the environment. The genetics-environment debate will continue as long as we do not have definitive answers, but I believe that it is much more beneficial for us as psychologists to understand that both play an important role in personality development and manifestation.
Dec 04, 2015 @ 10:04:19
Jillian,
I really enjoyed your read on the twin studies regarding romantic love and marriage. Your point about love and companionship having nothing to do with procreation, but rather, environmental influences is especially interesting. I completely agree with you also, about marriage being more about companionship opposed to procreation. I think this is demonstrated so often nowadays when you see more and more women deciding not to have children after getting married. It makes me wonder if the desire to have children has a genetic influence.
Dec 02, 2015 @ 13:07:36
(1) I found the twin studies in which twins are reared apart to be especially interesting. Specifically, I find it remarkable that researchers are even able to get sample sizes large enough to study when looking for twins who were separated at a young age (on a side note, it also makes me a little sad that so many siblings were separated at birth). I wonder how they were able to find these participants—I don’t know about the laws in Sweden, but I can’t imagine it was easy to find adopted twins in America. However, these studies give unique information that may not be known otherwise. It is especially interesting that many monozygotic twins who were reared in very different environments, and that many felt an emotional connections to their siblings even if they had lived completely separate lives. Many also shared similar mannerisms, postures, attitudes, and interests. This must have been exciting for the researchers working on these large-scale projects to learn. It isn’t surprising to me that they appeared similar physically, but the fact that a significant number of them had the same interests, number of marriages, and habits lends to the role of heredity and genetics in personality development. This doesn’t eliminate the environment as an important influence on an individual’s personality, but gives empirical support to the nature side of the “debate.”
My father and his two siblings were all adopted at young ages. Although they love each other and appear no different than a blood-related family, he and his siblings have incredibly different personalities. Many families with blood-relations have differences in personality, but I do see very few similarities between him and my aunt and uncle. For example, my dad tends to be quiet and very analytical. His sister and her two daughters are the loudest people I have ever met and can be a little impulsive. Also, his sister felt the need to track down her biological parents, but my dad has never had that desire. On the other hand, there are definitely some similarities between my father and his parents and there is no lack of emotional connection.
(2) It is easy to think that similarities in families come from living in the same environment, but the literature suggests a strong genetic influence. Although it can be very hard for parents to admit that they treat their children differently, I think that it’s hard not to. Most parents hope to be fair and don’t want to pick favorites. However, each child has his or her own temperament and the environment and situation changes as each child is born. Therefore, even though there is a shared environment, it is easy to understand how the environment may actually create differences in siblings’ personality rather than similarities. For example, in a lot of ways my first daughter taught me how to do better with taking care of my second daughter. I am a lot less nervous and have learned skills such as how to properly breastfeed, which makes things go a lot more smoothly than with my poor first child. However, there were clear differences in my daughters’ personality from the first moments they were born. My first didn’t want to eat and insisted on sitting up at all times. She was very independent from a very young age and has a strong will. My second didn’t even cry when she was born—she’s very mellow and easygoing. She nursed immediately and nothing has been a challenge for her. It will be interesting to see what similarities and differences develop in their personalities as they get older. I react to how they behave, whether I want to or not. As much as I want to treat them exactly the same, as I think every parent does, I am already acting toward them differently. The best I can do is strive to be fair and not give one an advantage over the other. As they get old enough to go to school and develop relationships outside the family, there will be more environmental influences that shape their personalities. As different things happen within and outside of the family, they will both react to situations in their own way.
Dec 02, 2015 @ 13:17:13
Colleen, your description of how children reared in the same household, and how they are treated differently by their parents, was very insightful. Treating your children differently does not imply favoritism, but individuality. That genetic expressions play a part in this is not surprising after seeing the research. Also I am glad that somebody pointed out the sample size of twins that were reared apart and participated in this study. I can’t imagine how this must have been for the participants, considering the average age of separation was two months old. It is a very sad occurrence.
Dec 04, 2015 @ 12:42:16
It makes me a little sad to when hear about all the siblings, especially twins, who are separated from each other at birth. A close friend of mine was adopted at birth and has grown up as an only child. She developed a relationship with her birth family in her late teens and has discovered many similarities between herself and members of her birth family. I always find those kinds of similarities and differences interesting, so I greatly enjoyed reading the brief differences between your dad and his sister.
Reading the personal insight of your experience with your daughters was a wonderful example of differences in experiences within a “shared” environment. I remember being told as a child that mom and dad try not to play favorites but I will think it they do from time to time. The emphasis was always that the perceived “favoritism” would come around to me in time, as my parents try to fairly divide up their attentions to meet the different needs of my brothers and I.
Dec 02, 2015 @ 13:07:39
(1) Twin studies are often used to understand the role of nature/nurture on certain personality types. What was one particular twin study you found especially interesting? Explain.
The study that I found the most interesting was the study done comparing identical to fraternal twins. This has long been an interest of mine, since I have a fraternal twin brother and two of my very good friends growing up were identical twins. I particularly find interesting the fact that general abilities, and to a lesser extent special abilities, are correlated on the higher end, whether the twins are identical or not. That twins of either sort are able to do the same things while still being different makes sense to me, as I grew up experiencing that. I did think that ideals, goals, and interests would be more strongly correlated for identical twins, especially those that were raised together. The study about twins who were reared apart gives a pretty good glimpse of what part genetics play in this formula, but environment cannot be dismissed as unimportant. Even when raised together, twins are treated differently by their family, friends, and teachers. This is especially true if they are making a conscious effort to be seen as independent. That the individuals may purposefully learn abilities or develop interests in things the other has no interest in must be accounted for.
(2) Share your thoughts on the concept of gene-environment interaction.
This hearkens back to the interactions we have seen between behavior and the environment. The two factors of genes and environment are intrinsically linked. That our genes are expressed in the environment is a constant. How they are expressed is another matter. That the environment around us focuses on or makes more important particular expressions is not surprising. That we then defect the environment to accommodate our particular brand of evolution is also not surprising. This can be seen in any environment that a person will find themselves; social interactions, domiciles, etc. The environments that we choose to enter is influenced by our genetic expressions, or at least our perceptions of them.
Dec 02, 2015 @ 13:25:13
1) The study that I find particularly interesting is the research by Bouchard and Tellegen studying the similarities between twins who were raised separately. I think that this line of research is very interesting and can provide a great deal of insight into what parts of personality are genetically influenced and which are environmental. Despite the incredibly interesting nature of this research, I can’t help but question the results of the research due to the very unclear way that the book reports the findings. The textbook authors use the phrase “there were instances of dramatic psychological similarities within the twins…” to describe the drastic similarities between twins that were raised apart (Mischel, Shoda, & Ayduk, 2008, 106). This focus on the similar cases that were shockingly similar seems to be the focus of the book’s discussion about the research. However, the wording leads me to wonder if these similarities were common amongst the twin pairings or if these referenced cases were rare and being used anecdotally. In the subsequent paragraph, the authors comment briefly on a 70% heredity finding which seems to be very high compared to other research discussed in the chapter in which the influence of heredity hovers around 50%. For these reasons this study raises questions for me that could potentially be alleviated by reading the initial research.
2) I’m was very pleased to see the book address the topic of unique home lives of siblings. It has always seemed, to me, like a fallacy for researchers to assume that because children are raised in the same home that their environment is the same. Although they may be raised in the same home there are many other factors that can determine the environment that each child experiences. For example, the first born child could be born into a more tenuous financial situation than later children however, for a time they have their parents’ undivided attention that later children may not experience. The way that parents treat their children is also not necessarily consistent. Pulling from my own childhood, my mom would regularly say to my sisters and I that we are not all treated the same because we are not the same people and that the way our parents raise us is a reflection of each of our individual personality and needs. It doesn’t sit well with me for many studies to say that because children were raised in the same home they are being reared the same. Factors like parent relationship, financial situations, parent treatment, and the timing of these factors can have a huge impact on the sum environment that the children are raised in. I can understand the argument that certain aspects of family life are the same when the children live together however, to say that the environment is the same doesn’t take into account a myriad of factors that can impact a child’s life.
Dec 04, 2015 @ 10:11:45
Taylor,
I really appreciated your discussion on the fallacy of children raised in the same environment means they have the same experience. I think this is so frequently demonstrated in siblings with polar opposite personalities. My younger brother and I were reared in exactly the same environment, and were inseparable, for the majority of our lives but anyone who has ever met him is shocked to hear we grew up together, let alone are related.
Dec 02, 2015 @ 13:54:39
1. I think it is intriguing to see that there is some possible genetic component to different personality factors, particularly as demonstrated in cases of twins raised apart. The more biologically based factors, such as height and weight, are not as surprising to find strong similarities, but the factors which are thought to be more related to nurture is what is surprising. Independently choosing similar jobs, having the same number of marriages and children, mannerisms, and other preferences seems to show that some things are wired into our DNA. Of course this is not to say that genes and DNA are the absolute main cause of these similarities. As mentioned in our textbook, especially for identical twins, certain physical characteristics could cause the environment to react a certain way leading to the cultivation of certain interests or occupations.
2. As I have already alluded to, I do think that there is a definite gene-environment interaction. Genes are a definitive fact which exists. Packed within DNA and genetic coding is every physical potential for an individual. Genetic coding can be mutated or changed overtime, or particular parts of the code can be activated by some stimuli from the environment. I have several friends who have developed various levels of gluten intolerance. This intolerance laid dormant for years until a triggering event caused just the right about of stress on their body, activating the intolerance which they will now carry for the rest of their lives. One friend in particular developed her gluten intolerance after getting a bit of sand in her eye. The inflammation in her eye caused by the sand activated the intolerance. Before the activating event she had no issues with gluten. Arguably, had the event never happened she might not have developed a gluten intolerance, or perhaps a different event later might have activated that genetic predisposition.
Dec 04, 2015 @ 15:58:40
Erin,
Your comments about genetic influences being instigated by environmental factors reminds me of the Stress Diathesis theory. I have to wonder if the stress diathesis model that can lead to psychopathology is the same mechanism by which many of our personality factors come into being? Both the example that you gave and the stress diathesis suggest that biological vulnerabilities paired with a certain type of environment can lead to a particular outcome. Favorable environments may lead to favorable characteristics being developed while stressfull environments may cause little to no damage or may change the course of someones life depending on the extent of their genetic vulnerability.
Dec 02, 2015 @ 14:36:54
1. There has been a substantial amount of twin studies in recent years, contributing to the field of behavior genetics. One particular twin study I find interesting is the one that was conducted on romantic love and marriage. There is indication that there is genetic influence on personality measures. However, one social area that appears exempt from genetic influence is romantic love (Mischel, Shoda, & Ayduk, 2008). This is shown through a “behavior genetic twin family study”– consisting of twin participants who were married to their spouses for over 12 years— which examined influences of genes and of the environment on the individual differences within styles of love for adults (Mischel et al., 2008). Of all the styles of love— from an individual who cherishes excitement, passion, self-disclosure, being in love from the beginning, and intimacy to an individual who cherishes the affection and close friendship within a relationship— every one was influenced environmentally and not genetically (Mischel et al., 2008). It is believed that such styles of love can be learned through communication with family. What I find even more interesting, however, is the fact that one’s inclination of getting married is impacted by genetics (Mischel et al., 2008). The idea of growing up, graduating college, getting a job, getting married, having kids, and retiring seems to be a culturally influenced lifestyle. Therefore, the findings that one’s tendency to marry has genetic influence is extremely interesting to me.
2. The gene-environment interaction is very interesting because it explains how both environment and genetics affect one’s personality. The interaction between both environment and genetics is illustrated throughout one’s life when one’s personality communicates with and chooses the events or situations that are found in his or her “world.” I appreciate the twin study that Mischel et al. (2008) provided, which consists of disproving the notion that siblings growing up in the same household will turn out very similar for reasons that are environmental. In other words, just because they grew up in the same household does not necessarily mean they had the same experiences (Mischel et al., 2008). Parents may connect better with one child than another, or those who were born before or after their siblings may have different experiences with the family. What was found in such research was that family members are alike especially due to genetic contributors, and the environment makes them unique (Mischel et al., 2008). This emphasizes the impact of environment on personality, which I find intriguing because, often times, I will hear individuals discussing personality as a genetic inheritance, leaving out the idea that perhaps environments that are not extreme play a role.
Mischel, W., Shoda, Y., & Ayduk, O. (2008). Introduction to personality: Toward an integrative science of the person (8th ed.). Hoboken, NJ: John Wiley & Sons.
Dec 02, 2015 @ 14:47:11
1) The twin study that I found most interesting was from Table 5.5, Twin Study Using Self-Report and Peer Ratings of “Big Five” Personality Traits (Mischel, Shoda, & Ayduk, 2008). I like this one in particular because it not only compares identical and fraternal twins based on five personality traits, but also compares their self-ratings to peer ratings. Identical twins have higher correlations than fraternal twins for sure, but additionally, twins appear to be rating their personalities as more highly correlated than their peers are rating them. This seems to be particularly true for identical twins across the board, and for fraternal twins in terms of extraversion and neuroticism. I find this interesting because one would think that outside observers would be more likely to rate twins more similarly, and the twins themselves would be more likely to exaggerate the differences in order to establish individuality, but this research suggests that it may be the opposite. Perhaps their peers, lacking a way to distinguish identical twins using physical characteristics, pay closer attention to the differences in personality.
2) It is difficult to contest the theory that genetics and environment both interact to develop an individual’s personality. Genetics by themselves often offer many answers, but do not reveal the entirety of human psychological development. The same could be said for environment as well. Two individuals could experience the same things, but could develop two different personalities, or two different diagnoses. Conversely, two individuals could have very similar personalities, or very similarly psychiatric symptoms, and could have two completely different sets of experiences. Although research may find consistencies by examining genetics alone, or by examining environment alone, it is the combination of the two that comes the closest to revealing the whole picture.
Dec 04, 2015 @ 16:51:58
Julia,
I agree that it seems pretty obvious to us now that genetics and environment both play an important role in our psychological development. There are many theories that we have learned about in this class that seem to make so much sense, it almost seems silly that they were revolutionary ideas at some time. However, at one point there was a real debate about whether nature or nurture caused differences in personality, just like there were differing ideas about behavior and learning. It makes me wonder what ideas and theories have yet to be discovered in our field and in many others that will someday seem obvious but that we haven’t even thought of yet.
Dec 04, 2015 @ 23:23:02
Colleen,
Since the genome project, research into genetic influence or contribution to certain disorders such as autism, has received lots of attention. One might think of Autism as more genetic than environmental but research shows that a mother’s exposure to environmental agents such as air pollution or pesticides while pregnant is correlated to high susceptibility to having a child diagnosed with autism. I was listening to NPR news and part of the discussion was on scientific research which revealed that scientists are currently researching into treatments aimed at correcting defective genes prenatally but part of the concern, aside on moral grounds, is that they are unsure the effects that these corrections may have on behavior and personality. So I completely agree with you that the field continues to expand in regard to theories and research as well as treatments which may be partially conceptualized now or not.
Dec 02, 2015 @ 15:28:59
In an attempt to understand the role of genes and the environment on the development of personality, twin studies involving genetically identical twins are often used. Twin studies can be quite interesting, especially if the identical twins are raised apart in different households. I found the conclusions of three studies to be quite interesting in their relation to one another. One study conducted by Tesser in 1993 was focused on specific attitudes or values. “He found that the more heritable attitudes were harder to influence and also more important in determining the person’s judgments of interpersonal attraction” (Mischel, 2008, pg. 104). More heritable attitudes included thoughts surrounding things like the death penalty and about jazz music. Another study was conducted to determine the genetic and environmental factors surrounding how people love. “The findings showed that how people love is almost completely due to the environment and essentially unaffected by genetic influences” (Mischel, 2008, pg. 105). On the other hand, another study found that “the tendency to get married is itself genetically influenced” (Mischel, 2008, pg. 106). I find it interesting that some values and attitudes that are influenced by genes are maintained throughout life, while the way in which we choose partners is determined by the environment. In my opinion, values and attitudes can shape the people that we choose as romantic partners. I find it interesting that the way in which we conceptualize how we love people is not influenced by genetic factors, but rather the environment. I am also shocked to learn that although the way in which we love others is environmentally influenced, the tendency to get married is genetically influenced. Taken together, the conclusions from these various studies show how complex the gene-environment interactions are.
Gene-environment interaction is an important concept to consider in the development of personality. I particularly enjoyed how the chapter in the textbook, included the full range of gene-environment interactions, encompassing ideas central to psychology such as the diathesis stress model, and also ideas found in other fields such as epigenetics. For example, the chapter discusses the role of genes, and how they influence the development of certain characteristics, but it also discusses the idea that the environment is unique for each individual, including members of the same family. Family members may share many of the same heritable characteristics, but due to birth order, and different life experiences, they can be quite different. Genes and the environment can also interact with one another to influence a person, for example, a person’s environment can be dependent on a person’s heritable characteristics. A person who is attractive, and outgoing will be treated differently than an individual with different characteristics. Also an outgoing person will choose different environments than an introverted person. To add even more complexity to this concept, there are circumstances in which despite genetic tendencies towards a certain behavior, the environment or the way in which people are raised can cause a person to display different behavior. The main conclusion of the chapter was to focus more on the complexities of the gene-environment interaction and how influential they are, rather than simply debate, which is more influential, genes or the environment.
Dec 04, 2015 @ 16:10:28
Megan,
Your post reminded me of some questions that arose while I was reading the chapter. I thought that it was very interesting that the book mentioned that certain personality traits are more heritable than others, attitudes about the death penalty and jazz music in particular. It would not have occurred to me prior to reading this chapter that attitudes could be heritable. I thought it was very cool that science is able to differentiate these factors from others but I am curious how they go about doing that, it seems like it would be entirely based on environment.
Dec 02, 2015 @ 15:43:28
The twin study that I found most interesting was the longitudinal pioneer study that looked at 800 pairs of adolescent twins. Even more interesting, this study looked at both identical and fraternal twins. This 1976 study, by Loehlin and Nicholas, found that identical twins have the strongest correlation for general ability. Out of the four trait areas that were tested, identical twins showed a higher positive correlation in all four trait areas when compared to fraternal twins. Identical twins were almost twice as likely as fraternal twins to have similar personality scales. I found it especially interesting that in all situations, identical twins show higher positive correlation in comparison to fraternal twin pairs. Growing up, I knew a pair of fraternal twins are seemed similar in just about every way imaginable. While they looked nothing alike, they were clearly cut from the same cloth. They had very similar goals. I found it interesting that there is only .2 correlation for this trait.
The environment-gene interaction is when two different genotypes respond to an environment in different ways. One of the first concepts that I learned in psychology was the nature vs. nurture debate. I find it interesting how our book touches upon the now archaic assumption that one’s environment was primarily responsible for genetic differences between twins. Now it is stated in our text that genetics play a more crucial role. First, researchers have found that twins reared apart are only slightly different in personality than those who grew up together. Secondly, in a study of adopted families that have more than one adopted child, it has been proven that the genetically different children did not tend to have similar personalities. This was despite being raised in the same exact environment.
Dec 02, 2015 @ 15:55:15
To be honest, I enjoyed nearly all the studies quite a bit! I really liked the study that focused on twin temperament differences though. Two of my closest friends are identical twins and even after knowing them for years, I am still often amazed at how similar they really are. Their emotional states, physical states, and how they think and socialize are almost one and the same. In the study, depending on age different methods of data collection were used. For children the parents were involved to help obtain accurate information, where as with adult participants, self reports were used. It was no surprise to see that identical twin temperaments are very similar to each other. While some believe this similarity is due to “nature” factors such as biological components and shared genes, others believe the similarity in temperament is caused by “nurture” and how the children are raised. I personally believe that the high correlation in temperament between twins to be caused by a mixture of these components. This study was also interesting to me because it backed up just how important temperament and disposition are in how personality develops for a person. Overall, these studies really caught my interest and they even made me want to look into twin studies with outside research in the future.
I believe gene environment interaction is definitely apparent. Everyone has genes with DNA codings that define a person physically and in some aspects, mentally. Still though the environment plays a large part in personality. Consider the fact that some people develop asthma later in life due to environmental factors. One could say that if the environment were different these cases of asthma would not develop at all. I understand that this example is not related directly to how personality can be affected by the interaction of genes and the environment but I believe helps to show just how this interaction can work. In one study twins were observed who did not live together and it was found that they were quite dissimilar form each other. The idea that environment affected each twin differently and was influential in their differing personalities seems to quite evident. (Mischel & Shoda,2008). While everyone has different genes, including twins, the similarities between those who live in the same environment are quite interesting to look at especially when considering how environment plays a role in personality development.
Mischel, W., Shoda, Y., & Ayduk, O. (2008). Introduction to personality: Toward an integrative science of the person (8th ed.). Hoboken, NJ: John Wiley & Sons.
Dec 04, 2015 @ 12:56:09
The similarities and differences in temperaments is a really interesting component. I would be more inclined to think of temperaments as being more influenced by genetics, at least initially in life, although both certainly do play a role. It is very important for everyone to not discredit the importance of both nature and nurture. I don’t know that we will ever fully account for every aspect of personality development, but with the twin studies we certainly know more than we would otherwise have known.
Dec 03, 2015 @ 01:01:38
Twins studies are mostly used to understand the nature/nurture discussion and most results have proven quite fascinating. On attitudes, one study sought to determine the heritability of attitudes among twins, as well as the genetic variables, such as intelligence, that could affect attitudes among pairs of twins.The results of the study showed that differences between attitudes of the twin participants were at least partially correlated to genetic factors and also partially related to non-shared environmental factors(Olson et al., 2001). In high school, I knew fraternal twin brothers who expressed aggressive attitudes in interaction with classmates, and they were noted as the bully-twins. In this case, one might question how fraternal twins sharing only half of their genes, exhibit such high aggressive attitudes.
On the gene-environment interaction, one of the questions to ask for example is whether in the development of schizotypical personality disorder, an individual is genetically predisposed, or environmental factors unlock genetic predispositions at a certain time? Obviously, Many human traits and behaviors result from both genetic and environmental factors. Moreover, genetic and environmental influences on a trait are not simply additive. As such, genes interacts with the environments to provide the potential for a trait to be expressed, but environmental conditions can influences the realization of a potential.
Olson, J. M., Vernon, P. A., Harris, J. A., & Jang, K. L. (2001). The heritability of attitudes: A study of twins. Journal of Personality and Social Psychology, 80, 845-860.