What we would like you to do is to
find a topic from this week's chapter that you were interested in and search
the internet for material on that topic.
Please be sure to use at least 3
quality resources. If you use videos, please limit it to one video.
Once you have completed your search
and explorations we would like you to:
1a) State what your topic is.
1b) Discuss how the topic relates to the chapter.
1c) Discuss why you are interested in it.
2) Next, we would like you to take
the information you read or viewed related to your topic, integrate/synthesize
it, and then write about the topic in a knowledgeable manner. By
integrating/synthesizing we mean taking what your read/experienced from the
internet search organize the information into the main themes, issues, info,
examples, etc. about your topic and then write about the topic in your own
words using the information you have about the topic.
3) At the end of your post, please
include working URLs for the three websites. For each
URL you have listed indicate why you chose the site and the extent to which it
contributed to your post.
1a) For this week’s topical blog I decided to do more research on the topic of childhood amnesia.
1b) This topic relates to the chapter because it deals with memory. On page 357 childhood amnesia is mentioned. A sample study by Usher and NEisser is explained and they go on to talk about the age of our first memory, traumatic events, and then another study done by Holbrook and Schindler is mentioned
1c) All of these studies done really fascinated me and I wanted to learn more about the theory, specifically some of the other explanations for it. It is so crazy to me that I can hardly remember anything from my childhood and it is weird that we are structured that way.
2) Childhood amnesia can be defined as an adult’s inability to remember early life events (episodic memories), including their birth. Childhood amnesia (CA) was first reported and published in 1893. A big reason why this occurs is because during the first 1-2 years of our lives our brain structures, specifically the limbic system, are not fully developed so we don’t have as efficient memory storage. When asked to report our first memories, the average age is 3.5 years but it ranges from 2-5 years depending on many different factors; research has shown that there are differences between gender and culture. CA is also really important when considering false memories and brain development.
There are many different proposed explanations as to why CA occurs. Differences in the emotions experienced by infants and adults may be a cause, and also faster retrieval times have an influence too. Also the way our parents talk to us effects it too. For many cultures female daughters have a different relationship with their mothers. Moms are more likely to elaborate and reminisce, but this varies between cultures but these all play a role in emotions too. One interesting theory, which has been heavily criticized for it’s dependence on anecdotal evidence, includes Freud’s trauma theory. This theory says that CA is the result of the mind’s attempt to repress memories of traumatic events that occurred in the psychosexual development of every child. This supposedly led to the repression of a majority of our memories in our first few years of life because we were obsessed with exploring sexulaity. Also it implies that trauma can disrupt the formation of early childhood memories, but does not give evidence for Freud’s theory of repression.
A few differences between gender and culture I found interesting include: females have earlier memories because their mothers are more elaborative, evaluative, and emotional reminiscence with their daughters than with their sons; Women tend to have more information dense memories than men; women refer to others more than themselves in their earliest memories; men are more likely to mention negative memories; girls are more likely to remember traumatic and transitional events; boys more often remember play events; Chinese females had later first memories average age=6 because sons are prized over daughters so the role is reversed; black women have later memories than males.
The two different studies I looked at were very similar to the ones mentioned in the book, it dealt with children and adults reporting on their first memories and the age and then their parents were used to compare. What they found was that younger children’s earliest memories seemed to change, with memories from younger ages being replaced from older ages, but older children became more consistent in their memories as they grew older. All in all our psychological childhood begins much later than our real childhood.
3) http://en.wikipedia.org/wiki/Childhood_amnesia
This website gave a ton of information on the subject, some of which related very well to the direction I wanted to go with this research but some that was a little to in depth that I didn’t care much about. Different topics including the history, methods of retrieval, specific results including memories, fading, differences, implications, explanations, and many other things were discussed.
http://curiosity.discovery.com/question/what-is-childhood-amnesia
This website was very useful in giving a basic definition and then expanding giving an example study done. All of the studies are very similar but this one was interesting because it used 4 different age groups.
http://www.sciencedaily.com/releases/2011/05/110511074803.htm
This website once again gave a very detailed sample study, but then summarized and drew conclusions that made the point hit home and made things make more sense.
Topical Blog Chapter 12
My topic for this week’s blog is Vygotsky’s theory of cognitive development. Chapter 12 of our textbook discusses psychologist Vygotsky’s research on cognitive development. Our textbook shares the significant observations made by Vygotsky and his theories of child language development. I am interested in his theory of cognitive development as he saw cognitive development differently than Piaget. According to our textbook, Vygotsky believed that there was no biological connection to an individual’s cognitive development. Therefore, I want to research Vygotsky’s theory at a deeper level and what he believed about the thought and language in children.
First, Vygotsky believed children’s thinking is affected by their social environment and that language is the most important thing in order to gain this social knowledge. Vygotsky believed children learn from instruction or by a “More Knowledgeable Other” (MKO). An MKO can be a parent or guardian, teacher, mentor, or coach. Further, Vygotsky theorized about a zone of proximal development (ZPD). The ZPD has two levels. Level 1 describes what a child is capable of doing without the help of an MKO or higher authority. Level 2, however, is what a child could be capable of doing with the help from an MKO. The gap between level 1 and level 2 is what Vygotsky described as the ZPD. With the help from another, a child could gain knowledge that is held by the other person. Overall, with the help from others, therefore, having social connections, allows for a child to learn more.
Scaffolding is also a component of Vygotsky’s theory. Scaffolding is known as the instruction a teacher or MKO provides depending on the child’s learning process. The more a child develops an intellectual ability, the less an elder will provide guidance to the child. The nature of the environment in which a child learns will determine how quickly they develop intellectually.
Overall, Vygotsky’s theory is more of an outline of cognitive development as it only emphasizes the social aspects of learning. Until children learn to use mental tools to learn cognitive tasks, learning is largely controlled by their social environment. When reading about Vygotsky’s theory, it seems that children remember something if it has been repeated to them many times. It is the mental tools that Vygotsky does not look at, in which children become in charge of their own learning and abilities.
http://psychohawks.wordpress.com/2010/11/03/theories-of-cognitive-development-lev-vygotsky/
This website discussed the MKO’s and ZPD’s. The website also explained the importance of a positive social environment in which a child can learn and the importance of a mentor that knows when to step in and help a child with their learning abilities.
http://highered.mcgraw-hill.com/sites/0072820144/student_view0/chapter9/
This website discussed scaffolding. It discussed the learning abilities of children and how they learn best. The website also talked about the environment in which a child learns and the rate of development of a child’s intelligence.
http://www.toolsofthemind.org/philosophy/vygotskian-approach/
This website discussed the mental tools of a child’s learning and the vagueness of Vygotsky’s theory. It mentioned that Vygotsky only looks at the social aspects of cognitive development and that it is when children learn to use mental tools that they really prosper intellectually.
I chose to do my blog today on the hemispheric asymmetry reduction in older adults model or HAROLD. I am interested in this topic because it was something I wasn't aware of before reading the chapter and it caught my attention because it involves a shift in how our brains process information. I also wondered if it had any similarities to people who are ambidextrous and utilize both sides of their brains throughout their lives.
The HAROLD model holds that as adults age our brains become less lateralized and our frontal cortexes start working more bilaterally. One study that was done involved 24 subjects between 18-30 years of age and 24 subjects that were between 50-80 years old. They gave them two tasks that were linguistic/semantic tasks. The first task was a picture-naming task and the second was a sentence judgment task. They also did two long-term memory, episodic recognition tasks using the same materials. The hemisphere lateralization was assessed by using statistical lateralization maps (SLMs). Interestingly, in this study they found that when the effects were significant the effects weren't restricted to the prefrontal cortex itself. In young adults, when encoding most use their left hemisphere and recall tends to be right lateralized. In older adults encoding and recall are bilateral. In young adults the left prefrontal cortex was almost twice as big as is right prefrontal activity. As we age, the level of activity in the left prefrontal cortex drops gradually until the brain is bilateral due to the levels of activity evening out.
There doesn't seem to be any information about a similarity with older people's bilateral brains and ambidextria. Instead it just explains that as we age our brains go through some changes. I did not find any information about what parts of the brain aside from the prefrontal cortex, are affected by this bilateralization. This subject is interesting because although I know we are constantly changing, I think it's interesting just how much our bodies will change to make up for any weaknesses. I think HAROLD is similar to brain damage patients. When one area of the brain is damaged our brains make up for that weakness in other areas.
Terminology: hemispheric, asymmetry, ambidextrous, frontal cortex, lateralization, bilateral, linguistic, semantic, picture-naming task, judgment task, LTM, episodic recognition, statistical lateralization maps, prefrontal cortex
Hemispheric Asymmetry Reduction in Older Adults: The HAROLD Model
http://www.ncbi.nlm.nih.gov/pubmed/11931290
This source gave the definition of HAROLD. It gave a nice summary of what hemispheric asymmetry reduction in older adults is.
Reassessing the HAROLD model: Is the hemispheric asymmetry reduction in older adults a special case of compensatory-related utilization of neural circuits?
http://link.springer.com/article/10.1007%2Fs00221-012-3319-x#page-1
This source gave a few good studies and included more details on the HAROLD effect.
Hemispheric Asymmetry Reduction in Older Adults: The HAROLD Model
http://link.springer.com/article/10.1007%2Fs00221-012-3319-x#page-1
This source was written by the neuroscientist that developed the HAROLD model. It went into detail about the model and different effects on people of different age groups.
1a) State what your topic is.
For this week’s exploration blog I decided to do some research on the HAROLD model and hemispheric asymmetry.
1b) Discuss how the topic relates to the chapter.
This chapter discussed cognition across the lifespan, and included a section toward the end about the reduction of hemispheric asymmetry in older adults.
1c) Discuss why you are interested in it.
This is interesting to me because it doesn’t make immediate sense. Also, as we are aware that there is some localization of functions restricted to specific hemispheres, it intrigued me that a brain region not generally involved in a task would be active, as that specific brain region may be associated with other functions.
2) In this week’s chapter, the topic of the HAROLD model was brought up. The HAROLD model (hemispheric asymmetry reduction in older adults) provides a framework for understanding how elderly people often require more brain regions than younger people when performing a task. The HAROLD model, which was proposed by Cabeza in 2002, suggests that old age is simply characterized by a significant reduction in the neurofunctional lateralization of the prefrontal cortex. This was a good model, as it presented evidence that age-related changes in cognitive abilities are the result of age-related changes in the brain. It is limited in one aspect though, and that is that it restricts the reduction of asymmetry to the prefrontal cortex (PFC). A newer model intends to incorporate the evidence for the HAROLD model into a more encompassing CRUNCH model (Compensation-related utilization of neural circuits hypothesis). This model posits that elderly people recruit additional brain regions for more demanding cognitive tasks, and that these brain regions are not necessarily the contralateral equivalents of the previously relied upon brain regions, and they are not restricted to the PFC.
One neuroimaging study assessed the neural activity of 48 participants (24 healthy elderly participants & 24 healthy young control participants) while doing several different cognitive tasks. There was a picture recognition task (PRT), a picture naming task (PNT), a sentence recognition task (SRT), and a sentence judgment task (SJT). The findings of this study were incredibly interesting, albeit somewhat confusing. In the PRT and the PNT, the elderly group showed no significant lateralization of function, whereas with the SRT and the SJT, the elderly group showed the same lateralized network as the young participants (although not as extended). Here is the interesting thing though, in the SRT, SRJ, and PNT, the normal lateralization of function is predominantly with the left hemisphere, whereas the PRT evoked a right-lateralized network of function. This is interesting, because it shows that cognitive decline is not necessarily specific to one hemisphere. This is shown by elderly participants matching the lateralization of some left hemisphere tasks, but not others. However, there was no section of this study where elderly participants matched the lateralization of young participants in a right-hemisphere dominated task, so we cannot rule out that one hemisphere declines faster than the other with age. What is interesting still is that the brain regions that match the lateralization of younger participants in some tasks show no significant functional lateralization in others. For example, in the SRT, elderly participants showed a left lateralization of function in the inferior frontal gyrus, the precentral gryus, the insula, and the middle occipital gyrus. Whereas in the PNT (also a left-lateralized task), the elderly participants showed no lateralization of function in these exact same brain regions.
Another thing that interested me about the reduction of asymmetry in the brain would be the results of activating brain regions that are not generally active. Even if the reduction of asymmetry was restricted to the PFC (which we’ve seen it is not), there would still be implications. Activation in the left PFC is associated with greater positive affect, and warm emotions. Activation of the right PFC is associated with emotions of withdrawal. I would be interested to know (I found nothing about this online) if the reduction of hemispheric asymmetry would require the activation of otherwise inactive brain regions that would affect the individual’s mood without them being aware of a clear reason for the change in mood.
3)
Berlingeri, M., Danelli, L., Bottini, G., Sberna, M., and Paulesu, E. (2012). Reassessing the HAROLD model: is the hemispheric asymmetry reduction in older adults a special case of compensation-related utilization of neural circuits? Experimental Brain Research. Retrieved from: http://link.springer.com/article/10.1007%2Fs00221-012-3319-x/fulltext.html
This link provided me with overall information about the HAROLD model, as well as the alternative CRUNCH model, and included a number of imaging studies assessing the hemispheric asymmetry of young and old participants during various cognitive tasks.
Urry, H.L., Nitschke, J.B., Dolski, I., Jackson, D.C., Dalton, K.M., Mueller, C.J., Rosenkranz, M.A., Ryff, C.D., Singer, B.H., and Davidson, R.J. (2004). Making a life worth living: the neural correlates of well-being. Psychological Science 15 (6): 367-372. Retrieved from: http://pss.sagepub.com/content/15/6/367.full.pdf+html
This link contained a study assessing the hemispheric differences in the Prefrontal Cortex and their effect on emotion.
http://www.brainwellcenter.com/HemisphericSymmetry.html
This link gave me an overview of hemispheric symmetry and led me to various studies and articles regarding the topic.
1. I chose to research childhood amnesia for this weeks topical blog. This week's chapter focused on the development of cognitive abilities. Childhood amnesia relates to the development of memory processes and functioning. Childhood amnesia refers to the forgetting of memories from childhood that during childhood you were once able to remember. I wanted to research this topic because there are many pictures from my childhood of different activities that I would have no recollection of without the stories and pictures that were provide to me. I wanted to understand why it is a common phenomenon to not have memories that are able to be recalled as adults from the first few years of out lives.
2. Childhood amnesia is also known as infantile amnesia. Childhood amnesia refers to the fact that adults often are unable to retrieve episodic memories from their childhood before around the ago of three or four years old. There are two different ways that have been developed to define a person's first memory. One definition the age from which a first memory can be retrieved. The other definition refers to a first memory as the age at which memories change from general memories to more specific autobiographical events.
There are two known categories of theories for childhood amnesia. One group believes that childhood amnesia is caused due to the fact that no memories were actually formed. The other group believes that memories were formed but become inaccessible as a result of cognitive changes. As children of this age our brains are not yet fully developed and changes in the structure and processes that come with development may be the cause of childhood amnesia. It was shown in a study that children twelve years of age and younger were able to describe episodic memories from childhood that adults are not able to recall and describe. This shows that at one point those memories were encoded into memory and so researchers began to focus on reasons that the memories can no longer be recalled as aging continues. Specifically, for the first few years of life the limbic system which is where the hippocampus and amygdala are located is not yet fully developed. These structures are particularly important for memory processing which may be one reason for childhood amnesia. Another possible theory for childhood amnesia is the fact that memories that were encoded before a child developed verbal language abilities encoded memories without the verbal encoding aspect. Once the ability to encode verbal information developed those memories that do not include verbal encoding may become unavailable for recall.
There are certain memories that are more susceptible to forgetting than others. It is shown that earlier memories have less emotional content than later memories which makes them less meaningful. These memories are more easily forgotten. Research has shown that public events are not encoded and remembered until age six. Memories that are salient from early childhood are more likely to be able to be recalled in adulthood.
3. http://en.wikipedia.org/wiki/Childhood_amnesia
This website gave a basic framework of childhood amnesia including what is forgotten, what ages are effected, and the different techniques that are used to study these recalled memories.
https://www.apa.org/science/about/psa/2004/12/bauer.aspx
This website introduced the history of theories for childhood amnesia and the importance that forgetting plays as well as remembering in childhood amnesia.
http://www.psychologytoday.com/blog/the-child-in-time/201012/the-shifting-boundary-childhood-amnesia
This article explained a study focused on the shift of childhood amnesia and what the findings suggest about further forgetting with age of childhood memories.
This week I was interested in learning more about senescence. It’s an interesting topic for me because I’m also taking a biology course. I wanted to research the aging process and how it affects our level of functioning over the years.
Senescence is the aging of living things. It can be viewed at either the celular level or the level of the organism as a whole. At the cellular level, cells age as they divide. The more the divide the less life span they have left. Cells have a protective covering called a telomere. Every time the cell divides the telomere wears away a little bit at a time. When the telomere is completely worn away and the cell is aged the cell knows it’s time to die.
The development of cancer is actually partially caused by a mutation in the cells response to know when it’s time to die. The mutation causes the cell to be able to disregard the telomeres and ignore the signals of when it’s time to die. The cell therefore keeps dividing and begins piling up. There are other mutations also necessary to be present for cancer to develop but one of these mutations directly involves that the cell doesn’t age.
Cells can also undergo senscence prematurely. These cases are really rare but do exist at times in humans. In these cases scientists believe that the telomeres become shortened, meaning they wear away more quickly than they should and signal the cell it’s time to die at a premature time. Science has been working to take what we know about these conditions and use them to battle cancer. Because cancer cells are essentially immortal, if they could be reversed back into dying when they should, we’d have a realistic way to effectively fight cancer. The trick to this, which scientists claim they’re getting closer to figuring out, is how to attack these cancer cells and shorten their life without shortening the life of other healthy cells.
At the level of the organism as a whole senescence does still lead to death. The organisms ability to function normally declines and vulnerability to age-related diseases is increased. However, old age still isn’t viewed as the cause of death because there’s usually other causes that contributed to the death. Senescence often made it easier for these other causes to occur, though.
It’s interesting to learn about aging because we see it around us all the time and will experience ourselves. It’s also interesting to consider the process at the cellular level along with the level of the whole organism.
http://en.wikipedia.org/wiki/Senescence
I liked this link because it had a lot of information on senescence at different levels that I was able to use to describe the process in my post.
http://genesdev.cshlp.org/content/24/22/2463.full
I liked this link because it explained the process more on the cellular level, and helped me to put together information from the other posts to more thoroughly describe that particular level of the process.
https://www.youtube.com/watch?v=Yqs7x3m6I0c
I liked this link because it described cellular senescence in regards to cancer. I was able to connect that information in my post with related information in other links.
I chose to look up the effects of being put in sensory isolation. I chose this topic because in the Environment and Neural Development section it touched a tiny bit on this saying that the environment can affect cognitive and brain development. I am interested in learning different ways that your cognition and brain development can change or react to different isolations.
Sensory isolation or deprivation is where a stimulus is purposely removed from one or more of a person’s senses. When a stimuli is taken away, arousal is high. Short term sensory deprivation is considered to be a type of meditation and relaxing, such as being blind folded for a short amount of time. There are also effects for long term deprivation, which would include: anxiety, hallucinations, bizarre thoughts, and depression. Other effects that this may have on people are vivid fantasies and hallucinations.
Originally these techniques were made for the military to interrogate their prisoners which ended up being ruled as inhumane.
There was a study done where people were put in a completely dark room that was sound proof for 15 minutes. They took a pretest questionnaire that measures the tendencies of healthy people to see things not really there. After they gave them another test they were given a test to measure psychosis-like experiences that were used before on recreational drug users. Out of 19 people in this test, 5 of them reported seeing hallucinations of faces, 6 people seeing face/shapes not there, 4 people seemed to have a higher smell sense, and 2 people felt like there was a “presence of evil” in the room. The rest of the people who were those who scored lower on the first test seemed to not have as many perceptual issues, but did report some delusions and hallucinations.
Flotation tanks are where people are placed in a sound proof area (tank) with salt water and they lay there. The water in the ears or ear plugs blocks out the rest of the sound in the tank. This technique is called Flotation Therapy, and can reduce a person’s stress. Epsom salt and, magnesium sulfate are used, so it has also shown to correct a magnesium deficiency some people may have.
Sensory isolation, neural, cognitive development, delusions, hallucinations,
http://en.wikipedia.org/wiki/Sensory_deprivation
I chose this website, because it told what different sensory deprivations are and also gave a study that was done as well as some back ground to how it started.
http://www.britannica.com/EBchecked/topic/534812/sensosensoryry-deprivation
Told what people can experience when in social isolation.
http://en.wikipedia.org/wiki/Isolation_tank
This website talked about flotation therapy and how sensory isolation can be a form of meditation.
For this week I wanted to talk more about problem solving. I think that this chapter did a good job of expanding off of the last chapter. This chapter was a good expansion because of how it talked more about problem solving. For this weeks topical blog I would like to see if there was some more research about problem solving, and to expand on the topics that the chapter talked about. I want to learn more about creativity, and maybe a little more about cultural blocks. I thought these topics were interesting because they are just other ways for people to problem solve that best fit the situation of the problem. If I learned one thing from this chapter and the last, it was that there are many problem solving styles, and there is one best fit for the situation/problem at hand. I will start my research with just some basic knowledge about problem solving to see if there is more information out there that the chapter did not cover.
The article that I found came from a site that I have found a lot of my research on, and once again it provided me with some useful information. For this article I wanted to find some more information about what problem solving is, and if there was any other information out there that could be useful in my understanding of cognitive psychology. This article broke downs problem solving a lot like the book did. This article went a lot more in depth in the sense of breaking it down into a 7 step cycle that helps in decision making. The basic steps that the article talked about was identifying the problem, solving the problem, organizing materials, allocating resources, maintaining process, and then evaluating the results. I thought that this was a lot like the chapter talked about, but I found out some more information about the topic. I thought that this article was useful and provided some information that I did not get from the chapter.
The next article that I found was about creativity psychology. I had said earlier that I wanted to learn more about creativity problem solving in problem solving because there are many ways to problem solve. I think that there is a prefect way or solution for each problem, and part of the way in getting to that solution is picking the right problem solving technique. This article was actually written be someone who was summarizing a chapter, and it provided some good information. He went on to discuss what the chapter had talked about in the way we creative problem solve. The way the creative process works is that we use a more obscure way of coming to a solution. The way that I best comprehend creativity is that it is a lot like brain storming. It is not as effective as deductive reasoning, but that is just personal opinion. I thought that this article did a good job in providing some new information that was helpful in my understanding of cognitive psychology. There was a lot of information that the book had already talked about, but useful none the less.
The last thing that I wanted to talk about that was in the chapter was on cultural blocks. I found a really cool article on cultural blocks. This article was also very informative in a lot of other areas that the chapter talked about, along with new information that I enjoyed ready about because it related to problem solving. The article talked about cultural blocks as a thing we place on ourselves because of society. What this article did was help me clear up the definition of what a cultural block was. I had thought that a cultural block was a inhibitor between two different groups/races. What this article said was that a cultural block is the refusal to believe that some other person might interpret the same information differently than you. I think that this ties into a lot with ignorance. This article also talked about perceptual blocks, environmental blocks, emotional blocks, and intellectual blocks. I thought that the information on those topics were very interesting, but they got away from cultural blocks which was what I really wanted to research. I think that this article was very useful in my understanding of cognitive psychology along with the cultural blocks that we face in problem solving.
http://psychology.about.com/od/problemsolving/f/problem-solving-steps.htm
This article helped in providing me with background information on problem solving.
http://www.eamonfulcher.com/CogPsych/page8.htm
This article was helpful in my understanding of creativity when it comes to problem solving.
http://http-server.carleton.ca/~gkardos/88403/CREAT/Block4.html
This article had some useful information on cultural blocks, along with some other information on previous chapters.
My topic is infant memory. This topic relates to the chapter because chapter 12 was about cognitive development and cognition throughout the lifespan and infant memory starts in the beginning of life. I am interested in learning about infant memory because I want to know why we don’t have memories of being an infant. We have the cognitive ability to remember things as infants but we do not have any autobiographical memories before a certain point usually around 3-4 years of age.
The inability to remember information from infancy is called “infantile amnesia.” Infantile amnesia is not a result of the inability to form memories in infancy but rather the inability to recall these memories later in life. There are two theories that explain infantile amnesia. One theory suggests that the memories are not transformed into long term memories properly so they are not stored correctly. This is called the storage failure. Storage failure is thought to be a result of the still developing brain. The neural networks are exist in the infant brain but they are not fully functional. More recent research has not supported this theory. Children as young as 2 years of age can recall events after six months or more suggesting that the memory structures are fully functional.
The other theory suggests that the memories are properly stored in long term memory but the memories cannot be recalled. This is called retrieval failure. Retrieval failure may be the result of changing perceptions. Perceptions change as one ages and perceptions might change so drastically that retrieval cues that are associated with early memories no longer exist. The formation of language might also explain retrieval failure. First memories tend to be 3-4 years of age which coincides with language development. This part of the retrieval failure theory suggests that memory recall after infancy relies on language so the memories from infancy are stored in a way that prevents recall.
Infantile amnesia might also be due to neurogenesis in the hippocampus. Research suggests that the formation of new neurons might create new neural pathways as children age that push out the old neural pathways. As the new neural pathways develop, the old neural pathways that were used to store memory are repurposed or no longer exist along with the memories stored in these neural pathways. This helps explain why memories cannot be recalled before 3-4 years of age and why memories from 4-7 are fuzzy. Researchers have tested this theory in mice. Slowing neurogenesis in young mice increased retention of early memories.
http://brainconnection.positscience.com/gone-but-not-forgotten-the-mystery-behind-infant-memories/ This resource explained the term infantile amnesia and different theories about why infantile amnesia exists.
http://www.nimh.nih.gov/about/director/2013/infantile-amnesia.shtml This resource discussed the link between language and infantile amnesia.
http://www.sciencedaily.com/releases/2013/05/130524104634.htm This resource discussed infantile amnesia as a result of neurogenesis.
1a) State what your topic is.
I have chosen to do more research on twin studies. I am also curious how twin studies contribute to the nature vs. nurture debate.
1b) Discuss how the topic relates to the chapter.
Twin studies were mentioned briefly in this chapter so I wanted to go more in depth.
1c) Discuss why you are interested in it.
I am interested in this because I am a twin.
2) Next, we would like you to take the information you read or viewed related to your topic, integrate/synthesize it, and then write about the topic in a knowledgeable manner.
The heritability of human behavioral traits is now well established due to classical twin studies. There is little need for further studies of the heritability of individual traits in behavioral science, but twin studies are still far from having outlived its usefulness. Twins are often used in studies when researching nature and nurture. Some researchers hypothesize that differences between twins must be due to the environment because they share the exact same genes. Fraternal twins also have a role to play even though they don’t share the same genes. By comparing results between fraternal twins and identical twins, researchers have begun to determine the extent that nature or nurture played in any given outcome. The classical twin study design relies on studying twins raised in the same family environments.
Identical twins share all of their genes while fraternal twins share only about half of their genes. If a researcher compares the similarity between sets of identical twins and the similarity between the sets of fraternal twins for a certain trait, then any likeness between the identical twins should be due to genes rather than the environment. The original twin study design has now expanded to include the extended families of the twins, longitudinal studies, and other variations. Some of these limitations allow researchers to address previous limitations, such as the effects of nonrandom mating by including the spouses of twins in the study. Psychologist Dorret Boosma, from the Netherlands says that all of these assumptions can be tested given the proper data and that they should not even be seen as assumptions. She says that they should be seen as mechanisms whose relevance can be tested using study designs that go beyond the classical twin study design.
One experiment I read about had to do with was about triplets and twins being separated at birth. Fifty years ago, psychiatrist Peter Neubauer and psychologist Viola Bernard evaluated twins and triplets who were separated at birth and then given up for adoption. The children were required to participate in a blind study throughout their lives without knowing they had twin siblings. The Psychologists discovered amazing information about what the twins had in common despite being raised in different environments. However, that information is sealed at Yale University until 2066. Until this study, some studies on twins have shown that the nurture and nature argument isn’t an “all or nothing” theory. Each of us is affected by genetic makeup and environment depending on various circumstances. When identical twins are brought up apart from each other, they are more similar to each other than two random people might be. This is because they share some genes but no environment. Further study is still needed on twins and others if we ever want to truly understand what makes us alike and what makes us different. When identical twins are brought up together, only about half of their traits are alike. They have the same genes, the same environment, and the same exposure to peers but still have differences. Obviously, much more is at work than just genes and parenting.
3) At the end of your post, please include working URLs for the three websites. For each URL you have listed indicate why you chose the site and the extent to which it contributed to your post.
http://www.apa.org/monitor/apr04/second.aspx
This source was helpful because it gave me information on the methods and the value of the twin studies.
http://curiosity.discovery.com/question/understanding-nature-nurture-twins
This source was the most helpful because it gave me information on why twin studies are done as well as a little bit of information on an experiment that was performed.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2899491/
I liked this source because it let me know why twin studies are important and why further twin studies are needed.
The topic that I chose to research more this week was childhood amnesia. This is a topic that everyone can relate to, as it is something that everyone experiences. I remember the subject being brought up in my first psychology class ever and my teacher thought it was odd that I could vividly remember things from when I was 3 years old. Maybe that is the reason that I was interested in this topic and chose it this week but regardless of whether that is true, the topic is still a really interesting one and managed to capture my attention from the chapter.
Childhood amnesia is the inability to recall events before the ages of roughly 2-4 years old. It is also referred to as infantile amnesia. The term also applies to the common occurrence of having few memories from up to age of 10 as well. This doesn't mean that children and infants aren't experiencing the world and forming memories during this time however. Children as young as 2 years old are capable of answering questions about recent events that occurred to them. Young children around age 7 or so can recall these earlier memories as well but doing so is often plagued by false memories from the questioner. By the time they are an adult, it is nearly impossible for them to recall memories from their infancy.
Many causes of this phenomenon have been suggested. One such explanation was offered up by Freud, who suggested that it was caused by "the mind’s attempt to repress memories of traumatic events that occurred in the psychosexual development of every child". This theory is fairly unsubstantiated, like much of Freud's work. Another explanation offered involved emotions connected to memories. This theory suggests that memories from older ages are encoded with more vivid emotional experiences and therefore lead to greater recall. A third theory that seems the best to me involves are more biological and specifically neurological approach. This theory suggests that due to the undeveloped nature of the prefrontal cortex and the hippocampus before the ages of 3-4, infants aren't capable of forming stable, long-term autobiographical memories. I also read theories involved with development of a "self" view in infants as well as one that used the development of language to explain the cause of the phenomenon. I still feel that the neurological explanation is the most likely however.
Another interesting thing that I found while reading about this topic was the fact that females tend to have earlier memories than their male counterparts. There also seem to be differences across ethnicities and cultures as well.
All in all, the subject was just as interesting to research as it seemed it would be. I was a bit disappointed that there wasn't a single, unified explanation as to why the phenomenon occurs but I suppose that it is just something to be excited about finding out eventually.
http://en.wikipedia.org/wiki/Childhood_amnesia
Like most weeks, this is where I got most of my information from and what formed the backbone of my research.
http://curiosity.discovery.com/question/what-is-childhood-amnesia
This was also a decent overview of the subject that handled the topic more succinctly than the wikipedia article.
http://www.psychologytoday.com/blog/media-spotlight/201404/exploring-childhood-amnesia
Another article that helped me fact-check the other sources and also provided a better overview of some studies that have been done on the subject.
1a. My topic is senescence, which is the deterioration of various forms of an organism’s functioning through its maturation.
1b. It relates to the chapter because it helps to explain the way and the reason why people and animals deteriorate as they grow older.
1c. It interests me because I have always wondered why it is that some people’s bodies begin to fail before others, and some people’s minds begin to fail before others do. Diseases like Alzheimer’s and ALS have always intrigued me in the way that they can impact the brain while not affecting the body, or vice versa.
In its broadest terms, senescence is just a fancy term for a living thing getting older. It refers to the increasing mortality rate for most organisms that occurs following maturation. Senescence, as mentioned is a broad term, so it can refer to senescence on the cellular level or in terms of an entire organism aging and growing older. It is by and large the leading cause of death in the modern world; age related causes account for roughly two-thirds of all current deaths in the entire world.
One of the articles I researched for this assignment mentioned how some scientists had been doing research with mice where they removed their old, worn-out cells (senescent cells) in order to slow the aging process and help counteract age related diseases like muscle loss, cataracts, etc. It’s not that these were abnormal or mutated cells. Rather a lot of the cells in an organism grow old with age and show signs of deterioration so far as their body will “turn them off” because of bodily concerns that they will lead to cancer or other degenerative diseases. In the mice used in this study, once these cells were “turned off” they led to one of two outcomes; either they would die off or hang around in a state of senescence.
The dying off of these aging, senescence cells is the desired outcome. This is because when they stick around, they start becoming unpredictable and often start distributing fluctuating levels of differing proteins. This hurts the cells around them and is speculated to be the reason for them leading to age-related disorders, as up to 15% of cells in an older organisms body can be made up of these senescent cells. Another article I researched noted that senescence is not only gradual but can also be triggered different kinds of stress stimuli, such as oncogene activation or DNA damage. It is thought that the growing presence of these types of cells is a substantial reason for the fact that not only degenerative diseases but also cancer increase with one’s age.
I found this topic and the wealth of information on them to be very informative. In a way it leads back to the fact that we have become so advanced in our research of not only basic science, but also genetics, cells and all of the above. Our modern medicine is keeping people alive longer, but their older, less adaptive bodies often fall victim to aging disorders or cancers that they could have fought off in their younger years and that are very likely caused by the very fact that their cells are aging and morphing from normal cells into senescence cells. Basically we have advanced modern medicine so far that a lot of people out live or can survive serious disorders even late in life, but eventually old age and its related complications (including senescence cells and their lead to cancer and other diseases) are what ultimately sends one to the undertaker.
http://en.wikipedia.org/wiki/Senescence
This Wikipedia page gave me a lot of the basics behind senescence. It explained the difference between cellular and organismal senescence. I had no idea previously that even accounting for developing and undeveloped countries around two-thirds of all deaths are related to old age.
http://www.livescience.com/16845-longevity-aging-cellular-cleaning.html
This site explained the experiments conducted on mice that showed the fact that when senescence cells are removed from mice it helps to improve the aging process. It also explained the two ways these cells can go once the body recognizes them, either dying off or sticking around in a state of senescent.
http://emboj.embopress.org/content/33/2/99
This article pointed out that although they are typically thought of as the result of aging, senescence is also directly related to stress and can lead to oncogene activation and DNA damage.
1a) State what your topic is.
The HAROLD model or hemispheric asymmetry reduction in older adults.
1b) Discuss how the topic relates to the chapter.
Hemispheric asymmetry was a topic discussed in the chapter that dealt with individuals who many experience head trauma or other various injuries to the head and lose function, however the brain will move the task to another area of the brain. Research has now also shown that a reduction in asymmetry occurs in aging adults to get the most out of what they have left neurologically.
1c) Discuss why you are interested in it.
I was first interested in doing my blog on dementia, then I stumbled across the HAROLD model and was intrigued. I read into it a little more and discovered there have been numerous studies that have proved hemispheric asymmetry is reduced in aging adults. What interested me more as I read was that it suggested a new possibility for brain plasticity and younger adults could also learn to do it.
2)
The HAROLD model (Hemispheric Asymmetry Reduction in Older Adults) refers to the phenomenon that brain activation during cognitive performance tends to be less asymmetrical in older adults than in younger adults. Since the proposal of the model several studies have been produced. In the recent years, a series of studies have provided considerable evidence in support of the model from different fields such as memory, inhibition, language, sense-motor process and brain structure. However, it is suggested that HAROLD is a task-specific model and that other hypotheses offer an explanation for the age-related differences in functional brain imaging. Successful cognitive aging means that we can make the best use of our brains, however large or small it might be. Another theory that was discussed which goes right along with HAROLD is the scaffolding theory, people can build upon their existing brain structures to put them to peak use. If one brain region is lagging behind, another can chime in and help make up for it. This concept takes plasticity to new heights, not only would you be able to build more onto your existing neurons, but you would be able to switch out one brain region to compensate for losses in another. Yet another form of brain switching recently discovered is called the Posterior–Anterior Shift with Aging (PASA) in this shift the frontal lobes take up the extra work when the posterior lobes are not unable to carry out their tasks. While the plasticity model does evidence to back it up for many years, proponents of the plasticity model of brain aging have been fighting with the neural fallout advocates. The fallout supporters point to the loss of neurons and synapses that occurs over the lifespan. The plasticity side points to research showing that the remaining neurons never stop, they continue developing new connections and maintaining the overall balance of brain resources, basically the brain learns to work with what it’s got. Fortunately even if you don’t believe the plasticity model there are ways to build your brain muscle. One way is to exercise normally, brain seems to benefit from a workout that makes you sweat as much as does your heart. Watching what you eat can also help build your brain, we have known for years that foods high in omega-3, such as salmon, are essentially brain food. Also good for your brain are flavonoids, which can be found in foods like fruits, vegetables, red wine and dark chocolate.
3) https://web.duke.edu/cabezalab/pdf/02HAROLD.pdf
This was a useful website because it is the entire study that Roberto Cabeza conducted, I used many of his models to conceptualize the model.
http://www.psychologytoday.com/blog/fulfillment-any-age/201303/successful-brain-aging-is-bigger-always-better
This article was very useful because it spoke about the HAROLD model as well as other brain aging theories.
http://www.psychologytoday.com/blog/fulfillment-any-age/201004/building-better-brain-strengthening-your-mental-muscle
This article was useful to because it gave a lot of background about the scaffolding theory of brain building and also a lot of good insight to maintaining a healthy brain.
Chapter 12 Topical Blog
The topic that I chose to learn more about is the topic of gerontology and geriatrics. Gerontology is the study of aging. And geriatrics is the study of disease due to aging. These concepts relate to the chapter because chapter 12 is all about cognitive abilities throughout the lifespan. The chapter talks about how we develop cognitively from birth to death. At the end of the chapter there is information of gerontology and geriatrics. I am interested in this topic because I only have one grandparent left in my life. My grandmother that is still living is showing signs of dementia and Alzheimer’s disease. I would like to learn more about this topic so that I can more effectively communicate with her when I go home. She rarely can recall who I am and what relation I have to her. And sometimes she doesn’t remember my aunts and uncles either. This is something that my family has been struggling with, so I would like to me more informed on the topic.
Dementia is the most common form of Alzheimer’s disease. When a person has dementia, they are said to have severe memory loss. Alzheimer’s disease accounts for 60-80 percent of dementia cases. Dementia is one of the most severe symptoms of Alzheimer’s disease. One of the main things to remember with Alzheimer’s is that just because someone’s memory is getting worse, doesn’t mean they have the disease. When someone has memory loss that starts to disrupt their everyday life - that is when you should be worried. A person with dementia might also experience difficulty planning or problem solving, difficulty completing at home tasks, trouble with time or place, difficulty with visual perception, new problems with speaking or writing, losing the ability to retrace steps (misplacing objects), poor judgment, withdrawal from social functions, or changes in mood or personality. Once a person starts to experience all of these, it is more likely that they have dementia or Alzheimer’s disease.
What I am mainly interested in is how to lessen the effects of dementia and Alzheimer’s disease. I have found that there is no cure. Dementia is something that takes over someone’s brain, and there is no way to cure that. There are ways to make it easier on the person with dementia and the family of the person though. The main thing for family members to remember is that this person is not acting different on purpose. Their brain functions are slowly deteriorating, and that is going to cause stress on the person and everyone involved. People with dementia sometimes will act out. They will become anxious, or maybe even angry. When the person acts out, it is important to not take this personally. You much learn to stay calm, even when the person with dementia is not. You must also learn to redirect the person’s attention to a more calming relaxed stimulus. It would also help to keep in mind what sets this person off and trying to avoid that.
A person with dementia will also wander. The person might pace or walk around aimlessly because they are experiencing a heightened state of confusion. For some with dementia, this is a way of showing that they are essentially “looking” for something that they need. In order to avoid or decrease wandering, you must make sure that this person’s needs are met. Make sure they are fed properly and that they are getting enough rest. Some people might even suggest that you sort or child proof your house.
One of the most interesting things I found was information on what to do when the dementia patient gets agitated or stressed. There are many things that can be done – ranging from the way you talk to the person to what their environment looks and sounds like. The most interesting thing to me was using music to relieve stress. During times that may be especially stressful, the person should try humming a simple tune. When singing or playing a song that is familiar to this person, you may notice changes in facial expression, increased eye contact, vocal activity, and movement. This was very interesting to me because I have witnessed this first hand. When my grandma first started showing signs of dementia, we would always take her to my brother’s jazz band concerts. Sometimes she would be confused, but once the jazz music started, she just couldn’t stop moving her feet. I have never related her frequent humming, and her love of music to her dementia. But I think this would be really good for my family and I to remember when she starts to get anxious and stressed out.
Since there is no way to cure dementia, we need to look at other solutions. I have already discussed how to cope with dementia and make it an easier transition on the person and the people surrounding the person. But now I want to look into how to prevent dementia. Since there is no cure, we might as well learn how to be proactive about it. The main thing that I have found is this: “if it is good for your heart, it is good for your brain.” I like how they summed that up into one sentence. So what this means is that in order to prevent and be proactive about Alzheimer’s and dementia, we need to be healthier. It is suggested that people should start by not smoking, being physically active, being mentally active, and treat and prevent chronic diseases (high blood pressure, high cholesterol, diabetes, obesity, etc.). Studies have found that Alzheimer’s disease is more common is those who have certain cardiovascular problems. So literally – if it is good for your heart, it is good for your brain.
URLs:
http://www.alz.org/alzheimers_disease_10_signs_of_alzheimers.asp#signs
There was a lot of good information on the signs and symptoms of dementia and Alzheimer’s disease. There was also a chart that compares symptoms of Alzheimer’s to symptoms of someone who is merely aging.
http://www.geronguide.com/gg/How+to+Improve+the+Quality+of+Life+of+an+Elder+with+Dementia
This website had a ton of advice on what to do to help out someone with dementia. Sometimes the person will act out and feel anxious. And there are tips as to what you can do to make it easier on them, and everyone around them.
http://www.medicalnewstoday.com/articles/263769.php
Since there is no cure for Alzheimer’s disease and dementia, we must figure out ways to be proactive about preventing it. This website contains a lot of simple, healthy ways to prevent a person from getting Alzheimer’s disease.
Terms: Gerontology, Geriatrics, Cognitive
1a. My topic is intelligence, and if it is possible to increase it.
1b. This topic relates to the chapter because the book talked about how our intelligence develops throughout the lifespan and it made the case that our intelligence is largely biologically determined.
1c. I am interested in this topic because if our intelligence is largely predetermined through our genes than I wanted to explore if there were any ways in which we could increase our intelligence at all. Is it really so fixed or can we become more intelligent through some environmental mean?
2.Many researchers have deemed Intelligence as many different things. Intelligence has been linked to our logic, abstract thought, perception, understanding, self-awareness, communication, learning, and problem solving, and memory. Intelligence seems to be wide in scope and encompasses a large array of our cognitive ability. It has been found that intelligence is highly heritable, that is that the majority of our IQ comes from our parents. There have been studies shown that adopted children are very close in intelligence to their birth parents rather than their adoptive parents. But, does the environment have any effect on our intelligence and is there any way that our intelligence can be further increased? Our IQ is very stable trait across time with a 95% confidence level from when we test on an IQ quotient, that leaves room for a plus or minus 5 or 6 point spread from the score you test at. This shows that there is room in certain areas for improvement, which have been seen and tested with neuroplasticity type games which help the brain stay sharp in areas like problem solving and attention. There are two types of intelligence; Fluid intelligence is the ability to reason in abstract ways and solve problems. This ability seems to decrease as we get into old age. This is the type of intelligence we can supposedly work on and improve. The other type of intelligence is deemed crystallized intelligence, and this is the acquisition of intellectual skills such as reading comprehension; this type of intelligence stays relatively stable over time. So rather than saying that we can increase our intelligence in any one way, what is really being done is working on making our brain function better. With neural plasticity games, and different teaching methods we can fine tune our neural functioning to perform at our biologically determined highest rate of intellectual performance. There is also another realm of study which I read up on and that is linked increasing our cognitive abilities, and that is the realm of pharmacology. Specifically, I read up on how certain stimulant medications in small doses can increase working memory, and attentional aspects which translated into better intellectual cognitive functioning, but this is essentially a “fake” boost in performance which fades over time.
http://www.livescience.com/36143-iq-change-time.html
This website helped in that it gave 5 differing opinions from experts on if and how we could increase our intelligence.
http://en.wikipedia.org/wiki/Intelligence
This website was very helpful because it gave several definitions of what intelligence has been thought of to include. I really had no clue there were so many ways intelligence has been defined.
http://www.psychologicalscience.org/index.php/publications/observer/2011/july-august-11/improving-intelligence.html
This website was helpful in that it explored different means in which we improve our intelligence. The pharmacological way in which we can improve our cognitive functioning was particularly interesting.
This week I decided to look into what makes up intelligence. This was talked about in the chapter this week along with twin studies and the heredity of intelligence. I wanted to look further into this in order to try to find our more about intelligence and if there are ways to increase or decrease it.
Intelligence is defined by intellectual functioning. IQ tests allow you to measure your intelligence and compare it with others. Intelligence is something that is consistent throughout life. While you may learn more and more as you grow, your IQ stays about the same. While there is no exact standard for intelligence, there are several theories of intelligence.
General theory states that people who perform well on one aptitude test likely perform well on another. This was noticed by Charles Spearman and the pattern caused him to conclude that intelligence is a general cognitive ability that can be measured and expressed using a number. Another popular theory was the theory of primary mental abilities by Louis Thurstone. Thurstone believed that intelligence was not one set ability. He ended up categorizing intelligence into multiple abilities such as verbal comprehension, reasoning, perceptual speed, and more. Howard Gardner believed there were multiple abilities or intelligences, but he also believed that they should not be represented by a number. This caused the multiple intelligences theory to emerge. This theory looks at eight different intelligence scores that vary based on what the culture requires. A final theory is Robert Sternberg's triarchic theory of intelligence. This theory states that intelligence is based on adaption and selection towards real life abilities and skills. It is also broken down into analytical intelligence, creative intelligence, and practical intelligence.
In current times, intelligence is defined by perception, self-awareness, consciousness, and volition. There are many things that are correlated to intelligence, both positively and negatively. An increased birthweight has been linked to increased intelligence, for example, while sexual activity has been negatively linked to intelligence.
There have been many attempts throughout history to improve the overall level of intelligence of a society. One of the goals of the eugenics movement, for example, was to stop the reproduction of unintelligent people. This would have allowed only intelligent people to pass on their genes, increasing the rate of intelligence in society. There has also been research that shows that it is possible to enhance intelligence using genetic engineering. This has been shown to work with rats, but has not been tested in humans.
http://psychology.about.com/od/cognitivepsychology/p/intelligence.htm
This website gave me information about the theories of intelligence
http://en.wikipedia.org/wiki/Human_intelligence
This website told me about attempts to improve intelligence
http://en.wikipedia.org/wiki/Intelligence_quotient
This website gave me background info on IQ tests
This week I decided to do some research regarding aging. As I surfed the internet, I encountered many myths people have of aging. I want to narrow down my search so I will focus on the myths of aging.
Aging is a process of growing old. Everyone grows old and the experiences can be very different. Some retire and travel the world while feeling like teenagers, but some lose mental alertness and become more and more confused overtime. There are many myths regarding aging: people have some certain expectation, mostly negative, related to aging. Most people are scared of growing old and becoming wrinkly. However, it is not as bad as people make it seem.
Aging does not mean that you will feel old. Research has shown that as people grow older, they feel younger. The gap between the actual age and how old people feel gets larger overtime, and people fifty years of age or above generally feel 10 to 19 years younger, which is rather surprising considering how many people around us keep complaining that they feel old. There are two types of age, one is the chronological age, which is the one stated on your identifications; the other one is biological age, which indicate how well you are functioning. Biological age is calculated based on indications from blood pressure to body fat. A young teenager can have a biological age of 80, while an old man can have the biological age of a middle age, working man. Therefore, it is possible that you feel, and actually are, younger or older than your actual age, calculated by the birthdate on your birth certificate.
Another myth regarding aging is that brain will deteriorate as you get older. It can be true, however, it does not mean that you will lose more brain cells and those you lost will be gone forever. Research shows that some areas in the brain still continue to produce new cells every day. Therefore, while it is certain that you lose brain cells over time, you are gaining more every day. The best way to ensure you gain brain cells is to keep your brain active, by discovering new activities to do or learn a new language. Also, most disease related gene mutations are influenced by life styles, not genetics. The quality of sleep, the food you eat, and stress level can have an impact on your mental alertness.
http://www.nia.nih.gov/health/publication/aging-under-microscope/what-aging
This website provides great details regarding aging
http://www.huffingtonpost.com/2012/06/22/aging-myths_n_1592990.html
This slideshow gives me a good picture of the most popular myths regarding aging
http://www.nextavenue.org/article/2014-02/6-aging-myths-we-need-stop-believing
This website is less detailed than the previous two, but it is still a good source.
Childhood amnesia is where you can’t remember things before the age of 2-4, or having very few memories before 10.This doesn't mean that children aren’t making memories it’s just hard for them to recall them later. Even at age 7 kids still can remember some stuff but they are easily influenced by the one asking the questions and false memories are then made. And then as you get older it gets harder to go back and grab those memories. It think that its just because you have so much more stuff stuffed in your head. Researches have many reasons for why this happens, let’s take a look at Freud he claimed that it was the minds way of suppressing memories of bad experiences that happened in the psychosexual stages of development. Most people don’t think that this is the case though, poor Freud he was just trying to make answers when there was none. Another explanation is that emotions are connected to memories. This theory suggests that memories from older ages are connected with more emotional experiences and make it easier to remember that stuff. Then you got the theory that is more in the biological realm of things which if you are on the more science side of things makes sense. It states that sense the brain isn’t fully developed kids under the age of 4 or so aren’t capable of making long term memories and also sense there isn’t any language going on at that time there is no link to explain what you are seeing and that can hinder your memory. You can’t explain what happened if it is stored with scribbles.
http://en.wikipedia.org/wiki/Childhood_amnesia
http://curiosity.discovery.com/question/what-is-childhood-amnesia