今天是個躺在床上喝水吃喉糖的一天。
不過我發現一個很棒的Podcast網站，叫Library of Economics and Liberty. 我還沒有逛完全部的網站，但是它有一區叫Econtalk，是由一位經濟學教授訪問不同觀點的經濟學家，探討現今的經濟問題。現在經濟不景氣，到底政府給消費卷有沒有用，背後的機制是什麼? 又或者是大家到底要多消費刺激經濟還是多存錢投資未來? 我今天聽了一段談「凱因斯理論」的對話，就是針對上面那些問題做討論，非常有趣。
Showing posts with label Nerdy Stuff. Show all posts
Showing posts with label Nerdy Stuff. Show all posts
Tuesday, February 03, 2009
Friday, April 21, 2006
some thoughts on second language acquistion
L1 Tansfer, Phonological Working Memory in Predicting L2A, and Lingusitic Knowledge in General"
I have been reading some language acquistion articles about the concept of "working memory". The definition of this term by different people is a chaos, which I don't intend to tackle. But they all point to similar directions:
First, one's native language ability, whether literacy, or some kinda linguistic knowledge (e.g. vacabulary, the "legal" combination of phonemes in a word", reading or listening comeprehension) will affect his/her learning a foreign language.
Specifically, if this ability is tested under a short-term memory based test, (like a reading span test, listening span test, or word digit test in which the subjects were asked to recall words, answer comprehension questions, etc.) the test result usually correlates with one's performance on foreign language learning. It might look obvious to link these working memory tasks to linguistic performance because the these working memory tasks are designed to tesk some parts of one's language ability, and is done through the medium of language. Therefore, if one has high literacy/reading comprehension in L1, they tend to have better performance on L2 than those with low performance on literacy/reading comprehension/working memory tests.
Second, the short-term memory performance can be disrrupted, or inhanced with different techniques. For example, making the subject tap the table while listening or reading to learn a new foreign vocabulary can intervene subjects' learning. On the contrary, if the subjects read outloud the foreign words, they can remember more than just reading the words silently. To strech further from the working memory tasks themselves, some study found "noticing" has some correlation with high/low working memory capacity.
If I were to put a conclusion from what I have read, it seemed that linguistic knowledge, whether first or second language, has such an interrelated relationship. This is obvious through our world experiences, because we can easily find your L1 transfer, whether negative or positive, is affecting one's foreign language learning. We all draw references from something we already knew. But this interconnected linguistic knowledge still puzzles me. What would be the representaion of linguistic knowledge in the brain? Will it be just like other representations of the world?
Think of a word that you learned in a foreign language. You might be able to remember the episodic event relating to the context you learn the word. Or even your feelings, emotions, etc. Perhaps language is just like other constructive blocks that build up our cognition, our world, is like an association network, with different nodes (meaning, usage, episodic memory, emotions, etc.).
I have been reading some language acquistion articles about the concept of "working memory". The definition of this term by different people is a chaos, which I don't intend to tackle. But they all point to similar directions:
First, one's native language ability, whether literacy, or some kinda linguistic knowledge (e.g. vacabulary, the "legal" combination of phonemes in a word", reading or listening comeprehension) will affect his/her learning a foreign language.
Specifically, if this ability is tested under a short-term memory based test, (like a reading span test, listening span test, or word digit test in which the subjects were asked to recall words, answer comprehension questions, etc.) the test result usually correlates with one's performance on foreign language learning. It might look obvious to link these working memory tasks to linguistic performance because the these working memory tasks are designed to tesk some parts of one's language ability, and is done through the medium of language. Therefore, if one has high literacy/reading comprehension in L1, they tend to have better performance on L2 than those with low performance on literacy/reading comprehension/working memory tests.
Second, the short-term memory performance can be disrrupted, or inhanced with different techniques. For example, making the subject tap the table while listening or reading to learn a new foreign vocabulary can intervene subjects' learning. On the contrary, if the subjects read outloud the foreign words, they can remember more than just reading the words silently. To strech further from the working memory tasks themselves, some study found "noticing" has some correlation with high/low working memory capacity.
If I were to put a conclusion from what I have read, it seemed that linguistic knowledge, whether first or second language, has such an interrelated relationship. This is obvious through our world experiences, because we can easily find your L1 transfer, whether negative or positive, is affecting one's foreign language learning. We all draw references from something we already knew. But this interconnected linguistic knowledge still puzzles me. What would be the representaion of linguistic knowledge in the brain? Will it be just like other representations of the world?
Think of a word that you learned in a foreign language. You might be able to remember the episodic event relating to the context you learn the word. Or even your feelings, emotions, etc. Perhaps language is just like other constructive blocks that build up our cognition, our world, is like an association network, with different nodes (meaning, usage, episodic memory, emotions, etc.).
Sunday, April 16, 2006
Thoughts on using literature in ESL classrooms
References:
Gajdusek, L (1988). "Toward wider use of literature in ESL: How and why." TESOL Quarterly, 22, 227-258.
McKay, L. S. (2001). Literature as content for ESL/EFL. in Celce-Murcia(ed.), Teaching English as a Second of Foreign Language. United States: Dewey Publlishing Services.
I really like Gajdusek's article, which shows how using literature can actually be done in an ESL classroom. For me one of the most impressive take-home that I learned is the pre-reading vocabulary work. I think from a student's perspective, unknown or unfamiliar vocabulary is one source that might cause "anxiety" when reading in a foreign language. Unlike reading in native languages, students don't have linguistic or cultural resource to grasp onto, the tolerance for ambiguities or unresolved meaning is comparatively low. As for the teacher, he/she might get too eager about solving students' vocab problems so that they can get into the deeper discussion. As a result, both sides might lose sight that vocabulary actually has different valences in their function in an article. It's an important thing not just for teachers to distinguish the types of vocabulary (e.g. context, vital clue, and category), but also for students to see these different levels of dealing with unfamiliar words. I think it's a good strategy for students to overcome the anxiety of encountering new words, knowing that they don't have to stop every time and look them up in the dictionary in order to understand a text.
Another take-home message I got from the week is Mckay's perspective on cultural learning through literature. In her perspective, "...the ultimate goal of cultural learning is not to convey information about a culture nor to promote the acquisition of culturally influenced ways of behaving, but rather to help learners see their culture in relation to others so as to promote cross-cultural understanding."
As a non-native Englisn speaker, teaching the target culture is something that brings me anxiety and self-consciousness. If teaching culture means direct transmission, then I am definitely in an awkward position. Since I'm not from the culture, what can I offer to my students? What kinda role should I take in between the target culture and language and the students? As I take the stand with my students as an outsiders, am I perpetuating my perspective/stereotypes on the target culture to my students?
I haven't totally resolved these questions yet. But at least I feel a
little bit relieved after reading Mckay's perspective on developing
students' cultural awareness. It's not about transplanting a culture
into someone's head, but about showing students how their own cultures
can be connected with others by exploring cultures.
Gajdusek, L (1988). "Toward wider use of literature in ESL: How and why." TESOL Quarterly, 22, 227-258.
McKay, L. S. (2001). Literature as content for ESL/EFL. in Celce-Murcia(ed.), Teaching English as a Second of Foreign Language. United States: Dewey Publlishing Services.
I really like Gajdusek's article, which shows how using literature can actually be done in an ESL classroom. For me one of the most impressive take-home that I learned is the pre-reading vocabulary work. I think from a student's perspective, unknown or unfamiliar vocabulary is one source that might cause "anxiety" when reading in a foreign language. Unlike reading in native languages, students don't have linguistic or cultural resource to grasp onto, the tolerance for ambiguities or unresolved meaning is comparatively low. As for the teacher, he/she might get too eager about solving students' vocab problems so that they can get into the deeper discussion. As a result, both sides might lose sight that vocabulary actually has different valences in their function in an article. It's an important thing not just for teachers to distinguish the types of vocabulary (e.g. context, vital clue, and category), but also for students to see these different levels of dealing with unfamiliar words. I think it's a good strategy for students to overcome the anxiety of encountering new words, knowing that they don't have to stop every time and look them up in the dictionary in order to understand a text.
Another take-home message I got from the week is Mckay's perspective on cultural learning through literature. In her perspective, "...the ultimate goal of cultural learning is not to convey information about a culture nor to promote the acquisition of culturally influenced ways of behaving, but rather to help learners see their culture in relation to others so as to promote cross-cultural understanding."
As a non-native Englisn speaker, teaching the target culture is something that brings me anxiety and self-consciousness. If teaching culture means direct transmission, then I am definitely in an awkward position. Since I'm not from the culture, what can I offer to my students? What kinda role should I take in between the target culture and language and the students? As I take the stand with my students as an outsiders, am I perpetuating my perspective/stereotypes on the target culture to my students?
I haven't totally resolved these questions yet. But at least I feel a
little bit relieved after reading Mckay's perspective on developing
students' cultural awareness. It's not about transplanting a culture
into someone's head, but about showing students how their own cultures
can be connected with others by exploring cultures.
Tuesday, March 28, 2006
my brian hurts...the relationship between attention and WM
From the memory field studies done by Funahashi et al., a cell can be excited to certain direction, but at the same time being inhibited to other opposite directions. Similar to this phenomenon, in human visual cortex, when subjects attend to certain locations, the corresponding visual cortex are enhanced, but other areas are suppressed. What does such inhibitory and excitatory process tell us about the characteristics of working memory? Is it a synonym to attention, part of attention, or something else?
Monday, February 20, 2006
More thoughts on the neurobiological account for working memory
Central executive and attention control
The memory system is generally thought to be composed of two elements, short-term memory and long-term memory. Baddeley and Hitch (1974) developed "working memory" model from the short-term memory system, refering to short-term memory system that is involved in a temporary storage of information and processing (Gastherole & Baddeley, p. 2). The working memory system sublines human cognitive activities, such as "reasoning, language comprehension, long-term learning and mental arithmetic"(p.2). The WM system has three main componants that Baddeley use for explaning relationship between language and memory-with 'central executive' as center componant'; phonological loop', and 'sketchpad'serving as "slave systems" to central executive. The central executive involves in regulating information flow, and retrieval of information from long-term memory. Baddeley also quoted other people's studies in the book that the executive might be involved in planning, task coordination, and consious awareness, and selection and control of action. The concept comes from Shallice's (1988) model of the "attentional control of action." Shallice (quote) reported a paradoxical phenomanon of frontal lobe damage patients. Due to the impairment to the central executive (SAS, "Supervisory Attentional System), the patient can't selectively intervene the activated schemas for apporpriate actions. That is, the patient either have difficulty in inhibiting other distracting schemas, or show perseverance of an already activated schema.
Working memory cells
Coming from neurophysiological point of view, Fuster (2003) looks at memories as cortical networks. The formation of memory is through "the modulation of transmission of information acorss synapses, the neural elements anatomically associating cells with one another" (p. 113). Therefore, memorys are associative with one another. Working memory under such sense is what Fuster called "attention focused on the internal representation of a recent event for a pending action" (p.155). The main propoerties of working memory is not to form a new memory, but to hold active at the need of processing a new action. Thus it's components can be both new items such as sensory inputs, associations; and old, past experience (long-term memory).
The most notable neuronal evidence for this sustained attention is found in monkeys performing a "delayed-response task" (todo:elaboration). Cells in monkeys' prefrontal cortex were found to maintain discharged at a higher level in delayed period (i.e. when the stimulus is obsent from the environment) than in periods between trials. These cells are later called "memory cells". The characteristics of the finding are, first, the delayed-period activation was dependent on the impending need to perform an act "that's contingent on the signal in memory". Second, it was not dependent on the expectation of reward. Third, the accuracy is correlated with the monkey's ability to remember the signal. Forth, the performance could be attenuated when the animal was distracted. (p. 156). In short, these cells discharge selectively to the retention of a stimulus, and they can be distracted by other stimulus concommitently.
Physiologically, single neuron recordings (Goldman-Rakic et al.,1996) reveal neurons in prefrontal cortex firing specifically to the same one or a few locations in a two-dimentional visual field when the animal was performing visual delayed response tasks. According to Fuster, the significance of Goldman-Rakic and collegues' work is that they dissociate two subareas of cortex that's specialized in working memory function: neurons engaged in the memory of the object predominate in the ventral aspect of lateral prefrontal cortex, whereas the neurons for memory of special information predominate in the dorsal apspect. This examplifies that the nature of working memory is not a single unit or localization, but more a distributed network(p.158).
Other studies involving tasks during a state of attention, so called "working memory" tasks also found "memory cells" not limited to prefrontal areas. For example, visual memory were found in the inferior temporal cortex (quote) (Fuster & Jervey, 1981; Miller et al., 1993), spatial memory cells in posterior parietal cortex (quote) (Andersen et al., 1990), and tactile memory cells in somatosensory cortex (quote) (Zhou & Fuster, 1996). In human visual cortex, increased activity was found when the stimuli was obsent but the subject was attending a specific visual field (Kastner et al., 1999).
The inferences can be drown from these findings, according to Fuster (2003) are that, working memory consists of a large cognitive network (perceptual and executive memory), and the selective attention during a task of working memory consists of the sustained and selective activation of this network.
Dopamine projection
Dopamine in the prefrontal cortex:
In the study of Goldman-Rakic et al.(1996), they pointed out that pyramidal neurons and non-pyramidal neurons in prefrontal cortex is critical for the formation of a "memory field" found in the area. Dopamine has inhibitory and excitatory effect on the prefronal cells. Prefrontal cortex is also known as the richest in dopamine than any other cortical areas. Tus the role of dopamine projection to prefrontal area and its effect on working memory tasks worths further discussion.
More evidence has been made between the dopamine dysregulation in prefrontal cortex in dschizophrenia(Goldman-Rakic et al. 2004). Working memory deficits have been postulated to be "underlying the myriad impairment of disorders" in schizophrenia (p. 4). In Diamond (1989) young infants still can't perform without errors in working memory plus inhibition tasks due to late developmental maturity of human dorsal lateral prefronal cortex.
The memory system is generally thought to be composed of two elements, short-term memory and long-term memory. Baddeley and Hitch (1974) developed "working memory" model from the short-term memory system, refering to short-term memory system that is involved in a temporary storage of information and processing (Gastherole & Baddeley, p. 2). The working memory system sublines human cognitive activities, such as "reasoning, language comprehension, long-term learning and mental arithmetic"(p.2). The WM system has three main componants that Baddeley use for explaning relationship between language and memory-with 'central executive' as center componant'; phonological loop', and 'sketchpad'serving as "slave systems" to central executive. The central executive involves in regulating information flow, and retrieval of information from long-term memory. Baddeley also quoted other people's studies in the book that the executive might be involved in planning, task coordination, and consious awareness, and selection and control of action. The concept comes from Shallice's (1988) model of the "attentional control of action." Shallice (quote) reported a paradoxical phenomanon of frontal lobe damage patients. Due to the impairment to the central executive (SAS, "Supervisory Attentional System), the patient can't selectively intervene the activated schemas for apporpriate actions. That is, the patient either have difficulty in inhibiting other distracting schemas, or show perseverance of an already activated schema.
Working memory cells
Coming from neurophysiological point of view, Fuster (2003) looks at memories as cortical networks. The formation of memory is through "the modulation of transmission of information acorss synapses, the neural elements anatomically associating cells with one another" (p. 113). Therefore, memorys are associative with one another. Working memory under such sense is what Fuster called "attention focused on the internal representation of a recent event for a pending action" (p.155). The main propoerties of working memory is not to form a new memory, but to hold active at the need of processing a new action. Thus it's components can be both new items such as sensory inputs, associations; and old, past experience (long-term memory).
The most notable neuronal evidence for this sustained attention is found in monkeys performing a "delayed-response task" (todo:elaboration). Cells in monkeys' prefrontal cortex were found to maintain discharged at a higher level in delayed period (i.e. when the stimulus is obsent from the environment) than in periods between trials. These cells are later called "memory cells". The characteristics of the finding are, first, the delayed-period activation was dependent on the impending need to perform an act "that's contingent on the signal in memory". Second, it was not dependent on the expectation of reward. Third, the accuracy is correlated with the monkey's ability to remember the signal. Forth, the performance could be attenuated when the animal was distracted. (p. 156). In short, these cells discharge selectively to the retention of a stimulus, and they can be distracted by other stimulus concommitently.
Physiologically, single neuron recordings (Goldman-Rakic et al.,1996) reveal neurons in prefrontal cortex firing specifically to the same one or a few locations in a two-dimentional visual field when the animal was performing visual delayed response tasks. According to Fuster, the significance of Goldman-Rakic and collegues' work is that they dissociate two subareas of cortex that's specialized in working memory function: neurons engaged in the memory of the object predominate in the ventral aspect of lateral prefrontal cortex, whereas the neurons for memory of special information predominate in the dorsal apspect. This examplifies that the nature of working memory is not a single unit or localization, but more a distributed network(p.158).
Other studies involving tasks during a state of attention, so called "working memory" tasks also found "memory cells" not limited to prefrontal areas. For example, visual memory were found in the inferior temporal cortex (quote) (Fuster & Jervey, 1981; Miller et al., 1993), spatial memory cells in posterior parietal cortex (quote) (Andersen et al., 1990), and tactile memory cells in somatosensory cortex (quote) (Zhou & Fuster, 1996). In human visual cortex, increased activity was found when the stimuli was obsent but the subject was attending a specific visual field (Kastner et al., 1999).
The inferences can be drown from these findings, according to Fuster (2003) are that, working memory consists of a large cognitive network (perceptual and executive memory), and the selective attention during a task of working memory consists of the sustained and selective activation of this network.
Dopamine projection
Dopamine in the prefrontal cortex:
In the study of Goldman-Rakic et al.(1996), they pointed out that pyramidal neurons and non-pyramidal neurons in prefrontal cortex is critical for the formation of a "memory field" found in the area. Dopamine has inhibitory and excitatory effect on the prefronal cells. Prefrontal cortex is also known as the richest in dopamine than any other cortical areas. Tus the role of dopamine projection to prefrontal area and its effect on working memory tasks worths further discussion.
More evidence has been made between the dopamine dysregulation in prefrontal cortex in dschizophrenia(Goldman-Rakic et al. 2004). Working memory deficits have been postulated to be "underlying the myriad impairment of disorders" in schizophrenia (p. 4). In Diamond (1989) young infants still can't perform without errors in working memory plus inhibition tasks due to late developmental maturity of human dorsal lateral prefronal cortex.
Sunday, February 19, 2006
Thoughts on working memory (for self record)
man, I think I picked the hard topic to look at...
If I were to give the definition of "working memory", I would end up burying myself in the literatures of working memory, but still couldn't give out a clear model of definition for it without confusing myself to death. This is how I have been feeling whenever I found any study talking about this topic.
I gradually learned (still not very skillfuly) to first identify which camp they are coming from:
1. Second language acuqistion camp: these people are langauge educators, applied linguists, and people who like to borrow psychological concepts and studies. The implication of WM for them is the predictor for learning a second/foreign language. Intuitively everybody would think that if you can remember a sequence of foreign sounds and be able to repeat promptly, that means you have some kinda "talent" for learning languages.
But knowing this and to prove it doesn't solve my question. What's working meomry in a neurobiological sense?
2. Psychology camp: they are the people who first brought up the idea of working memory from the concept of short-term memory, including Baddaley himself. Since they made up the term, their studies are being quoted by others all the time, but only at the introduction. After that they just go on whatever directions they like to talk about this term.
3. Neurolinguistic people: looks like these people like fMRI very much. A lot of them believe in UG and language area it seems like. The attempt is to find out the location of working memory, which is prefronal cortex, along with some other regions like temporal gyrus, parietal areas being found in those imaging studies.
Sometimes these localization studies or ROI ("region of interest") look cool but couldn't explain what's going on underneath the cortex. When parietal cortex and cingulate both light up, what does it tell us about the brain?
4. Neuroscientist: Fuster, Goldman-Rakic et al...
These are the people whom I think have cool ideas about working memory. Fuster has this "cognit" neuronetwork explaning cognition in the cortex. He discovered the memory cells when monkeys doing delayed response task. Same kinda cells are found in different regions of the brain when doing other tasks such as tonal, visual-spatial, color, etc. Goldman-Rakic found cells firing at certain "memory field" when monkeys doing delayed response tasks through single cell recordings. Another way to understand WM and the relationship with prefrontal area might be through pathological studies, like autism or schizophrenia. For example, "autism" (though this term needs clear definitions too!) subjects tend to have working memory deficits, same as schizophrenia patients, WM integrity can even predict whether they can reintegrate socially or replase. Some studies connect these deficits to dopamine projection dysfunction in prefrontal cortex, which I am still trying to figure out. I got the feeling this might the direction I want to go just to avoid the endless debate on what working memory does and what it actually is.
If I were to give the definition of "working memory", I would end up burying myself in the literatures of working memory, but still couldn't give out a clear model of definition for it without confusing myself to death. This is how I have been feeling whenever I found any study talking about this topic.
I gradually learned (still not very skillfuly) to first identify which camp they are coming from:
1. Second language acuqistion camp: these people are langauge educators, applied linguists, and people who like to borrow psychological concepts and studies. The implication of WM for them is the predictor for learning a second/foreign language. Intuitively everybody would think that if you can remember a sequence of foreign sounds and be able to repeat promptly, that means you have some kinda "talent" for learning languages.
But knowing this and to prove it doesn't solve my question. What's working meomry in a neurobiological sense?
2. Psychology camp: they are the people who first brought up the idea of working memory from the concept of short-term memory, including Baddaley himself. Since they made up the term, their studies are being quoted by others all the time, but only at the introduction. After that they just go on whatever directions they like to talk about this term.
3. Neurolinguistic people: looks like these people like fMRI very much. A lot of them believe in UG and language area it seems like. The attempt is to find out the location of working memory, which is prefronal cortex, along with some other regions like temporal gyrus, parietal areas being found in those imaging studies.
Sometimes these localization studies or ROI ("region of interest") look cool but couldn't explain what's going on underneath the cortex. When parietal cortex and cingulate both light up, what does it tell us about the brain?
4. Neuroscientist: Fuster, Goldman-Rakic et al...
These are the people whom I think have cool ideas about working memory. Fuster has this "cognit" neuronetwork explaning cognition in the cortex. He discovered the memory cells when monkeys doing delayed response task. Same kinda cells are found in different regions of the brain when doing other tasks such as tonal, visual-spatial, color, etc. Goldman-Rakic found cells firing at certain "memory field" when monkeys doing delayed response tasks through single cell recordings. Another way to understand WM and the relationship with prefrontal area might be through pathological studies, like autism or schizophrenia. For example, "autism" (though this term needs clear definitions too!) subjects tend to have working memory deficits, same as schizophrenia patients, WM integrity can even predict whether they can reintegrate socially or replase. Some studies connect these deficits to dopamine projection dysfunction in prefrontal cortex, which I am still trying to figure out. I got the feeling this might the direction I want to go just to avoid the endless debate on what working memory does and what it actually is.
Thursday, January 05, 2006
近況; 人腦與其他
我跟Nick現在住在距離學校約20分鐘車程的一個公寓裡。目前家裡還是一團混亂，一堆之前搬家的箱子有很多還散在各處沒開箱。學校已經開學三週了。我還剩下這個學期和春季學期，六月就會畢業，目前打算先工作再想博士班的事情。這學期少了婚禮的忙碌，可是還是一樣的忙。(我好像從開始念研究所就一直很忙的樣子) 這學期我修了兩門課，一門是補大學的預修(語音學)，一門是腦神經解剖學(neuroanatomy)。會修腦解剖學有很多原因。一來是因為我的論文是作語言、記憶、跟大腦之間的關係，二來是因為這個老師開課的機會非常難得。老師是個MD，已經八十四歲了，教這門課已經有半世紀了。(我是聽說他就是那個發現insula的那個人，還有研究pyramidal cell成名的)總之…我常很驚訝一個八十幾歲的人頭腦可以這麼清楚，尤其是神經系統的學問是這麼複雜。上課的時候很像在聽Discovery Channel，聽老師娓娓道來。不過以非醫學或生物背景的我們去修這堂課，而且還是研究所的程度，很多時候是完全聽不懂老師在講什麼，連筆記都抄不起來。還好我們教授跟他有協議，讓我們的考試跟醫學院的人分開，我們不用跑檯，也不用考切片。不過讀起來還是滿有壓力的，我的生物只有國中程度，連細胞裡有什麼都搞不清楚。不過這堂課讓我們每個星期可以用真的人腦。老師不知道哪裡弄來了十二顆人腦，每四五個人分到一顆，就這麼裝在水桶裡，戴著手套捉出來放在墊好餐巾紙的餐盤上。
我們的同學都是醫工、生物、認知科學的研究生。有些人還是去年被當掉重修的…
就這樣，我又開始回復學校生活。只是突然覺得好累。也許有個婚禮當作目標還比較容易應付。現在要面對的是論文還有未來的道路，只覺得好難好難…
我們的同學都是醫工、生物、認知科學的研究生。有些人還是去年被當掉重修的…
就這樣，我又開始回復學校生活。只是突然覺得好累。也許有個婚禮當作目標還比較容易應付。現在要面對的是論文還有未來的道路，只覺得好難好難…
Monday, September 12, 2005
Prefrontal Cortex-where is it and why does it matter?
Prefrontal cortex is the subdivision of frontal lobes. Basically as the name tells us, they are on the front area of fronal cortex, which is around the above of our eyes. The frontal lobes include the important mortor cortex (which affects our somatic senses), and the famus "broca's area" which is thought by some linguists as "main language area".Compared to other mammals like cats, dogs, or even monkeys, we human beings have the most extended area (the biggest) of prefrontal cortex.
The part that's right above our eyes, (dorsal lateral prefrontal cortex, DLPFC) is thought to be important for "working memory," -things that can be held for a very short period of time. (dude, i feel this term takes another paper to explain the definition).
The developing and existence of this part of brain function can be seen on experiments done on infants, young children, and monkeys (whoes DLPFC are knocked out).
For example, the A-not-B experiment:
There are two wells in front of a subject (a monkey with DLPFC being removed or a cute baby). The subject watches a reward being put into one of them (say A). Then the wells are covered, a curtain might fall to block the vision and causes delay. Finally the subjects can reach to the well where they think the treat is.
Both the monkey and human baby would reach to A. Then they get the reward.
However, the next time, they would watch a reward being put in well B. This time, given the location they have already seen, they would still turn to the successful pattern of reaching to well A.
Another test they do on younger kids is to ask them to shout out "day!" when they see a card of moon and star, and "night" when they see a card of a sun. Children who were bellow 3 did a poor jobs than older kids. Even though they showed understanding of the rules.
In order to acoomplish the tasks, there must be some information being held active at hand (e.g. remembering the location of the treat, or remembering the rule of the test). But there's also another piece of information coming in/being held that are competing with the other (e.g. seeing the card change, remembering the successful, conditioned location of the treat). An adult or normal person w/o brain damage to DLPFC can inhibit one and reach to the other. DLPFC seems to be in important position in this "inhibitory" function of working memory.
It's actually a good news for us being human. That means we are not just reponsive to any stimulus, or old patterns. We can integrate the new information with the old data, and then make the best solution. Otherwise we would never have new ways of dealing things, like some brain damage patients, who kept pressing the same button or stick onto one way of sorting cards, despite the inspector told them the rule had changed.
Regarding the latency of 3 year old children in the "day-night" test (given that they know the rule correctly)--It's more of the cognitive difficulty. What about learning a language? Normal adults are assumed to have normal cognition. But sometimes I found that, although I know the grammar (maybe not perfectly, but pretty well), the setence just won't come out right. There might be some coordination problem, since motor cortex, especialy for the tongue, and mouth is close to this area. But what's the relationship of working memory, DLPFC, and language acquisition? We can’t be all brain-damaged for learning a language (or are we?)
The part that's right above our eyes, (dorsal lateral prefrontal cortex, DLPFC) is thought to be important for "working memory," -things that can be held for a very short period of time. (dude, i feel this term takes another paper to explain the definition).
The developing and existence of this part of brain function can be seen on experiments done on infants, young children, and monkeys (whoes DLPFC are knocked out).
For example, the A-not-B experiment:
There are two wells in front of a subject (a monkey with DLPFC being removed or a cute baby). The subject watches a reward being put into one of them (say A). Then the wells are covered, a curtain might fall to block the vision and causes delay. Finally the subjects can reach to the well where they think the treat is.
Both the monkey and human baby would reach to A. Then they get the reward.
However, the next time, they would watch a reward being put in well B. This time, given the location they have already seen, they would still turn to the successful pattern of reaching to well A.
Another test they do on younger kids is to ask them to shout out "day!" when they see a card of moon and star, and "night" when they see a card of a sun. Children who were bellow 3 did a poor jobs than older kids. Even though they showed understanding of the rules.
In order to acoomplish the tasks, there must be some information being held active at hand (e.g. remembering the location of the treat, or remembering the rule of the test). But there's also another piece of information coming in/being held that are competing with the other (e.g. seeing the card change, remembering the successful, conditioned location of the treat). An adult or normal person w/o brain damage to DLPFC can inhibit one and reach to the other. DLPFC seems to be in important position in this "inhibitory" function of working memory.
It's actually a good news for us being human. That means we are not just reponsive to any stimulus, or old patterns. We can integrate the new information with the old data, and then make the best solution. Otherwise we would never have new ways of dealing things, like some brain damage patients, who kept pressing the same button or stick onto one way of sorting cards, despite the inspector told them the rule had changed.
Regarding the latency of 3 year old children in the "day-night" test (given that they know the rule correctly)--It's more of the cognitive difficulty. What about learning a language? Normal adults are assumed to have normal cognition. But sometimes I found that, although I know the grammar (maybe not perfectly, but pretty well), the setence just won't come out right. There might be some coordination problem, since motor cortex, especialy for the tongue, and mouth is close to this area. But what's the relationship of working memory, DLPFC, and language acquisition? We can’t be all brain-damaged for learning a language (or are we?)
Saturday, May 21, 2005
Evolution of Language
"人類語言到底是怎麼開始的??"
這問題橫跨了生物、人類、考古、社會、心理、語言、民族學等等學科的範疇。這也是我在這裡的研究所處理的問題之一。身為基督徒，我相信上帝創造人類的獨特性。人不是猴子變來的，但是光是去思考為何我們能生為人H. Sapiens，就算從一個接受進化論基礎的角度來看，也是夠複雜的了。如果現在的人類是進化來的，那從什麼時候開始，人除了肢体表情動作以外，開始使用語言? 又是怎麼樣的因素使黑猩猩們到現在還是黑猩猩(註:人和黑猩猩有98%基因相似)? 像Kanzi之類在實驗室長大的黑猩猩(Bonobo)，如果真的承認他們有使用抽象符號思考溝通的能力，這對人類語言(也是種抽象符號)又有什麼啟示?
這問題橫跨了生物、人類、考古、社會、心理、語言、民族學等等學科的範疇。這也是我在這裡的研究所處理的問題之一。身為基督徒，我相信上帝創造人類的獨特性。人不是猴子變來的，但是光是去思考為何我們能生為人H. Sapiens，就算從一個接受進化論基礎的角度來看，也是夠複雜的了。如果現在的人類是進化來的，那從什麼時候開始，人除了肢体表情動作以外，開始使用語言? 又是怎麼樣的因素使黑猩猩們到現在還是黑猩猩(註:人和黑猩猩有98%基因相似)? 像Kanzi之類在實驗室長大的黑猩猩(Bonobo)，如果真的承認他們有使用抽象符號思考溝通的能力，這對人類語言(也是種抽象符號)又有什麼啟示?
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