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发表于 2010-1-26 03:15:30
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http://www.ied.edu.hk/autism/Weak%20Central%20Coherence.htm
整體和重點思考能力的缺失 (Weak Central Coherence)
它是什麼？
最簡單來說，它指偏好細節部分多於全盤思考；它也指長於分拆的技巧，對細節有很強的觀察力，這從解開層疊畫謎 (指從一堆線條中找出隱藏物件)，或拼砌積木圖案 (指把多個立體積木的其中一面圖畫合併組成一個圖案) 的優異能力可見；它也指自閉症人士不能將物件的零星部分整合，或將句子重組成段落。
自閉症人士的世界是一個零碎分裂的世界，有一位自閉症人士說：「我把自閉症人士的視覺比作昆蟲的小眼面視覺 - 同時看到眾多零碎且細微、不同的資料。」
整體重點思考和建立相關概念的能力有關，它不是天生有便有，沒有便沒有。它是循認知能力發展而來的，有些人學到多一些，有些人少一些。說自閉症人士完全沒有整體重點思考能力是錯的，它只是發展得不夠好。令到問題更複雜的是：這個障礙在自閉症人士身上會顯現出不同的程度。
在一般的認知方式裡，可以見到人類有一個天生的傾向，就是喜歡盡量為外界刺激找出聯繫，也喜歡盡量類化所知到其他情景。整體和重點思考的正常運作驅使人類最注重事物的意義，由此方可分辨有意義和無意義的材料。自閉症兒童就是這方面的能力薄弱，結果就是無論處理資料的機制或是他們的社交群處能力，同樣予人突兀之感。
學者Frith, U. (1989) 的理論
人類的思考模式可分為中央資料處理過程和邊緣資料處理過程，邊緣資料處理過程包括種種個別的領域，如說話，它們最後匯聚在中央經過處理成為進一步的資料。但局部的凝聚力是很強的，它要抵抗高層次的中央凝聚力來處理邊緣的資料，如中央凝聚力比局部凝聚力弱，它就造成局部領域的獨立運作，這正好解釋了自閉症人士分拆畫謎的高超能力。
自閉症人士缺乏「整體和重點思考能力」的行為表現
1.特強的硬記能力
對比一般兒童，自閉症兒童在記一些無意義的單字、句子、或資料時，不會感到更為困難。相對來說，一般兒童傾向於去記憶一個信息的意義或它的規律和結構。
2.處理空間的能力
在解開層疊畫謎測試方面，自閉症兒童的表現是他們智力歲數的中位以上。
3.能夠分辨微細的視覺和聽覺資料
4.類化的困難
自閉症人士可能不感到有類化不同東西的需要，而並不是不能為事物分類或找到事物的相同點。一成不變的行為可能因為他只是對處境裡某項資料作出反應，當該項資料在另一個場合沒出現的話，就不會有同樣的反應。
5.注意力問題
一般人留意的東西，自閉症兒童可能不會留意。他們所留意環境中的某些小節，一般人也未必會留意。對某些偏狹的題目，他們也許會長時間保持興趣，而其他兒童只會對整體的模式更感興趣，因為一般人覺得他們在整體方面更能找到共同意義。
6.堅持一成不變
它源自局部的凝聚力，範圍可以很偏狹和具有獨立運作性。它可以正式被稱為刻板的思維，或一些高度重複性預設的意念。
7.呆超人的能力
它其實包含了幾個因素：對一個題目的持久注意力、專門性資料處理系統的順利運作、和最重要的是重複的運作。
8.重複性行為
重複是輸入和輸出系統的自然屬性，當它們的產生受到高層次的中央監察系統認取後，這兩個系統正常情況下應會停止，通知輸入系統處理新的資料和輸出系統轉向別個活動。但患有自閉症的腦袋卻擁有兩個分隔的中央和邊緣資料處理系統，這是因為中央的監控系統太弱了，不能關閉輸入和輸出系統。
9.僵化的行為
較高層次的機制在適應場合時特別需要運用彈性，但對較低層次的處理機制來說，可靠性更為重要。從人類的進化過程中，明顯可見的是：原始的神經系統的表現是極為刻板的。
10. 不明白一些說話的用意
自閉症人士覺得溝通最困難的地方是不知道說話背後的意義。意義通常隱藏在背景內，而自閉症人士由於對背景資料未能完全掌握，很多時只會對其中部分資料作出反應。
11. 鸚鵡式學舌
語言方面似乎繞過了中央的思維。就算語音、聲律、語法準確，它們綜合的語言卻欠缺整體的意義。整體和重點思考能力的缺失，令自閉症人士不了解溝通的基本目的。
12.「你」、「我」；「這」、「那」；「來」、「去」等詞語的倒轉運用
這些詞語的運用須視乎誰是說話者、誰是聆聽者，所以掌握背景時較為困難。
13.異常的聲調、說話速度、流利程度、語氣的強調
這是由於不能做到真正的雙向性溝通。
14.缺乏想法解讀能力
從各方面看到、記得、聽取的不同資料綜合在一起，如果不把它們串連為一個有意義的整體，它們只是一堆零碎的資料，任何人也會感到難以理解。理解社交行為和推斷較高層次的意念，是尋找相關性和摘要的最高境界。自閉症人士不能在較高層面找出意義，所以造成社交方面的障礙。如果知道人有知道某些事的能力，也許就是為某些事找到意義的關鍵。
15.難以作出決定
一般人作出決定時，會將整體沒有意義的選擇刪除，但自閉症人士卻沒有把它們刪除，所以他們面對一大堆的選擇不知如何決定。
16.不能同時處理多件事物
他們的智力不平衡，使到他們要逐項地處理資料，也需要更多的時間來理解，反應也因而會較慢。
17.缺乏常識
這是由於他們賦予事物意義的方式與一般人不一樣。
18.長於記憶細節
由於他們找不到事物的相關性，所以只好倚賴細節的記憶。
「想法解讀」理論所不能解釋與社交無關的自閉症表現
l 偏狹的嗜好
l 強烈的意願去保持原狀
l 刻板性
l 呆超人能力
l 不能類化
l 特強的硬記能力
l 對物件部分的專注性
l 感官接收的零碎性
「想法解讀」理論不能解釋的測試結果
能力強項 能力弱項
記不相關的字串 記整句句子
記不相關的事物 記相關的事物
砌造圖案 找出圖案
利用形狀拼圖 拼砌成圖畫
循飾物配件把面孔分類 循人把面孔分類
「整體和重點思考能力的缺失」與「想法解讀」的關係
Happ, F (1994) 認為「想法解讀」有兩層意思：
1. 為事物套上想法的能力；
2. 對社交行為的理解也是基於上述的能力才能猜測別人的想法，但也是許多其它原因如性格、動機、代入感、智商、環境、經驗的作用達致的結果。
學者Frith, U. and Happ, F. (1994) 認為「整體和重點思考能力」和上述第一項能力是不同的東西，但卻不能脫離第二項。第一項能力不是「整體和重點思考能力的缺失」的結果，但就第二項來說，如要理解別人的想法和感受，就必須考慮整個情景和組合各方面的資料，所以循自然或對情景敏感角度來量度理解社交行為能力，會很容易找到「整體和重點思考能力」所產生的作用。
另一個可能就是兩者存在著因果的關係，把環境因素組合方能令「想法解讀」機制成熟，也可推想的是：我們抽取較高層面意義的傾向是和人類的群體性有關的。
「想法解讀」的最新理論如何評價「整體和重點思考能力」的缺失
Simon Baron-Cohen 的「想法解讀」理論加進了一個新的部分 - 「系統化處理機制」。它也涵蓋了自閉症人士對細節的特強觀察力。但在理解整個系統方面，「想法解讀」和「整體和重點思考能力」的缺失有不同的結論，根據「整體和重點思考能力」缺失的理論，自閉症人士應不能理解整個系統，與及它各個部分之間的關係。但「想法解讀」則說，只要這系統有規則可尋，自閉症人士很容易知道改變一個參數會為整個系統帶來什麼間接的後果。自閉症人士的重複性行為，源自他們對任何有規律的系統的強烈興趣，他們喜歡事物保持原狀，也許是在探究系統的規律或辨認物理因果關係。
「系統化處理機制」需要準確性，所以自閉症人士的說話常是學究味很重，充斥了不必要的細節，他們也常顯示出擁有詳盡的記憶。有時準確性機制太強時，自閉症人士發覺不能有一個準確的答案，就會不知道如何回答，同時也需要較長時間來選擇答案，它因此也影響了他們代入他人感受的能力，因為這方面的答案永遠不可能準確的。
Weak Central Coherence
Tracing back::
Kanner(1943) described, as a universal feature of autism, the ‘inability to experience wholes without full attention to the constituent parts’.
Present reference :
The term “central coherence” is not mentioned. Only its meaning or definition is indirectly given as follows :
教署2001年資料光碟「融合教育」之「自閉篇」第一章1.4學習特徵：
1.4.1 不明白事物的相關性
自閉症學生一般都不明白生活經驗背後的意義。由於他們的世界是由許多獨立的小節組成，他們未必能將這些小節連結成有意義的概念，以致不能明白小節之間的相互關係。經過適當訓練後，部分學生能夠依次序處理信思。不過，由於他們不容易明白較複雜的關係，因此認知上往往會出現困難。
1.4.2 過分執著事物的枝節
自閉症學生往往過分執著事物的枝節，而忽略了重要的部分
1.4.4 較難掌握抽象的概念
自閉症學生在處理語言符號及意思的統合可能有困難。他們一般比較留意影象而忽略語言，在處理信息時通常會著眼於片面的資料，而未能全面了解事件。
Sources of materials
Contents of the materials in the following section are either quoted or summarized from :
1. Vermeulen,P.(2001). Autistic Thinking – This is the title. London: Jessica Kingsley
2. Frith, U.(1989).Autism:explaining the enigma. Oxford:Blackwell
3. Happ, F. (2000). Parts and wholes, meaning and minds: central coherence and its relation to theory of mind Understanding Other Minds Second Edition Oxford : Oxford University Press
4. Baron-Cohen, S. (draft 4th May 2001). The exact mind: Empathising and systemizing in autism spectrum conditions? To appear in Goswami, U, (ed) Handbook of Cognitive Development. Blackwell:Oxford (in press)
What is ‘weak central coherence’?
In simplest terms, it refers to the individual’s preference for local detail over global processing. It means good segmentation skills and superior attention to details, as evidenced by Embedded Figures Task and Block Design Subtest. It also means an autistic deficit in integrating fragments of objects and integrating sentences within a paragraph, of which tests have also been made. (Simon Baron-Cohen, 2001)
Autistic people’s world is a fragmented world. In the word of a person with autism : ‘I compare autistic sight with the faceted vision of an insect: a host of different subtle details but all of it non-integrated.’
Central coherence, the ability to establish cohesion, is not something you are either born with or not. It is an ability that is developed, something people can acquire to a greater or lesser degree. It is wrong to think that people with autism entirely lack central coherence. It’s just that with them the ability is weakly developed: To further complicate things the degree of weakness of central coherence is not identical in all individuals with autism.
The misunderstanding about the talent of people with autism is the result of a mistaken understanding of intelligence. . Clearly, there are different kinds of intelligence. In what way is the structure of autistic people’s intelligence different from that of people without autism? .(Vermeulen, P. 2001).
In the normal cognitive system there is a built-in propensity to form coherence over as wide a range of stimuli as possible, and to generalize over as wide a range of contexts as possible. It is this capacity for coherence that is diminished in autistic children. As a result, their information-processing systems, like their very beings, are characterized by detachment. The normal operation of central coherence compels us human beings to give priority to understanding meaning. Hence, we can easily single out meaningful from meaningless material. .(Frith, U.,1989)
Frith explains further the concept of central coherence in the following:
We can draw on a simple model of the mind. The model is based on information-processing concepts. At its most basic this model of mind distinguishes central thought processes and more peripheral input and output processes. The peripheral processes are specialized for various domains, for instance speech. input devices transform sensations into perceptions going through many stages of processing. They can be thought of a custom-built, highly specialized modules. Their end-product is usable information, already interpreted. This information can be further interpreted by central thought processes. The central system too can provide many stages of processing in many specialized subsystems.
There might be a force which pulls together large amounts of information. The smaller amounts of information that eventually contribute to the larger picture too must be pulled together from even smaller amounts by some locally acting cohesive force. Local cohesive effects are very strong. Perhaps they are impossible to resist when they occur at a relatively peripheral level. Why should there be a centrally acting high-level cohesive force? Why is there a need to pull together information that is already processed and already interpreted? The answer might be: without this type of high-level cohesion, pieces of information would just remain pieces, be they small pieces or large pieces.
High-level central cohesive forces must be resistible to some extent. This is necessary in order to explain the achievement of disembedding.
A weak central cohesive force, weak relative to lower level cohesive forces, would simulate ‘field independence’ and all that it entails for performance on embedded figures.
Manifestations and explanations of autistic people’s abilities and behaviors in the ‘central coherence ‘context:
1. Good rote memory skills
In Word string tests – The meaning of a message to be repeated, or the structure of the pattern, the single most important feature for normal children, is not as significant for autistic children. They may remember unconnected words almost as well as meaningful sentences, and unconnected bits of information as well as those that are part of a meaningful context. It is this lack of preference for coherent over incoherent stimuli that must be regarded as abnormal.
The key word in rote memory is ‘rote’ as opposed to ‘meaningful’. Hence, it is appropriate to consider astounding isolated feats of rote memory of autistic children as a sign of dysfunction, rather than islets of intact ability.
2. Good spatial abilities
On the Embedded Figures test, autistic children scored above average for their mental age.(Shah and Frith,1983)
3. An ability to discriminate fine visual and auditory detail.
4. Problem of generalization – it is not the inability to categorize or inability to see similarities despite differences that prevents the application of learning. But perhaps it is an inability to see the need for generalization across differences. Not pulling information together in spite of perceived similarities might be traced to a weakness in a drive for central coherence.
Veumeulen : in your behavior you are oriented towards one particular detail and you fail to react when that detail happens to be absent from the situation – thus resulting in rigidity.
5. Attention control – incidental features of the environment can become an autistic person’s main focus of attention. That which is perceptually salient to most people may not be salient to an autistic child, and vice versa. An autistic individual can focus for a long time on a narrow topic for its own appeal, whereas a normal child would attend to it briefly, finding it interesting only as part of a greater pattern. It is probably only in the greater pattern that people share something of what they consider to have significant meaning.
6. Insistence on sameness – it is a type of local coherence. It is extremely limited in scope and quite self-contained. It can properly be called a thought stereotypy, a preoccupation of a highly repetitive nature.
7. Idiot savant – the ability depends on several factors; a capacity for sustained attention to one topic; the smooth running of specialized processing systems; and above all, repetitive activity.
8. Repetitive behavior – Repetition is the natural ‘setting’ for input and output systems, and that they are normally stopped from repeating when their products are acknowledged by a high-level central monitor. Such acknowledgement could be the signal for an input device to start processing new information and for output device to change to new action. The impaired brain, in the case of autism, would show a disengagement between central and peripheral devices, because the central control processes are too weak to control them and to switch them off appropriately.
9. Rigidity - flexibility is a quality particularly appropriate for a higher-level context using mechanism, but not for lower-level processing devices where reliability would be more important. From an evolutionary perspective it is obvious that the behavior of neurologically primitive organisms is rigidly programmed.
10. Pragmatics, idiosyncratic speech – picking up wrong meaning in a situation
Veumeulen : People with autism experience their greatest communication problem with what is not being said. Meaning is hidden within the context, which contains the information that is necessary to fully understand what is actually expressed. Because people with autism are slower in grasping context, they lack the information that is necessary to comprehend the whole. Often they react only to part of the whole.
11. Echolalia – the processing of speech seems to bypass involvement of central thought. Though they are perfect phonological, prosodic and syntactic units, these products do not become part of global meaning. Weak central coherence precludes the capacity to appreciate the deeper intentional aspects of communication.
12. Reversal use of ‘ I’ and’ you’, tenses, ‘this’ and ‘that’, ‘here’ and ‘there’, ‘come’ and ‘go’ – their use is relative to who is speaker and who is listener, therefore grasping of context is more difficult
13. Odd intonation, pitch, speech rate, fluency, word stress in speech – true intentional communication is impaired
14. Lack of a theory of mind – information from different sources, the results of seeing, remembering and telling, are all pulled together in a coherent interpretation of what happened. If it were not a coherent whole, perhaps because of a weak drive for coherence, but remained a complex set of separate pieces of information, then anybody would find it difficult. Improbable behavior is improbable because it does not belong to a coherent system of thought.
Implication : deficits in ToM were conceptualized as just one consequence of weak central coherence. Understanding social interaction and extracting the higher-level representation of thoughts underlying behavior, was seen as the pinnacle of coherent processing and gist extraction. Thus, people with autism were socially impaired because they were unable to derive higher-level meaning..
Mentalizing ability can be seen as a cohesive interpretative device par excellence: it forces together complex information from totally disparate sources into a pattern which has meaning. The ability which allows us to know that we know may be the key to the ability to make sense. (metarepresentation)
Veumeulen’s other interpretations of weak central coherence manifestations:
15. Difficulty in decision making. When autistic people are required to make choices, they see themselves confronted with a host of possible alternatives, as well as those alternatives that coherent thinkers have eliminated beforehand because they do not fit into the context of the whole.
16. Difficulty in dealing with various things at the same time. Information is processed ‘piece by piece’; their intelligence is characterized by ‘piecemeal processing’. In this, they need time to gain an understanding. They always have a delayed reaction time.
17. Lack of common sense – they assign meanings in an ‘idiosyncratic’ way (in contrast to ‘communal’).
18. Good memory of details – autistic people detect much less cohesion. They are dependent on their memory of details.
The Relationship between Weak central Coherence and ToM
Happ, F. (2000).
Non-social features of autism that ToM has limitations in explaining (as pointed out by Happ) :
1. restricted repertoire of interests
2. obsessive desire for sameness
3. stereotypies
4. savant abilities
5. lack of generalization
6. excellent rote memory
7. preoccupation with parts of objects
8. fragmented sensory perception
Experimental findings not accounted for by mind-blindness
assets deficits
Memory for word strings Memory for sentences
Memory for unrelated items Memory for related items
Echoing nonsense Echoing with repair
Pattern imposition Pattern detection
Jigsaw by shape Jigsaw by picture
Sorting faces by accessories Sorting faces by person
The central coherence account of autism, then, predicts skills as well as failures, and as such can best be characterized not as a deficit account, but in terms of cognitive style. As such it is better able than most accounts to explain the many things that people with autism are good at .
Weak central coherence characterizes the spontaneous approach or processing preference of people with autism, and for this reason is best captured in open-ended tasks, i.e. autistic people fail to use preceding sentence context to determine the pronunciation of homographs. When instructed in reading for meaning, group differences on the homograph disappear.
Later developments in explaining the relationship between Central Coherence and ToM
Frith and Happ (1994) modified their previous view and proposed as a working hypothesis that that the two aspects of autism, weak central coherence and impaired ToM, were independent (though interacting) facets of the disorder..
There is evidence, too, that the non-social features of autism persist even in the minority of people with autism who do develop some theory of mind ability (albeit with a significant delay). They still have self-injurious behavior and peculiar mannerism, tics, twitches, preoccupations, and equally high levels of insistence on sameness, circumscribed interests, and repetitive movement and language.
It suggests weak central coherence and ToM are distinct. Frith and Happ have not devised measures of them sensitive enough to degree of abnormality to reveal a true relation between the two.
It seems that there is indirect evidence which says that tasks that weak central coherence will excel such as Embedded Figures test correlate negatively with ToM tasks.
The relationship between ToM and weak central coherence depends on what is meant by ToM.
Happ proposed that ToM has 2 meanings, namely :
1. a basic ability to form representations capable of capturing prepositional attitudes (M-representations) – an ability which is necessary for passing false-belief tests.
2. there is the individual’s emergent social understanding, which is based on the ability to form m-representations in order to attribute mental states, but which is clearly also a function of many other characteristics including personality, motivation, empathy, intelligence, and environmental and experiental factors (e.g. Dunn et al. 1991)
In Frith and Happ’s current conceptualization, central coherence is independent from ToM in its former, but not its latter, meaning. The autistic impairment in forming m-representations is not the cause or result of weak central coherence. However, when we consider ToM in its second (and broader) sense, then social understanding cannot be considered independent of coherence – because in order to appreciate people’s thoughts and feelings in real life, one needs to take into account context and to integrate diverse information. So when we measure social understanding in a more naturalistic or context-sensitive way, we are likely to find a contribution from central coherence – and that individuals with weak central coherence and detail-focused processing are less successful in putting together the information necessary for sensitive social inference.
Another alternative in determining the relationship between central coherence and ToM is that they are casually connected. It is conceivable that integrative processing of environment provides the inputs necessary for the maturation of the ToM mechanism. It is also conceivable that our tendency for extraction of higher-level meaning is socially-mediated.
What does Simon Baron-Cohen say about weak central coherence in his new paper ‘The exact mind: Empathising and systemizing in autism spectrum conditions (in press draft 4th May 2001)?
Simon Baron-Cohen’s new ToM theory consists of 2 theories :
1. Empathising – it encompasses ToM, mind-reading, intentional stance and some affective reaction.
2. Systemising – it explains the repetitive behavior and obsessions and a superior ability in an initial analysis of the system (be it a technical system, a natural system, an abstract system, a social systems, SBC says systems are all around us in our environment and fall into the above 4 kinds) down to its lowest level of detail in order to identify potentially relevant parameters that may play a causal role in the behavior of the system.
SBC claims that systemizing in his new ToM theory embraces aspects of the central coherence theory, say excellent attention to detail. However they make opposite predictions when it comes to an individual with autism being able to understand a whole system, so long as there are underlying rules and regularities that can be discovered and he will readily grasp that a change of one parameter in one part of the system may have distant effects on another part of the system. This kind of reasoning clearly involves good central coherence of the system. In contrast, the central coherence theory should predict that he should fail to understand whole (global) systems or the relationships between parts of a system.
In explaining repetitive behavior, SBC says much of it involves the child’s obsessional or strong interests with mechanical systems or other systems that can be understood in terms of rules and regularities. This and what is often described as their “need for sameness” in attempting to hold the environment constant, might be signs of the child as a superior systemiser. The child might be conducting mini-experiments in his or her surroundings, in an attempt to identify physical-causal or other systematic principles underlying events.
Superior systemizing depends on exactness in information processing. This exactness is seen in autistic people’s pedantic speech ,the inclusion of more details than necessary in their answers, and their very detailed memory., However if the exactness mechanism is too highly tuned, it is not possible to answer questions to which an exact answer is unavailable. It also takes longer to select an answer from many possible ones. It therefore affects one’s empathizing skills, as in this domain, answers are never exact. |
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发表于 2010-1-25 08:21:02
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发表于 2010-1-25 09:23:19