Transcript Working Memory Capacity and Processes - CELTA

An Attempt of a Neuropsychological
Foundation of MIC Theory
Presentation
at
the Interdisciplinary Conference
MIC Sorbonne 2010
Context-bound Communication
Université Paris-Sorbonne
CELTA
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Nov 19, 2010
Prof. Dr. Franz J. Stachowiak
Institut für Heil- und Sonderpädagogik
Sprachheilpädagogik
OUTLINE OF THE PRESENTATION
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2.
3.
4.
5.
6.
7.
8.
Introduction
Some examples from German as a FWO language
New and old information from a neurobiological perspective
Human memory as a differentiated system and its relation to text
comprehension
Working memory capacity and processes form the basis of topiccomment structuring and meta-informative processing in language
Attention; Topic and Comment and other centers of informational
saliency in texts
The MIC Component in models of language production and
comprehension
Neurolinguistic findings: text comprehension in aphasia
1. Introduction
• In the following I will try to establish a connection between some aspects
of the MIC Theory and neuropsychological findings about memory and
attention. I will argue that verbal processing of information is strongly
influenced by or even rests on the capacity and mode of operation of
working memory and other types of memory and is intricately related to
attentional processes. In fact I assume that the basic slot structure for
marking the information as new or old in verbal utterances derives from
operational principles, limits and strategies of working memory as a gate to
long term memory.
•
Ericsson and Kintsch (1995) have presented a model of text comprehension, in
which they assume an interaction of two kinds of processes: the short term
activation of information while text segments are being processed and the storage
and retrieval of information that forms episodic text structures in long term
memory. However, their psychological approach lacks some linguistic
fundamentals.
2. Some examples from German as a FWO language
Mein Mann
Kann
morgens
gut
Kaffee
Kochen
Variations
Interaction of pragmatic and grammatical factors
3. New and old information from a neurobiological
perspective
4. Human memory as a differentiated system and its
relation to text comprehension
Classification of Memory Types
Working Memory
Working memory refers to our capacity to simultaneously process and store
information. According to Baddeley´s (2003) model working memory consists of
several subcomponents which play an active role in the process of holding new
information while processing or changing it in the visual and the verbal system (for
instance in text production and and comprehension). The central executive serves the
attentional control of information that is actively dealt with in the visual or verbal
subsystems and it controls the transfer of information from and to long term memory.
In other words, this component is a good candidate for a mechanism that is engaged
in pragmatic decisions on the meta-informative status of information as organized in
utterances
5. Working memory capacity and processes form the basis of
topic-comment structuring and meta-informative processing in
language
• George A. Miller (1956) : the magical number 7 plus or minus 2, number
of information units that an average human can hold in working memory.
• In a very careful literature review Nelson Cowan (2000) came to the
conclusion that a single, central capacity limit between three and four
unrelated chunks, which can be attended at one time, characterizes human
short term meory. Chunks are understood as a collection of concepts that
have strong associations to one another and much weaker associations to
other chunks currently in use.
• Memory span = maximum list of items that a person can repeat correctly
immediately after presentation
Working Memory Capacity
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Waugh and Norman (1965) investigated the causes for forgetting. In their probe
method they presented lists of random numbers such as 5 2 6 8 7 2. Only the last
number, here the 2, appeared twice. This repeated number was called the “probe”.
The subjects were asked to pay attention to the appearance of the “probe” and then
report the number that had followed the probe after its first appearance in the list,
i.e. the 6.
Working Memory Capacity and Processes
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Sternberg (1966) examined whether we search the elements that are held in
working memory one item at a time (serially) or all at once (in parallel) and
whether this search stops when the item is located (self-terminating search) or
whether it continues till the entire content of the memory store has been checked
(exhaustive search) even if a match was found beforehand. He concluded that the
search is serial and exhaustive.
Scanning a brief list of digits contrasts sharply with a higher cognitive task, in
which the information is related to other information and is available to a person
within a communicative or situational context or which he/she might have stored in
long term memory. Considering the mass of information exchanged in verbal
communication, it must be assumed that an exhaustive serial search of all items of a
given linguistic surface structure would prevent the decoding of the message rather
than support it.
Considering these results together, it becomes understandable why centers of
attention within a text are used as boot straps against the decay of information on
the one hand and against inefficient unterminated scanning processes on the other.
Working Memory Capacity and Processes
The serial position effect
The serial position effect: basis of topic and comment?
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The serial position effect refers to the fact that in free list recall – i.e. when subjects
are asked to recall the items of a list of digits, words or other symbols in free order
– the accuracy of the recall depends on the position of the items in the list. In
immediate recall the last items of a list are usually better remembered than the first
ones (Recency Effect). The first items of the list are better recalled than the middle
ones (Primacy Effect). An explanation of the recency effect is that in short-term
memory the processing of new items overwrites old ones. At the time of recall the
last ones have not been overwritten and are still held active in working memory.
The primacy effect comes about, because initial items are more readily encoded
into long-term memory, as they could be rehearsed before new items came to be
processed. Thus in recall the first items are retrieved from long term memory. They
can also be processed by tghemselves, whereas the following ones have to be
incrementally dealt with together with the subsequent items. The recency effect
is eliminated when an interfering task is given before recall, as the new task
requires attention and processing capacity. Fast presentation of the items reduces
the primacy effect. Very late recall increases it.
Reading Span
• As it was recognized that memory span for symbols such as digits, letters
or single words is only weakly related to demanding cognitive tasks such as
text processing, a more complex type of span was developed with the
purpose of jointly tapping the storage and processing functions of Working
Memory (Danemann and Carpenter, 1980). The reading span task consists
in the presentation of groups of sentences which the test persons are asked
to read aloud. After that they are required to recall, in the sequential order
in which the sentences were presented, the last word of each sentence.
• The original reading span task was used in a variety of versions (see
Conway et al. 2005), which regularly showed impressive correlations with
language comprehension and other language processing tasks.
The necessity of Centers of Attention
• Although these psychological studies do not investigate meta-informative
strategies in sentence and text processing directly - a task that calls for
more linguistically based research - it appears that some basic
neuropsychological preconditions for dealing with new and old information
in texts can be traced in these results. The limitation of working memory
capacity is a factor in a cognitively demanding task such as text production
and comprehension. It imposes the necessity to select centers of attention as
bootstrapping devices to cope with the workload of simultaneously storing
and manipulating bits of information and arranging the linear surface
structure in such a way that communication partners are supported in
decoding the gist of the intended message. In this sense the skillfull filling
of the slots of a sentence´s topological field structure as for instance in
sentence (3) is part of necessary and universal properties of language
induced lastly by human biology and cognitive capabilities.
6. Attention; Topic and Comment and other centers of
informational saliency in texts
• “Everyone knows what attention is. It is the taking possession by the mind,
in clear and vivid form, of one out of what seem several simultaneously
possible objects or trains of thought. Focalization, concentration, of
consciousness are of its essence. It implies withdrawal from some things in
order to deal effectively with others, and is a condition which has a real
opposite in the confused, dazed, scatter-brained state which in French is
called distraction, and Zerstreutheit in German” (James, 1890: 75).
• Broadbent (1958). the classical filter model
• Treisman and Geffen (1967): the “attenuator” model of attention
• Norman (1968): the Pertinence Model of Selection and Attention
The pertinence model of selection and attention
Attention Capture
• Relevant chunks of information in human language need to be marked in
such a way as to catch the attention of the communication partner. Word
order change and intonation may be primary instruments, but equally and
additionally effective are “adverbial” lexical focus markers such as “eben”
(“just”), “gerade” (“exactly”), “insbesondere” (“especially”) which can
even be used cumulatively in order to draw the attention to that part of the
information that is considered as particularly relevant by its producer. My
colleague Henning Lobin, who has written a book on “Computerlinguistics
and Text-Technology” applied this instrument in his introductory speech to
the conference “Digital Science” (20.09.2010 in Cologne) when he said:
CA Marking
• (6) Und auch hier wird gerade im BMBF ja eine Art Integration all dieser
Förderungen diskutiert, eh.. eine Zusammenführung dieser eh
..Fördervorhaben, die eh.., wenn man sie alle zusammenrechnet, ein
unglaublich hohes Fördervolumen auch im Moment aufweisen, um eben
gerade insbesondere im Bereich der Gesellchaftswissenschaften, Geistesund Kulturwissenschaften so etwas wie ein E-Science Initiative ins Leben
zu rufen”
• “... and also here is in the BMBF (Federal Ministry of Education and
Research) surely a kind of integration (of) all those eh – fundings being
discussed, eh... a joining (of) those support projects, which eh... , if one
them all together counts, an unbelievably high funding volume also at the
moment exhibit, in order to just exactly especially in the area of the social
sciences, arts and cultural sciences (so) something like an E-Science
initiative into life to call”.
•
CA Marking
The speaker is guided by the listener´s need for
attentention capture aids
The MIC-Component in models of language production
and comprehension
Where to place the MIC Component?
Evidence from Speech Errors
A MIC-Component in language comprehension
8. Neurolinguistic findings: text comprehension in
aphasia
Grammatical Problems are compensated by
„contextualization“ factors
Less „redundancy“ – more comprehension problems
The MIC-Component in language comprehension needs
input
Word order variation and text comprehenion in aphasia
Vielen Dank für Ihre Aufmerksamkeit
Many thanks for your attention!
Remagen am Rhein