The Visual Cognitive Process - Essay Example

www.allwriting.net Sumanta Sanyal Dated: 1/12/06 A Critical Examination: The Visual Cognitive Process Abstract The paper is an investigation in the human visual process of reading. It initially finds that there are two parallel sets of processes involved in this – the distal processes that are indirectly involved and the proximal processes that are directly involved. Distal processes may be verbal skills and retrieval from long-term memory (Kirby, J.R., 1999). Proximal processes may be - orthography (this is the graphic dimension of the letters in the text which may collectively be recognizable as words; common grammatical signs such as punctuation marks etc. are also taken in by this initial task; orthography is the first task that is performed in visual reading); phonology (this is the sound element of words and pseudowords that allows the reader to associate them with their semantics and other properties; it is noted here that humans usually learn language through the spoken means and phonology allows them to more easily associate with other properties); syntactics (each language prescribes a particular order in which it may be spoken or written in a grammatical sense and this is syntactics; the reader has to decode the syntactics to move forward to the next reading tasks – lexicology and semantics); lexicology (this is the signified meaning of the words as they are posited in the text and is construed as per the previously realized tasks); semantics (this is the signified associated implications and inferences that can be drawn on the words and sentences taken in conjunction or in singularity and this task assists primarily in comprehension) and thematic processing (this is the task that allows individual components of a text to be aligned to others so that a comprehensive meaningful overview of the text is available to the reader) (McCallum, R.D., 2006). The paper also finds hat these processes, in visual reading are deployed in two manner of approaches – the bottom-up approach adopted by less-skilled readers who use the orthography of the textual components to proceed further into visual processing for understanding and storing textual meaning and the top-down approach employed by skilled readers who can almost instantaneously interpret orthography of certain textual components into comprehension (Healey, C.G., 2006). The paper also finds that preattentive reading skills assist the reader in focusing on textual components while post-attentive ones allow him or her to enable further comprehension and memorial retention (Healey, C.G., 2006). The paper has eschewed lengthy discussion on relevant process regions in the brain as the evidence to date is too copious to include within its brevity. It has fairly concluded that both the cerebral cortex and, as more recently found, parts of the cerebellum are involved in the processes of visual reading, regions and activation varying with differentiation in presented text and, sometimes, gender of reader. Introduction Reading is fundamentally a set of processes by which an individual utilizes text to gain meaning, knowledge or experience from it (Henry, D.J., Undated). It is a process that allows human individuals to access a particular phenomenon, the text being read, in their immediate physical environment. In essence, the individual is utilizing his or her perception, with and without prior knowledge to assist it, to subjectivise, as thoroughly as possible, an objective in the world. All the processes involved in this, the perceptive processes, shall be dealt with here to some detail. These may be available from a number of interrelated disciplines such as – cognitive and developmental psychology, educational research and neuroscientific research. Thus, it is noted that both the psychological and physiological aspects of a human individual’s techniques that are employed to read text shall be elucidated. As the title implies, reading is a highly visual process as the main stimulus is the letters of the text provided from the outside and the eyes, in turn, access the letters of the texts. The importance of this paper can easily be borne out by the following statistics: Over the past 30 years, for the United States, the difficulty of text being read in the workplace has increased by several grades and more than 60% of US jobs require quite a high level of reading skills yet the US ‘National Center for Educational Statistics’ reveal that the reading proficiency of US high school students have not increased significantly in the past few decades (Walker, S., et al, 2005). This statistics does prove that there is still a very good reason why more has to be done to investigate how humans read – what inherent and acquired processes assist them to be efficient at this presently almost everyday exercise for a large part of the world population. Only thus can more and more people be taught more efficiently the required skills that can allow them to become proficient readers. The paper’s motive is thus amply justified. Neurological Components: Neurologically, visual reading involves focusing eyes on particular segments of the text, letters or words, allowing the orthography of the text segments to be conveyed to the brain by neural processes from the eyes. The fovea is a focal point on the retina most richly supplied with nerve ends and, as such, the area of clearest vision. Readers focus by allowing the viewed parts of the text to fall on the fovea. Extra-foveal vision allows the reader to review what they perceive via the fovea. The following steps may be taken to comprise the process of visual reading. 1. Foveal vision allows the reader to focus on particular segments of the text. 2. The reader’s eyes pause regularly (these pauses are called fixations) to make meaning of the orthography of the textual parts taken in during initial foveal vision. The focused period between fixations is called ‘saccade’. Fixations may last for 0.5 seconds while saccade may endure for 0.25 seconds. 3. Extra-foveal vision is utilized to review textual components already taken in to get the larger perception of the text. 4. Visual processing of individual textual components may take up to 0.5 seconds. The above is a very simplistic rendition of the visual reading process but it will enable the paper to base the real complexity on. The paper shall now begin the quest for neuroscientific processes associated with visualization in reading by positing two simplistic approaches to alignment of such processes in cognitive reading. Two Simplistic Approaches Top-Down/Bottom-Up Approach: When reading is taken as a cognitive process, as in part it is, then there are two acknowledged branches of sub-processes that readers with differing skills employ. The first is the bottom-up process that less skilled readers employ – where words and letters are taken in first, as stimuli from the outside world, and information is extracted out of them. Here it is noted that though apriori knowledge of the reading process is inevitable for a high level skill such as reading but bottom-up readers are able to apply such knowledge minimally (Treiman, R., 2001). Highly proficient readers, on the other hand, with their high level of apriori knowledge of the reading process, are able to apply that to such an extent that they use preconceived hypotheses of what words they may encounter in the reading process and later use certain words within the text to test out their hypotheses (Treiman, R., 2001). Bottom-up readers are, in contrast, more complete and systematic in their task as they are not proficient enough to read selectively on the basis of preformed hypotheses of what they may encounter while reading (Treiman, R., 2001). Distal/Proximal Approach: Another simplistic approach asserts that the cognitive processes required to accomplish reading tasks, easy or difficult, utilize two sets of such –processes. The first set is the distal set that is somewhat removed from the exact task at hand – reading. Such processes may be those related to verbal skills and memory (Kirby, J.R., 1999). These have a weak correlation with core reading skills and processes (.4-.5) and the causal link with reading skills is also weak (Kirby, J.R., 1999). Paradoxical results such as children with very weak reading skills excelling at other tasks that require high cognitive abilities can be explained by this approach. The second part of the approach presents the view that there are other cognitive processes that are highly correlated (.6-.8) to reading skills and these are termed as proximal ones (Kirby, J.R., 1999). There is evidence that there is a definite causal link between these processes and the ones used in reading (Kirby, J.R., 1999). Such proximal processes may be all the reading-relevant processes as the orthographic, semantic, lexical, syntactic and thematic and any others that may be. While these two approaches may seem a rather simplistic manner in which processes that are inherently highly complex are explained the paper believes that they, nevertheless, are still very valuable schema to base the subsequent complexities upon. They are schema that are based upon innate human cognitive processes and as such can be used as reliable guidelines with which the more complex neuroscientific components of reading can find successful elucidation. General Explanation This is not exactly an exclusive neuroscientific explanation as cognitivists also acknowledge the same but the reading process is a composite one that requires skills in many directions – orthographic, phonological, semantic, thematic and syntactic, for example. This is true language comprehension, as reading may be more universally called (Keller, T.A., et al, 2001). Theoretically, there are two broad approaches to understanding how this composite strategy works. The first approach is that these differing areas of language comprehension are accessed separately in an informationally encapsulated manner. This seems to be the initial approach to reading when the separate processes proceed without help or knowledge of the other processes (Keller, T.A., et al, 2001). Thus, lexical access to the semantic content of the words in a sentence may proceed without considering the other involved processes that may come before or after it. In contrast, the second theoretical approach believes that a more interactive or constraint-satisfaction strategy achieves comprehension through the very interaction of the various involved processes or through constraints place on some processes while others are promoted at their expense (Keller, T.A., et al, 2001). In the constraint-satisfaction approach a part of the involved processes are utilized as is necessary to gain the targeted satisfaction out of reading. The controversy that arose as a result of these conflicting ideas on the approach to reading has, in fact, allowed researchers to discover that there are definite indications that lexical/semantic factors affect the speed and accuracy of syntactic/thematic processing and vice versa (Keller, T.A., et al, 2001). At this point in the paper it is noted that the distal/proximal approaches are applicable to all reading theories, whether psychological or neurophysical. The bottom-up/top-down approaches can also be applied to both the modulated/constraint-satisfaction theories as, whichever neural process – modulated or constraint-satisfaction – is accepted it is highly likely that the level of competence works neurophysically and either enables the reader with established mnemonic pathways to read top-down or constrains the reader to slow down and read bottom-up. Neurophysical Visualization Visualization is a very important part of the broader process of perception through which humans gain access to their environs and their inner beings. Thus it is necessary to understand how the visualization process works scientifically – in the sense as to what mechanisms within human physiology enables the process. The following portions elucidate the visualization process though they do not do so specifically in relation to reading. Nevertheless, it is assumed by the paper that such general reckoning of the visualization process will enable later elucidation of it. Preattentive Skills: It takes the human eye at least 200-250 milliseconds to focus (gather attention) on an object but researchers have found that there is visual perception even within this time-frame. This is called preattentive vision – a very low level one with which humans can tell ‘at a glance’ some distinct property/properties within the viewable object/objects (Healey, C.G., 2006). For example, as per Diagram 1 (Appendix), in Fig. (a) preattentive vision immediately allows the viewer to become visually aware of the conflicting red spot within the sea of distracting blue spots. In contrast, in Fig. (b) the viewer’s visual perception does not begin before the threshold 200-250 milliseconds as there is nothing distinct within the images (Healey, C.G., 2006). Many more such distinctions can be enabled by this preattentive vision and the paper envisions that the same may be true for special words the reader is familiar with and that is immediately perceived as soon as the viewer’s eyes are subjected to the text. This is one explanation as to how bottom-up reading is possible. It is also noted that orthographic properties of words, the familiar ones, allow preattentive skills in reading (Healey, C.G., 2006). Thus, for the sentence – ‘There is a cat on the floor’ – it may be that the reader immediately, preattentively, visually perceives the words ‘cat’ and ‘floor’ which, though assumed familiar to the reader, are placed differentially among a sea of very common words that help distinguish them by their relative uncommonality. Associated words that are both familiar and stand out from the rest of the sentence assist in bottom-up visualization in a time-dependent manner. The preattentive bottom-up perception allows the reader to focus on the perceived objects, the words ‘cat’ and ‘floor’ and derive their semantics subsequently. Timewise, bottom-up processing is still slower than top-down, as shall be explained subsequently, because the reader becomes preattentively aware of the unique orthography of certain words in the text which he or she derives semantics and other properties of after attention is focused. Maps of the orthography of familiar words in the brain do assist in this form of visual perception (Healey, C.G., 2006). Preattentive skills require low-level visualization and operate on the basis of the short-term memory (Healey, C.G., 2006). Preattentive visualization also focuses on an object hierarchy of degree of uniqueness (familiarity or distinctness among peer objects) of the object/objects among other objects in the visualized scene. Post-Attentive Skills: While preattentive skills draw human attention to an object through visual interaction with its innate properties and focus it on the object, post-attentive visual skills determine what happens to that focused objective representation after the attention has drifted elsewhere (Healey, C.G., 2006). Post-attentive visualization may be taken to be top-down in the context that it allows the viewer to make sense of what he or she has just perceived pre-attentively. If the preattentive part has been so that a number of objects (say, a number of words in a sentence) has been perceived conjunctively such that more than their orthographic properties, i.e. phonological, syntactic, semantic and thematic ones, can be mapped from the brain post-attentive visualization springs into attention and the sense that is perceived of the set of objects, in this case the words in the sentence, is recorded in the long-term memory. Thus, while preattentive viewing utilizes only the short-term memory post-attentive viewing utilizes the long-term memory to perceive properties other than the simple orthographic ones realized in the preattentive context of the viewed objects. Thus, post-attentive visualization in reading allows the reader to make sense of the words that may be viewed preattentively and marked for further action in the post-attentive period – more than 350 milliseconds (Healey, C.G., 2006). Post-attentive visualization in reading is only possible if the reader is expert and has existing brain maps of properties other than the orthographic of the words earmarked during preattentive viewing. This is the top-down reading process where the reader skims over certain words to extract meaning out of them almost instantaneously. Though, on the surface, it may seem that preattentive visualizations allows more speed in reading this is bottom-up and slower than top-down as only the orthographic properties are earmarked for further processing for other properties, which takes more time. Conclusion While the previous sections of the paper have adequately and quite precisely pin-pointed the psycho-neurological basis of human visual reading signifying an accurate brain map of the same is much more difficult. Extensive literature review reveals that while there is consensus on broader processing regions in the brain for particular component visual reading processes there is very little consensus on accurate regions in the sense that more and more new regions are being discovered continuously for the same processes. This creates a bewildering range of regions to choose from and the paper eschews this confusion by sticking to the broader regions. Techniques used to map such process regions are functional magnetic resonance imaging (fMRI), positron emission tomography (PET), electroencephalography (EEG) and magnetoencephalography (MEG). That accuracy of findings is not total is borne out by the findings that recent fMRI data results have not been consistent with lesion studies that can often pinpoint process regions by correlation between lesion regions and dysfunctional processes (Saykin, A.J., et al, 1999). Nevertheless, it is well-known that human though processes are mostly posited in the cerebral cortex and so are most of the visual reading processes but recent evidence suggests strongly that certain regions of the cerebellum also participate differentially in phonological and semantic visual reading (Fulbright, R.K., et al, 1999). Differential in the process sense means, i.e., phonologically words and pseudowords create activation in slightly different regions at slightly different rates in a time-dependent manner. Words are processed faster phonologically while pseudowords, being less known, take greater time (Fulbright, R.K., et al, 1999). While acknowledging overlapping processes, such as orthography being mapped onto lexical or sublexical phonology, the paper finds that a large part of the visual reading processes take place in the cerebral cortex with often distinction between male and female process regions for particular processes (Xu, B., et al, 2001). Lexical access and syntactic processing during visual reading is also located in the cerebral cortex regions and these processes at different levels share a common infrastructure (Keller, T.A., et al, 2001). All in all, the paper believes that it has placed a useful view of the visual processing humans employ, consciously or unconsciously, in reading tasks. Reference Fulbright, R.K., et al, The Cerebellum’s Role in Reading: A Functional MR Imaging Study, American Journal of Neuroradiology, 20, 1925-1930, (11 1990). Extracted on 24th November, 2006, from: http://www.ajnr.org/cgi/content/abstract/20/10/1925 Healey, C.G., 2006, Perception in Visualization. Extracted on 22nd November, 2006, from: http://www.csc.ncsu.edu/faculty/healey/PP/index.html#War:2000 Henry, D.J., Undated, Reading-Science Integration. Extracted on 24th November, 2006, from: http://faculty.dbcc.cc.fl.us/henrydj/reading%20science%20information.htm Keller, T.A., et al, 2001, The Neural Bases of Sentence Comprehension: a fMRI Examination of Syntactic and Lexical Processing, Cerebral Cortex, Vol. 11, No. 3, 223-237, March 2001. Extracted on 22nd November, 2006, from: http://cercor.oxfordjournals.org/cgi/content/full/11/3/223#top McCallum, Dr. R., 2006, A Reading Specialist’s View of the Reading Process. Extracted on 22nd November, 2006, from: http://www.homeschool.com/LetsGoLearn/Articles/ReadingProcess/default.asp Saykin, A.J., et al, Functional differentiation of medial temporal and frontal regions involved in processing novel and familiar words: and fMRI study, Brain, Vol. 122, No. 10, 1963-1971, October, 1999. Extracted on 24th November, 2006, from: http://brain.oxfordjournals.org/cgi/content/abstract/122/10/1963 Treiman, R., 2001, Reading. Extracted on 24th November, 2006, from: http://www.artsci.wustl.edu/~rtreiman/Selected_Papers/Treiman_Handbook_of_linguistics_2001.pdf Xu, B., et al, Conjoint and Extended Neural Networks for the Computation of Speech Codes: The Neural Basis of Selective Impairment in Reading Words and Pseudowords, Cerebral Cortex, Vol.11, No.3, 267-277, March 2001. Extracted on 22nd November, 2006, from: http://cercor.oxfordjournals.org/cgi/content/abstract/11/3/267 Appendix Diagram 1: Preattentive Vision (a) (b) (Source: Fig. 1, Healey, C.G., 2006) Read More