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1 Reading and Information Processing
1
Reading and Information Processing
The processes by which words are recognized during reading have concerned psychologists and educators for almost a century. The basic assumption is that a thorough understanding of the processes involved in word recognition will afford a major advance in the understanding of how people read. Every major treatise on reading from Huey (1908/1968) to Gibson and Levin (1975) has discussed this issue at length, but generally has concluded, as did Huey (1908/1968, p. 111l2) , that "it is very difficult to draw final conclusions concerning visual perception in reading ..•. " Recently two different panels which recommended funding priorities in basic skills research to the National Institute of Education assigned high priorities to studies on word recognition. Consequently, a high priority currently is being given to obtaining a better understanding of word recognition with stress on the basic stages of visual information processing. Information processing during reading is currently the primary concern of many experimental psychologists, and therefore, an expanding body of experimental data is being brought to bear on these questions. Since word recognition forms a bridge between visual information processing skills and comprehension, it is important for understanding how the two relate to each other. Research on word recognition processes is seen as having a high potential for improving reading instruction. Good and poor readers have been shown to differ in performance on a variety of general tasks but until recently, little attempt has been made to explore how children with different levels of reading ability might differ in basic word recognition processes. We believe that basic word recognition processes,
2
CHAPTER 1
once defined for competent adult readers, can be used to assess word recognition abilities of good and poor readers in the elementary grades. If good and poor readers utilize the same processes, but differ in speed or accuracy, then remediation methods based on common approaches to reading instruction would be warranted. However, if fundamental differences in visual recognition processes are found, then totally different remedial methods would be required. The overall objective of this research project is to assess how the reader's higher-order knowledge of the language interacts with lower-level perceptual analyses during reading. The specific question that is addressed is how the reader's abstract knowledge about orthographic structure is combined with the information derived from visual featural analysis in word recognition. Orthographic structure refers to the spelling constraints in a written language. There is a considerable amount of predictability in English writing, for example, and the reader may actively utilize this information in word recognition. Visual featural analysis refers to the evaluation of component properties of letters in the course of letter and word recognition. Given evidence that both of these sources of information contribute to word recognition, the goal is to define what information the reader actually utilizes (what information is psychologically real) and to define how these sources of information are integrated together in reading. This requires examination of the psychological reality of various descriptions of visual features, of orthographic structure, and of quantitative models that describe how visual features and orthographic structure are integrated during word perception and recognition.
AN INFORMATION PROCESSING MODEL OF READING Evaluation of the contributions of visual features and orthographic structure to word recognition requires that we describe in some detail the processes involved in reading. The model for describing these processes is part of a more general language processing model which has been developed and tested over the past few years (Massaro, 1975, 1978, 1979a). Figure 1.1 presents a schematic representation of the stages of processing in reading. At each stage of processing, memory and process components are represented. Each memory component (indicated by a rectangle) corresponds to the information available at a particular stage of processing. Each process
READING AND INFORMATION PROCESSING
3
component (indicated by a circle) corresponds to the operations applied to the information held by the memory component. The memory components are temporary storages except for long-term memory which is relatively permanent and, in addition, supplements the information at some of the processing stages. This model provides a framework from which hypotheses about word recognition can be derived and tested. The typical text in reading is a sequence of letters and spaces which conform to orthographic, syntactic, and semantic constraints of the written language. The average English reader begins at the top left-hand corner of the page and reads each line from left to right. The reader's eye movements across a line are not continuous but occur in a series of short jumps called saccades. The fixation time between saccades is roughly ten times longer than the saccade. The typical saccade of 1 to 2 degrees requires 20 to 30 msec, whereas fixation time averages 250 msec (Shebilske, 1975; Woodworth, 19381. Initial processing of the visual stimulus must occur during the fixation time because the stimulus pattern is blurred during a saccade and its duration is too short for sufficient processing to occur. During an eye fixation, the light pattern reflected from letters is transduced by the visual receptors and a process detects and transmits visual features to preperceptual visual storage (see Figure 1.11. In our model, we call this initial process feature detection. The features are described as visual because it is assumed that there is a direct relationship between the stimulus properties of the letters and
LONG TERM MEMORY
I FEATURE DETECTION
PREPERCEPTUAL VISUAL STORAGE
Figure 1.1
SYNTHESIZED VISUAL MEMORY
A stage model of reading printed text.
4
CHAPTER 1
the information in preperceptual visual storage. The passive transduction of feature detection contrasts with the active construction of the subsequent processing stages. There is no exact one-to-one relationship between the input and output of the following processing stages since these later stages actively utilize information stored in long-term memory. Given the set of visual features in preperceptual visual storage, the primary recognition process attempts to transform these isolated features into a sequence of letters and spaces in synthesized visual memory. To do this, the primary recognition process can utilize information held in long-term memory which for the accomplished reader includes a list of features for each letter of the alphabet along with information about the orthographic structure of the language. The primary recognition process utilizes both the visual features in preperceptual storage and knowledge of orthographic structure in its synthesis of the letter strings. The time-honored belief that recognition of letter strings becomes progressively easier as the strings more closely approximate words implies that readers capitalize on the presence of orthographic structure. Recognition usually means the process of discriminating, identifying, and correctly ordering the letters of a letter string (Smith, 1971). Given this interpretation of recognition, the facilitating effect of orthographic structure on letter-string recognition must almost be true by definition. Recognition involves accessing knowledge built up through experience. It is only natural that a reader's experience with words will generalize more to wordlike than nonwordlike strings. Our goals in this research endeavor are to provide a better understanding of the recognition process and to evaluate which aspects of orthographic structure the reader knows and utilizes. The central assumption addressed here is that orthographic structure influences perceptual recognition (primary recognition in our model), in addition to other influences at later stages of processing. We believe that orthographic structure also facilitates processing from a perceptual to a conceptual level (secondary recognition in our model). By focusing on the facilitating effects of orthographic structure on visual perception, we have aligned ourselves with a tradition over 100 years old concerned with how knowledge influences perception. James (1890/1950, p. 444) captured the spirit of the work begun by Wundt with the often quoted statement, " ... the only things which we commonly see are those which we preperceive."
READING AND INFORMATION PROCESSING
5
In our model, the primary recognition process evaluates the features in preperceptual visual storage and compares or matches these features to descriptions of perceptual units in long-term memory. A perceptual unit or prototype represents each of the letters in long-term memory as it would be ideally represented in preperceptual visual storage. The primary recognition process seeks for each letter position the perceptual prototype that provides the best match to the featural information. It is at primary recognition that orthographic structure reduces uncertainty or contributes information. The outcome of primary recognition is, therefore, the joint product of featural information in preperceptual visual storage and knowledge of letter constraints in long-term memory. Since there are a limited number of ways that sequences of letters and letter groups can be assembled to form English words, knowledge of these sequences can help the reader to resolve the letters in strings that conform to the language (cf. Massaro, 1975, Chapter 7). It also has been hypothesized that this knowledge can assist the reader in determining the relative positions of letters once they are recognized (Estes, 1975a, 1975b). For example, given the letters ch, knowledge of orthographic structure does not allow these letters to be read in the opposite order. However, Geoffrion (1976) found that the contribution of orthographic structure is not dependent on determining the relative positions of letters. In addition, recent research by Massaro (1979a) found a large effect of orthographic structure on letter recognition but no effect on the determination of relative spatial position. In the present research, the experiments are designed such that any facilitating effect of orthographic structure at primary recognition must be due to letter recognition and not position uncertainty. The primary recognition process operates on a number of letters simultaneously (in parallel). The visual features detected at each spatial location define a set of possible letters for that position. The primary recognition process chooses from this set of candidates the letter alternative which has the best correspondence in terms of visual features. However, the selection of a best correspondence can be facilitated by knowledge of orthographic structure. The primary recognition process, therefore, attempts to utilize both the featural information in preperceptual storage and knowledge about the structure of legal letter strings. A critical concern is with the interaction of these two sources
6
CHAPTER 1
of information1 in our model, it is assumed that the two sources of information make independent contributions to primary recognition (Massaro, 1973, 1975, 1978, 1979b1 Thompson & Massaro, 1973). The present analysis of the facilitation of orthographic structure in letter recognition is identical in spirit to the original analysis provided by Miller, Bruner, and Postman (1954). They observed that the number of letters correctly reported from a tachistoscopic exposure increased with increases in familiarity of the letter pattern. The familiarity of the letter sequences was varied by the degree to which the sequence approximated printed English (Shannon, 1948). utilizing the theory of information developed by Shannon (1948), however, they observed that the number of letters reported is not a direct index of the amount of stimulus information derived from the exposure itself since the redundancy of contextually constrained sequences is not taken into account. Miller et al. (1954) calculated the redundancy of their sequences at each order of approximation to English using the counts given by Shannon (1951) and counts of their own. When performance was corrected for redundancy, there was no effect of familiarity (see also Tulving, 1963). This result was interpreted to mean that the amount of stimulus information received from the exposure did not depend on the familiarity of the letter pattern. In terms of our analysis, over two decades later, the results can be interpreted to mean that orthographic structure and visual information contribute independent sources of information in reading. The current view was developed, in part, on the basis of experiments carried out using the Reicher-Wheeler paradigm in word recognition (Reicher, 19691 Wheeler, 19701 Thompson & Massaro, 1973). In this paradigm, subjects are presented with either a test word or a single test letter for a short duration followed immediately by a masking stimulus and two response alternatives. The response alternatives both spell words in the test word condition1 for example, given the test stimulus WORD, the response alternatives ---Q and ---! would be presented. In the corresponding single test letter condition, Q is presented and followed by the response alternatives Q and !. In these studies, recognition of the test word is about 10% better than recognition of the test letter. Given the two-alternative forced-choice control, it is assumed that the reader utilizes orthographic structure to eliminate possible alternatives during the perception of the
READING AND INFORMATION PROCESSING
7
test display (Thompson & Massaro, 1973). As an example, presented with the test stimulus WORD and given recognition of test letters WOR and a curvilinear segment of the final letter, the reader could narrow down the alternatives for the final letter to D, 0, and Q. If 0 and Q are considered to be orthographically illegal in the context WOR-, then D represents an unambiguous choice. The reader will therefore perceive the word WORD given just partial information about the final letter. If the reader recognizes the same curvilinear segment in the corresponding single test letter condition, however, any of the three letters (D, 0, and Q) are possible and the perceptual synthesis will result in D only one out of three times. What is critical in this analysis is that the better performance on words compared to single letters is obtained even though the visual featural information available to the primary recognition process is equivalent in the word and letter conditions. The orthographic structure of the word simply provides an additional but independent source of information. The featural information available to the recognition process does not change with changes in orthographic structure. In this view, although orthographic structure facilitates word perception, it does not modify the feature analysis of the printed pattern (Krueger & Shapiro, 1979; Massaro, 1979a). As we have discussed, one role of orthographic structure is concentrated in the primary recognition process and serves to facilitate the recognition of individual letters. In addition, orthographic structure is functional at later stages of processing, such as its facilitating effect in short-term memory (Massaro, in press). Baddeley (1964), for e x amp l e , showed that a well-structured string of letters is easier to remember and recall than a random string. Whether orthographic structure facilitates perceptual recognition is a more controversial issue. We assume that it is utilized in the following manner. Upon presentation of a letter string, the primary recognition process begins integrating and synthesizing featural information passed on by feature detection to preperceptual visual storage. Featural information is resolved at different rates and there is some evidence that gross features are available before the more detailed features (Massaro & Schmuller, 1975). The primary recognition process is faced with a succession of partial information states. These partial visual information states are supplemented with knowledge about orthographic structure. Assume, for example, an initial th has been perceived in a
8
CHAPTER 1
letter string, and the features available for the next letter eliminate all alternatives except ~ or e. The primary recognition process might synthesize ~ without waiting for further visual information, since initial thc is not acceptable while initial the is. The primary recognition process transmits a sequence of recognized letters to synthesized visual memory. Figure 1.1 shows ho~ the secondary recognition process transforms this synthesized visual percept into meaningful form in generated abstract memory. We assume secondary recognition attempts to close off the letter string into a word. The secondary recognition process makes this transformation by finding the best match between the letter string and a word in the lexicon in long-term memory. Knowledge of orthographic structure can also contribute to secondary recognition; word recognition can occur without complete recognition of all of the component letters. Given the letters bea and the viable alternatives 1 and t in final position, only! makes a word, and therefore word identification (lexical access) can be Bchieved (Massaro, 1977). Each word in the lexicon contains both perceptual and conceptual codes. The word which is recognized is the one whose perceptual code gives the best match and whose conceptual code is most appropriate in that particular context. Generated abstract memory corresponds to the short-term or working memory of most information processing models. In our model, this memory is common to both speech perception and reading. Recoding and rehearsal processes build and maintain semantic and syntactic structures at the level of generated abstract memory. It is also possible to go from meaning to a visual or auditory percept in our model. The recoding operation can transform the meaning of a concept into its surface structure in an auditory or visual form. Two issues concerning letter and word recognition in reading will be addressed in the present research. First, what are the visual features of letters utilized by the primary recognition process? Second, how is knowledge of orthographic structure psychologically represented? To address these issues, any study must be concerned with how these sources of information are evaluated, integrated, and combined in perceptual recognition (Massaro, 1979b). The discussion of visual features is presented in Chapter 2 and the discussion of orthographic structure is presented in Chapter 3. The fourth chapter focuses on how the reader utilizes both sources of information in a variety of perceptual recognition and overt
READING AND INFORMATION PROCESSING
9
judgment tasks. To sustain the logical continuity of the presentation of the experiments, details of the method, procedure, and results are placed in appendices at the end of the chapter. The fifth chapter presents a detailed evaluation of the psychological reality of many descriptions of orthographic structure. The data base derived from the present experiments is also presented to allow additional tests of other descriptions of orthographic structure. In addition, normative counts of letter and letter cluster occurrences in text are presented. These counts make possible the measurement of a variety of stimulus and test items according to a number of formal descriptions of orthographic structure. The last chapter summarizes the contributions of the present research. The central concern of the empirical and theoretical work presented here is to evaluate the nature of the processes involved in letter and word recognition and to discover how knowledge about orthographic structure is represented and utilized.
Reading and Information Processing
The processes by which words are recognized during reading have concerned psychologists and educators for almost a century. The basic assumption is that a thorough understanding of the processes involved in word recognition will afford a major advance in the understanding of how people read. Every major treatise on reading from Huey (1908/1968) to Gibson and Levin (1975) has discussed this issue at length, but generally has concluded, as did Huey (1908/1968, p. 111l2) , that "it is very difficult to draw final conclusions concerning visual perception in reading ..•. " Recently two different panels which recommended funding priorities in basic skills research to the National Institute of Education assigned high priorities to studies on word recognition. Consequently, a high priority currently is being given to obtaining a better understanding of word recognition with stress on the basic stages of visual information processing. Information processing during reading is currently the primary concern of many experimental psychologists, and therefore, an expanding body of experimental data is being brought to bear on these questions. Since word recognition forms a bridge between visual information processing skills and comprehension, it is important for understanding how the two relate to each other. Research on word recognition processes is seen as having a high potential for improving reading instruction. Good and poor readers have been shown to differ in performance on a variety of general tasks but until recently, little attempt has been made to explore how children with different levels of reading ability might differ in basic word recognition processes. We believe that basic word recognition processes,
2
CHAPTER 1
once defined for competent adult readers, can be used to assess word recognition abilities of good and poor readers in the elementary grades. If good and poor readers utilize the same processes, but differ in speed or accuracy, then remediation methods based on common approaches to reading instruction would be warranted. However, if fundamental differences in visual recognition processes are found, then totally different remedial methods would be required. The overall objective of this research project is to assess how the reader's higher-order knowledge of the language interacts with lower-level perceptual analyses during reading. The specific question that is addressed is how the reader's abstract knowledge about orthographic structure is combined with the information derived from visual featural analysis in word recognition. Orthographic structure refers to the spelling constraints in a written language. There is a considerable amount of predictability in English writing, for example, and the reader may actively utilize this information in word recognition. Visual featural analysis refers to the evaluation of component properties of letters in the course of letter and word recognition. Given evidence that both of these sources of information contribute to word recognition, the goal is to define what information the reader actually utilizes (what information is psychologically real) and to define how these sources of information are integrated together in reading. This requires examination of the psychological reality of various descriptions of visual features, of orthographic structure, and of quantitative models that describe how visual features and orthographic structure are integrated during word perception and recognition.
AN INFORMATION PROCESSING MODEL OF READING Evaluation of the contributions of visual features and orthographic structure to word recognition requires that we describe in some detail the processes involved in reading. The model for describing these processes is part of a more general language processing model which has been developed and tested over the past few years (Massaro, 1975, 1978, 1979a). Figure 1.1 presents a schematic representation of the stages of processing in reading. At each stage of processing, memory and process components are represented. Each memory component (indicated by a rectangle) corresponds to the information available at a particular stage of processing. Each process
READING AND INFORMATION PROCESSING
3
component (indicated by a circle) corresponds to the operations applied to the information held by the memory component. The memory components are temporary storages except for long-term memory which is relatively permanent and, in addition, supplements the information at some of the processing stages. This model provides a framework from which hypotheses about word recognition can be derived and tested. The typical text in reading is a sequence of letters and spaces which conform to orthographic, syntactic, and semantic constraints of the written language. The average English reader begins at the top left-hand corner of the page and reads each line from left to right. The reader's eye movements across a line are not continuous but occur in a series of short jumps called saccades. The fixation time between saccades is roughly ten times longer than the saccade. The typical saccade of 1 to 2 degrees requires 20 to 30 msec, whereas fixation time averages 250 msec (Shebilske, 1975; Woodworth, 19381. Initial processing of the visual stimulus must occur during the fixation time because the stimulus pattern is blurred during a saccade and its duration is too short for sufficient processing to occur. During an eye fixation, the light pattern reflected from letters is transduced by the visual receptors and a process detects and transmits visual features to preperceptual visual storage (see Figure 1.11. In our model, we call this initial process feature detection. The features are described as visual because it is assumed that there is a direct relationship between the stimulus properties of the letters and
LONG TERM MEMORY
I FEATURE DETECTION
PREPERCEPTUAL VISUAL STORAGE
Figure 1.1
SYNTHESIZED VISUAL MEMORY
A stage model of reading printed text.
4
CHAPTER 1
the information in preperceptual visual storage. The passive transduction of feature detection contrasts with the active construction of the subsequent processing stages. There is no exact one-to-one relationship between the input and output of the following processing stages since these later stages actively utilize information stored in long-term memory. Given the set of visual features in preperceptual visual storage, the primary recognition process attempts to transform these isolated features into a sequence of letters and spaces in synthesized visual memory. To do this, the primary recognition process can utilize information held in long-term memory which for the accomplished reader includes a list of features for each letter of the alphabet along with information about the orthographic structure of the language. The primary recognition process utilizes both the visual features in preperceptual storage and knowledge of orthographic structure in its synthesis of the letter strings. The time-honored belief that recognition of letter strings becomes progressively easier as the strings more closely approximate words implies that readers capitalize on the presence of orthographic structure. Recognition usually means the process of discriminating, identifying, and correctly ordering the letters of a letter string (Smith, 1971). Given this interpretation of recognition, the facilitating effect of orthographic structure on letter-string recognition must almost be true by definition. Recognition involves accessing knowledge built up through experience. It is only natural that a reader's experience with words will generalize more to wordlike than nonwordlike strings. Our goals in this research endeavor are to provide a better understanding of the recognition process and to evaluate which aspects of orthographic structure the reader knows and utilizes. The central assumption addressed here is that orthographic structure influences perceptual recognition (primary recognition in our model), in addition to other influences at later stages of processing. We believe that orthographic structure also facilitates processing from a perceptual to a conceptual level (secondary recognition in our model). By focusing on the facilitating effects of orthographic structure on visual perception, we have aligned ourselves with a tradition over 100 years old concerned with how knowledge influences perception. James (1890/1950, p. 444) captured the spirit of the work begun by Wundt with the often quoted statement, " ... the only things which we commonly see are those which we preperceive."
READING AND INFORMATION PROCESSING
5
In our model, the primary recognition process evaluates the features in preperceptual visual storage and compares or matches these features to descriptions of perceptual units in long-term memory. A perceptual unit or prototype represents each of the letters in long-term memory as it would be ideally represented in preperceptual visual storage. The primary recognition process seeks for each letter position the perceptual prototype that provides the best match to the featural information. It is at primary recognition that orthographic structure reduces uncertainty or contributes information. The outcome of primary recognition is, therefore, the joint product of featural information in preperceptual visual storage and knowledge of letter constraints in long-term memory. Since there are a limited number of ways that sequences of letters and letter groups can be assembled to form English words, knowledge of these sequences can help the reader to resolve the letters in strings that conform to the language (cf. Massaro, 1975, Chapter 7). It also has been hypothesized that this knowledge can assist the reader in determining the relative positions of letters once they are recognized (Estes, 1975a, 1975b). For example, given the letters ch, knowledge of orthographic structure does not allow these letters to be read in the opposite order. However, Geoffrion (1976) found that the contribution of orthographic structure is not dependent on determining the relative positions of letters. In addition, recent research by Massaro (1979a) found a large effect of orthographic structure on letter recognition but no effect on the determination of relative spatial position. In the present research, the experiments are designed such that any facilitating effect of orthographic structure at primary recognition must be due to letter recognition and not position uncertainty. The primary recognition process operates on a number of letters simultaneously (in parallel). The visual features detected at each spatial location define a set of possible letters for that position. The primary recognition process chooses from this set of candidates the letter alternative which has the best correspondence in terms of visual features. However, the selection of a best correspondence can be facilitated by knowledge of orthographic structure. The primary recognition process, therefore, attempts to utilize both the featural information in preperceptual storage and knowledge about the structure of legal letter strings. A critical concern is with the interaction of these two sources
6
CHAPTER 1
of information1 in our model, it is assumed that the two sources of information make independent contributions to primary recognition (Massaro, 1973, 1975, 1978, 1979b1 Thompson & Massaro, 1973). The present analysis of the facilitation of orthographic structure in letter recognition is identical in spirit to the original analysis provided by Miller, Bruner, and Postman (1954). They observed that the number of letters correctly reported from a tachistoscopic exposure increased with increases in familiarity of the letter pattern. The familiarity of the letter sequences was varied by the degree to which the sequence approximated printed English (Shannon, 1948). utilizing the theory of information developed by Shannon (1948), however, they observed that the number of letters reported is not a direct index of the amount of stimulus information derived from the exposure itself since the redundancy of contextually constrained sequences is not taken into account. Miller et al. (1954) calculated the redundancy of their sequences at each order of approximation to English using the counts given by Shannon (1951) and counts of their own. When performance was corrected for redundancy, there was no effect of familiarity (see also Tulving, 1963). This result was interpreted to mean that the amount of stimulus information received from the exposure did not depend on the familiarity of the letter pattern. In terms of our analysis, over two decades later, the results can be interpreted to mean that orthographic structure and visual information contribute independent sources of information in reading. The current view was developed, in part, on the basis of experiments carried out using the Reicher-Wheeler paradigm in word recognition (Reicher, 19691 Wheeler, 19701 Thompson & Massaro, 1973). In this paradigm, subjects are presented with either a test word or a single test letter for a short duration followed immediately by a masking stimulus and two response alternatives. The response alternatives both spell words in the test word condition1 for example, given the test stimulus WORD, the response alternatives ---Q and ---! would be presented. In the corresponding single test letter condition, Q is presented and followed by the response alternatives Q and !. In these studies, recognition of the test word is about 10% better than recognition of the test letter. Given the two-alternative forced-choice control, it is assumed that the reader utilizes orthographic structure to eliminate possible alternatives during the perception of the
READING AND INFORMATION PROCESSING
7
test display (Thompson & Massaro, 1973). As an example, presented with the test stimulus WORD and given recognition of test letters WOR and a curvilinear segment of the final letter, the reader could narrow down the alternatives for the final letter to D, 0, and Q. If 0 and Q are considered to be orthographically illegal in the context WOR-, then D represents an unambiguous choice. The reader will therefore perceive the word WORD given just partial information about the final letter. If the reader recognizes the same curvilinear segment in the corresponding single test letter condition, however, any of the three letters (D, 0, and Q) are possible and the perceptual synthesis will result in D only one out of three times. What is critical in this analysis is that the better performance on words compared to single letters is obtained even though the visual featural information available to the primary recognition process is equivalent in the word and letter conditions. The orthographic structure of the word simply provides an additional but independent source of information. The featural information available to the recognition process does not change with changes in orthographic structure. In this view, although orthographic structure facilitates word perception, it does not modify the feature analysis of the printed pattern (Krueger & Shapiro, 1979; Massaro, 1979a). As we have discussed, one role of orthographic structure is concentrated in the primary recognition process and serves to facilitate the recognition of individual letters. In addition, orthographic structure is functional at later stages of processing, such as its facilitating effect in short-term memory (Massaro, in press). Baddeley (1964), for e x amp l e , showed that a well-structured string of letters is easier to remember and recall than a random string. Whether orthographic structure facilitates perceptual recognition is a more controversial issue. We assume that it is utilized in the following manner. Upon presentation of a letter string, the primary recognition process begins integrating and synthesizing featural information passed on by feature detection to preperceptual visual storage. Featural information is resolved at different rates and there is some evidence that gross features are available before the more detailed features (Massaro & Schmuller, 1975). The primary recognition process is faced with a succession of partial information states. These partial visual information states are supplemented with knowledge about orthographic structure. Assume, for example, an initial th has been perceived in a
8
CHAPTER 1
letter string, and the features available for the next letter eliminate all alternatives except ~ or e. The primary recognition process might synthesize ~ without waiting for further visual information, since initial thc is not acceptable while initial the is. The primary recognition process transmits a sequence of recognized letters to synthesized visual memory. Figure 1.1 shows ho~ the secondary recognition process transforms this synthesized visual percept into meaningful form in generated abstract memory. We assume secondary recognition attempts to close off the letter string into a word. The secondary recognition process makes this transformation by finding the best match between the letter string and a word in the lexicon in long-term memory. Knowledge of orthographic structure can also contribute to secondary recognition; word recognition can occur without complete recognition of all of the component letters. Given the letters bea and the viable alternatives 1 and t in final position, only! makes a word, and therefore word identification (lexical access) can be Bchieved (Massaro, 1977). Each word in the lexicon contains both perceptual and conceptual codes. The word which is recognized is the one whose perceptual code gives the best match and whose conceptual code is most appropriate in that particular context. Generated abstract memory corresponds to the short-term or working memory of most information processing models. In our model, this memory is common to both speech perception and reading. Recoding and rehearsal processes build and maintain semantic and syntactic structures at the level of generated abstract memory. It is also possible to go from meaning to a visual or auditory percept in our model. The recoding operation can transform the meaning of a concept into its surface structure in an auditory or visual form. Two issues concerning letter and word recognition in reading will be addressed in the present research. First, what are the visual features of letters utilized by the primary recognition process? Second, how is knowledge of orthographic structure psychologically represented? To address these issues, any study must be concerned with how these sources of information are evaluated, integrated, and combined in perceptual recognition (Massaro, 1979b). The discussion of visual features is presented in Chapter 2 and the discussion of orthographic structure is presented in Chapter 3. The fourth chapter focuses on how the reader utilizes both sources of information in a variety of perceptual recognition and overt
READING AND INFORMATION PROCESSING
9
judgment tasks. To sustain the logical continuity of the presentation of the experiments, details of the method, procedure, and results are placed in appendices at the end of the chapter. The fifth chapter presents a detailed evaluation of the psychological reality of many descriptions of orthographic structure. The data base derived from the present experiments is also presented to allow additional tests of other descriptions of orthographic structure. In addition, normative counts of letter and letter cluster occurrences in text are presented. These counts make possible the measurement of a variety of stimulus and test items according to a number of formal descriptions of orthographic structure. The last chapter summarizes the contributions of the present research. The central concern of the empirical and theoretical work presented here is to evaluate the nature of the processes involved in letter and word recognition and to discover how knowledge about orthographic structure is represented and utilized.