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RE 5120: Psychological Bases of Reading Summer 2010. Psychological Bases of Reading. This course examines current theories of reading processes, supporting research, and implications for teaching reading.
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Psychological Bases of Reading • This course examines current theories of reading processes, supporting research, and implications for teaching reading. • Course topics will include research on word recognition, phonemic awareness and decoding, beginning reading, vocabulary acquisition, reading comprehension, and fluency.
Components of Reading RC= D X LC According to the Simple View of Reading, as one’s decoding skills go down so does his/her reading comprehension (RC) no matter the strength of their language comprehension (vocabulary). Likewise, as one’s language comprehension (LC) goes down so does his/her reading comprehension (RC) no matter the decoding ability. (Simple View of Reading; Hoover & Gough, 1990)
Sources of Variance in Reading: Deficits in reading comprehension may be due to deficits in any one or a combination of the following: Alphabetics: Underdeveloped decoding skills may cause the reading problem. This is the case for beginning readers. Vocabulary: Inadequate vocabulary knowledge may the problem for those who come from low-literate homes. Fluency: Efficient and rapid reading rate is needed for reading with comprehension. Developmentally, transitional readers who have grasped the sound layer of English but are negotiating the pattern layer of English lack fluency. A large-scale training study by Kuhn et al. (2005) aims to increase fluency in transitional readers. Comprehension Processes: Integrating information, making inferences and predictions are some of the comprehension processes that are general to both listening and reading; they are domain-general processes. Working memory deficits are usually implicated. Studies by Oakhill and colleagues in England have identified that 10% of readers may experience comprehension problems in the absence of problems in lower level skills (e.g., decoding, fluency).
The Science of Word Reading • What is the Bouma effect? • What is the word superiority effect? • What is the duration of a typical fixation? • Where in the word do we fixate? • What is the typical letter-span of a fixation? • What kind of words are usually fixated? Why? • How long is the perceptual span? • What is the average saccade length?
Word Shape Model • Words are read as complete patterns rather than the sum of their letters; • According to this model, the pattern of ascending, descending, and neutral characters, e.g., , or the envelope, e.g., , created by the outline of the word allows word recognition. • According to the model, we do not process the letters but the word by its shape.
Word Shape Model • Word Superiority Effect (Cattell, 1886; Reicher, 1969; Woodworth, 1938) is used to support this model. • Cattell presented letter and word stimuli to subjects for a very brief period of time (5-10ms), and found that subjects were more accurate at recognizing the words than the letters. • He concluded that this is because whole words are the units that we recognize. • Reicher replicated Cattell’s findings in 1969. Reicher found that subjects were more accurate at recognizing d when it was in the context of word than when in the context of orwd. • Further evidence for this model is that lowercase text is easier to read because it allows for the shapes of words (Woodworth, 1938) . Uppercase letters do not allow for ascending and descending shapes; letters in an uppercase word are all neutral resulting in a monotonic shape, e.g., SHAPE vs. shape.
Word Shape Model • Studies where subjects were asked to proofread texts with misspellings provide further support for the Word Shape model. • Subjects were asked to carefully read passages of text for comprehension and at the same time mark any misspelling they found in the passage. • The passage had been carefully designed to have an equal number of two kinds of misspellings: misspellings (tesf) that are consistent with the shape of the target word (test) shape, and misspellings (tesc) that are inconsistent with the target word’s shape. • Haber & Schindler (1981) and Monk & Hulme (1983) found that misspellings consistent with the target word’s shape were twice as likely to be missed as misspellings inconsistent with the shape of the target word. • Target word: test Error Rate • Misspelling with consistent word shape (tesf) 13% • Misspelling with inconsistent word shape (tesc) 7%
Serial Letter Recognition • Recognizing a word in the mental lexicon is like looking up a word in a dictionary (Gough, 1972). The process is not one of recognizing words by their shapes. • The evidence to support the model comes from a study by Sperling (1963). • Sperling showed participants strings of random letters, asking if a particular letter was contained in the string. • He found that if participants were given 10 milliseconds (ms) per letter, they could successfully complete the task. • For example, if the target letter was in the fourth position and the string was presented for 30ms, the participant couldn’t complete the task successfully, but if string was presented for 40ms, they could complete the task successfully. • Gough noted that a rate of 10ms per letter would be consistent with a typical reading rate of 300 words per minute.
Serial Letter Recognition (SLR) Remember that Cattell presented letter and word stimuli to subjects for a very brief period of time (5-10ms), and found that subjects were more accurate at recognizing the words than the letters. • This model predicts that the shorter a word the faster its recognition. A short word has fewer letters to process than a long word. • However, the model cannot explain the Word Superiority Effect, which assumes that words are recognized more accurately than single letters when presented in a very brief period of time. • The serial letter recognition model would expect that a word with four letters should take four times as long to recognize as a letter in isolation.
Parallel Letter Recognition (PLR) • Just like the SLR model, this model postulates that letter information is used to recognize the words. • Unlike SLR, this model assumes that letters within a word are recognized simultaneously (in parallel), not serially.
Evidence for PLR Model from Eye Movement Research • There are three zones of visual identification: (a) fixation point, (b) fixation point plus 3-4 letters, (c) fixation point plus 15 letters. These three zones constitute the perceptual span. • Readers collect information from all three zones during a fixation. • In Zone a, we fixate our eyes on a point to the left of the middle of the word. We have clear vision of 3 letters to the left and 3 letters to the right of this fixation point. • Zone b is where the first few letters of the next word are recognized. • Zone c is where the length and shape of upcoming words is identified and the best location for the next fixation point is determined.
Perceptual Span • The perceptual span is like a tunnel into the visual periphery within which visual information is acquired and used during eye fixations. • Perceptual span has been found to be very limited. Average perceptual span of English readers is about four letters to the left of fixation and 14 letters to the right (McConkie & Rayner, 1976). • Only letters in within eight character positions to the right of the fixation can be distinguished. Beyond that point, in Zone c, letters become indistinguishable and only word boundary and word shape information is obtained (Tsai, C.-H., 2001).
Evidence for PLR Model from Eye Movement Research Cont’d • Our perceptual span is roughly 15 letters (Zones a, b, and c). • While readers are recognizing words in zone a (i.e., center of fixation), they are also using additional information further out to guide their reading. • After we recognize the word in zone a and have determined the fixation point in the next word, we jump (saccade) our eyes to the next word. Average saccade length is 7-9 letters. Fixation point Zone a Zone b Zone c
Processing Unit is the Letter • Mounting research has refuted the assumptions of the Word Shape Model: • The word superiority effect is caused by familiar letter sequences and not word shapes. • Reading lowercase text is faster than uppercase text because of practice. If you practice reading uppercase text, uppercase text will become easy to read as well. • Letter shape similarities rather than word shape similarities cause mistakes in the proofreading task. • And pseudowords also suffer from decreased reading speed with alternating case text.
Neural Networks: How the Brain Works • Neurons pass information to one another through synaptic connections. • When a neuron becomes “excited” via information by another neuron, it will become active; when it receives inhibition from another neuron, its activation will decrease. • Learning is based on the modification of connections between neurons: When the information coming from a synapse is important, the connection between the two neurons will become physically stronger, and when information from a synapse is less important the synapse will weaken or even die off. Neural networks gave rise to Connectionist Models of Reading, e.g., Adams’s model.
Connectionist Models of Reading • In the figure to the right, a Connectionist Model is at work processing a word that starts with the letter T. • First, features in the letter are extracted: a horizontal and a vertical line. • The feature nodes in the model pass activation to letters (at the next level of Letter Detectors) that have either a horizontal or a vertical line. Letters A, T, G are activated. • Because letter T receives the most activation from feature detectors, it wins over the other letters (i.e., A, G, and S) by inhibiting their activation. • Letter T then sends activation to all words that start with the letter T and sends inhibition to all the other words, such as ABLE, CART. • This process continues simultaneously with the other letters in the input word TRIP. Letter R sends activation to all words with R in the second position, letter I to all words with I in the 3rd position, and letter P to all words with P in the final position after they are detected by their features. The word with most activation wins over the competitors by inhibiting their activation TRIP
Connectionist Models of Reading • Information about what letters go together activates (excites) letters that are more frequently used with the letter T, e.g., the letter H, the letter R, or a vowel. Letter T will never activate letter Q because they never occur together in English.
Discussion Points • According to Larson, what should be the unit of processing? Letter or word? • What is the best explanation to the processing of letters? Serial or parallel processing? • What is at stake with a word-shape model of reading instruction? • Should we teach typical eye-movements (of a reader) to struggling readers?
Modeling the Connections (Adams 2004) The figure on the left depicts the processing that occurs for letter T. Feature detectors identify the feature that make up this letter. Separate features in the letter activate separate associated letters. The vertical line sends activation to both letters N and T. The horizontal line also sends activation to letters G, S, and R which are written with a horizontal line in this typeset. The activated letters send inhibition to all other letters. It is at this point that connections between the activated letters and their corresponding sounds in the phonological processor are made.
Modeling the Connections (Adams 2004) • As all the letters in the word are processed, letter order/position guides processing, e.g., letter Q never occurs following letter T. Therefore, letter T will never activate letter Q. As the words TRIP, TAKE, TIME, CART, ABLE, TRAP are activated, their meanings are activated in the Meaning Processor along with their full pronunciations in the Phonological Processor.
Gough’s Model • A bottom-up information processing model; • Depicts reading as processing from lower order to higher order stages. • [SEE MODEL FIGURE]
LaBerge and Sameuls Model • Another bottom-up model of reading; • [SEE MODEL FIGURE]
LaBerge and Sameuls Model • With exposure and practice, the visual features in stimuli like letters become unitized and then perceived as a single unit. • As these units accumulate and letter perception becomes increasingly automatic, attention to early visual coding processes decreases. • This decrease allows attentional resources to be reallocated to other areas. • Attention is limited capacity; therefore, a behavior (e.g., decoding) must be automatic for it to be conducted simultaneously with another behavior (reading comprehension).
Repeated Readings: Outgrowth of the Automaticity Model • Repeated Readings was designed by Samuels based on the Automaticity Model. • With corrective feedback, a reading disabled child trained in Repeated Readings. • Over five sessions, it took him fewer sessions to reach the criterion of 85 words per minute. Over the sessions, not only did he start reading a passage at a higher rate, he also started reading the passages with fewer errors. (Figure from Samuels, 1997, p. 378)
Why Is Reading Interactive? • Bottom up models can’t explain how we can read degraded word stimuli. • We can’t complete processing the word because the final letter is degraded. It can be an R or a K.
Why Is Reading Interactive? • A variety of processors must converge on the visual information simultaneously, rather than in a linear process. • The simultaneous processing of syntactic, semantic, orthographic, and lexical information allows for higher and lower level processes to simultaneously interact on the visual input. • The result is the most probable word: WORK
Why Is Reading Interactive? • Figure in the right shows the early activation equally rising for the k and r letter nodes. • This is because the visual feature information supports both of those letters, while the d letter node is unsupported. • Early in processing, the letter nodes are only receiving activation from the visual feature nodes, but later activation is provided by the word nodes.
Reading Words: Interactions • Word reading is neither solely bottom-up nor top-down. [SEE MODEL FIGURE]
Adams (2004) • Parts of the reading system are not discrete like the parts of a car. • We cannot proceed by completing each one in isolation and then fastening it to another. • The parts of the reading system must grow together. They must grow to and from one another. • Subcomponents of reading develop interconnectedly. • Development in one cannot proceed without development in the other.
Adams (2004) • Connectionist models posit that learning progresses as the learner comes to respond to the relationships among patterns or events. • Overlearned relations among the letters of a word enable the word's recognition. • Connectionist models are neither top-down nor bottom-up; all relevant processes are simultaneously active and interactive; all simultaneously issue and accommodate information to and from one another.
Adams (2004) • Just like a car which does not fire well and stops unpredictably every few seconds, a reader who cannot transform print (gas) into mental energy and execute mental operations on it will operate inefficiently with consequent failures in comprehension and overall reading. • Unless the processes involved in individual word-recognition operate properly, nothing else in the system can either (p. 1219).
Research Concepts • Independent Variable: what the experimenter changes or enacts in order to do the experiment • Dependent Variable: what changes when the independent variable changes - the dependent variable depends on the outcome of the independent variable
Example* • Does amount of time (4 vs. 8 hr) per day of full sunlight affect growth rate of plants? *Adapted from http://www.cool-science-projects.com/independent-and-dependent-variables.html
Example Experiment • Independent Variable: Amount of sunlight per day (4 hr vs. 8 hr) • Dependent Variable: Growth rate of plants • Is there anything else that could influence the dependent variable? • There may be extraneous factors might affect the change in Dependent Variable independently of or in interaction with the Independent Variable, e.g., amount of water that each plant receives.
Control Variables • If left uncontrolled, extraneous variables could mess up your experiment by making your results false or unreliable. • Control variables must be carefully monitored and kept equal in your experiments. • You have to make sure that each plant got the same amount of water as every other plant in the experiment.
Discussion Questions Identify the following in the Perfetti & Hogaboam (1975) study and add your answers to your Perfetti & Hogaboam Research Summary on your blog. • Independent Variable(s): Reading comprehension skill (skilled vs. less skilled readers) • Dependent Variable: Vocalization latency (time it takes to read words and nonwords projected on a screen. • Control Variable(s): All real words were known to the subjects. Word knowledge was controlled.
Perfetti & Hogaboam Review • Real words and nonwords were randomly presented through a shutter on a screen. When the shutter was opened, the stimulus appeared. A digital timer started. When the subject named the stimulus, the timer stopped and the shutter closed. Just like in the following slides.
Ehri and Wilce (1979) • The lexicon consists of abstract word units having several different identities: phonological identities (how words sound and are articulated); syntactic identities (grammatical roles in sentences); and semantic identities (meanings). • These identities are acquired as children learn to speak.
Mental Lexicon • In the course of learning to read, one other identity is added to the lexicon: orthographic identities, which are represented as visual images.
The Amalgam for the word CAT Meaning unit for animal The sound meow • The term amalgamation refers to processes by which the various identities are combined to form a single unit in lexical memory. the phoneme /t/ the phoneme /ae/ Meaning unit for legs the phoneme /k/ Meaning unit for fur
Adding Spelling (CAT) to the Amalgam that Already Exists in the Lexicon Meaning unit for animal The sound meow The letter a • A beginning reader adds the orthographic identity (spelling) of the word to the amalgam that already exists for that word in the lexicon. The existing amalgam includes phonological and semantic identities. the phoneme /t/ the phoneme /ae/ Meaning unit for legs the phoneme /k/ The letter t The letter k Meaning unit for fur The letter a
The Amalgamation Theory Cont’d • Orthographic identities must also merge with syntactic and semantic identities so that images symbolize them as well. • Printed word learning is complete when a word’s orthographic image has been formed in lexical memory and this image has been amalgamated with its phonological, syntactic, and semantic identities.
The Study • The current study examined the process by which orthographic forms are established as images symbolizing sounds in memory in beginning readers. • Does spelling aides help learning of non-sense words?
The Study Identify the following in the Ehri & Wilce (1979) study: • Independent Variable(s) • Dependent Variable • Control Variable(s)