Word recognition

Bouma shape, named after the Dutch vision researcher Herman Bouma, refers to the overall outline, or shape, of a word.[11] Herman Bouma discussed the role of "global word shape" in his word recognition experiment conducted in 1973.[12] Theories of bouma shape became popular in word recognition, suggesting people recognize words from the shape the letters make in a group relative to each other.[3] This contrasts the idea that letters are read individually. Instead, via prior exposure, people become familiar with outlines, and thereby recognize them the next time they are presented with the same word, or bouma.

The slower pace with which people read words written entirely in upper-case, or with alternating upper- and lower-case letters, supports the bouma theory.[3] The theory holds that a novel bouma shape created by changing the lower-case letters to upper-case hinders a person's recall ability. James Cattell also supported this theory through his study, which gave evidence for an effect he called word superiority. This referred to the improved ability of people to deduce letters if the letters were presented within a word, rather than a mix of random letters. Furthermore, multiple studies have demonstrated that readers are less likely to notice misspelled words with a similar bouma shape than misspelled words with a different bouma shape.

Though these effects have been consistently replicated, many of their findings have been contested. Some have suggested that the reading ability of upper-case words is due to the amount of practice a person has with them. People who practice become faster at reading upper-case words, countering the importance of the bouma. Additionally, the word superiority effect might result from familiarity with phonetic combinations of letters, rather than the outlines of words, according to psychologists James McClelland and James Johnson.[13]

Parallel letter recognition is the most widely accepted model of word recognition by psychologists today.[3] In this model, all letters within a group are perceived simultaneously for word recognition. In contrast, the serial recognition model proposes that letters are recognized individually, one by one, before being integrated for word recognition. It predicts that single letters are identified faster and more accurately than many letters together, as in a word. However, this model was rejected because it cannot explain the word superiority effect, which states that readers can identify letters more quickly and accurately in the context of a word rather than in isolation.

A more modern approach to word recognition has been based on recent research on neuron functioning.[3] The visual aspects of a word, such as horizontal and vertical lines or curves, are thought to activate word-recognizing receptors. From those receptors, neural signals are sent to either excite or inhibit connections to other words in a person's memory. The words with characters that match the visual representation of the observed word receive excitatory signals. As the mind further processes the appearance of the word, inhibitory signals simultaneously reduce activation to words in one's memory with a dissimilar appearance. This neural strengthening of connections to relevant letters and words, as well as the simultaneous weakening of associations with irrelevant ones, eventually activates the correct word as part of word recognition in the neural network.

Using positron emission tomography (PET) scans and event-related potentials, researchers have located two separate areas in the fusiform gyrus that respond specifically to strings of letters. The posterior fusiform gyrus responds to words and non-words, regardless of their semantic context.[14] The anterior fusiform gyrus is affected by the semantic context, and whether letter combinations are words or pseudowords (novel letter combinations that mimic phonetic conventions, ex. shing). This role of the anterior fusiform gyrus may correlate to higher processing of the word's concept and meaning. Both these regions are distinct from areas that respond to other types of complex stimuli, such as faces or colored patterns, and are part of a functionally specialized ventral pathway. Within 100 milliseconds (ms) of fixating on a word, an area of the left inferotemporal cortex processes its surface structure. Semantic information begins to be processed after 150 ms and shows widely distributed cortical network activation. After 200 ms, the integration of the different kinds of information occurs.[15]

The accuracy with which readers recognize words depends on the area of the retina that is stimulated.[16] Reading in English selectively trains specific regions of the left hemiretina for processing this type of visual information, making this part of the visual field optimal for word recognition. As words drift from this optimal area, word recognition accuracy declines. Because of this training, effective neural organization develops in the corresponding left cerebral hemisphere.[16]

Eyes make brief, unnoticeable movements called saccades approximately three to four times per second.[17] Saccades are separated by fixations, which are moments when the eyes are not moving. During saccades, visual sensitivity is diminished, which is called saccadic suppression. This ensures that the majority of the intake of visual information occurs during fixations. Lexical processing does, however, continue during saccades. The timing and accuracy of word recognition relies on where in the word the eye is currently fixating. Recognition is fastest and most accurate when fixating in the middle of the word. This is due to a decrease in visual acuity that results as letters are situated farther from the fixated location and become harder to see.[18]

Serif fonts, i.e.: fonts with small appendages at the end of strokes, hinder lexical access. Word recognition is quicker with sans-serif fonts by an average of 8 ms.[20] These fonts have significantly more inter-letter spacing, and studies have shown that responses to words with increased inter-letter spacing were faster, regardless of word frequency and length.[21] This demonstrates an inverse relationship between fixation duration and small increases in inter-letter spacing,[22] most likely due to a reduction in lateral inhibition in the neural network.[20] When letters are farther apart, it is more likely that individuals will focus their fixations at the beginning of words, whereas default letter spacing on word processing software encourages fixation at the center of words.[22]

Both PET and functional magnetic resonance imaging (fMRI) are used to study the activation of various parts of the brain while participants perform reading-based tasks.[23] However, magnetoencephalography (MEG) and electroencephalography (EEG) provide a more accurate temporal measurement by recording event-related potentials each millisecond. Though identifying where the electrical responses occur can be easier with an MEG, an EEG is a more pervasive form of research in word recognition. Event-related potentials help measure both the strength and the latency of brain activity in certain areas during readings. Furthermore, by combining the usefulness of the event-related potentials with eye movement monitoring, researchers are able to correlate fixations during readings with word recognition in the brain in real-time. Since saccades and fixations are indicative of word recognition, electrooculography (EOG) is used to measure eye movements and the amount of time required for lexical access to target words. This has been demonstrated by studies in which longer, less common words induce longer fixations, and smaller, less important words may not be fixated on at all while reading a sentence.

According to the LINCS website, the role of word recognition results in differences between the habits of adults and the habits of children learning how to read.[8] For non-literate adults learning to read, many rely more on word recognition than on phonics and word analysis. Poor readers with prior knowledge concerning the target words can recognize words and make fewer errors than poor readers with no prior knowledge.[24] Instead of blending sounds of individual letters, adult learners are more likely to recognize words automatically.[8] However, this can lead to errors when a similarly spelled, yet different word, is mistaken for one the reader is familiar with. Errors such as these are considered to be due to the learner's experiences and exposure. Younger and newer learners tend to focus more on the implications from the text and rely less on background knowledge or experience. Poor readers with prior knowledge utilize the semantic aspects of the word, whereas proficient readers rely on only graphic information for word recognition.[24] However, practice and improved proficiency tend to lead to a more efficient use of combining reading ability and background knowledge for effective word recognition.[8]

The role of the frequency effect has been greatly incorporated into the learning process.[8] While the word analysis approach is extremely beneficial, many words defy regular grammatical structures and are more easily incorporated into the lexical memory by automatic word recognition. To facilitate this, many educational experts highlight the importance of repetition in word exposure. This utilizes the frequency effect by increasing the reader's familiarity with the target word, and thereby improving both future speed and accuracy in reading. This repetition can be in the form of flash cards, word-tracing, reading aloud, picturing the word, and other forms of practice that improve the association of the visual text with word recall.[25]

Improvements in technology have greatly contributed to advances in the understanding and research in word recognition. New word recognition capabilities have made computer-based learning programs more effective and reliable.[8] Improved technology has enabled eye-tracking, which monitors individuals' saccadic eye movements while they read. This has furthered understanding of how certain patterns of eye movement increases word recognition and processing. Furthermore, changes can be simultaneously made to text just outside the reader's area of focus without the reader being made aware. This has provided more information on where the eye focuses when an individual is reading and where the boundaries of attention lie.

With this additional information, researchers have proposed new models of word recognition that can be programmed into computers. As a result, computers can now mimic how a human would perceive and react to language and novel words.[8] This technology has advanced to the point where models of literacy learning can be digitally demonstrated. For example, a computer can now mimic a child's learning progress and induce general language rules when exposed to a list of words with only a limited number of explanations. Nevertheless, as no universal model has yet been agreed upon, the generalizability of word recognition models and its simulations may be limited.[26]

Despite this lack of consensus regarding parameters in simulation designs, any progress in the area of word recognition is helpful to future research regarding which learning styles may be most successful in classrooms. Correlations also exist between reading ability, spoken language development, and learning disabilities. Therefore, advances in any one of these areas may assist understanding in inter-related subjects.[27] Ultimately, the development of word recognition may facilitate the breakthrough between "learning to read" and "reading to learn".[28]