Typing letter strings varying in orthographic structure

Subjects typed six-letter strings varying in orthographic structure. Lexical status, word frequency, position-sensitive log bigram frequency, and regularity of letter sequencing were systematically varied. Cumulative reaction times (RTs) of the keystrokes were adequately described by a linear function of letter position in the test string. Overall, words were typed faster than nonwords, and regular strings faster than irregular strings. Although the effect of log bigram frequency was not significant, this variable interacted with regularity and word frequency. Post hoc analyses of performance on each of the 200 letter strings revealed significant effects of the number of irregularities, log bigram frequency, and log word frequency. Transition times between successive keystrokes were significantly longer for illegal than for legal letter transitions. These results are similar to previous findings on the role of orthographic structure in the perceptual recognition of letter strings and provide a more complete analysis of context effects in typing.     

Distribution effects of orthographic similarity and priming by masked repetition]

This research centres on the effect that the orthographic neighbourhood has in the visual recognition of words. Specifically, we studied to what extent orthographic neighbourhood distribution, that is, the number of letter positions allowing formation of at least one neighbour (Pugh, Rexer, Peter, & Katz, 1994), influences the masked repetition priming effect. In a previous study (Mathey, Robert, & Zagar, 2004), interaction between neighbourhood distribution and orthographic priming was obtained in the lexical decision task. The Interactive Activation Model (IA; McClelland & Rumelhart, 1981) simulated this interaction. With the orthographic priming effect modified for distribution of the neighbourhood of target words, it was necessary to study whether the repetition priming effect also varied as a function of this indicator. Studying this interaction presents a major theoretical issue in specifying the activating and inhibiting processes presented in the IA model. Simulations were produced to obtain precise model predictions regarding the neighbourhood distribution effect in a repetitive priming situation for our experimental material. Target words all had two neighbours that were most frequent. These neighbours were isolated, that is, distributed over two letter positions (e.g.: TAUX/faux-toux), or associated, i.e., concentrated on one single position (e.g., SEAU/beau-peau). Targets were preceded by an identical priming (repetitive priming; e.g.: seau-SEAU) or by controlled priming (e.g., &-SEAU). The simulation results obtained using the IA model show the facilitating effects of neighbourhood distribution and repetitive priming, but no interaction between these factors. The experimental results obtained in a lexical decision task confirm these predictions. Thus, the empirical data replicate the neighbourhood distribution's facilitating effect (Mathey & Zagar, 2000) as well as the facilitating effect of masked repetition (Forster & Davis, 1984). Finally, the most interesting result is that the facilitating effect of repetition is comparable for target words with associated neighbours and target words with isolated neighbours. An explanation of the combined effects of the orthographic neighbourhood and orthographic masked repetition priming, integrating data from literature as well as from the current study, is proposed within the framework of the IA model.     

Shared neighborhood effects in masked orthographic priming

Several studies have found effects of orthographically related masked nonword primes on lexical decisions to target words. These effects have been explained by the neighborhood characteristics of the target word (Forster, 1987), but the neighborhood characteristics of the prime in combination with the target are also found to be important (Hinton, Liversedge, & Underwood, 1998). In this study, we present a new account of masked form-priming effects based on the shared neighborhood of prime and target. Shared neighbors are words that are activated by both prime and target. According to the interactive activation model (McClelland & Rumelhart, 1981), shared neighborhood determines the size of priming effects. This prediction was tested and confirmed in a masked priming experiment that manipulated the shared neighborhood density of complete primes.     

Contrasting five different theories of letter position coding: evidence from orthographic similarity effects

Five theories of how letter position is coded are contrasted: position-specific slot-coding, Wickelcoding, open-bigram coding (discrete and continuous), and spatial coding. These theories make different predictions regarding the relative similarity of three different types of pairs of letter strings: substitution neighbors, neighbors-once-removed, and double-substitution neighbors. In Experiment 1, we used an illusory word paradigm and found that neighbor-once-removed similarity contexts resulted in fewer illusory word reports than substitution neighbors but more illusory words than double-substitution neighbors. In Experiments 2 and 3, we used a masked form priming technique with a lexical-decision task. The pattern of facilitation was as predicted by spatial coding but was incompatible with slot-coding, Wickelcoding, and both versions of open-bigram coding. These results provide further support for the SOLAR (self-organizing lexical aquisition and recognition) model of visual word identification.     

Phonological and orthographic overlap effects in fast and masked priming

We investigated how orthographic and phonological information is activated during reading, using a fast priming task, and during single-word recognition, using masked priming. Specifically, different types of overlap between prime and target were contrasted: high orthographic and high phonological overlap (track–crack), high orthographic and low phonological overlap (bear–gear), or low orthographic and high phonological overlap (fruit–chute). In addition, we examined whether (orthographic) beginning overlap (swoop–swoon) yielded the same priming pattern as end (rhyme) overlap (track–crack). Prime durations were 32 and 50?ms in the fast priming version and 50?ms in the masked priming version, and mode of presentation (prime and target in lower case) was identical. The fast priming experiment showed facilitatory priming effects when both orthography and phonology overlapped, with no apparent differences between beginning and end overlap pairs. Facilitation was also found when prime and target only overlapped orthographically. In contrast, the masked priming experiment showed inhibition for both types of end overlap pairs (with and without phonological overlap) and no difference for begin overlap items. When prime and target only shared principally phonological information, facilitation was only found with a long prime duration in the fast priming experiment, while no differences were found in the masked priming version. These contrasting results suggest that fast priming and masked priming do not necessarily tap into the same type of processing.     

The effects of forced serial processing on identification of words and random letter strings

Skilled readers identified words and random letter strings displayed one letter at a time on the screen of a computer-controlled oscilloscope. Letters were either displayed in a single position, or painted left-to-right in adjacent positions. Adjacent displays were either unmasked, masked by a letter-like pattern following each letter (backward masking) or masked by a pattern preceding each letter (forward masking). Unmasked words were identified with a high degree of accuracy, and accuracy was independent of the exposure duration of the letters over the range 50–200 msec. Masked adjacent word displays and one-position word displays were identified much less accurately, and accuracy was highly dependent on letter exposure duration. In contrast to these results, identification of random strings, or of letters within random strings, was almost unaffected by the presence of the mask and was dependent on letter exposure duration under all display conditions. The results are interpreted as evidence that (a) masking forces subjects to process serial displays one letter at a time, and (b) words, or large segments of words, are habitually processed in parallel, while random strings are processed as a series of individual letters or small chunks.     

Alphabetic letter identification: effects of perceivability, similarity, and bias

The legibility of the letters in the Latin alphabet has been measured numerous times since the beginning of experimental psychology. To identify the theoretical mechanisms attributed to letter identification, we report a comprehensive review of literature, spanning more than a century. This review revealed that identification accuracy has frequently been attributed to a subset of three common sources: perceivability, bias, and similarity. However, simultaneous estimates of these values have rarely (if ever) been performed. We present the results of two new experiments which allow for the simultaneous estimation of these factors, and examine how the shape of a visual mask impacts each of them, as inferred through a new statistical model. Results showed that the shape and identity of the mask impacted the inferred perceivability, bias, and similarity space of a letter set, but that there were aspects of similarity that were robust to the choice of mask. The results illustrate how the psychological concepts of perceivability, bias, and similarity can be estimated simultaneously, and how each make powerful contributions to visual letter identification.     

Tracking the acquisition of orthographic skills in developing readers: masked priming effects

A masked priming procedure was used to explore developmental changes in the tuning of lexical word recognition processes. Lexical tuning was assessed by examining the degree of masked form priming and used two different types of prime-target lexical similarity: one letter different (e.g., rlay-->PLAY) and transposed letters (e.g., lpay-->PLAY). The performance of skilled adult readers was compared with that of developing readers in Grade 3. The same children were then tested again two years later, when they were in Grade 5. The skilled adult readers showed no form priming, indicating that their recognition mechanisms for these items had become finely tuned. In contrast, the Grade 3 readers showed substantial form priming effects for both measures of lexical similarity. When retested in Grade 5, the developing readers no longer showed significant one letter different priming, but transposed letter priming remained. In general, these results provide evidence for a transition from more broadly tuned to more finely tuned lexical recognition mechanisms and are interpreted in the context of models of word recognition.     

Visual similarity effects in detecting letter rhymes

Previous demonstrations of "visual" effects in auditory tasks have been largely restricted to orthographic effects with word stimuli. As a result, explanations of such effects have centered around a shared orthography--the similarity of the spelling patterns at the ends of the words. In the present study, these effects were extended to single-letter stimuli. Subjects made rhyming decisions about pairs of letters presented auditorily. Visually similar letter pairs facilitated responses to rhyming pairs and inhibited responses to nonrhyming pairs. The results indicate that visual effects are not restricted to word stimuli and suggest that additive effects of visual similarity and shared orthography may be responsible for these findings.     

Enemies and friends in the neighborhood: orthographic similarity effects in semantic categorization

Studies investigating orthographic similarity effects in semantic tasks have produced inconsistent results. The authors investigated orthographic similarity effects in animacy decision and in contrast with previous studies, they took semantic congruency into account. In Experiments 1 and 2, performance to a target (cat) was better if a previously studied neighbor (rat) was congruent (i.e., belonged to the same animate-inanimate category) than it was if it was incongruent (e.g., mat). In Experiments 3 and 4, performance was better for targets with more preexisting congruent neighbors than for targets with more preexisting incongruent neighbors. These results demonstrate that orthographic similarity effects in semantic categorization are conditional on semantic congruency. This strongly suggests that semantic information becomes available before orthographic processing has been completed.     

The role of letter identity and letter position in orthographic priming

Four experiments are reported investigating orthographic priming effects in French by varying the number and the position of letters shared by prime and target stimuli. Using both standard masked priming and the novel incremental priming technique (Jacobs, Grainger, & Ferrand, 1995), it is shown that net priming effects are affected not only by the number of letters shared by prime and target stimuli but also by the number of letters in the prime not present in the target. Several null results are thus explained as a tradeoff between the facilitation generated by common letters and the inhibition generated by different letters. Inhibition was significantly reduced when different letters were replaced by nonalphabetic symbols. Facilitation effects disappeared when the common letters did not have the same relative position in the prime and target strings, thus supporting a relative-position coding scheme for letters in words.     

The role of letter identity and letter position in orthographic priming.

Four experiments are reported investigating orthographic priming effects in French by varying the number and the position of letters shared by prime and target stimuli. Using both standard masked priming and the novel incremental priming technique (Jacobs, Grainger, & Ferrand, 1995), it is shown that net priming effects are affected not only by the number of letters shared by prime and target stimuli but also by the number of letters in the prime not present in the target. Several null results are thus explained as a tradeoff between the facilitation generated by common letters and the inhibition generated by different letters. Inhibition was significantly reduced when different letters were replaced by nonalphabetic symbols. Facilitation effects disappeared when the common letters did not have the same relative position in the prime and target strings, thus supporting a relative-position coding scheme for letters in words.     

Flanker and negative flanker effects in letter identification

In a speeded choice reaction time task, responses to centrally presented letter targets can be altered by the identity of surrounding task-irrelevant letters (flankers). In the standard flanker effect, flankers associated with the same response as the target lead to faster and more accurate responses, whereas flankers associated with a different response lead to slower and more error-prone responses. B. A. Eriksen and C. W. Eriksen (1974, pp. 143-149) have argued that these flanker effects occur through response competition. We present data from a novel version of the Eriksen task, in which some targets and flankers consist of letter forms that are morphed versions of target letters. In this paradigm, flankers induce classic flanker effects on well-formed targets. But flankers induce an opposite effect, termed a negative flanker effect on morphed letter targets. For example, targets that are morphs between the letters "A" and "H" are more likely to be identified as an "A" when flanked by an "H." The interpretation advanced here is that there are two distinct kinds of flanker effects contrast enhancement in perceptual processes and response competition in response selection processes.     

Image rotation of misoriented letter strings: effects of orientation cuing and repetition

Three experiments were designed to investigate whether the characteristic function relating response time to stimulus orientation reflects the observer imagining the rotation of the stimulus to upright (the "image rotation" hypothesis) or rotation of an internal reference frame in response to the misoriented stimulus (the "frame rotation" hypothesis). Identification times in response to misoriented words were measured in Experiment 1, whereas in Experiments 2 and 3, lexical decision times in response to misoriented letter strings were measured. Trials occurred in blocks; words within a block were presented at the same orientation. It was argued that this mode of presentation would facilitate the use of a frame rotation strategy by allowing for a gradual readjustment of an internal reference frame. The characteristic "mental rotation" function was observed in all three experiments. However, the data indicated that observers continued to imagine the rotation of the word to upright in each trial; there was no evidence of readjustment of an internal reference frame. An additional finding of interest occurred in Experiment 1, in which observers identified the same set of misoriented words across two sessions. The identification times were faster, and the slope of the mental rotation function was lower, in the second session. These results are discussed as in relation to the image rotation hypothesis of mental rotation and to "instance-based skill acquisition" (Masson, 1986) in word recognition.     

When lust is lost: orthographic similarity effects in the encoding and reconstruction of rapidly presented word lists

A reconstructive account of memory is presented to explain the finding that report of a word (C2) appearing in a rapidly presented list is reduced when it is orthographically similar to an earlier word (C1) in the list. By this account, the effect arises when the list is reconstructed from memory, not at the time of list presentation as proposed by accounts based on failure of encoding or tokenization. The reconstructive account is supported by a series of experiments that show a retroactive effect in which report of C1 is enhanced by similarity to C2; a nonword C1 can either interfere with or enhance report of C2, depending on how accurately C1 is encoded; manipulation of reconstructive processes can eliminate or enhance the effect of orthographic similarity; and a bidirectional trade-off in the report of an orthographically similar C1-C2 pair, whereby report of one member compromises report of the other.     

Negative congruence effects in letter and pseudo-letter recognition: the role of similarity and response conflict

Letters and pseudo-letters were presented in three experiments using a sequential same-different task. While first items were always presented in isolation, the second item was either presented in isolation or surrounded by geometrical non-target shapes that could be congruent or incongruent to the target. In two experiments, a physical sameness criterion was used. In Experiment 1, in one condition, different pairs were always distinct in shape, in another they were similar in shape. Negative congruence effects were obtained for different pairs that are similar. In Experiment 2, this effect is replicated within participants. In this experiment, similar and dissimilar stimuli were mixed. The results were explained in terms of the difficulty of responding different to stimuli that are similar in shape: when the second item is surrounded by a congruent shape, the similarity is emphasized, making this response even more difficult. In Experiment 3, the same stimuli were presented using a categorical sameness criterion. This reduces the role of physical similarity and thus eliminates the response conflict. As a result, negative congruence effects were no longer observed. Taken together, the three experiments identify another source of negative congruence effects besides the ones recently reported in the literature.     

The role of orthographic and phonotactic rules in perceiving letter patterns.

Three experiments examined the role of orthographic and phonotactic rules in the tachistoscopic recognition of letter strings. Experiment 1 showed that the presence of a vowel or multiletter spelling patterns facilitates perceptual accuracy. To account for these results a model was proposed in which an input string is first parsed into syllablelike units, which are then recorded into speech. It was demonstrated that the perceptual accuracy for a string is correlated with the number of recoding steps needed to convert that string into speech. Experiment 2 further demonstrated that this recoding process can predict perceptibility differences among strings with varying numbers of phonotactic violations, and Experiment 3 assessed some of the specific assumptions of the recoding process.     

The effects of acoustic and semantic similarity on concept identification

Since both acoustic and semantic similarity exert an influence on memory, the role of memory in concept identification (CI) was investigated by varying the acoustic and semantic similarity of the stimuli used in the CI task. Varying acoustic similarity had no effect on CI, but CI was significantly impaired when the dimensions of a CI task were semantically similar.     

The role of syllabic and orthographic properties of letter cues in solving word fragments

The present research examined the role of phonological and orthographic properties of cues in mediating the retrieval of words from the mental lexicon. The task required subjects to resolve fragmented words when provided with semantically related cues (e.g., spiteful:---DIC----). Phonological properties of the letter cues were manipulated such that the letters either corresponded to the syllables (e.g., DIC in vindictive) or nonsyllables (NDI) in the word. Orthographic properties of the letter cues were manipulated by selecting letter groups that either co-occurred frequently in the language or did not. In two experiments, results revealed little or no effect of the phonological variable (syllables) but a reliable effect of the orthographic variable (letter-cue frequency). Letter cues with a low frequency of co-occurrence in the language led to better completion of the fragmented words. We interpret these findings as support for models of lexical representation that are based on orthographic properties (e.g., Seidenberg & McClelland, 1989) rather than those based on phonological constraints.     

The role of lateral masking and orthographic structure in letter and word recognition.

The present experiments evaluated the contribution of orthographic structure and lateral masking in the perception of letter, word, and nonword test displays. Performance was tested in a backward recognition masking experiment in which a masking stimulus followed the test display after a variable blank interstimulus interval. In agreement with previous findings across different experiments, words were recognized better than single letterd at short interstimulus intervals, but the opposite was the case at long intervals. Performance on the nonwords resembled performance on letters at short masking intervals and performance on words at long masking intervals. The quantitative results were described by a processing model that incorporates the effects of lateral masking and orthographic structure in the dynamic processing of letter strings. Lateral masking tends to lower the potential perceptibility of letters whereas orthographic structure can reduce the uncertainty of the candidate letters in the letter sequence. The present model predicts that the quantitative contribution of each of these processes to performance is critically dependent upon the processing time available before the onset of the masking stimulus.