Letter detection in very familiar texts

In the present study, we investigated whether patterns of letter detection for function and content words in texts are affected by the familiarity of the material being read. In Experiment 1, subjects searched for target letters in sentences that had been rehearsed prior to performing the letter detection on them as well as on unfamiliar sentences. In Experiment 2, subjects searched for target letters in highly familiar verses (e.g., nursery rhymes) and in unfamiliar sentences that were matched to the familiar verses. A disadvantage in letter detection for function as compared with content words consistently found with unfamiliar passages was reduced significantly with the familiar material in both experiments. Specifically, letter detection for content words grew worse in familiar text, but letter detection for function words showed a contrasting modest, though nonsignificant, improvement. The results are consistent with the proposition that in very familiar texts, parafoveal analysis permits the identification of generally less familiar content words. Simultaneously, the normal pattern of weighing the structure and content elements of text changes so that more fixations on function words occur than when one is reading unfamiliar texts.     

Visual detection of multi-letter patterns

This study addressed two basic questions about the detection of multi-letter patterns: (a) How is the detection of a multi-letter pattern related to the detection of its individual components? (b) How is the detection of a sequence of letters influenced by the observer's familiarity with that sequence? In three experiments observers searched for one-, two-, or three letter patterns embedded in a rapid series of multiple six-letter frames. In Experiment 1, unfamiliar two-letter patterns were detected more accurately than their one-letter components. This two-letter advantage reflects the fact that in an array of fixed size, larger target stimuli contain more information and are easier to discriminate from nontarget alternatives. Quantitative analyses indicated that observers combine information not decisions, about the component letters in a pattern. In Experiment 2, with statistical and physical properties equated, a familiar three-letter pattern (i.e., CAT) was detected more accurately than its unfamiliar anagram (i.e., TCA). This word advantage in word (not letter) detection persisted even after extensive practice and was uninfluenced by the lexical character of distractor items. In Experiment 3, words (e.g., FIB), pronounceable non words (e.g., FIF(, and familiar acronyms (e.g., FBI) were detected more readily than unfamiliar items (e.g., IBF). Thus both orthographic knowledge and familiarity with specific sequences can facilitate perceptual processing in "word" detection.     

Letter search through words and nonwords: The effect of fixed,absent, or mutilated targets

The present study attempted to eliminate the word superiority effect found in letter search by holding the target letter fixed across trials. The expectation was that the target would thereby become so familiar and salient that the subject would "see" only that letter during search. Even with the target-letter held fixed (Experiment I), however, search was still faster through words than through nonwords, indicating that nontarget letters had been "seen" as well. Search also remained faster through words than through nonwords when the number of exposures to the target was further increased by having the subject search for the absence rather than the presence of the target letter (Experiment III). In line with the notion of "proofreader's errors," however, search became relatively more accurate on nonwords than on words when it required detection of the "mutilation" produced by substituting an F for an E, e.g., BASKFT, BAKFRY (Experiment IV).     

Attentional cueing effect in the identification of words and pseudowords of different length.

Three experiments studied the influence of spatial attention on familiar and unfamiliar letter string identification. Siéroff and Posner's (1988) cueing procedure was used: A cue indicated in advance either the beginning (left) or the end (right) of a foveally presented letter string that participants were instructed to read aloud. Results showed that the precue had a stronger influence on pseudoword than on word identification. Similar results were obtained when participants were instructed to report the identity of the cue or not. For pseudowords, a cueing effect was obtained regardless of length (6, 8, and 10 letters), whereas only 10-letter words showed such an effect, though to a lesser degree than pseudowords of the same length. However, results showed that shorter words were also influenced by the cue location when the exposure duration was reduced. Results are compatible with an early role of spatial attention in letter string processing, but they also suggest that the lexical status of a letter string can directly influence the distribution of attention before the identification process is completely achieved. Although orienting of spatial attention seems heavily involved in a pseudoword identification, some spatial attention mechanism could also take place in the case of familiar words. The results are discussed within two theoretical frameworks concerning the involvement of spatial attention in word identification: The "replacement" theory and the "redistribution" theory.     

Detecting phonemes and letters in text: Interactions between different types and levels of processes

In six experiments, subjects detected phonemes or letters in text presented auditorily or visually. Experiments 1 and 2 provided support for the hypothesis that a mismatch between the phoneme and letter representations of a target leads to detection errors. In addition, visual word unitization processes were implicated. Experiments 3 and 4 provided support for the hypothesis that the Gestalt goodness of pattern affected detection errors when subjects searched for letters. Experiments 5 and 6 demonstrated that the effects of unitization on the detection of letters in common words were decreased by altering the familiar configuration of the test words. The combined results of all six experiments lead to the conclusion that both visual and phonetic processes influence letter detection, that these processes communicate through a type of cross-checking, and that there are at least two levels of visual (and perhaps of phonetic) processing involved in the letter detection task.     

Evidence for a parallel input serial analysis model of word processing

A parallel input serial analysis (PISA) model of word processing was developed and tested. The goal was to expand on the "critical processing duration" hypothesis of Johnson, Allen, and Strand (1989) so that both single-word and multiple-word presentation, letter detection data could be explained. In Experiments 1-3 four different word frequency categories on a single-presentation, letter detection task were used. These three experiments indicated that there was a curvilinear relationship between word frequency and letter detection reaction time (RT). That is, letter detection RTs for medium-high-frequency words were significantly longer than letter detection RTs for very-high-, low-, and very-low-frequency words. These results support the PISA model rather than the Healy, Oliver, and McNamara (1987) version of the unitization model. In Experiments 4-5 multiple-presentation (i.e., two words), letter detection tasks were used. The PISA model could also account for the results from these two experiments, but the unitization model could not.     

Detection errors onthe andand: Evidence for reading units larger than the word

In five experiments, subjects read lO0-word passages and circled instances of a given target letter, letter group, or word. In each case subjects made a disproportionate number of detection errors on the common function wordsthe andand. The predominance of errors on these two words was reduced for passages in which the words were placed in an inappropriate syntactic context and for passages in which word-group identification was disturbed by the use of mixed typecases or a list, rather than a paragraph, format. These effects for the wordand were not found for the control wordant. These results were taken as evidence that familiar word sequences may be read in units larger than the word, probably short syntactic phrases or word frames. A tentative model of the reading process consistent with these results is proposed.     

Effect of direction of sequential presentation and redundancy on short-term recognition memory

Short-term recognition memory was tested by presenting six letters, one after the other, followed by a target letter and having S indicate whether or not the target matched one of the six letters. Recognition memory for a letter was better when it was embedded in a six-letter word, rather than a nonword, and when it was included in a sequence presented left-to-right, rather than right-to-left (Experiment 1). Reducing the presentation rate from 4/sec to 2.5/sec largely eliminated the left-to-right effect (Experiment 2). The effect of direction of presentation was greater for redundant (Experiment 1) than for nonredundant sequences (Experiment 3) and was greater for Ss who more frequently formed a word out of the sequence (Experiments 1 and 2), but was no greater for words than nonwords (Experiments 1 and 2) and no greater for letter than for line-figure sequences (Experiment 3). These findings suggest that the left-to-right effect depends as much, or more, on “peripheral” processes (e.g., eye movements) as on “central” processes (e.g., reading).     

Detection of intraword and interword letter repetition: A test of the word unitization hypothesis

Do words, as familiar units or gestalts, tend to swallow up and conceal their letter components (Pillsbury, 1897)? Letters typically are detected faster and more accurately in words than in nonwords (i.e., scrambled collections of letters), and in more frequent words than in less frequent words. However, a word advantage at encoding, where the representation of the string is formed, might compensate for, and thus mask, a word disadvantage at decoding and comparison, where the component letters of the representation are accessed and compared with the target letter. To better reveal any such word disadvantage, a task was used in this study that increased the amount of letter processing. Subjects judged whether a letter was repeated within a six-letter word or a nonword (Experiment 1; intraword letter repetition) or was repeated between two adjacent unrelated six-letter words or nonwords (Experiment 2; interword letter repetition). Contrary to Pillsbury's word unitization hypothesis, both types of letter repetition (intraword and interword) were detected faster and just as accurately with words as with nonwords. In Experiment 2, however, interword letter repetition was detected less accurately on common words (but not on rare words or third-order pseudowords) than on the corresponding nonwords. Thus, although the familiar word does not deny access to its own component letters, it does make their comparison with letters from other words more difficult.     

Sex differences in phonological processes: Speeded matching and word reading

Sex differences in phonological processing were investigated in four experiments. Two experiments required college students to decide whether two five-letter strings matched. Same-case (AA) pairs of letter strings could be matched using physical features, whereas mixed-case (Aa) pairs of letter strings required the mediation of a speech-based code (letter name) for the comparison. Women were significantly faster than men when the comparisons required the speech-based codes. In another experiment, college students read lists of words and lists of pseudohomophones to determine whether there was a sex difference in the computation of phonology for unfamiliar words (assembled phonology). In a final experiment, students read lists of words with phonologically inconsistent spelling patterns to determine whether there was a sex difference in accessing pronunciations of familiar words (addressed phonology). Women were more proficient than men under both of these conditions. Results were interpreted in terms of a female advantage in both prelexical and lexical processing, an advantage that may stem from a sex difference in the quality of the phonological representations.     

Word recognition with forced serial processing: Effects of segment size and temporal order variation

Serial processing was forced by displaying words one letter or letter cluster at a time. Letters or clusters appeared in adjacent spatial positions and in rapid sequence, followed immediately by a mask. Under these conditions, there was a sharp increase in the percentage of words correctly identified as the size of the letter clusters presented in series increased. In a control condition without masking, designed to permit parallel processing across clusters, words were identified near-perfectly, regardless of the size of the clusters displayed. Words displayed one letter at a time without masking were identified fairly well even when letters were presented in random order. The results are interpreted as evidence that skilled readers tend to process letters within words in parallel.     

Subjective judgments of spelling-sound correspondences: Effects of word regularity and word frequency

Subjects asked to judge which of two pronunciations of a letter sequence is typical of how that sequence is pronounced in English showed a strong tendency to nominate the linguistically “regular” word in preference to the “irregular” or “exceptional” word. Experiment 1 showed that this tendency was uninfluenced by the frequencies of the words being compared. The effect of regularity was replicated in Experiment 2, which also demonstrated the importance of the method of cuing the common letter sequence; when it was printed beside the words being judged, a stronger regularity effect was obtained than when the words were presented alone. Both experiments also showed a variation in the subjective strength of spelling-sound correspondences, and it was concluded that all-or-nothing conceptualizations of “rules” and "regularity" are oversimplifications. The implications of the findings for the concept of analogies in pronunciation were also considered.     

Detection and identification of words and letters in simulated visual search of word lists

Ss were shown a rapid sequence of words and had to (a) make a speeded response to the presentation of a predefined target and (b) report a "response word" which they thought immediately followed the target in the sequence. In Experiment I presentation rate was varied orthogonally with the number of alternative targets. Detection errors and latency increased with target set size, as did the distance of the response word from the target in the list sequence. Increases in presentation rate produced greater target-response distance without affecting detection time. In Experiment II Ss were in some conditions given only the initial letter of the targets; the response could be either the whole word following the target or only its initial letter. The results indicated that Ss could, within limits, concurrently detect initial letters and identify words. Alternatives to hierarchical-type models of stimulus processing in visual search were discussed.     

Investigating the boundaries of reading units across ages and reading levels

In Experiments 1 and 2 first-, third-, and seventh-grade children and college subjects circled the letter a while reading passages constructed of words familiar to first graders. First graders made more errors on the letter a embedded in a word than on the word a, whereas the converse was true of the other age groups. In Experiments 3 and 4 first-, second-, fourth-, and seventh-grade children and college students read passages and circled the letter t, making more errors on the common word the than on other words and on correctly spelled than on misspelled words. The effect of misspelling the other words increased with age and reading skill. Our combined results suggest that reading unit size increases with age and reading ability and that, whereas younger children, like adults, unitize common words, the unitization of less common words increases as word configurations become more familiar.     

Contextual control over lexical and sublexical routines when reading English aloud

Are the processes responsible for reading aloud single well-formed letter strings under contextual control? Despite the widespread contention that the answer to this question is “yes,” it has been remarkably difficult to provide a compelling demonstration to that effect. In a speeded naming experiment, skilled readers read aloud exception words (such asPint) that are atypical in terms of their spelling sound correspondences and nonwords (such asFlad) that appeared in a predictable sequence. Subjects took longer to name both words and nonwords when the item on the preceding trial was from the other lexical category, relative to when the preceding item was from the same lexical category. This finding is consistent with the relative contributions of lexical and sublexical knowledge being controlled. We note a number of different ways that this control could arise and suggest some directions for future research.     

Visual statistical learning produces implicit and explicit knowledge about temporal order information and scene chunks: Evidence from direct and indirect measures

We examined whether visual statistical learning (VSL) produced implicit and/or explicit knowledge about temporal order information and scene chunks, using a rapid serial visual presentation target detection task and a two-alternative forced-choice (2AFC) familiarity test as indirect and direct measures of VSL, respectively. In the familiarization phase, participants viewed a visual stream of natural scenes consisting of four triplets (i.e., three images that always appeared in the same order). In the subsequent target detection task, participants were required to detect target items embedded in a stream of 12 images or 12 words representing each natural scene. In the final 2AFC familiarity test, participants observed two test sequences (statistically related triplets vs. unrelated foils) and decided whether the first or second sequence was more familiar based on the familiarization phase. In both test phases, we included the same (forward) and reverse (backward) order of scenes as presented during the familiarization phase to examine whether the expression of VSL was based on temporal order of scenes or scene chunks. The results of the target detection task showed a learning effect for both temporal order in the forward condition and chunks in the backward condition, irrespective of whether stimuli were images or words; in contrast, we did not observe a learning effect in the backward condition for scene images in the familiarity test. Our findings are compatible with a learning mechanism that has both implicit and explicit components based on temporal order information and scene chunks.     

Visuospatial perceptual sequence learning and eye movements

We examined perceptual sequence learning by means of an adapted serial reaction time task in which eye movements were unnecessary for performing the sequence learning task. Participants had to respond to the identity of a target letter pair ("OX" or "XO") appearing in one of four locations. On the other locations, similar distractor letter pairs ("QY" or "YQ") were shown. While target identity changed randomly, target location was structured according to a deterministic sequence. To render eye movements superfluous, (1) stimulus letter pairs appeared around a fixation cross with a visual angle of 0.63°, which means that they appeared within the foveal visual area and (2) the letter pairs were presented for only 100 ms, a period too short to allow proper eye movements. Reliable sequence knowledge was acquired under these conditions, as responses were both slower and less accurate when the trained sequence was replaced by an untrained sequence. These results support the notion that perceptual sequence learning can be based on shifts of attention without overt oculomotor movements.     

Contrasting effects of age of acquisition in lexical decision and letter detection

Two experiments studied attention in beginning and skilled readers of Dutch to letter information in function words and content words. Early and late acquired nouns and function words were presented to third-grade students and skilled adolescent readers. Target words were presented in short story contexts, as in the study of Greenberg, Koriat, and Vellutino (1998). Target nouns were matched on word frequency. Predictions of the structural account hypothesis of letter detection (Koriat, Greenberg, & Goldshmid, 1991) were confirmed. No age-of-acquisition effect was found. In contrast, a separately conducted lexical decision experiment using the same content word stimulus sets showed shorter decision latencies for early acquired words. The combined results suggest that during silent reading, when attention is focused on meaning, phonological processes may play a less prominent role than in lexical decision tasks that demand explicit control of phonological codes. The letter detection results confirmed predictions of the structural account hypothesis for both beginning and skilled readers. Taken together, these studies demonstrate that phonological processes in silent reading may play a less prominent role and that the structural account of letter processing is valid for languages other than Hebrew and English but probably is not the unique mechanism involved in letter detection.     

The impact of familiarization strategies on the missing-letter effect

When reading a text and searching for a target letter, readers make more omissions of the target letter if it is embedded in frequent function words than if it is in rare content words. While word frequency effects are consistently found, few studies have examined the impacts of passage familiarity on the missing-letter effect and studies that have present conflicting evidence. The present study examines the effects of passage familiarity, as well as the impacts of passage familiarization strategy promoting surface or deep encoding, on the missing-letter effect. Participants were familiarized with a passage by retyping a text, replacing all common nouns with synonyms, or generating a text on the same topic as that of the original text, and then completed a letter search task on the familiar passage as well as an unfamiliar passage. In Experiment 1, when both familiar and unfamiliar passages use the same words, results revealed fewer omissions for the retyping and synonyms conditions. However, in Experiment 2, when different words are used in both types of texts, no effect of familiarization strategy was observed. Furthermore, the missing-letter effect is maintained in all conditions, adding support to the robustness of the effect regardless of familiarity with the text.