The role of familiar units in perception of words and nonwords

This paper investigates the effects of familiarity with whole-word units and letter-cluster units in perceptual encoding of letter strings. Subjects viewed brief, masked presentations of words and pronounceable pseudowords differing in letter cluster frequency. Identification of both display types was compared to control single letters. Perceptual accuracy was indexed by probe forced-choice responses and full verbal reports of the displays. Evidence that familiarity of whole-word units facilitated encoding was mixed but, on balance, favorable. Evidence that familiarity of letter-cluster units facilitated encoding was completely absent. This negative finding is surprising in view of the fact that we did obtain a large advantage of letters in pseudo-words as well as words over single letters. The discussion section considers an alternative to the view that perceivers use detectors for familiar letter-cluster units in the process of forming representations of pronounceable, orthographically regular letter strings.     

Preliminary letter identification in the perception of words and nonwords.

Words with mixed uppercase and lowercase letters (e.g. fAdE) were perceived more accurately than mixed-case pseudowords (e.g. gAdE), and mixed-case pseudowords were perceived more accurately than mixed-case unrelated letter strings (e.g. eFdT). In addition, same-case words were perceived more accurately than their mixed-case counterparts. The same held true for pseudowords but not for unrelated letter strings. The results are compatible with the view that both letter identify and visual form information are used in word perception.     

The role of bigram frequency in the perception of words and nonwords

Memory & Cognition - Adult subjects decided whether strings of four, five, or six letters formed words or nonwords. Words and nonwords were equally probable stimuli, and there were equal...     

Lateralization in the visual perception of Chinese characters and words

It has been reported that tachistoscopic perception of single Chinese characters is better with a left-visual-field (LVF) than with a right-visual-field (RVF) presentation and that of Chinese words consisting of characters is better with a RVF presentation (O. J. L. Tzeng, D. L. Hung, B. Cotton, & S.-Y. Wang, 1979, Nature (London), 382, 499-501). In this study, the nature of this character-word difference in lateralization was explored in a task in which stimuli were presented unilaterally to a visual field for recognition test. Four types of stimuli were used: Single character, single pseudo- or noncharacter, two-character word, and two-character pseudoword. Results show (a) no visual-field advantage for illegal characters and words, (b) a LVF-advantage effect for characters associated with a more prominent LVF than RVF character-superiority effect, (c) a RVF-advantage effect for words associated with a more prominent RVF than LVF word-superiority effect, and (d) these two visual-field effects for characters and words being not absolute, they occur only with a low rather than with a high recognition for their respective illegal counterparts. These results suggest that the character-word difference is due to a more efficient lexical interpretation of character stimuli in the right than in the left hemisphere and a more efficient lexical interpretation of word stimuli in the left than in the right hemisphere.     

Rhyme decisions to spoken words and nonwords

Lexical effects in auditory rhyme-decision performance were examined in three experiments. Experiment 1 showed reliable lexical involvement: rhyme-monitoring responses to words were faster than rhyme-monitoring responses to nonwords; and decisions were faster in response to high-frequency as opposed to low-frequency words. Experiments 2 and 3 tested for lexical influences in the rejection of three types of nonrhyming item: words, nonwords with rhyming lexical neighbors (e.g.,jop after the cuerob), and nonwords with no rhyming lexical neighbor (e.g.,vop afterrob). Words were rejected more rapidly than nonwords, and there were reliable differences in the speed and accuracy of rejection of the two types of nonword. The advantage for words over nonwords was replicated for positive rhyme decisions. However, there were no differences in the speed of acceptance, as rhymes, of the two types of nonword. The implications of these results for interactive and autonomous models of spoken word recognition are discussed. It is concluded that the differences in rejection of nonrhyming nonwords are due to the operation of a guessing strategy.     

Whole and part comparisons of words and nonwords

Under conditions of sequential presentation, two words are matched more quickly than are a single letter and the first letter of a word. An exception to this whole-word advantage was reported in 1980 by Umansky and Chambers, who used word pairs as stimuli, and asked subjects to compare the entire words or the words’ first letters. Experiment 1 showed that the stimulus lists used by Umansky and Chambers may not have constrained subjects to process the displays differently for wholistic and component comparisons. In those studies, the two words were identical onsame trials for both wholistic and first-letter comparisons, so that first-letter decisions could have been based on wholistic information. In the present study, lists were constructed so that first-letter decisions could not be determined correctly by wholistic information (e.g., BLAME/BEACH), and the whole-word advantage was replicated. Experiment 2 tested whether wholistic comparisons are generally superior to component comparisons. For consonant strings, first-letter comparisons were made more quickly than were whole-string comparisons. These results are interpreted as support for hierarchical models of visual word processing.     

Repetition priming of words, pseudowords, and nonwords

In 5 experiments, the authors assessed repetition priming for words, pseudowords, and nonwords using a task that combines an implicit perceptual fluency measure and a recognition memory assessment for each list item. Words and pseudowords generated a consistently strong repetition effect even when there was a failure to recognize the stimulus. In 2 of the experiments, the repetition effect for nonwords was reliably above chance even when there was a failure to recognize the stimulus. The authors propose a parallel distributed processing (PDP) model based on the work of J. McClelland and D. Rumelhart (1985) as a way to understand the mechanisms potentially responsible for the pattern of findings. Although the error-driven nature of learning in the model results in a poor fit to the nonword priming data, this is not endemic to all PDP models. Using a model based on Hebbian learning, the authors instantiate a property that they believe is characteristic of implicit memory--that learning is primarily based on the strengthening of connections between units that become active during the processing of a stimulus. This model provides a far more satisfactory account of the data than does the error-driven model.     

Divided attention and prerecognition processing of spoken words and nonwords

Three recognition memory experiments examined phonemic similarity and false recognition under conditions of divided attention. The manipulation was presumed to have little effect on automatic, perceptual influences of memory. Prior research demonstrated that false recognition of a test word (e.g., discrepancy) was higher if the study list included a nonword derived from the future test word by changing a phoneme near the end of the item (e.g., discrepan/l/y) relative to an early phoneme change (e.g., /l/iscrepancy). The difference has been attributed to automatic, implicit activation of test words during prerecognition processing of related nonwords. Three experiments demonstrated that the late-change condition also contributed to higher false recognition rates with divided attention at encoding. Dividing attention disrupted recognition memory of studied words in Experiments 1 and 3. Results are discussed in terms of their relevance for an interpretation emphasizing the automatic, implicit activation of candidate words that occurs in the course of identifying spoken words and nonwords.     

On the processes underlying stimulus-familiarity effects in recognition of words and nonwords

The authors investigated the recognizability of recently studied word and nonword stimuli in relation to both experimentally controlled prior frequency of occurrence and, for words, normative frequency (assessed by counts of occurrences in printed English). The interaction between these variables was small and nonsignificant across all conditions of 2 experiments. Patterns of recognition measures in relation to controlled prior frequency, but not normative frequency, appeared interpretable in terms of response biases generated by long-term priming. Application of a global memory model and analyses of correlations among item categories yielded evidence for a lexicality dimension underlying normative-frequency effects and an implication that "word-frequency effects" on recognition are better termed lexicality effects.     

Stroop-like serial position effects in color naming of words and nonwords

Color-naming latencies to noncolor words and nonwords were faster when the onset or final phoneme of the displays corresponded to the onset or final phoneme of the color response. For example, for displays printed in red, the word rack and nonword rask, which share the initial onset phoneme with the response, led to faster naming than did the control word chap and nonword chup. Conversely, when the onset or final phoneme of the displays matched the onset or final phoneme of a conflicting color response (e.g., rack printed in blue), latencies were longer than to control items. Facilitation effects were stronger than interference effects, and the onset phoneme facilitation effect was augmented by coloring only the initial letter in the display. It is hypothesized that nonlexical processes that govern the translation of print to speech may be a source of facilitation in Stroop-like tasks, whereas lexical processes are more likely to contribute to interference.     

Children's reading of words, pseudohomophones, and other nonwords

In Experiment 1 children aged 8-9 and 9-10 years were tested for neighbourhood and pseudohomophone effects in nonword reading. Neighbourhood effects ( N effects) were robust irrespective of group or type of nonword. Pseudohomophones were read more accurately than other nonwords but this finding was robust only for the younger 8-9-year-olds. High-frequency words were read more accurately than low-frequency words, but the reverse applied to pseudohomophones based on high- and low-frequency words, although this was not robust. Error rates for the 9-10-year-olds in Experiment 1 were low, and so it was difficult to interpret the lack of a pseudohomophone advantage for reading nonwords in this age group. Experiment 2 was therefore carried out, which consisted of a replication of the first study with a further group of 9- 10-year-olds, but pronunciation latencies were measured, as well as accuracy. All the effects obtained in Experiment 1 were replicated but, in addition, an advantage for pseudohomophones in terms of pronunciation latencies was observed. The implications for accounts of reading development are discussed.     

Immediate serial recall of words and nonwords: Tests of the retrieval-based hypothesis

In two experiments, the immediate serial recall of lists of words or nonwords was investigated under quiet and articulatory suppression conditions. The results showed better item recall for words but better order recall for nonwords, as measured with proportion of order errors per item recalled. Articulatory suppression hindered the recall of item information for both types of lists and of order information for words. These results are interpreted in light of a retrieval account in which degraded phonological traces must undergo a reconstruction process calling on long-term knowledge of the tobe-remembered items. The minimal long-term representations for nonwords are thought to be responsible for their lower item recall and their better order recall. Under suppression, phonological representations are thought to be minimal, producing trace interpretation problems responsible for the greater number of item and order errors, relative to quiet conditions. The very low performance for nonwords under suppression is attributed to the combination of degraded phonological information and minimal long-term knowledge.     

Visual search through words and nonwords in horizontal and vertical orientations.

In a repeated measurement design, 18 college women searched for target letters in 18 lists of common words, rare words, and nonwords arranged either vertically or horizontally. The mean search time in seconds for three trials in each of six conditions was expected to be significantly slower for nonwords than for words and for vertical orientations than for horizontal orientations. More importantly, a significant interaction was predicted between direction of search and the type of list searched. Results confirmed earlier findings that the two main effects were significant; the significant interaction provided empirical evidence that consideration needs to be given to both intraword redundancy and direction of visual search.     

A re-evaluation of the phonological similarity effect in adults' short-term memory of words and nonwords

The phonological similarity effect (PSE) was studied in two tasks of serial recall, in one task of serial recognition and one item identification task. PSE occurred only in the former three tasks involving memory of order when study items were words and nonwords with an associative connectedness to long-term memory. Nonwords that, according to a reaction time assessment of associative value, were less well connected to long-term memory mechanisms, were not sensitive to phonological similarity. These results are discussed in relation to contemporary models of short-term memory that explain the PSE as a result of confusions of items that are similarly encoded in a phonological layer. This layer is identified as a higher-level phonological space that is accessed by words and nonwords of high associative value and not by nonwords of low associative value.     

A Web-based interface to calculate phonotactic probability for words and nonwords in English

Phonotactic probability refers to the frequency with which phonological segments and sequences of phonological segments occur in words in a given language. We describe one method of estimating phonotactic probabilities based on words in American English. These estimates of phonotactic probability have been used in a number of previous studies and are now being made available to other researchers via a Web-based interface. Instructions for using the interface, as well as details regarding how the measures were derived, are provided in the present article. The Phonotactic Probability Calculator can be accessed athttp://www.people.ku.edu/~mvitevit/PhonoProbHome.html.     

Detection of letter repetition in words and nonwords: the effect of opposite-case distractors.

This study tested whether it is the repetition of the letter's name and not its shape that is detected faster in a word than in a nonword (Krueger, 1989). Ss judged whether the same letter shape or the same letter name was repeated in a 6-letter word or nonword. When the shape was repeated, the word advantage was nearly as large (about 50 ms) when Ss looked for a physical match as when they looked for a name match. When the 2 repeated letters differed in case, however, the word advantage was very large (208 ms) when Ss looked for a name match and were thus rewarded for nonvisual coding, but the advantage vanished ((-35)-ms word deficit) when Ss looked for a physical match and were thus penalized for nonvisual coding. This indicates that letter names are much more accessible in words than in nonwords, and that words are primarily encoded nonvisually.     

Judgments of duration, figure-ground contrast, and size for words and nonwords

Does the word-superiority effect on letter discrimination result in a word-superiority effect on duration judgments? We examined this question in five experiments. In the first four experiments, we have demonstrated that (1) words shown for 32-80 msec were judged as presented longer than non-words shown for the same duration; (2) this word-superiority effect persists if the stimuli are shown for an objective duration of up to 250 msec; and (3) these effects can be extended to judgments of figure-ground contrast and letter size. These findings extend existing data on effects of processing fluency on perceptual judgments. In Experiment 5, we found that duration judgments were higher for words than for pronounceable nonwords, and duration judgments were higher for pronounceable non-words than for nonpronounceable nonwords. We discuss the implications of this finding for the discrepancy-attribution hypothesis.