Transposed-letter and laterality effects in lexical decision

Two divided visual field lexical decision experiments were conducted to examine the role of the cerebral hemispheres in transposed-letter similarity effects. In Experiment 1, we created two types of nonwords: nonadjacent transposed-letter nonwords (TRADEGIA; the base word was TRAGEDIA, the Spanish for TRAGEDY) and two-letter different nonwords (orthographic controls: TRATEPIA). In Experiment 2, the controls were one-letter different nonwords (TRAGEPIA) instead of two-letter different nonwords (TRATEPIA). The effect of transposed-letter similarity was substantially greater in the right visual field (left hemisphere) than in the left visual field. Furthermore, nonwords created by transposing two letters were more competitive than the nonwords created by substituting one or two letters of a target word. We examine the implications of these findings for the models of visual word recognition.     

Semantic involvement in the lexical and sentence processing of Japanese kanji

This study examined how skilled Japanese readers activate semantic information when reading kanji compound words at both the lexical and sentence levels. Experiment 1 used a lexical decision task for two-kanji compound words and nonwords. When nonwords were composed of kanji that were semantically similar to the kanji of real words, reaction times were longer and error rates were higher than when nonwords had kanji that were not semantically similar. Experiment 2 used a proofreading task (detection of kanji miscombinations) for the same two-kanji compound words and nonwords at the sentence level. In this task, semantically similar nonwords were detected faster than dissimilar nonwords, but error rates were much higher for the semantically similar nonwords. Experiment 3 used a semantic decision task for sentences with the same two-kanji compound words and nonwords. It took longer to detect semantically similar nonwords than dissimilar nonwords. This indicates that semantic involvement in the processing of Japanese kanji produces different effects, depending on whether this processing is done at the lexical or sentence level, which in turn is related to where the reader's attention lies.     

Conformity to Experimenter‐Provided Examples: Will People use an Unusual Feature?

Undergraduates studied nonword exemplars and then created their own novel nonwords. In Experiment 1, people studied legal or illegal nonwords. In Experiment 2, people studied illegal nonwords, but to increase awareness of the features, half of the participants assessed the features of the nonwords. Despite instructions to avoid copying any aspect of the examples, people incorporated features from the examples into their own novel creations. Although people do not spontaneously create illegal nonwords, those people that studied illegal nonwords were more likely to create illegal nonwords. Assessing the features of the examples did not reduce the likelihood that people would copy features of the examples. We discuss these results in the context of Ward's (1994) structured imagination account.     

Primacy and recency in nonword repetition

An increasing body of evidence suggests that nonword repetition is related to immediate serial memory (e.g., Baddeley, Gathercole, & Papagno, 1998; Gathercole & Baddeley, 1993). One possible account of this relationship is that a nonword is processed like a list when it is first encountered. If this is the case, it should be possible to detect serial position effects in repetition of single nonwords. Three experiments tested this prediction. Experiment 1 examined whether there would be syllable serial position primacy and recency effects in repetition of polysyllabic nonwords, and obtained both primacy and recency effects. Experiments 2 and 3 showed that these effects were not due to the controlled duration of the nonwords or the requirements of concurrent articulation or the procedure by which nonwords were created.     

Primacy and recency in nonword repetition

An increasing body of evidence suggests that nonword repetition is related to immediate serial memory (e.g., ; ). One possible account of this relationship is that a nonword is processed like a list when it is first encountered. If this is the case, it should be possible to detect serial position effects in repetition of single nonwords. Three experiments tested this prediction. Experiment 1 examined whether there would be syllable serial position primacy and recency effects in repetition of polysyllabic nonwords, and obtained both primacy and recency effects. Experiments 2 and 3 showed that these effects were not due to the controlled duration of the nonwords or the requirements of concurrent articulation or the procedure by which nonwords were created.     

The word-detection effect: Sophisticated guessing or perceptual enhancement?

Subjects discriminate letters in words better than letters in nonwords. The sophisticated guessing hypothesis attributes this word advantage to a guessing strategy. In words, the possible letters at each letter position are constrained by letters at other positions, whereas letters in nonwords are not restricted in this manner. A critical test of this hypothesis is that if subjects are givenexplicit knowledge of the letters in nonwords before the trial, the word advantage would disappear. We investigated the effect of preknowledge of the alternatives in the word-detection effect. In the word-detection effect, subjects decide which of two character strings contains letters and which contains pseudoletters. In four experiments, subjects were more accurate with words than with nonwords, and subjects were more accurate when they were told the word or nonword before the trial. However, even with foreknowledge of the alternatives, subjects were more accurate with words than with nonwords.     

Dissociating mere exposure and repetition priming as a function of word type

The mere exposure effect is defined as enhanced attitude toward a stimulus that has been repeatedly exposed. Repetition priming is defined as facilitated processing of a previously exposed stimulus. We conducted a direct comparison between the two phenomena to test the assumption that the mere exposure effect represents an example of repetition priming. In two experiments, having studied a set of words or nonwords, participants were given a repetition priming task (perceptual identification) or one of two mere exposure (affective liking or preference judgment) tasks. Repetition priming was obtained for both words and nonwords, but only nonwords produced a mere exposure effect. This demonstrates a key boundary for observing the mere exposure effect, one not readily accommodated by a perceptual representation systems (Tulving & Schacter, 1990) account, which assumes that both phenomena should show some sensitivity to nonwords and words.     

List context effects on masked phonological priming in the lexical decision task

A lexical decision experiment tested the effects of briefly presented masked primes that were homophones or pseudohomophones of target words. Different types of nonword foil (pseudohomophones, orthographically regular nonwords, orthographically irregular nonwords) were mixed with the word targets. Pseudohomophone priming effects were independent of nonword foil variations, whereas homophone priming effects varied from being facilitatory in the presence of orthographically regular nonwords, inhibitory in the presence of pseudohomophones, and null in the presence of irregular nonwords. This dissociation in the way nonword foil variations influence masked pseudohomophone and homophone priming effects in the lexical decision task is discussed within the framework of a bimodal extension of the multiple readout model of visual word recognition (Grainger & Jacobs, 1996).     

Statistical frequency in perception affects children’s lexical production

Children’s early word production is influenced by the statistical frequency of speech sounds and combinations. Three experiments asked whether this production effect can be explained by a perceptual learning mechanism that is sensitive to word-token frequency and/or variability. Four-year-olds were exposed to nonwords that were either frequent (presented 10 times) or infrequent (presented once). When the frequent nonwords were spoken by the same talker, children showed no significant effect of perceptual frequency on production. When the frequent nonwords were spoken by different talkers, children produced them with fewer errors and shorter latencies. The results implicate token variability in perceptual learning.     

Left hemisphere superiority for pronounceable nonwords,but not for unpronounceable letter strings

Right-handed adults were asked to identify bilaterally presented linguistic stimuli under three experimental conditions. In Condition A, stimuli were three-letter pronounceable nonwords (such as TUP), and subjects were asked to report them by naming them. In Condition B, stimuli were three-letter pronounceable nonwords, and subjects were asked to report them as strings of letters. In Condition C, stimuli were more or less unpronounceable letter strings (such as UTP) created by rearranging the letters of pronounceable nonwords, and subjects reported them as strings of letters. Pronounceable nonwords were found to be better identified from the right visual hemifield irrespective of the way in which they were reported. Unpronounceable letter strings did not produce any visual hemifield difference. Nonwords are of interest because they can be seen as potential words that lack both specific semantic properties and entries in the subject's internal lexicon. The results of the experiment are consistent with the view that both the left and right cerebral hemispheres are able to identify letters but the left hemisphere is more sensitive to the pronounceability of the nonwords. This may happen either because the left hemisphere can make better use of resemblances to real words or because it has access to spelling to sound correspondence rules.     

Sensitivity to sub-syllabic constituents in brain-damaged patients: evidence from word games

Two experiments were conducted to examine whether left- (LHD) and right-hemisphere-damaged (RHD) patients exhibit sensitivity to sub-syllabic constituents (i.e., onsets and codas) in the generation of nonwords, using a word games paradigm adapted from. Four groups of individuals (including LHD fluent and nonfluent aphasic patients, RHD patients and normal controls) were trained to add syllables to monosyllabic CVC nonwords either after the initial consonant (Experiment 1) or prior to the final consonant (Experiment 2) to create bisyllabic nonwords. Experimental stimuli consisting of CCVC or CVCC nonwords tested whether participants would preserve or split the onset and coda constituents in producing the novel bisyllabic nonwords. Results revealed that the majority of subjects demonstrated sensitivity to the sub-syllabic constituents, preserving the onsets and codas. The fluent aphasic patients exhibited a greater than normal tendency to split the onset and coda constituents; however, the small number of individuals in that group whose data met inclusion criteria limits the conclusions that may be drawn from these findings. The results are discussed in relation to theories of phonological deficits in aphasia.     

Artificially induced valence of distractor words increases the effects of irrelevant speech on serial recall

In a game context, nonwords either were artificially associated with negative valence or were in some sense neutral or irrelevant. Subsequently, participants memorized target words in silence or while attempting to ignore the negatively valent, irrelevant, or neutral auditory distractor nonwords. The presence of distractor nonwords impaired recall performance, but negative distractor nonwords caused more disruption than neutral and irrelevant distractors, which did not differ in how much disruption they caused. These findings conceptually replicate earlier results showing disruption due to valence with natural language words and extend them by demonstrating that auditory features that may possibly be confounded with valence in natural language words cannot be the cause of the observed disruption. Explanations of the irrelevant speech effect within working memory models that specify an explicit role of attention in the maintenance of information for immediate serial recall can explain this pattern of results, whereas structural models of working memory cannot.     

Repetition blindness occurs in nonwords

Theorists have predicted that repetition blindness (RB) should be absent for nonwords because they do not activate preexisting mental types. The authors hypothesized that RB would be observed for nonwords because RB can occur at a sublexical level. Four experiments showed that RB is observed for word-nonword pairs (noon noof), orthographically similar nonwords (glome glame), and identical repetitions (plass plass). More RB was found for words than for nonwords. Prior researchers may have failed to find RB for nonwords because display conditions that allow 2 words to be reliably encoded are insufficient for nonwords, or because observers coped with low ability to encode nonwords by using guessing strategies that do not require creating a mental type or tokenizing it.     

Vocabulary learning in primary school children: Working memory and long-term memory components

The goal of this study was to investigate which working memory and long-term memory components predict vocabulary learning. We used a nonword learning paradigm in which 8- to 10-year-olds learned picture-nonword pairs. The nonwords varied in length (two vs. four syllables) and phonology (native sounding vs. including one Russian phoneme). Short, phonologically native nonwords were learned best, whereas learning long nonwords leveled off after a few presentation cycles. Linear structural equation analyses showed an influence of three constructs—phonological sensitivity, vocabulary knowledge, and central attentional resources (M capacity)—on nonword learning, but the extent of their contributions depended on specific characteristics of the nonwords to be learned. Phonological sensitivity predicted learning of all nonword types except short native nonwords, vocabulary predicted learning of only short native nonwords, and M capacity predicted learning of short nonwords but not long nonwords. The discussion considers three learning processes—effortful activation of phonological representations, lexical mediation, and passive associative learning—that use different cognitive resources and could be involved in learning different nonword types.     

Recognition and lexical decision without detection: unconscious perception?

Stimulus detection and concurrent measures of stimulus recognition were compared to establish whether perception occurs in the absence of detection. The target stimuli were familiar words (Experiments 1 and 2), nonwords (Experiment 3), or both words and nonwords (Experiment 4). On each trial, either a stimulus or a blank field was presented. Ss first decided whether a stimulus had been presented and then made either a forced-choice recognition decision (Experiments 1, 2, and 3) or a lexical decision (Experiment 4). Both words and nonwords were recognized and discriminated following correct detections (i.e., hits). However, in the absence of stimulus detection (i.e., misses), only words were recognized or discriminated. These qualitatively different patterns of results following hits and misses for words and nonwords suggest that stimulus detection may provide an adequate measure of conscious awareness.     

Initial phonemes are detected faster in spoken words than in spoken nonwords

In two experiments, subjects monitored sequences of spoken consonant-vowel-consonant words and nonwords for a specified initial phoneme. In Experiment I, the target-carrying monosyllables were embedded in sequences in which the monosyllables were all words or all nonwords. The possible contextual bias of Experiment I was minimized in Experiment II through a random mixing of target-carrying words and nonwords with foil words and nonwords. Target-carrying words were distinguished in both experiments from target-carrying nonwords only in the final consonant, e.g., /bit/ vs. /bip/. In both experiments, subjects detected the specified consonant /b/ significantly faster when it began a word than when it began a nonword. One interpretation of this result is that in speech perception lexical information is accessed before phonological information. This interpretation was questioned and preference was given to the view that the result reflected processes subsequent to perception: words become available to awareness faster than nonwords and therefore provide a basis for differential responding that much sooner.     

Interrupting recognition memory: Tests of a criterion-change account of the revelation effect

The revelation effect is evidenced by an increase in positive recognition responses when the test probe is immediately preceded by an unrelated problem-solving task. As an alternative to familiarity-based explanations of this effect (Hicks & Marsh, 1998; Westerman & Greene, 1998), Niewiadomski and Hockley (2001) proposed a decision-based account in which it is assumed that the problem-solving task displaces the study list context in working memory, leading subjects to adopt a more liberal recognition criterion. In the present study, we show that the revelation effect is seen when the stimulus materials are pure lists of very rare words or nonwords. In contrast, for mixed lists of common words and very rare words or nonwords, the revelation effect is found for common words but disappears for very rare words and nonwords. We argue that, in mixed lists, the liberal decision bias following the revelation task and the criterion changes between common words and very rare words and nonwords serve to offset each other.     

Isolating visual units in the perception of words and nonwords

In three experiments, reaction times for same-different judgments were obtained for pairs of words, pronounceable nonwords (pseudowords), and unpronounceable nonwords. The stimulus strings were printed either in a single letter case or in one of several mixtures of upper- and lowercase letters. In Experiment 1, the stimuli were common one- and two-syllable words; in Experiment 2, the stimuli included both words and pseudowords; and in Experiment 3, words, pseudowords, and nonwords were used. The functional visual units for each string type were inferred from the effects that the number and placement of letter case transitions had onsame reaction time judgments. The evidence indicated a preference to encode strings in terms of multiletter perceptual units if they are present in the string. The data .also suggested that whole words can be used as functional visual units, although the extent of their use depends on contextual parameters such as knowledge that a word will be presented.     

Nonword repetition and phoneme elision in adults who do and do not stutter: Vocal versus nonvocal performance differences

PurposeThe purpose of the present study was to enhance our understanding of phonological working memory in adults who stutter through the comparison of nonvocal versus vocal nonword repetition and phoneme elision task performance differences.MethodFor the vocal nonword repetition condition, participants repeated sets of 4- and 7-syllable nonwords (n = 12 per set). For the nonvocal nonword repetition condition, participants silently identified each target nonword from a subsequent set of three nonwords. For the vocal phoneme elision condition, participants repeated nonwords with a target phoneme eliminated. For the nonvocal phoneme elision condition, participants silently identified the nonword with the designated target phoneme eliminated from a subsequent set of three nonwords.ResultsAdults who stutter produced significantly fewer accurate initial productions of 7-syllable nonwords compared to adults who do not stutter. There were no talker group differences for the silent identification of nonwords, but both talker groups required significantly more mean number of attempts to accurately silently identify 7-syllable as compared to 4-syllable nonwords. For the vocal phoneme elision condition, adults who stutter were significantly less accurate than adults who do not stutter in their initial production and required a significantly higher mean number of attempts to accurately produce 7-syllable nonwords with a phoneme eliminated. This talker group difference was also significant for the nonvocal phoneme elision condition for both 4- and 7-syllable nonwords.ConclusionPresent findings suggest phonological working memory may contribute to the difficulties persons who stutter have establishing and/or maintaining fluent speech.Educational Objectives: (a) Readers can describe the role of phonological working memory in planning for and execution of speech; (b) readers can describe two experimental tasks for exploring the phonological working memory: nonword repetition and phoneme elision; (c) readers can describe how the nonword repetition and phoneme elision skills of adults who stutter differ from their typically fluent peers.     

Letter detection with rapid serial visual presentation: evidence against word superiority at feature extraction

Letter detection typically is faster and more accurate in words than nonwords. Experiments 1, 2, and 3 tested the robustness of the word superiority effect using rapid serial visual presentation of words or nonwords. Letter detection was better in words even when the six-letter items were presented one after the other at rapid rates, up to about 10 items per second. At yet faster rates, however, the word advantage vanished. Experiments 4 and 5 tested whether word context aids feature extraction or the subsequent interpretation stage. In Experiment 4, subjects had to discriminate whether a mutilated A or mutilated E was present; in Experiment 5, subjects had merely to decide whether a mutilated A was present. Mutilation discrimination in Experiment 4 was better on words than nonwords; once a mutilation was detected, the word context revealed whether it was an A or an E. Mutilation detection in Experiment 5 did not differ between words and nonwords, though on words there was a response bias toward not reporting a mutilation as present. The results indicate that familiarity aids the interpretation process alone: Letters are not seen any more clearly or rapidly in words, but are simply filled in or inferred more accurately from the familiar context.