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PubMed2005

Orthographic structure versus morphological structure: principles of lexical organization in a given language.

Most models of visual word recognition in alphabetic orthographies assume that words are lexically organized according to orthographic similarity. Support for this is provided by form-priming experiments that demonstrate robust facilitation when primes and targets share similar sequences of letters. The authors examined form-orthographic priming effects in Hebrew, Arabic, and English. Hebrew and Arabic have an alphabetic writing system but a Semitic morphological structure. Hebrew morphemic units are composed of noncontiguous phonemic (and letter) sequences in a given word. Results demonstrate that form-priming effects in Hebrew or Arabic are unreliable, whereas morphological priming effects with minimal letter overlap are robust. Hebrew bilingual subjects, by contrast, showed robust form-priming effects with English material, suggesting that Semitic words are lexically organized by morphological rather than orthographic principles. The authors conclude that morphology can constrain lexical organization even in alphabetic orthographies and that visual processing of words is first determined by morphological characteristics.

Humans↗
PubMed2001

An electrophysiological response to different pitch contours in words.

A spoken word with more than one syllable contains a specific stress pattern found to be processed during spoken word recognition. The present study investigated the word's pitch contour as a single auditory parameter that marks stress. Event-related brain potentials (ERPs) were recorded while subjects made decisions to artificially pitch manipulated words. ERPs revealed that pitch contours are discriminated already within the first syllable of a word. Furthermore, behavioral responses for words with incorrect pitch contours were longer than for words with correct pitch contours. The results suggest that the pitch contour is an auditory feature of the spoken word that a listener automatically processes during spoken word recognition.

Acoustic Stimulation↗
PubMed2005

[The effect of deleting schwa (mute e) on spoken word recognition in French].

We studied the processing of two word strings in French made up of a determiner and a noun which contains a schwa (mute e). Depending on the noun, schwa deletion is present ("la tir'lire"), optional ("le ch(e)min") or absent ("la cornemuse"). In a production study, we show that schwa deletion, and the category of the noun, have a large impact on the duration of the strings. We take this into account in two perception studies, which use word repetition and lexical decision, and which show that words in which the schwa has been deleted usually take longer to recognize than words that retain the schwa, but that this depends also on the category of the word. We explain these results by examining the influence of orthography. Based on the model proposed by Grainger and Ferrand (1996), which integrates the written dimension, we suggest that two sources of information, phonological and orthographic, interact during spoken word recognition.

Adult↗
PubMed1998

Word-type effects in word-stem priming: evidence for semantic processing in the perceptual representation system?

While a presemantic Perceptual Representation System is believed to mediate implicit memory tasks such as word-stem priming, clinical studies suggest semantic information can be processed during priming. To clarify the nature of this system, we investigated word-type effects in word-stem priming in a nonclinical sample of 41 undergraduates who rated the pleasantness of threatening and nonthreatening words, performed implicit and explicit memory tasks, and completed measures of mood state. More nonthreatening words were primed and scores on the Beck Depression Inventory were negatively correlated with production of nonthreatening words. During cued recall, more threatening than nonthreatening words were remembered and ratings of state anxiety were negatively correlated with recall of nonthreatening words. Our findings support the contention that semantic information is processed during priming and that mood congruent biases also operate. These results may call for a reconceptualization of the Perceptual Representation System.

Adolescent↗
PubMed2005

Levels-of-processing effect on frontotemporal function in schizophrenia during word encoding and recognition.

OBJECTIVE: Patients with schizophrenia improve episodic memory accuracy when given organizational strategies through levels-of-processing paradigms. This study tested if improvement is accompanied by normalized frontotemporal function. METHOD: Event-related blood-oxygen-level-dependent functional magnetic resonance imaging (fMRI) was used to measure activation during shallow (perceptual) and deep (semantic) word encoding and recognition in 14 patients with schizophrenia and 14 healthy comparison subjects. RESULTS: Despite slower and less accurate overall word classification, the patients showed normal levels-of-processing effects, with faster and more accurate recognition of deeply processed words. These effects were accompanied by left ventrolateral prefrontal activation during encoding in both groups, although the thalamus, hippocampus, and lingual gyrus were overactivated in the patients. During word recognition, the patients showed overactivation in the left frontal pole and had a less robust right prefrontal response. CONCLUSIONS: Evidence of normal levels-of-processing effects and left prefrontal activation suggests that patients with schizophrenia can form and maintain semantic representations when they are provided with organizational cues and can improve their word encoding and retrieval. Areas of overactivation suggest residual inefficiencies. Nevertheless, the effect of teaching organizational strategies on episodic memory and brain function is a worthwhile topic for future interventional studies.

Adult↗
PubMed2001

Essential and perceptual attributes of words in reflective and on-line processing.

Access to essential and perceptual attributes of word meanings was investigated in a series of tasks. First, perceptual attributes of a number of natural kind concepts were determined by asking participants to generate the most salient features of those concepts; they were asked to assess the importance of both thosefeatures and features that fit criteria for essential attributes. Attributes fitting the criteria for essential attributes were found to be judged more important than perceptual attributes in identifying an object and to have more connections to other attributes of the concept. Semantic priming for both types offeatures was then investigated. Prime-target pairs consisting of the natural kind concept term and the perceptual or essential attribute were presented for lexical decision (Experiments 1a and 1b) or naming (Experiments 2a and 2b). Interstimulus intervals were either 0 or 200 ms. Both types of features were primed at a 200 ms interstimulus interval but only in the lexical decision task.

Humans↗
PubMed2006

The Bayesian reader: explaining word recognition as an optimal Bayesian decision process.

This article presents a theory of visual word recognition that assumes that, in the tasks of word identification, lexical decision, and semantic categorization, human readers behave as optimal Bayesian decision makers. This leads to the development of a computational model of word recognition, the Bayesian reader. The Bayesian reader successfully simulates some of the most significant data on human reading. The model accounts for the nature of the function relating word frequency to reaction time and identification threshold, the effects of neighborhood density and its interaction with frequency, and the variation in the pattern of neighborhood density effects seen in different experimental tasks. Both the general behavior of the model and the way the model predicts different patterns of results in different tasks follow entirely from the assumption that human readers approximate optimal Bayesian decision makers.

Attention↗
PubMed1984

A horse race of a different color: Stroop interference patterns with transformed words.

Four experiments investigated Stroop interference using geometrically transformed words. Over experiments, reading was made increasingly difficult by manipulating orientation uncertainty and the number of noncolor words. As a consequence, time to read color words aloud increased dramatically. Yet, even when reading a color word was considerably slower than naming the color of ink in which the word was printed, Stroop interference persisted virtually unaltered. This result is incompatible with the simple horse race model widely used to explain color-word interference. When reading became extremely slow, a reversed Stroop effect--interference in reading the word due to an incongruent ink color--appeared for one transformation together with the standard Stroop interference. Whether or not the concept of automaticity is invoked, relative speed of processing the word versus the color does not provide an adequate overall explanation of the Stroop phenomenon.

Attention↗
PubMed1981

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.

Cognition↗
PubMed1989

A distributed, developmental model of word recognition and naming.

A parallel distributed processing model of visual word recognition and pronunciation is described. The model consists of sets of orthographic and phonological units and an interlevel of hidden units. Weights on connections between units were modified during a training phase using the back-propagation learning algorithm. The model simulates many aspects of human performance, including (a) differences between words in terms of processing difficulty, (b) pronunciation of novel items, (c) differences between readers in terms of word recognition skill, (d) transitions from beginning to skilled reading, and (e) differences in performance on lexical decision and naming tasks. The model's behavior early in the learning phase corresponds to that of children acquiring word recognition skills. Training with a smaller number of hidden units produces output characteristic of many dyslexic readers. Naming is simulated without pronunciation rules, and lexical decisions are simulated without accessing word-level representations. The performance of the model is largely determined by three factors: the nature of the input, a significant fragment of written English; the learning rule, which encodes the implicit structure of the orthography in the weights on connections; and the architecture of the system, which influences the scope of what can be learned.

Dyslexia↗
PubMed2006

Chronic partial sleep loss increases the facilitatory role of a masked prime in a word recognition task.

Neurobehavioural performance deficits associated with sleep loss have been extensively studied, in particular, the effects on psychomotor performance. However, there is no consensus as to which, if any, cognitive functions are impaired by sleep loss. To examine how sleep loss might affect cognition, the automatic processes supporting word recognition were examined using the masked priming paradigm in participants who had been exposed to two consecutive days of sleep restriction. Twelve healthy volunteers (mean age 24.5 years) were recruited. Nocturnal sleep duration was restricted to 60% of each participant's habitual sleep duration for two consecutive nights by delaying scheduled time of sleep onset and advancing time of awakening. In controlled laboratory conditions, participants completed the Psychomotor Vigilance Task and Karolinska Sleepiness Scale and a masked priming word recognition task. As expected, significant increases in subjective sleepiness and impaired psychomotor performance were observed after sleep loss. In contrast, response times and error rate on the masked priming task were not significantly affected. However, the magnitude of the masked priming effect, which can be taken as an index of automaticity of lexical processing, increased following sleep loss. These findings suggest that while no evidence of impairment to lexical access was observed after sleep loss, an increase in automatic processing may occur as a consequence of compensatory mechanisms.

Adolescent↗
PubMed2000

An ERP study of the temporal course of the Stroop color-word interference effect.

The electrophysiological correlates of the Stroop color-word interference effect were studied in eight healthy subjects using high-density Event-Related Potentials (ERPs). Three response modalities were compared: Overt Verbal, Covert Verbal, and Manual. Both Overt Verbal and Manual versions of the Stroop yielded robust Stroop color-word interference as indexed by longer RT for incongruent than congruent color words. The Incongruent vs Congruent ERP difference wave presented two effects. A first effect was a medial dorsal negativity between 350-500 ms post-stimulus (peak at 410 ms). This effect had a significantly different scalp distribution in the Verbal and Manual Stroop versions, with an anterior-medial focus for overt or covert speech, and a broader medial-dorsal distribution for the manual task. Dipole source analysis suggested two independent generators in anterior cingulate cortex. Later on in time, a prolonged positivity developed between 500-800 ms post-stimulus over left superior temporo-parietal scalp. This effect was present for all the three response modalities. A possible interpretation of these results is that Stroop color-word interference first activates anterior cingulate cortex (350-500 ms post-stimulus), followed by activation of the left temporo-parietal cortex, possibly related to the need of additional processing of word meaning.

Adult↗
PubMed2003

Differential brain responses when applying criterion attribute versus family resemblance rule learning.

Subsystems of category learning have been identified on the basis of general domains of content (e.g., tools, faces). The present study examined categories from the standpoint of internal structure and determined brain topography associated with expressing two fundamentally different category rule structures (criterion attribute, CA, and family resemblance, FR). CA category learning involves processing stimuli by isolated features and classifying by properties held by all members. FR learning involves processing stimuli by integral wholes and classifying on overall similarity among members without sharing identical features. fMRI BOLD response to CA and FR categorization was measured with pseudowords as stimuli. Category knowledge for both tasks was mastered prior to brain imaging. Areas of activation emerged unique to the structure of each category and followed from the nature of the rule abstraction procedure. CA categorization was implemented by strong target monitoring and expectation (medial parietal), rule maintenance in working memory, feature selection processes (inferior frontal), and a sensitivity to high frequency components of the stimulus such as isolated features (anterior temporal). FR categorization, consistent with its multi-featural nature, involved word-level processing (left extrastriate) that evoked articulatory rehearsal (medial cerebellar). The data suggest category structure is an important determinant of brain response during categorization. For instance, anterior temporal structures may help attune visual processing systems to high frequency components to support the learning of criterial, highly predictive rules.

Adolescent↗
PubMedDate not supplied

Keeping birth normal: research findings on midwifery care during childbirth.

OBJECTIVE: This study describes processes and outcomes of midwifery care through narratives told by exemplary midwives. DESIGN: Narrative analysis. SETTING: Midwifery practices in hospital, birth center, and home settings. PARTICIPANTS: Purposive sample of 14 midwives drawn from a large national Delphi panel on exemplary midwifery practice. DATA ANALYSIS: Systematic analysis of interview data was conducted until interpretive consensus was achieved across all text and codes. Results were compared with two prior qualitative studies conducted by the first author on midwifery practice for congruence and emergence of new findings. RESULTS: The support of normalcy was identified as a significant process of midwifery care during labor and birth. CONCLUSIONS: The midwives believed that birth is normal, and many of their actions were specifically aimed toward the support of it as a physiologic, rather than pathologic, process. Through their words, we see subtle care processes focused on meeting a woman's individual needs and tapping into her personal strength. Implications for practice and further research to link their approach to caring for women with perinatal outcomes are reviewed.

Adult↗
PubMed2001

Absence of syllable effects: multisyllabic [correction of monosyllabic] words are easier than monosyllabic [correction of multisyllabic] words.

The role of syllables using the conventional lexical task of naming was examined with 107 college students. Equal numbers of four- and six-letter mono syllabic and multisyllabic words were presented for naming. There were significant syllable effects for 4-letter words as in previous studies but not for 6-letter words. In stead, monosyllabic words take more time to process than multisyllabic words. Most monosyllabic words are exceptional words with irregular correspondence of letter to sound. These results confirm that letter-to-sound consistency is more important in word recognition than the number of syllables.

Humans↗
PubMed1993

A multinomial processing tree model for degradation and redintegration in immediate recall.

When items are presented for immediate recall, a verbal trace is formed and degrades quickly, becoming useless after about 2 sec. The span for items such as digits equals the number of items that can be pronounced in the available time. The length of the items affects span by affecting pronunciation rate. Other properties, such as phonological similarity and lexicality, can affect span without affecting pronunciation rate. These properties change the trace's useful lifetime by affecting redintegration. An analogy is drawn between trace reconstruction and repair of errors in speech. When a trace is degraded, one process attempts to form a phoneme string, and another process attempts to form a word. The two processes are autonomous and can be selectively influenced by lexicality and phonological similarity. The resulting processing tree models make simple predictions that depend on whether or not the influenced processes are sequential. The results are illustrated with data from experiments by Besner and Davelaar (1982).

Attention↗