Biomedical subjects

A M Jacobs

Publications and source records attributed to A M Jacobs.

At least 19 recordsLinked to original sources

PubMed2001

Identical words are read differently in different languages.

It is hypothesized that written languages differ in the preferred grain size of units that emerge during reading acquisition. Smaller units (graphemes, phonemes) are thought to play a dominant role in relatively consistent orthographies (e.g., German), whereas larger units (bodies, rhymes) are thought to be more important in relatively inconsistent orthographies (e.g., English). This hypothesis was tested by having native English and German speakers read identical words and nonwords in their respective languages (zoo-Zoo, sand-Sand, etc.). Although the English participants exhibited stronger body-rhyme effects, the German participants exhibited a stronger length effect for words and nonwords. Thus, identical items were processed differently in different orthographies. These results suggest that orthographic consistency determines not only the relative contribution of orthographic versus phonological codes within a given orthography; but also the preferred grain size of units that are likely to be functional during reading.

Adolescent↗

PubMed2001

Pseudohomophone effects in lexical decision: still a challenge for current word recognition models.

Computational models that implement a serial mechanism of phonological assembly predict interactions between the size of the pseudohomophone (PsH) effect and stimulus length. Models with frequency-sensitive word representations predict baseword frequency effects. These predictions were tested in a lexical-decision task. The results showed constant PsH effects across different word lengths (in favor of parallel phonological activation) and baseword frequency effects (in favor of frequency-sensitive representations). However, the baseword frequency effect was opposite of what the models predicted. This result is most easily accommodated by models that assume an orthographic verification mechanism. The plausibility of such a mechanism was further supported by the results of 2 additional experiments investigating the effects of response speed and spelling probability (feedback consistency) on the size of the PsH effect.

Adult↗

PubMed2000

Graphemes are perceptual reading units.

Graphemes are commonly defined as the written representation of phonemes. For example, the word 'BREAD' is composed of the four phonemes /b/, /r/, /e/ and /d/, and consequently, of the four graphemes 'B', 'R', 'EA', and 'D'. Graphemes can thus be considered the minimal 'functional bridges' in the mapping between orthography and phonology. In the present study, we investigated the hypothesis that graphemes are processed as perceptual units by the reading system. If the reading system processes graphemes as units, then detecting a letter in a word should be harder when this letter is embedded in a multi-letter grapheme than when it corresponds to a single-letter grapheme. In Experiment 1A, done in English, participants were slower to detect a target letter in a word when the target letter was embedded in multi-letter grapheme (i.e. 'A' in 'BEACH') than when it corresponded to a single-letter grapheme (i.e. 'A' in 'PLACE'). In Experiment 1B, this effect was replicated in French. In Experiment 2, done in English, this grapheme effect remained when phonemic similarity between the target letter alone and the target letter inside the word was controlled. Together, the results are consistent with the assumption that graphemes are processed as perceptual reading units in alphabetic writing systems such as English or French.

Humans↗

PubMed2000

Visual and phonological codes in letter and word recognition: evidence from incremental priming.

Critical issues in letter and word priming were investigated using the novel incremental priming technique. This technique adds a parametric manipulation of prime duration (or prime intensity) to the traditional design of a fast masked priming study. By doing so, additional information on the time course and nature of priming effects can be obtained. In Experiment 1, cross-case letter priming (a-A) was investigated in both alphabetic decision (letter/non-letter classification) and letter naming. In Experiment 2, cross-case word priming was investigated in lexical decision and naming. Whereas letter priming in alphabetic decision was most strongly determined by visual overlap between prime and target, word priming in lexical decision was facilitated by both orthographic and phonological information. Orthographic activation was stronger and occurred earlier than phonological activation. In letter and word naming, in contrast, priming effects were most strongly determined by phonological/articulatory information. Differences and similarities between letter and word recognition are discussed in the light of the incremental priming data.

Adult↗

PubMed1999

Foot-ulcer prevention in the elderly diabetic patient.

Diabetic foot ulceration is frequently the result of repetitive trauma, foot deformity, malfunction, or ill-fitting footwear. The failure of such ulcers to heal is most often a consequence of the failure to provide protection from continuing trauma. Risk evaluation of the diabetic patient, with appropriate correction or accommodation of deformity or mechanical pressure, can be expected to reduce the incidence of serious infection secondary to ulceration.

Aged↗

PubMed1998

A phoneme effect in visual word recognition.

In alphabetic writing systems like English or French, many words are composed of more letters than phonemes (e.g. BEACH is composed of five letters and three phonemes, i.e./biJ/). This is due to the presence of higher order graphemes, that is, groups of letters that map into a single phoneme (e.g. EA and CH in BEACH map into the single phonemes /i/ and /J/, respectively). The present study investigated the potential role of these subsyllabic components for the visual recognition of words in a perceptual identification task. In Experiment 1, we manipulated the number of phonemes in monosyllabic, low frequency, five-letter, English words, and found that identification times were longer for words with a small number of phonemes than for words with a large number of phonemes. In Experiment 2, this 'phoneme effect' was replicated in French for low frequency, but not for high frequency, monosyllabic words. These results suggest that subsyllabic components, also referred to as functional orthographic units, play a crucial role as elementary building blocks of visual word recognition.

Humans↗

PubMed1998

Simulating individual word identification thresholds and errors in the fragmentation task.

This article presents a large-scale study that collected word identification thresholds and errors in the fragmentation task for all four-letter French words. In the first part of this article, we identify some of the variables (e.g., word frequency, neighborhood size, letter confusability) that affect performance in the fragmentation task. In the second part, we analyze individual response performance and identify different response strategies. We demonstrate that the interactive activation model can account for individual response strategies by adapting two of its original parameters: word-letter feedback and letter-word inhibition. In the third part, we demonstrate that the adaptation of the interactive activation model to the fragmentation task makes it possible to successfully simulate a facilitatory frequency effect on identification thresholds, an inhibitory neighborhood size effect on error rates, and an inhibitory letter confusability effect on identification thresholds. When the task-specific processes of the fragmentation task are specified and individual response strategies are considered, the interactive activation model provides a parsimonious architecture for modeling the task-independent processes involved in word perception.

Attention↗

PubMed1998

Letter legibility and visual word recognition.

Word recognition performance varies systematically as a function of where the eyes fixate in the word. Performance is maximal with the eye slightly left of the center of the word and decreases drastically to both sides of this optimal viewing position. While manipulations of lexical factors have only marginal effects on this phenomenon, previous studies have pointed to a relation between the viewing position effect (VPE) and letter legibility: When letter legibility drops, the VPE becomes more exaggerated. To further investigate this phenomenon, we improved letter legibility by magnifying letter size in a way that was proportional to the distance from fixation (e.g., TABLE). Contrary to what would be expected if the VPE were due to limits of acuity, improving the legibility of letters has only a restricted influence on performance. In particular, for long words, a strong VPE remains even when letter legibility is equalized across eccentricities. The failure to neutralize the VPE is interpreted in terms of perceptual learning: Since normally, because of acuity limitations, the only information available in parafoveal vision concerns low-resolution features of letters; even when magnification provides better information, readers are unable to make use of it.

Adult↗

PubMed1997

Phonology can help or hurt the perception of print.

Phonological manipulations affect performance in a letter search task that requires only a shallow level of processing. In Experiment 1, phonology reduced accuracy in the letter search task when a pseudohomophone (GAIM) contained a target letter ("i") that was missing in the spelling of its (nonpresented) sound-alike base word (GAME). In Experiment 2, phonology increased accuracy in the letter search task when the target letter was present in both the spelling of the pseudohomophone and the spelling of its sound-alike base word ("m" in GAIM and GAME). In Experiment 3, we showed that the phonology-hurts effect of Experiment 1 is not peculiar to nonword letter strings but generalizes to familiar words. In Experiment 4, we obtained a phonology-hurts effect on correct response times when stimuli were visible until participants responded (stimuli were not masked).

Humans↗

PubMed1997

Ankle arthrodesis following avascular necrosis of the talus in a patient with lupus.

Avascular necrosis of bone is a common manifestation of systemic lupus erythematosus, particularly in those patients receiving corticosteroids. The authors review the pathogenesis and diagnosis of avascular necrosis and describe an ankle arthrodesis in a patient with systemic lupus erythematosus who developed avascular necrosis of the talus.

Adrenal Cortex Hormones↗

PubMed1996

Orthographic processing in visual word recognition: a multiple read-out model.

A model of orthographic processing is described that postulates read-out from different information dimensions, determined by variable response criteria set on these dimensions. Performance in a perceptual identification task is simulated as the percentage of trials on which a noisy criterion set on the dimension of single word detector activity is reached. Two additional criteria set on the dimensions of total lexical activity and time from stimulus onset are hypothesized to be operational in the lexical decision task. These additional criteria flexibly adjust to changes in stimulus material and task demands, thus accounting for strategic influences on performance in this task. The model unifies results obtained in response-limited and data-limited paradigms and helps resolve a number of inconsistencies in the experimental literature that cannot be accommodated by other current models of visual word recognition.

Adult↗

PubMed1996

Considerations of prescription medications for the pregnant podiatric patient.

Prescription medications are thought to cause less than 1% of all congenital abnormalities. However, prescribing a medication to treat the foot disorder of a pregnant patient can be a source of anxiety for the physician. The authors review some of the medications commonly prescribed in podiatric medical practice and evaluate their use and safety during pregnancy.

Abnormalities, Drug-Induced↗

PubMed1995

The incremental priming technique: a method for determining within-condition priming effects.

A novel priming technique is applied in two experiments using an alphabetic decision and a lexical decision task to study effects of repetition, and form-related priming on letter and word recognition. The incremental priming technique consists of a gradual increase of the prime's informational value (operationalized as prime intensity). The minimum prime-intensity level serves as a within-condition baseline for each priming condition. Thus, we can define any priming effect with respect to two baseline conditions: one is the minimum-intensity condition of the particular priming condition (within-condition baseline), and the other is a different priming condition (across-condition baseline). This double-baseline approach makes measuring of priming effects more reliable and imposes stronger constraints on our interpretations of these effects.

Arousal↗

PubMed1993

Masked partial-word priming in visual word recognition: effects of positional letter frequency.

In 4 primed lexical decision experiments, it was found that the positional frequencies of letters shared by the prime and target relative to the overall positional letter frequency of the target determined the magnitude of priming effects. The lower the positional frequency of shared letters, the stronger the facilitatory effect observed. Both an interactive and noninteractive semistochastic version of the interactive activation model captured the principal trends in the data. It is argued that masked partial-word priming arises from a tradeoff between the facilitation generated by prime-target letter overlap and the inhibition generated from all lexical representations activated by letters in the prime that receive further support on target presentation.

Adult↗

PubMed1993

Diabetes mellitus.

Diabetes mellitus occurs commonly in the older patient and is frequently undiagnosed. In many cases, the initial manifestations of diabetes mellitus are lower extremity complications with which this disease is known to be associated. Unfortunately, these complications are similar to other age-related degenerative processes; therefore, vigilance for the detection of undiagnosed diabetes mellitus is essential in the evaluation and treatment of lower extremity pathologic conditions.

Adult↗

PubMed1992

Testing a semistochastic variant of the interactive activation model in different word recognition experiments.

A semistochastic variant of the interactive activation (IA) model of context effects in letter perception (McClelland & Rumelhart, 1981) was used to simulate response time distributions and means in different experiments investigating the effects of word frequency, neighborhood size and frequency, and orthographic priming in visual word recognition. The results provide evidence in favor of the connectivity assumption underlying the model but question the necessity of the interactivity assumption for simulating latencies in word recognition tasks. Together with those of a recent study by McClelland (1991), the present results suggest that 10 years after its appearance, the IA model's potential for testing hypotheses about the structure and dynamics of basic phenomena of human information processing in a variety of perceptual and cognitive tasks is not yet fully exploited.

Arousal↗

PubMed1992

Neighborhood frequency effects and letter visibility in visual word recognition.

Two experiments are described that measured lexical decision latencies and errors to five-letter French words with a single higher frequency orthographic neighbor and control words with no higher frequency neighbors. The higher frequency neighbor differed from the stimulus word by either the second letter (e.g., ASTRE-AUTRE) or the fourth letter (CHOPE-CHOSE). Neighborhood frequency effects were found to interact with this factor, and significant interference was observed only to CHOPE-type words. The effects of neighborhood frequency were also found to interact with the position of initial fixation in the stimulus word (either the second letter or the fourth letter). Interference was greatly reduced when the initial fixation was on the critical disambiguating letter (i.e., the letter P in CHOPE). Moreover, word recognition was improved when subjects initially fixated the second letter relative to when they initially fixated the fourth letter of a five-letter word, but this second-letter advantage practically disappeared when the stimulus differed from a more frequent word by its fourth letter. The results are interpreted in terms of the interaction between visual and lexical factors in visual work recognition.

Adult↗

PubMed1992

Opioid receptor affinity for agonist-antagonist analgesics.

Analgesic medications are distributed to a variety of receptors within the central nervous system. Activity at these receptors (mu 1, mu, sigma, delta, kappa) results in both the beneficial pain-relieving effects of analgesics as well as undesirable side effects. The mixed agonist-antagonist class of analgesics offers the potential benefit of greater receptor site selectivity while diminishing the incidence of adverse sequelae, such as respiratory depression. Traditionally, it has been suggested that mixed agonist-antagonist medications may be associated with decreased analgesic effectiveness. However, newer agents of this mixed class may result in effective analgesia while diminishing the incidence of side effects.

Analgesics, Opioid↗