Biomedical subjects

K I Forster

Publications and source records attributed to K I Forster.

At least 19 recordsLinked to original sources

PubMed2000

Decomposing morphologically complex words in a nonlinear morphology.

Most Hebrew words are composed of 2 intertwined morphemes: a triconsonantal root and a phonological word pattern. Previous research with conjugated verb forms has shown consistent priming from the verbal patterns, suggesting that verbal forms are automatically parsed by native speakers into their morphemic constituents. The authors investigated the decomposition process, focusing on the structural properties of verbal forms that are perceived and extracted during word recognition. The manipulations consisted of using verbal forms derived from "weak" roots that have one consonant missing in some of the forms. The results demonstrated that if 1 consonant is missing, the parsing system collapses, and there is no evidence for morphological priming. In contrast, when a random consonant is inserted into the weak form, the verbal-pattern priming re-emerges. This outcome suggests that the constraint imposed on the decomposition process is primarily structural and abstract. Moreover, the all-or-none pattern of results is characteristic of rule-based behavior and not of simple correlational systems.

Adult↗

PubMed2000

The potential for experimenter bias effects in word recognition experiments.

Word recognition experiments that involve comparisons between two different matched sets of words allow for possible experimenter bias if there are many equally well-matched pairs to choose from. The possible extent of this bias depends on the experimenter's intuitive knowledge of the likely difficulty of individual items. This is assessed by asking a number of experimenters to decide which of two frequency-matched words would produce the fastest reaction time in a lexical decision experiment, and then comparing their predictions with actual data. All experimenters demonstrated substantial above-chance accuracy, which was unrelated to the amount of experience they had in the field. It was concluded that the experimenters could potentially produce spurious effect sizes ranging from 16 to 38 msec.

Humans↗

PubMed1999

An event-related potential examination of masked and unmasked repetition priming in Alzheimer's disease: implications for theories of implicit memory.

Fifteen patients diagnosed with Alzheimer's disease (AD) and 26 matched older controls engaged in a lexical-decision task with a list of words and nonwords while event-related brain potentials (ERPs) were recorded. Two repetition conditions were embedded in the list: words repeated at relatively long lags or words repeated shortly after a brief masked presentation. Although older controls displayed behavioral and ERP repetition priming for words repeated at long lags, consistent with previous studies, AD patients displayed neither. In contrast, both controls and AD patients displayed an ERP repetition priming effect for words repeated shortly after a brief masked presentation. ERP priming effects for masked and unmasked repetition differed in older controls, and additionally, the ERP masked priming effect differed between controls and AD patients. Results are discussed in the context of studies that have examined memory performance in brain-damaged populations using an impaired-intact dichotomy.

Acoustic Stimulation↗

PubMed1998

The pros and cons of masked priming.

Masked priming paradigms offer the promise of tapping automatic, strategy-free lexical processing, as evidenced by the lack of expectancy disconfirmation effects, and proportionality effects in semantic priming experiments. But several recent findings suggest the effects may be prelexical. These findings concern nonword priming effects in lexical decision and naming, the effects of mixed-case presentation on nonword priming, and the dependence of priming on the nature of the distractors in lexical decision, suggesting possible strategy effects. The theory underlying each of these effects is discussed, and alternative explanations are developed that do not preclude a lexical basis for masked priming effects.

Humans↗

PubMed1998

The prime lexicality effect: form-priming as a function of prime awareness, lexical status, and discrimination difficulty.

G. W. Humphreys, D. Besner, and P. T. Quinlan (1988) found that form-primes (e.g., contrast-CONTRACT) were effective only with masked primes. C. Veres (1986) obtained the same effect for word primes but found that nonword primes (e.g., controct) were effective regardless of masking. In a lexical-decision task, the present study failed to find any priming with word primes but only when the nonword distractors were very close to a particular word (e.g., UNIVORSE). With more distant nonword distractors (e.g., ANIVORSE), priming with word primes was restored in the masked condition. In terms of an entry-opening model of priming, this effect was interpreted as a blocking of priming by a postaccess checking operation. Alternatively, in an interactive activation model, this effect could be modeled either by decreasing the strength of lexical competition or by changing the decision criterion from local to global activation.

Adult↗

PubMed1998

Verbs and nouns are organized and accessed differently in the mental lexicon: evidence from Hebrew.

A masked priming paradigm was used to examine the role of the root and verbal-pattern morphemes in lexical access within the verbal system of Hebrew. Previous research within the nominal system had showed facilitatory effects from masked primes that shared the same root as the target word, but not when the primes shared the word pattern (R. Frost, K. I. Forster, & A. Deutsch, 1997). In contrast to these findings, facilitatory effects were obtained for both roots and word patterns in the verbal system. In addition, verbal pattern facilitation was obtained even when the primes were pseudoverbs consisting of illegal combinations of roots and verbal patterns. Significant priming was also found when the primes and the targets contained the same root. The results are discussed with reference to the factors that may determine the lexical status of morphological units in lexical organization. A model of morphological processing of Hebrew words is proposed.

Humans↗

PubMed1997

What can we learn from the morphology of Hebrew? A masked-priming investigation of morphological representation.

All Hebrew words are composed of 2 interwoven morphemes: a triconsonantal root and a phonological word pattern. the lexical representations of these morphemic units were examined using masked priming. When primes and targets shared an identical word pattern, neither lexical decision nor naming of targets was facilitated. In contrast root primes facilitated both lexical decisions and naming of target words that were derived from these roots. This priming effect proved to be independent of meaning similarity because no priming effects were found when primes and targets were semantically but not morphologically related. These results suggest that Hebrew roots are lexical units whereas word patterns are not. A working model of lexical organization in Hebrew is offered on the basis of these results.

Decision Making↗

PubMed1997

Translation priming with different scripts: masked priming with cognates and noncognates in Hebrew-English bilinguals.

Hebrew-English cognates (translations similar in meaning and form) and noncognates (translations similar in meaning only) were examined in masked translation priming. Enhanced priming for cognates was found with L1 (dominant language) primes, but unlike previous results, it was not found with L2 (nondominant language) primes. Priming was also obtained for noncognates, whereas previous studies showed unstable effects for such stimuli. The authors interpret the results in a dual-lexicon model by suggesting that (a) both orthographic and phonological overlap are needed to establish shared lexical entries for cognates (and hence also symmetric cognate priming), and (b) script differences facilitate rapid access by providing a cue to the lexical processor that directs access to the proper lexicon, thus producing stable noncognate priming. The asymmetrical cognate effect obtained with different scripts may be attributed to an overreliance on phonology in L2 reading.

Adult↗

PubMed1997

Event-related brain potential examination of implicit memory processes: masked and unmasked repetition priming.

The proposition that cortically based perceptual representation systems (PRSs) are responsible for some implicit priming phenomena was examined by using event-related potentials (ERPs) in repetition and masked word priming. Experiment 1 used an explicit recognition task, in which repeated words replicated previous ERP repetition priming effects, whereas masked repetition priming revealed a new ERP effect with a posterior topography. Experiment 2 demonstrated ERP and behavioral priming in a lexical decision task for repetition and masked repetition priming. Topographical mapping of ERP repetition priming effects involved both early and late effects over the right and left anterior regions, whereas masked priming produced only an early ERP effect posteriorly. These results suggest differences between early and late ERP priming effects in terms of explicit recollection. Moreover, a posterior PRS may not be involved in some longer term implicit repetition priming effects.

Adolescent↗

PubMed1996

No enemies in the neighborhood: absence of inhibitory neighborhood effects in lexical decision and semantic categorization.

The effect of neighborhood density on visual word recognition was found to be facilitatory for words but inhibitory for nonwords in 3 lexical-decision experiments. However, the facilitation virtually disappeared when the task was changed to semantic categorization (animal vs. nonanimal), despite the presence of a strong frequency effect. None of these experiments showed a consistent inhibitory effect of a higher frequency neighbor. The absence of inhibitory effects suggests that competition does not play a key role in visual word recognition. The data also suggest that the neighborhood density effect is not an access effect but is a task-dependent effect instead.

Adult↗

PubMed1994

Computational modeling and elementary process analysis in visual word recognition.

An attempt is made to isolate the assumptions that make a connectionist approach to visual word recognition distinctive. These include the commitment to distributed representations, the claim that there is no distinction between lexical and nonlexical systems in the naming task, and the claim that it is possible to map from orthography to meaning without using localized representations. It is argued that merely demonstrating that a network model can perform these tasks is not sufficient and that a detailed theory of how the network performs its tasks must accompany the simulation, because a simulation is not equivalent to an explanation. It is argued that further progress requires detailed modeling and experimental study of the elementary processes assumed to be involved in networks and that it is premature to dismiss alternative models of lexical access such as serial search models.

Humans↗

PubMed1994

Bodies, antibodies, and neighborhood-density effects in masked form priming.

Facilitatory priming effects due to similarity of orthographic form are obtained for high-N target words provided that they have low-frequency bodies and the body is shared between the prime and target (e.g., perd-HERD). Conversely, it is shown that low-N target words show priming regardless of the frequency of the body, provided that the prime and target do not share the same body (e.g., drice-DRIVE). If the body is shared, then priming occurs only for targets with low-frequency bodies. These results suggest that neighborhood density should be defined in terms of both individual letter units and subsyllabic units and that both types of density jointly determine priming.

Decision Making↗

PubMed1987