Biomedical subjects

Penny M Pexman

Publications and source records attributed to Penny M Pexman.

9 recordsLinked to original sources

PubMed2007

Priming the meaning of homographs in typically developing children and children with autism.

Two explanations for deficits underlying autism were tested: weak central coherence (WCC) and executive dysfunction. Consistent with WCC, Happé (British Journal of Developmental Psychology 15 (1997) 1) found that children with autism failed to use sentence context in pronouncing homographs. In an alternate approach, we investigated whether children with autism can use meanings of related word primes. We presented children with autism and controls with primes for homographs, semantically related, and unrelated targets. Children with autism used primes to correctly pronounce homographs upon first presentation but showed difficulty inhibiting prior responses upon later presentation of the homographs with different primes. Children with autism also showed semantic priming effects. We conclude that children with autism do not show an absolute deficit in ability to use contextual information.

Autistic Disorder↗

PubMed2005

An fMRI investigation of strategies for word recognition.

A common procedure used to study visual word recognition is the lexical decision task (LDT). Behavioral studies have demonstrated that overall performance in this task is modulated by the type of foils presented. There are divergent claims about the impact of different types of foils on overall processing strategies in the LDT: some researchers claim that pseudohomophone foils (e.g., BRANE) encourage participants to selectively de-emphasize phonological processing, while other researchers claim that pseudohomophone foils encourage participants to engage in more extensive processing of all types (orthographic, phonological, and semantic). To evaluate these claims, we conducted a functional magnetic resonance imaging study. Participants (N = 18) completed three lexical decision tasks, each with a different foil type: consonant strings (e.g., BVRNT), pseudowords (e.g., BLINT), and pseudohomophones (e.g., BRANE). We presented homophones (e.g., MAID) and nonhomophones (e.g., MESS) on word trials in order to be able to calculate the homophone effect as a marker of phonological processing for word stimuli in each foil condition. Comparison of behavioral results in the different foil conditions showed that reaction times were longest, error rates were highest, and homophone effects were largest in the LDT with pseudohomophones. Imaging results showed the greatest magnitude of activity in several regions, including the inferior frontal cortex, during the LDT with pseudohomophone foils. A comparison to inferior frontal activity produced during an additional task (rhyme judgment) supported the conclusion that LDT with pseudohomophone foils is a difficult task in which readers engage in an overall response strategy involving extensive processing of phonological information.

Adult↗

PubMed2004

Semantic ambiguity and the process of generating meaning from print.

An ambiguity disadvantage (slower responses for ambiguous words, e.g., bank, than for unambiguous words) has been reported in semantic tasks (L. R. Gottlob, S. D. Goldinger, G. O. Stone, & G. C. Van Orden, 1999; Y. Hino, S. J. Lupker, & P. M. Pexman, 2002; C. D. Piercey & S. Joordens, 2000) and has been attributed to the meaning activation process. The authors tested an alternative explanation; The ambiguity disadvantage arises from the decision-making process in semantic tasks. The authors examined effects of ambiguity on unrelated trials in a relatedness decision task, because these trials are free from response competition created by ambiguous words on related trials. Results showed no ambiguity effect on unrelated trials (Experiments 2, 3c, and 5c) and an ambiguity disadvantage on related trials (Experiments 3a, 3b, 5a, and 5b).

Cognition↗

PubMed2003

The impact of reader skill on phonological processing in visual word recognition.

There has been much debate about the role of phonology in reading. This debate has been fuelled, in part, by mixed findings for phonological effects in lexical decision tasks. In the present research we investigated the impact of reader skill on three phonological effects (homophone, homograph, and regularity effects) in a lexical decision task and in a phonological lexical decision task. In both tasks, the more skilled readers showed different patterns of phonological effects from those of the less skilled readers; in particular, less skilled readers showed regularity effects in both tasks whereas more skilled readers did not. We concluded that more skilled readers activate phonology in these tasks but do so more efficiently, with less spurious phonological activation.

Adult↗

PubMed2003

Number-of-features effects and semantic processing.

Participants list many semantic features for some concrete nouns (e.g., lion) and fewer for others (e.g., lime; McRae, de Sa, & Seidenberg, 1997). Pexman, Lupker, and Hino (2002) reported faster lexical decision and naming responses for high number of features (NOF) words than for low-NOF words. In the present research, we investigated the impact of NOF on semantic processing. We observed NOF effects in a self-paced reading task when prior context was not congruent with the target word (Experiment 1) and in a semantic categorization task (concrete vs. abstract; Experiment 2A). When we narrowed our stimuli to include high- and low-NOF words from a single category (birds), we found substantial NOF effects that were modulated by the specificity of the categorization task (Experiments 3A, 3B, and 3C). We argue that these results provide support for distributed representation of word meaning.

Decision Making↗

PubMed2002

Phonological effects in visual word recognition: investigating the impact of feedback activation.

P. M. Pexman, S. J. Lupker, and D. Jared (2001) reported longer response latencies in lexical decision tasks (LDTs) for homophones (e.g., maid) than for nonhomophones, and attributed this homophone effect to orthographic competition created by feedback activation from phonology. In the current study, two predictions of this feedback account were tested: (a) In LDT, observe homophone effects should be observed but not regularity or homograph effects because most exception words (e.g., pint) and homographs (e.g., wind) have different feedback characteristics than homophones do, and (b) in a phonological LDT ("does it sound like a word?"), regularity and homograph effects should be observed but not homophone effects. Both predictions were confirmed. These results support the claim that feedback activation from phonology plays a significant role in visual word recognition.

Feedback, Psychological↗

PubMed2002

The impact of feedback semantics in visual word recognition: number-of-features effects in lexical decision and naming tasks.

The notion of feedback activation from semantics to both orthography and phonology has recently been used to explain a number of semantic effects in visual word recognition, including polysemy effects (Hino & Lupker, 1996; Pexman & Lupker, 1999) and synonym effects (Pecher, 2001). In the present research, we tested an account based on feedback activation by investigating a new semantic variable: number of features (NOF). Words with high NOF (e.g., LION) should activate richer semantic representations than do words with low NOF (e.g., LIME). As a result, the feedback activation from semantics to orthographic and phonological representations should be greater for high-NOF words, which should produce superior lexical decision task (LDT) and naming task performance. The predicted facilitory NOF effects were observed in both LDT and naming.

Decision Making↗

PubMed2002

Ambiguity and synonymy effects in lexical decision, naming, and semantic categorization tasks: interactions between orthography, phonology, and semantics.

In this article, ambiguity and synonymy effects were examined in lexical decision, naming, and semantic categorization tasks. Whereas the typical ambiguity advantage was observed in lexical decision and naming, an ambiguity disadvantage was observed in semantic categorization. In addition, a synonymy effect (slower latencies for words with many synonyms than for words with few synonyms) was observed in lexical decision and naming but not in semantic categorization. These results suggest that (a) an ambiguity disadvantage arises only when a task requires semantic processing, (b) the ambiguity advantage and the synonymy disadvantage in lexical decision and naming are due to semantic feedback, and (c) these effects are determined by the nature of the feedback relationships from semantics to orthography and phonology.

Attention↗

PubMedDate not supplied

The elusive nature of early phonological priming effects: are there individual differences?

Lukatela and Turvey (2000) demonstrated a phonological priming effect in the lexical decision task (LDT) with a 14-ms prime and concluded that phonology plays a central role in word meaning activation. In contrast, several other researchers reported that phonological priming is significant only at much longer prime durations (e.g., Ferrand & Grainger, 1994). In two replication attempts (Experiments 1a and 1b), involving a 15-ms prime duration, we found a clear phonological priming effect in one LDT and no evidence of phonological priming in another virtually identical LDT. In Experiment 2, in an attempt to determine whether individual differences may account for the presence or lack of a phonological priming effect, we also tested phonological and perceptual skill. Only participants higher in perceptual and phonological skill showed a phonological priming effect. We conclude that these (and potentially other) variables may have been responsible for previous inconsistent findings of early phonological priming effects.

Decision Making↗