Role of Selected Lexical Factors

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The role of selected lexical factors on confrontation naming accuracy and speed in children : 

1 The role of selected lexical factors on confrontation naming accuracy and speed in children Lisa King, M.A. Amy Strekas, B.A. Rochelle Newman, Ph.D. Nan Bernstein Ratner, Ed.D. University of Maryland, College Park

Lexical Access : 

2 Lexical Access Many factors are thought to influence lexical access, including word frequency, neighborhood density, and neighborhood frequency. It is not known whether the effects of these lexical factors remain constant once a particular word is learned, or if the effects of these factors change with additional vocabulary development.

Lexical factors : 

3 Lexical factors Word frequency: measure of how often a word occurs in the language Neighborhood density: measure of how many words are phonologically similar to a particular word “Let” (dense) versus “kept” (sparse) Neighborhood frequency: measure of the frequency with which phonological neighbors occur “Weld” (high) versus “kept” (low)

Lexical neighborhoods : 

4 Lexical neighborhoods Some words are phonologically similar to many words E.g., Let is similar to bet, less, lent and light, among others Let “resides” in a dense neighborhood

Lexical neighborhoods : 

5 Lexical neighborhoods Other words are similar to few words E.g., kept is similar only to three English words (crept, Celt and wept). The Neighborhood Activation Model (Luce & Pisoni, 1998) suggests that similarity to other words influences lexical organization. Words that sound similar are stored together in neighborhoods

Previous Findings : 

6 Previous Findings High-frequency words are produced more quickly (Jescheniak & Levelt, 1994) and more accurately (Vitevitch, 2002) than low-frequency words in adults. Word frequency effects are even stronger in children (Newman & German, 2005)

Previous Findings : 

7 Previous Findings Words from dense neighborhoods tend to be produced more slowly (Luce & Pisoni, 1998) but more accurately (Vitevitch, 2002) in adults. In children, words with high neighborhood frequency tend to be named more accurately (Newman & German, 2002)

Current Study : 

8 Current Study To investigate: The role of various lexical factors on naming accuracy and speed in children Word frequency Neighborhood density Neighborhood frequency How these lexical factors change with lexical development

Participants : 

9 Participants 69 typically-developing children 25 5-year-olds, 24 7-year-olds, 20 9-year-olds 25 adults Divided into three vocabulary groups: Adult High Vocabulary Children(23 children >140 raw score on PPVT) Low Vocabulary Children (23 children <100 raw score on PPVT)

Procedure : 

10 Procedure Children named pictures as they appeared on a computer screen Responses were coded according to accuracy and reaction time Peabody Picture Vocabulary Test - III (Dunn & Dunn, 1997)

Stimuli : 

11 Stimuli Stimuli were pictures of 107 common nouns & verbs These could be divided into 6 subsets . . . Words high vs. low in word frequency Words high vs. low in neighborhood density Words high vs. low in average frequency of neighbors This can be thought of as a measure of the frequency with which the sound pattern in general is encountered.

Words that are : 

12 Words that are High in frequency Low in frequency

Words that have : 

13 Words that have Dense neighborhoods Sparse neighborhoods

Words with : 

14 Words with High neighborhood frequency Low neighborhood frequency

Accuracy : 

15 Accuracy Proportion of word-finding errors was calculated for each child Correct responses: Intended responses (most commonly-used name for picture) Synonyms (“garbage” for “trash”) Elaborations (“Canadian goose” for “goose”) Word finding errors: Wrong word (“money” for “dime”) Circumlocution (“it’s the thing you use to X”) “I don’t know”

Reaction time : 

16 Reaction time Reaction times were calculated from presentation of picture to onset of speech Reaction times were only calculated on items named as intended

Stimuli : 

17 Stimuli 107 pictures of common nouns and verbs Represent vocabulary known by 5 years of age Divided into 6 subsets: Word frequency (high vs. low) Neighborhood density (dense vs. sparse) Neighborhood frequency (high vs low)

Word FrequencyError Rate : 

18 Word FrequencyError Rate Low Frequency words were produced with less accuracy than high frequency words, F(1, 68)=48.96, p<.0001 Individuals with larger vocabulary size made fewer errors, F(2,68)=20.67, p<.0001 The interaction between frequency and vocabulary size was significant, F(2,68)=11.85, p<.0001 The effect of wordfrequency decreased as vocabulary increased

Word FrequencyReaction Times : 

19 Word FrequencyReaction Times High frequency words were produced more quickly than low frequency words, F(1,68)=70.11, p<.0001 Individuals with larger vocabulary size responded more quickly than those with a smaller vocabulary, F(2,68)=22.19, p<.0001 The interaction between frequency and vocabulary size was significant, F(2,68)=8.98, p<.0005 The effect of wordfrequency decreased as vocabulary increased

Neighborhood FrequencyError Rate : 

20 Neighborhood FrequencyError Rate Individuals made more errors on items with low neighborhood frequency than on those with high neighborhood frequency, F(1,68)=21.13, p<.0001 Individuals with a larger vocabulary size made fewer errors than those with a smaller vocabulary, F(2,68)=28.39, p<.0001 There was no interaction between neighborhood frequency and vocabulary size, F<1

Neighborhood FrequencyReaction Times : 

21 Neighborhood FrequencyReaction Times Individuals responded more quickly to words with high neighborhood frequency than to words with low neighborhood frequency, F(1,68)=17.22, p<.0001 Individuals with a larger vocabulary responded more quickly than those with a smaller vocabulary, F(2,68)=25.96, p<.0001 There was no interaction between neighborhood frequency and vocabulary size, F<1

Neighborhood DensityError Rate : 

22 Neighborhood DensityError Rate Individuals made more errors on low neighborhood density words than on high, F(1,68)=32.82, p<.0001 Individuals with a larger vocabulary size made fewer errors than those with a smaller vocabulary, F(2,68)=29.36, p<.0001 The interaction between neighborhood density and vocabulary size was not significant, F<1

Neighborhood DensityReaction Times : 

23 Neighborhood DensityReaction Times There was no effect of neighborhood density on reaction times, F<1 Individuals with a larger vocabulary size responded more quickly than individuals with a smaller vocabulary, F(2,68)=17.29, p<.0001 There was no interaction between neighborhood density and vocabulary size for reaction time, F<1

Discussion : 

24 Discussion In general, individuals were more accurate in responding to high frequency, high neighborhood density, and high neighborhood frequency items. Individuals responded more quickly to high frequency, high neighborhood frequency items.

Discussion : 

25 Discussion Children with low vocabulary were particularly impaired on low-frequency words relative to high-frequency words. Older children and adults, those with larger vocabulary sizes, show a relatively greater increase in their performance on less frequent words. This suggests that increased exposure and usage of these words facilitates retrieval.

Discussion : 

26 Discussion Both children and adults show effects of word frequency, neighborhood density and neighborhood frequency on the speed and accuracy of lexical naming. Children with lower vocabularies (who also tended to be the youngest in the study) were slower and less accurate than those with higher vocabularies Word frequency had a marked effect on their performance.

Conclusions : 

27 Conclusions Despite the fact that the words were selected so as to all be within the vocabularies of children in this age range, children with lower vocabularies were especially hampered by words with lower frequency.  Yet they showed comparable effects to adults on neighborhood-based properties. This might suggest that as one's vocabulary becomes richer and more varied, frequency effects become smaller.   In contrast, neighborhood properties mayhave more to do with whether a child knows a word or not, but not on the depth or richness of that knowledge.

References : 

28 References Dunn, L. M., & Dunn, L. M. (1997). Peabody Picture Vocabulary Test–III. Circle Pines, MN: American Guidance Service. Jescheniak, J. D., & Levelt, W. J. M. (1994). Word frequency effects in speech production: Retrieval of syntactic information and of phonological form. Journal of Experimental Psychology: Learning, Memory & Cognition, 20(4), 824-843. Luce, P. A., & Pisoni, D. B. (1998). Recognizing spoken words: The Neighborhood Activation Model. Ear & Hearing, 19(1), 1-36. Newman, R. S., & German, D. J. (2002). Effects of lexical factors on lexical access among typical language-learning children and children with word-finding difficulties. Language & Speech, 43(3), 285-317. Newman, R. S., & German, D. J. (2005). Life span effects of lexical factors on oral naming. Language & Speech, 48(2), 123-156. Vitevitch, M. S. (2002). The influence of phonological similarity neighborhoods on speech production. Journal of Experimental Psychology: Learning, Memory & Cognition, 28, 735-747.

Acknowledgments : 

29 Acknowledgments Recipient of a 2006 ASHA Student Research Travel Award The following individuals contributed by assisting in collecting or coding the data: Robyn Amendola, Shannon Auxier, Emilie Clingerman, Hannah Couch, Nicole Craver, Kristin Crawford, Casey DiBicarri, Shoshana Dickler, Annie Ferruggiaro, Darlene Foster, Sarah Haszko, Grace Ji, Lacey Kahner,  Hannah Kim, Arielle Laurie, Amanda McAdoo, Michele McEntee, Heather McIntosh, Sarah Michael, Abimbola Odukoya, Ashley Orkin,  Jillian Parry, Shannon Rice, Andrea Riffenacht, Kate Shapiro, Emily Singer, Audry Singh, Stephanie Souder, Lisa Surrell, Rachel Weitzner, Patricia Yudd, Jenni Zobler