This article was downloaded by: [University of Cambridge] On: 02 January 2015, At: 20:13 Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Journal of Clinical and Experimental Neuropsychology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ncen19
The effect of picture priming on event-related potentials of normal and disabled readers during a word recognition memory task a
Robert M. Stelmack & Jennifer Miles
a
a
School of Psychology University of Ottawa , Published online: 04 Jan 2008.
To cite this article: Robert M. Stelmack & Jennifer Miles (1990) The effect of picture priming on event-related potentials of normal and disabled readers during a word recognition memory task, Journal of Clinical and Experimental Neuropsychology, 12:6, 887-903, DOI: 10.1080/01688639008401029 To link to this article: http://dx.doi.org/10.1080/01688639008401029
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sublicensing, systematic supply, or distribution in any form to anyone is expressly
Downloaded by [University of Cambridge] at 20:13 02 January 2015
forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
H 1990, Vol. 12, NO.6, pp. 887-903
0 Swets t Zeitlinger
The Effect of Picture Priming on Event-related Potentials of Normal and Disabled Readers During a Word Recognition Memory Task*
Downloaded by [University of Cambridge] at 20:13 02 January 2015
Robert M. Stelmack and Jennifer Miles School of Psychology, University of Ottawa
ABSTRACT Normal and one subtype of disabled readers were compared in their visual eventrelated potentials (ERPs) that were elicited by primed and unprimed words during a recognition memory task. The primed words were preceded by a picture having the same denotative meaning, while unprimed words were preceded by a picture having a non-associated meaning. Normal readers exhibited consistently greater amplitude than the disabled readers to unprimed words with a negative wave at 455 ms (N400). For the disabled readers, this N400 was evident, though somewhat smaller, than for controls, at fronto-central placements, but absent at the lateral parietal and occipital sites. Priming a word with a picture reduced N400 amplitude for both the normal and disabled readers. There were no remarkable differences between groups in their ERPs to the pictures. The pattern of ERP results obtained seems to reflect a failure of this subtype of disabled readers to engage long-term, semantic memory, while their short-term linguistic processing is intact. During the past several years, there has been significant progress i n t h e application of event-related potential (ERP) methods t o basic problems i n cognitive psychology, notably attention (Picton & Hillyard, 1988), m e m o r y (Donchin, 1981), and language (Kutas & Van Petten, 1988). In the present study, E R P methods were employed to examine differences in ERP waveforms between normal and disabled readers that were previously observed during a word recognition m e m o r y task (Stelmack, Saxe, Noldy-Cullum, Campbell, & Armitage, 1988). For the normal readers, a large amplitude negative wave developed at
* This research was supported by the University of Ottawa Faculty of Social Science research fund and the Social Sciences and Humanities Research Council of Canada (41088-0226). The authors express their appreciation to A. Schleiper and J. Goodman of the Children’s Hospital of Eastern Ontario for their assistance. The important contributions to this project by K. Campbell, M. Makasare, H. Van Den Bergen, R. Spratt, B. Saxe, and R. Armitage are gratefully acknowledged. Mailing Address: Robert M. Stelmack, School of Psychology, Montpetit Hall, Room 416, 125 University Priv., Ottawa, Canada, K1N 6N5. Accepted for publication: March 2, 1990.
Downloaded by [University of Cambridge] at 20:13 02 January 2015
888
ROBERT M.STELhWCK AND JENNIFER MILES
about 440 ms (N400) during the presentation of the words, but this wave was reduced or absent in the ERP of the disabled readers. There is now compelling evidence that a negative wave in this latency range is an especially sensitive index of effects that are attributed to semantic evaluation (Kutas t Hillyard, 1989). A principal objective of the present study was to determine whether the failure of reading disabled (RD) subjects to develop an N400 was influenced by a difficulty in accessing the semantic representation of words. This was achieved by manipulating the amplitude of the N400 wave using a picture priming procedure in which words were primed by preceding them with pictures having the same denotative meaning. This priming procedure is thought to bring the pictorial representation to focal attention in short-term memory and to facilitate subsequent access of the verbal label. Priming is a useful procedure for investigatingthe representation of meaningful information in memory (Ratcliff & McKoon, 1981). The technique involves the facilitation of the response to a test item that was preceded (primed) by a similar item or by a related context. The majority of work with this procedure exploits the facilitative effects of semantic priming on lexical decision and word recognition tasks. In addition, there is good evidence that cross-form priming, in which a concrete word is preceded by a picture of the same denotative meaning, has facilitative effects on lexical decision and recognition memory that are as large as the priming provided by the words themselves (Vanderwart, 1984). These effects were interpreted as consistentwith a single system of semanticrepresentation that is accessed by both the pictures and words, rather than separate form-specific semantic systems. In the present study, it is of particular interest to examine differences in the effects of the activation of meaningful representations by the pictorial stimuli between the normal and disabled readers because of the important role that associative context plays in the reading process. The priming picture is expected to access its name, which will match the subsequent word. Such linguistic repetition would facilitate recognition memory for the normal and possibly for the RD readers. The pattern of ERP differences that emerges may also elaborate differences in linguistic processing underlying the deficit in recognition memory for words evident in the RD. A high amplitude negative ERP wave at about 400 ms, maximum at frontal electrode placements, has been frequently observed in children in their response to photographic slides (Symmes & Eisengart, 1971), novel patterned slides (Courchesne, 1983), and complex stimuli (Schulman-Galambos 8z Galambos, 1978). The amplitude of this wave is typically larger for children than for adults. However, the effects of linguistic stimuli have not been extensively studied in children and the functional significance of this negative wave has not yet been established. During the past 10 years, ERP studies of language processing in adults have clearly demonstrated that a negative wave that develops between 300 and 500 ms (N400) is especially sensitive to linguistic differences, notably semantic incongruity (cf. Kutas & Hillyard, 1980; Kutas & Van Petten, 1988). The most robust effect
Downloaded by [University of Cambridge] at 20:13 02 January 2015
READING DISABILITY, PRIMING, AND ERPS
889
was demonstrated in the serial presentation of words in a sentence. If the terminal word was incongruous with the meaning of the preceding text, a high amplitude negative wave was elicited that was maximum at centro-parietal placements. A similar negative wave, though less prominent and often more frontally distributed, has been reported in lexical decision tasks (Bentin, McCarthy, & Wood, 1985; Campbell, Karam, & Noldy-Cullum, 19871, category decision tasks (Boddy & Weinberg, 1981; Neville, Kutas, Chesney, & Schmidt, 1986). phonological and orthographic matching tasks (Rugg, 1985), and picture naming tasks (Stuss, Picton, & Cerri, 1986). In a recent word priming task, a posteriorly-distributed N400 increased in amplitude as an inverse function of the degree of semantic association with the preceding word (Kutas & Hillyard, 1989). Some lateralization has also been observed in language-related tasks, with words eliciting larger and more prolonged N400 waves over the left- than right- hemisphere recording sites (Neville, Kutas, & Schmidt, 1982), although opposite effects have been reported (eg.. Kutas & Hillyard, 1980). From this perspective, the pictures in the priming task that are semantically associated to the subsequent words are expected to attentuate the N400 amplitude of those primed words, particularly for the normal readers. Some lateralization is also anticipated. The RD subjects in the present study were classified as Group 2, following the typology of learning disabilities that was proposed by Rourke and Finlayson (1978). This typology is based on patterns of academic achievement on the Reading, Spelling, and Arithmetic subtests of the Wide Range Achievement Test (WRAT; Jastak & Jastak, 1965). The Group 2 RD subjects are characterized by poor performance in reading and spelling, but they display relatively better performance in arithmetic. In the context of Rourke’s (1982) model of neuropsychological development, this reading disability group suffers from deficiencies in left hemisphere systems. In our previous study using a single series of unrelated words (Stelmack et al., 1988), there were no remarkable differences between groups observed with lateral electrodes, perhaps because the placement of the electrodes was central rather than posterior. There were, however, several ERP waves that distinguished the Group 2 RD from normal readers during the recognition memory task. A salient effect was the larger amplitude positive wave at 270 ms displayed by the RD group at all midline electrode sites during both the acquisition and recognition memory test phase. A negative wave at 440 ms was exhibited by the normal readers, notably at the fronto-central electrode placements during the recognition memory test phase. Some marginal enhancement of this negative wave for the control group compared to the RD group was also evident at the central and parietal sites. Although these were robust effects that clearly differentiated the normal and RD subjects, it could not be determined, with these data, that the effects were independent. That is, it was not clear whether the enhanced positive wave apparent for the disabled readers at 270 ms attenuated their N400.amplitude, or if the
Downloaded by [University of Cambridge] at 20:13 02 January 2015
890
ROBERT M.STELMACK AND JENNFER MILES
larger N400 of the normal readers attenuated their earlier positive peak. Consequently, the significance of the ERP differences for the reading disabled could not be ascertained with confidence. By manipulating the N400 with the priming procedure, these peaks can be dissociated. If picture priming reduces N400 amplitude to words for the normal readers, and also attenuates the P200 differences between groups, then the P200 differences to the non-associatedwords between normal and disabled readers could be attributed to the development of the N400 wave by normal readers. By inference, these effects would be referred to differences in linguistic processing that are indexed by the N400 wave. Moreover, if Group 2 RD are characterized by deficiencies in left hemisphere sytems but intact right hemisphere sytems, as proposed, then, to the extent that the processing of pictures engages right hemisphere systems, differences between normal and disabled readers are not anticipated in their ERP to pictures.
METHOD Subjects Subjects were 5 normal readers and 5 reading disabled (RD) English speaking righthanded males between 9- and 12-years of age. The mean age was 10.2 years for the RD group and 10.4 for the control group. The RD sample was drawn from the Learning Disabilities Program at the Children’s Hospital of Eastern Ontario. Extensive personal and medical histories and psychological assessments were provided by staff psychologists at that institution. In the present study, the following criteria were observed for the RD group: (1) normal IQ (290) as determined by the WISC-R; (2) no identifiable auditory or visual deficits; (3) no evidence of brain damage or emotional disability; (4) right handed; ( 5 ) no medication; (6)standard reading scores at least 1.5 standard deviations below the Hamilton Sample Norms establishedfor the reading subscale of the Wide Range Achievment Test (WRAT; Jastak & Jastak, 1965). The RD subjects were specifically selected on criteria defining Group 2, by Rourke and Finlayson (1978) which features poorer reading and spelling performance relative to arithmetic. The Control sample also met the first five criteria but scored within the average or above average levels for their age group on the reading and arithmetic subscales of the WRAT. The Peabody Picture Vocabulary Test (PPVT) was also administered to both groups. The mean PPVT and WRAT scores were significantly higher for the controls as compared to the RD group t (8) = 4 . 9 4 , ~c.01 and t (8) = 6 . 8 3 , ~
Journal of Clinical and Experimental Neuropsychology Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ncen19
The effect of picture priming on event-related potentials of normal and disabled readers during a word recognition memory task a
Robert M. Stelmack & Jennifer Miles
a
a
School of Psychology University of Ottawa , Published online: 04 Jan 2008.
To cite this article: Robert M. Stelmack & Jennifer Miles (1990) The effect of picture priming on event-related potentials of normal and disabled readers during a word recognition memory task, Journal of Clinical and Experimental Neuropsychology, 12:6, 887-903, DOI: 10.1080/01688639008401029 To link to this article: http://dx.doi.org/10.1080/01688639008401029
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sublicensing, systematic supply, or distribution in any form to anyone is expressly
Downloaded by [University of Cambridge] at 20:13 02 January 2015
forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
H 1990, Vol. 12, NO.6, pp. 887-903
0 Swets t Zeitlinger
The Effect of Picture Priming on Event-related Potentials of Normal and Disabled Readers During a Word Recognition Memory Task*
Downloaded by [University of Cambridge] at 20:13 02 January 2015
Robert M. Stelmack and Jennifer Miles School of Psychology, University of Ottawa
ABSTRACT Normal and one subtype of disabled readers were compared in their visual eventrelated potentials (ERPs) that were elicited by primed and unprimed words during a recognition memory task. The primed words were preceded by a picture having the same denotative meaning, while unprimed words were preceded by a picture having a non-associated meaning. Normal readers exhibited consistently greater amplitude than the disabled readers to unprimed words with a negative wave at 455 ms (N400). For the disabled readers, this N400 was evident, though somewhat smaller, than for controls, at fronto-central placements, but absent at the lateral parietal and occipital sites. Priming a word with a picture reduced N400 amplitude for both the normal and disabled readers. There were no remarkable differences between groups in their ERPs to the pictures. The pattern of ERP results obtained seems to reflect a failure of this subtype of disabled readers to engage long-term, semantic memory, while their short-term linguistic processing is intact. During the past several years, there has been significant progress i n t h e application of event-related potential (ERP) methods t o basic problems i n cognitive psychology, notably attention (Picton & Hillyard, 1988), m e m o r y (Donchin, 1981), and language (Kutas & Van Petten, 1988). In the present study, E R P methods were employed to examine differences in ERP waveforms between normal and disabled readers that were previously observed during a word recognition m e m o r y task (Stelmack, Saxe, Noldy-Cullum, Campbell, & Armitage, 1988). For the normal readers, a large amplitude negative wave developed at
* This research was supported by the University of Ottawa Faculty of Social Science research fund and the Social Sciences and Humanities Research Council of Canada (41088-0226). The authors express their appreciation to A. Schleiper and J. Goodman of the Children’s Hospital of Eastern Ontario for their assistance. The important contributions to this project by K. Campbell, M. Makasare, H. Van Den Bergen, R. Spratt, B. Saxe, and R. Armitage are gratefully acknowledged. Mailing Address: Robert M. Stelmack, School of Psychology, Montpetit Hall, Room 416, 125 University Priv., Ottawa, Canada, K1N 6N5. Accepted for publication: March 2, 1990.
Downloaded by [University of Cambridge] at 20:13 02 January 2015
888
ROBERT M.STELhWCK AND JENNIFER MILES
about 440 ms (N400) during the presentation of the words, but this wave was reduced or absent in the ERP of the disabled readers. There is now compelling evidence that a negative wave in this latency range is an especially sensitive index of effects that are attributed to semantic evaluation (Kutas t Hillyard, 1989). A principal objective of the present study was to determine whether the failure of reading disabled (RD) subjects to develop an N400 was influenced by a difficulty in accessing the semantic representation of words. This was achieved by manipulating the amplitude of the N400 wave using a picture priming procedure in which words were primed by preceding them with pictures having the same denotative meaning. This priming procedure is thought to bring the pictorial representation to focal attention in short-term memory and to facilitate subsequent access of the verbal label. Priming is a useful procedure for investigatingthe representation of meaningful information in memory (Ratcliff & McKoon, 1981). The technique involves the facilitation of the response to a test item that was preceded (primed) by a similar item or by a related context. The majority of work with this procedure exploits the facilitative effects of semantic priming on lexical decision and word recognition tasks. In addition, there is good evidence that cross-form priming, in which a concrete word is preceded by a picture of the same denotative meaning, has facilitative effects on lexical decision and recognition memory that are as large as the priming provided by the words themselves (Vanderwart, 1984). These effects were interpreted as consistentwith a single system of semanticrepresentation that is accessed by both the pictures and words, rather than separate form-specific semantic systems. In the present study, it is of particular interest to examine differences in the effects of the activation of meaningful representations by the pictorial stimuli between the normal and disabled readers because of the important role that associative context plays in the reading process. The priming picture is expected to access its name, which will match the subsequent word. Such linguistic repetition would facilitate recognition memory for the normal and possibly for the RD readers. The pattern of ERP differences that emerges may also elaborate differences in linguistic processing underlying the deficit in recognition memory for words evident in the RD. A high amplitude negative ERP wave at about 400 ms, maximum at frontal electrode placements, has been frequently observed in children in their response to photographic slides (Symmes & Eisengart, 1971), novel patterned slides (Courchesne, 1983), and complex stimuli (Schulman-Galambos 8z Galambos, 1978). The amplitude of this wave is typically larger for children than for adults. However, the effects of linguistic stimuli have not been extensively studied in children and the functional significance of this negative wave has not yet been established. During the past 10 years, ERP studies of language processing in adults have clearly demonstrated that a negative wave that develops between 300 and 500 ms (N400) is especially sensitive to linguistic differences, notably semantic incongruity (cf. Kutas & Hillyard, 1980; Kutas & Van Petten, 1988). The most robust effect
Downloaded by [University of Cambridge] at 20:13 02 January 2015
READING DISABILITY, PRIMING, AND ERPS
889
was demonstrated in the serial presentation of words in a sentence. If the terminal word was incongruous with the meaning of the preceding text, a high amplitude negative wave was elicited that was maximum at centro-parietal placements. A similar negative wave, though less prominent and often more frontally distributed, has been reported in lexical decision tasks (Bentin, McCarthy, & Wood, 1985; Campbell, Karam, & Noldy-Cullum, 19871, category decision tasks (Boddy & Weinberg, 1981; Neville, Kutas, Chesney, & Schmidt, 1986). phonological and orthographic matching tasks (Rugg, 1985), and picture naming tasks (Stuss, Picton, & Cerri, 1986). In a recent word priming task, a posteriorly-distributed N400 increased in amplitude as an inverse function of the degree of semantic association with the preceding word (Kutas & Hillyard, 1989). Some lateralization has also been observed in language-related tasks, with words eliciting larger and more prolonged N400 waves over the left- than right- hemisphere recording sites (Neville, Kutas, & Schmidt, 1982), although opposite effects have been reported (eg.. Kutas & Hillyard, 1980). From this perspective, the pictures in the priming task that are semantically associated to the subsequent words are expected to attentuate the N400 amplitude of those primed words, particularly for the normal readers. Some lateralization is also anticipated. The RD subjects in the present study were classified as Group 2, following the typology of learning disabilities that was proposed by Rourke and Finlayson (1978). This typology is based on patterns of academic achievement on the Reading, Spelling, and Arithmetic subtests of the Wide Range Achievement Test (WRAT; Jastak & Jastak, 1965). The Group 2 RD subjects are characterized by poor performance in reading and spelling, but they display relatively better performance in arithmetic. In the context of Rourke’s (1982) model of neuropsychological development, this reading disability group suffers from deficiencies in left hemisphere systems. In our previous study using a single series of unrelated words (Stelmack et al., 1988), there were no remarkable differences between groups observed with lateral electrodes, perhaps because the placement of the electrodes was central rather than posterior. There were, however, several ERP waves that distinguished the Group 2 RD from normal readers during the recognition memory task. A salient effect was the larger amplitude positive wave at 270 ms displayed by the RD group at all midline electrode sites during both the acquisition and recognition memory test phase. A negative wave at 440 ms was exhibited by the normal readers, notably at the fronto-central electrode placements during the recognition memory test phase. Some marginal enhancement of this negative wave for the control group compared to the RD group was also evident at the central and parietal sites. Although these were robust effects that clearly differentiated the normal and RD subjects, it could not be determined, with these data, that the effects were independent. That is, it was not clear whether the enhanced positive wave apparent for the disabled readers at 270 ms attenuated their N400.amplitude, or if the
Downloaded by [University of Cambridge] at 20:13 02 January 2015
890
ROBERT M.STELMACK AND JENNFER MILES
larger N400 of the normal readers attenuated their earlier positive peak. Consequently, the significance of the ERP differences for the reading disabled could not be ascertained with confidence. By manipulating the N400 with the priming procedure, these peaks can be dissociated. If picture priming reduces N400 amplitude to words for the normal readers, and also attenuates the P200 differences between groups, then the P200 differences to the non-associatedwords between normal and disabled readers could be attributed to the development of the N400 wave by normal readers. By inference, these effects would be referred to differences in linguistic processing that are indexed by the N400 wave. Moreover, if Group 2 RD are characterized by deficiencies in left hemisphere sytems but intact right hemisphere sytems, as proposed, then, to the extent that the processing of pictures engages right hemisphere systems, differences between normal and disabled readers are not anticipated in their ERP to pictures.
METHOD Subjects Subjects were 5 normal readers and 5 reading disabled (RD) English speaking righthanded males between 9- and 12-years of age. The mean age was 10.2 years for the RD group and 10.4 for the control group. The RD sample was drawn from the Learning Disabilities Program at the Children’s Hospital of Eastern Ontario. Extensive personal and medical histories and psychological assessments were provided by staff psychologists at that institution. In the present study, the following criteria were observed for the RD group: (1) normal IQ (290) as determined by the WISC-R; (2) no identifiable auditory or visual deficits; (3) no evidence of brain damage or emotional disability; (4) right handed; ( 5 ) no medication; (6)standard reading scores at least 1.5 standard deviations below the Hamilton Sample Norms establishedfor the reading subscale of the Wide Range Achievment Test (WRAT; Jastak & Jastak, 1965). The RD subjects were specifically selected on criteria defining Group 2, by Rourke and Finlayson (1978) which features poorer reading and spelling performance relative to arithmetic. The Control sample also met the first five criteria but scored within the average or above average levels for their age group on the reading and arithmetic subscales of the WRAT. The Peabody Picture Vocabulary Test (PPVT) was also administered to both groups. The mean PPVT and WRAT scores were significantly higher for the controls as compared to the RD group t (8) = 4 . 9 4 , ~c.01 and t (8) = 6 . 8 3 , ~
