The effects of a memory load on syntactic processing by younger and older adults were examined. P... more The effects of a memory load on syntactic processing by younger and older adults were examined. Participants were asked to remember a noun phrase (NP) memory load while they read sentences varying in syntactic complexity. Two types of NPs were used as memory loads: proper names or definite descriptions referring to occupations or roles. The NPs used in the sentence
An important issue in experimental aging research is the accurate measurement of cognitive constr... more An important issue in experimental aging research is the accurate measurement of cognitive constructs, particularly in small-sample studies. Latent variable modeling approaches to assessing age-based construct similarity are difficult to implement in smaller-scale studies, which tend to have small samples and measurement of a single construct. We discuss factor score comparison methods for assessing age-based construct similarity that may be more appropriate for small-scale studies. We then examine these methods for a series of single-factor models of verbal working memory (VWM) based on data from three separate studies in which small samples of younger and older adults' completed VWM-based tasks. Our single-factor models accounted well for the associations among the sets of VWM tasks. This construct was also measured well across age groups and different samples. Our analyses suggest that factor score comparison methods may be useful for small-scale studies that require assessment of age-based measurement similarity in cognitive constructs.
Http Dx Doi Org 10 1080 02643298508252667, Aug 16, 2007
ABSTRACT The sentence processing abilities of EA, a conduction aphasic with a documented phonolog... more ABSTRACT The sentence processing abilities of EA, a conduction aphasic with a documented phonological coding deficit, were investigated in tests of sentence comprehension, production, and repetition. EA showed a syntactic comprehension deficit, relying heavily on word order information to make grammatical role assignments. Production tests revealed a generally intact ability to generate a variety of sentence constructions, although there were frequent errors in the use of grammatical morphemes in the written productions. The repetition tasks were used to identify the processing strategies EA used under heavy memory load conditions. EA's semantic and syntactic processing capabilities and the role of the phonological code in normal sentence processing are discussed.
The current study examines whether young and older adults have similar preferences for animate-su... more The current study examines whether young and older adults have similar preferences for animate-subject and active sentences, and for using the order of activation of a verb's arguments to determine sentence structure. Ninetysix participants produced sentences in response to three-word stimuli that included a verb and two nouns differing in animacy. Dependent variables included accuracy, sentence structure produced, and production times for active vs. passive sentences. Neither group shows a strict preference for active sentences, but the two groups are differentially sensitive to animacy and the order of noun activation. Results suggest that sentence structure choice is a probabilistic, constraint-satisfaction process during which these factors interact.
Three groups of subjects were tested to investigate the effect of language on the relationship be... more Three groups of subjects were tested to investigate the effect of language on the relationship between recall span and articulation rate. Native English-speaking monolinguals and native Chinese-speaking monolinguals recalled only English or Chinese words, respectively. Chinese-English bilinguals recalled both English and Chinese words. Articulation rates for English and Chinese monolinguals and Chinese-English bilinguals in each language were also obtained. When recall span was regressed on articulation rate, the slopes for Chinese and English words were significantly different for the Chinese-English bilinguals. This difference was not due to language proficiency but to phonological differences between English and Chinese.
Http Dx Doi Org 10 1080 07340669008251538, Sep 28, 2007
This experiment investigated age group differences in working memory by examining the effects of ... more This experiment investigated age group differences in working memory by examining the effects of word length on adults' recall span and repetition rate. College students and adults, 60 to 94 years of age, recalled lists of one-, two-, or three-syllable words and repeated aloud pairs of one-, two- or three-syllable words. Word recall spans and word repetition rates were computed. Main effects of age group and word length were obtained on both measures, although the interactions were not significant. A second analysis examined the relationship between individuals' recall span and their repetition rate. Across all age groups combined, recall span was a linear function of repetition rate and accounted for 25 percent of the variance on the recall task. A reanalysis of the word repetitions revealed that older adults' word durations and inter-word pauses are longer than young adults'.
The eye movements of young and older adults were tracked as they read sentences varying in syntac... more The eye movements of young and older adults were tracked as they read sentences varying in syntactic complexity. In Experiment 1, cleft object and object relative clause sentences were more difficult to process than cleft subject and subject relative clause sentences; however, older adults made many more regressions, resulting in increased regression path fixation times and total fixation times, than young adults while processing cleft object and object relative clause sentences. In Experiment 2, older adults experience more difficulty than young adults while reading cleft and relative clause sentences with temporary syntactic ambiguities created by deleting the "that" complementizers. Regression analyses indicated that readers with smaller working memories need more regressions and longer fixation times to process cleft object and object relative clause sentences. These results suggest that age-associated declines in working memory do affect syntactic processing.
Http Dx Doi Org 10 1080 03610739308253922, Sep 27, 2007
This study compared young and older adults&am... more This study compared young and older adults' summaries of expository texts under the hypothesis that older adults would be more experienced, hence more accurate, at summarizing texts. Two types of expository texts were used: procedural and descriptive texts. The texts were read by a panel of judges who wrote summaries of each text and identified the central ideas of each text; the judges' summaries were used to prepare lists of the central ideas of each text and to write standard summaries of each text. The participants read four texts, two orally and two silently, and then wrote summaries, which were limited to 50 words. Words-per-minute reading times were collected and the summaries were scored on two measures of content, how many ideas were reproduced from the original texts and the proportion of central ideas that were reproduced, and two measures of length, the number of sentences and the number of words. Although the older adults read more slowly than the young adults, the older adults reproduced more total and central ideas than the young ideas.
The Air Force Research Laboratory (AFRL) Space Vehicles Directorate has developed a mission to re... more The Air Force Research Laboratory (AFRL) Space Vehicles Directorate has developed a mission to research the technologies needed for large space structures, high-power generation, and protection of space assets within the high radiation environment of a medium earth orbit (MEO). The resulting Deployable Structures Experiment (DSX) will address a number of basic science experiments via a single MEO testbed platform.
The eye movements of young and older adults were tracked as they read sentences varying in syntac... more The eye movements of young and older adults were tracked as they read sentences varying in syntactic complexity. In Experiment 1, cleft object and object relative clause sentences were more difficult to process than cleft subject and subject relative clause sentences; however, older adults made many more regressions, resulting in increased regression path fixation times and total fixation times, than young adults while processing cleft object and object relative clause sentences. In Experiment 2, older adults experience more difficulty than young adults while reading cleft and relative clause sentences with temporary syntactic ambiguities created by deleting the "that" complementizers. Regression analyses indicated that readers with smaller working memories need more regressions and longer fixation times to process cleft object and object relative clause sentences. These results suggest that age-associated declines in working memory do affect syntactic processing.
Cognitive tasks performed while walking can be challenging for older adults, especially for those... more Cognitive tasks performed while walking can be challenging for older adults, especially for those with stroke. Conversational speech requires attention and working memory. The purpose of this study was to examine how older adults with and without stroke meet the demands of walking while talking. Community-dwelling older adults, 12 without stroke and 24 with, were videotaped walking an irregular elliptical pathway. Audio recordings were made as subjects discussed topics such as describing a memorable vacation. Each participant performed in single and dual task conditions: speaking, walking, and speaking while walking. Primary measures of interest included cadence and speech rate. Components of language including measures of fluency, grammatical complexity, and semantic content were analyzed to examine additional changes in speech. Paired t-tests were used to compare single and dual task performance for each group. Group differences for dual task effects were examined with independent sample t tests. Cadence decreased with the addition of talking for those without stroke, P < .007, and those with stroke, P < .001. Speech rates did not change with walking for either group; those without stroke did not alter the language components. Participants with stroke reduced the grammatical complexity and semantic content of speech when walking, P's < .013. Those without stroke spent more time doing both tasks at once than those with stroke, P < .023. Clinicians can expect older adults to reduce walking speed to meet the demands of walking and talking. Older adults with stroke may use additional strategies to walk and talk simultaneously.
For adults with stroke, walking while performing a cognitive task can be challenging, resulting i... more For adults with stroke, walking while performing a cognitive task can be challenging, resulting in slower walking, poorer cognitive performance, or decreased performance on both tasks. It is not known if dual-task deficits are also present for upper limb movements for adults with stroke. To determine if unilateral movements of the affected and less affected hand are compromised when walking or talking. Nineteen community-dwelling adults with stroke were video- and audiotaped while performing in single- and dual-task conditions. Tasks included repeated, rhythmic hand movements with the affected and less affected hand, walking a narrow pathway, and speaking. For dual-task conditions, movements of each hand were done while walking and while talking. The rate of hand movement, cadence, and speech rate were analyzed using repeated measures analyses of variance. Affected hand movement rate was the same for single- and dual-task conditions. The rate of less affected hand movement was affected by dual-task conditions; this was due to an increase in hand movement rate while talking. Examination of cadence and speech rates revealed that cadence was decreased when moving the affected hand. Speech rate increased when accompanied by hand movements, but post hoc analyses were not significant. For those with stroke, dual-task deficits are seen with slower walking while moving the affected hand. In contrast, hand movements while speaking may have a more complex relationship, with possible faster speech rates in dual-task conditions.
The effects of a memory load on syntactic processing by younger and older adults were examined. P... more The effects of a memory load on syntactic processing by younger and older adults were examined. Participants were asked to remember a noun phrase (NP) memory load while they read sentences varying in syntactic complexity. Two types of NPs were used as memory loads: proper names or definite descriptions referring to occupations or roles. The NPs used in the sentence
An important issue in experimental aging research is the accurate measurement of cognitive constr... more An important issue in experimental aging research is the accurate measurement of cognitive constructs, particularly in small-sample studies. Latent variable modeling approaches to assessing age-based construct similarity are difficult to implement in smaller-scale studies, which tend to have small samples and measurement of a single construct. We discuss factor score comparison methods for assessing age-based construct similarity that may be more appropriate for small-scale studies. We then examine these methods for a series of single-factor models of verbal working memory (VWM) based on data from three separate studies in which small samples of younger and older adults' completed VWM-based tasks. Our single-factor models accounted well for the associations among the sets of VWM tasks. This construct was also measured well across age groups and different samples. Our analyses suggest that factor score comparison methods may be useful for small-scale studies that require assessment of age-based measurement similarity in cognitive constructs.
Http Dx Doi Org 10 1080 02643298508252667, Aug 16, 2007
ABSTRACT The sentence processing abilities of EA, a conduction aphasic with a documented phonolog... more ABSTRACT The sentence processing abilities of EA, a conduction aphasic with a documented phonological coding deficit, were investigated in tests of sentence comprehension, production, and repetition. EA showed a syntactic comprehension deficit, relying heavily on word order information to make grammatical role assignments. Production tests revealed a generally intact ability to generate a variety of sentence constructions, although there were frequent errors in the use of grammatical morphemes in the written productions. The repetition tasks were used to identify the processing strategies EA used under heavy memory load conditions. EA's semantic and syntactic processing capabilities and the role of the phonological code in normal sentence processing are discussed.
The current study examines whether young and older adults have similar preferences for animate-su... more The current study examines whether young and older adults have similar preferences for animate-subject and active sentences, and for using the order of activation of a verb's arguments to determine sentence structure. Ninetysix participants produced sentences in response to three-word stimuli that included a verb and two nouns differing in animacy. Dependent variables included accuracy, sentence structure produced, and production times for active vs. passive sentences. Neither group shows a strict preference for active sentences, but the two groups are differentially sensitive to animacy and the order of noun activation. Results suggest that sentence structure choice is a probabilistic, constraint-satisfaction process during which these factors interact.
Three groups of subjects were tested to investigate the effect of language on the relationship be... more Three groups of subjects were tested to investigate the effect of language on the relationship between recall span and articulation rate. Native English-speaking monolinguals and native Chinese-speaking monolinguals recalled only English or Chinese words, respectively. Chinese-English bilinguals recalled both English and Chinese words. Articulation rates for English and Chinese monolinguals and Chinese-English bilinguals in each language were also obtained. When recall span was regressed on articulation rate, the slopes for Chinese and English words were significantly different for the Chinese-English bilinguals. This difference was not due to language proficiency but to phonological differences between English and Chinese.
Http Dx Doi Org 10 1080 07340669008251538, Sep 28, 2007
This experiment investigated age group differences in working memory by examining the effects of ... more This experiment investigated age group differences in working memory by examining the effects of word length on adults' recall span and repetition rate. College students and adults, 60 to 94 years of age, recalled lists of one-, two-, or three-syllable words and repeated aloud pairs of one-, two- or three-syllable words. Word recall spans and word repetition rates were computed. Main effects of age group and word length were obtained on both measures, although the interactions were not significant. A second analysis examined the relationship between individuals' recall span and their repetition rate. Across all age groups combined, recall span was a linear function of repetition rate and accounted for 25 percent of the variance on the recall task. A reanalysis of the word repetitions revealed that older adults' word durations and inter-word pauses are longer than young adults'.
The eye movements of young and older adults were tracked as they read sentences varying in syntac... more The eye movements of young and older adults were tracked as they read sentences varying in syntactic complexity. In Experiment 1, cleft object and object relative clause sentences were more difficult to process than cleft subject and subject relative clause sentences; however, older adults made many more regressions, resulting in increased regression path fixation times and total fixation times, than young adults while processing cleft object and object relative clause sentences. In Experiment 2, older adults experience more difficulty than young adults while reading cleft and relative clause sentences with temporary syntactic ambiguities created by deleting the "that" complementizers. Regression analyses indicated that readers with smaller working memories need more regressions and longer fixation times to process cleft object and object relative clause sentences. These results suggest that age-associated declines in working memory do affect syntactic processing.
Http Dx Doi Org 10 1080 03610739308253922, Sep 27, 2007
This study compared young and older adults&am... more This study compared young and older adults' summaries of expository texts under the hypothesis that older adults would be more experienced, hence more accurate, at summarizing texts. Two types of expository texts were used: procedural and descriptive texts. The texts were read by a panel of judges who wrote summaries of each text and identified the central ideas of each text; the judges' summaries were used to prepare lists of the central ideas of each text and to write standard summaries of each text. The participants read four texts, two orally and two silently, and then wrote summaries, which were limited to 50 words. Words-per-minute reading times were collected and the summaries were scored on two measures of content, how many ideas were reproduced from the original texts and the proportion of central ideas that were reproduced, and two measures of length, the number of sentences and the number of words. Although the older adults read more slowly than the young adults, the older adults reproduced more total and central ideas than the young ideas.
The Air Force Research Laboratory (AFRL) Space Vehicles Directorate has developed a mission to re... more The Air Force Research Laboratory (AFRL) Space Vehicles Directorate has developed a mission to research the technologies needed for large space structures, high-power generation, and protection of space assets within the high radiation environment of a medium earth orbit (MEO). The resulting Deployable Structures Experiment (DSX) will address a number of basic science experiments via a single MEO testbed platform.
The eye movements of young and older adults were tracked as they read sentences varying in syntac... more The eye movements of young and older adults were tracked as they read sentences varying in syntactic complexity. In Experiment 1, cleft object and object relative clause sentences were more difficult to process than cleft subject and subject relative clause sentences; however, older adults made many more regressions, resulting in increased regression path fixation times and total fixation times, than young adults while processing cleft object and object relative clause sentences. In Experiment 2, older adults experience more difficulty than young adults while reading cleft and relative clause sentences with temporary syntactic ambiguities created by deleting the "that" complementizers. Regression analyses indicated that readers with smaller working memories need more regressions and longer fixation times to process cleft object and object relative clause sentences. These results suggest that age-associated declines in working memory do affect syntactic processing.
Cognitive tasks performed while walking can be challenging for older adults, especially for those... more Cognitive tasks performed while walking can be challenging for older adults, especially for those with stroke. Conversational speech requires attention and working memory. The purpose of this study was to examine how older adults with and without stroke meet the demands of walking while talking. Community-dwelling older adults, 12 without stroke and 24 with, were videotaped walking an irregular elliptical pathway. Audio recordings were made as subjects discussed topics such as describing a memorable vacation. Each participant performed in single and dual task conditions: speaking, walking, and speaking while walking. Primary measures of interest included cadence and speech rate. Components of language including measures of fluency, grammatical complexity, and semantic content were analyzed to examine additional changes in speech. Paired t-tests were used to compare single and dual task performance for each group. Group differences for dual task effects were examined with independent sample t tests. Cadence decreased with the addition of talking for those without stroke, P < .007, and those with stroke, P < .001. Speech rates did not change with walking for either group; those without stroke did not alter the language components. Participants with stroke reduced the grammatical complexity and semantic content of speech when walking, P's < .013. Those without stroke spent more time doing both tasks at once than those with stroke, P < .023. Clinicians can expect older adults to reduce walking speed to meet the demands of walking and talking. Older adults with stroke may use additional strategies to walk and talk simultaneously.
For adults with stroke, walking while performing a cognitive task can be challenging, resulting i... more For adults with stroke, walking while performing a cognitive task can be challenging, resulting in slower walking, poorer cognitive performance, or decreased performance on both tasks. It is not known if dual-task deficits are also present for upper limb movements for adults with stroke. To determine if unilateral movements of the affected and less affected hand are compromised when walking or talking. Nineteen community-dwelling adults with stroke were video- and audiotaped while performing in single- and dual-task conditions. Tasks included repeated, rhythmic hand movements with the affected and less affected hand, walking a narrow pathway, and speaking. For dual-task conditions, movements of each hand were done while walking and while talking. The rate of hand movement, cadence, and speech rate were analyzed using repeated measures analyses of variance. Affected hand movement rate was the same for single- and dual-task conditions. The rate of less affected hand movement was affected by dual-task conditions; this was due to an increase in hand movement rate while talking. Examination of cadence and speech rates revealed that cadence was decreased when moving the affected hand. Speech rate increased when accompanied by hand movements, but post hoc analyses were not significant. For those with stroke, dual-task deficits are seen with slower walking while moving the affected hand. In contrast, hand movements while speaking may have a more complex relationship, with possible faster speech rates in dual-task conditions.
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