Thursday, March 5, 2015

Naps promote rule abstraction in language-learning infants

Gomez, R. L., Bootzin, R. R., & Nadel, L. (2006). Naps promote abstraction in language-learning infants. Psychological Science, 17(8).

Infants accomplish an incredible amount of learning during their waking hours. However, as many parents may know, infants spend most of their day asleep. It is possible that sleep is very important for an infant’s cognitive and linguistic development. The present study investigated infant’s learning of an artificial language following either a period of sleep or wakefulness, and compared learning across groups. The results demonstrated that naps promote a qualitative change in infants’ learning.

Infants, although not yet fluent in their native language, are well on their way to acquiring language. Indeed, past research using artificial language paradigms has shown that infants are incredibly adept at uncovering the regularities within speech. In the present study, infants were familiarized with a language comprised of nonadjacent dependencies. Such a structure requires participants to track the dependencies between the first and third element, for example: pel-wadim-jic, or pel-kicey-jic. Here, the first nonsense word predicts the third, and the middle nonsense word can vary. This structure is also evident within English where there is a dependency between an auxiliary and an inflection with an intervening verb, for example: is playing.

The artificial language study was composed of 48 nonadjacent dependency strings (e.g.: pel-X-jic). Infants in the experimental condition heard each string 5 times in a familiarization phase. Infants were tested on their knowledge of strings from the familiarization phase, and novel strings that followed the same nonadjacent dependency rule. Testing took place four hours after the familiarization phase. During the four-hour break, infants either took a nap or stayed awake. Results demonstrated that infants who took a nap between the familiarization and test phase were better able to abstract the nonadjacenet dependency rule to novel stimuli. Infants who did not take a nap demonstrated memory for nonadjacent word pairs from the familiarization phase, but not novel items. It might be that infants who took a nap learned the “relationship in general” between the first and third word strings. This ability to abstract from a rule and apply it to novel situations is an essential process in language and cognitive development, and results from this study suggest that sleep may play an important role in this process.

Blogger: Nicolette Noonan, PhD Student

Wednesday, March 4, 2015

Naming speed and reading: From prediction to instruction

Kirby, J. R., Georgiou, G. K., Martinussen, R., & Parrila, R. (2010). Naming speed and reading: From prediction to instruction. Reading Research Quarterly, 45(3), 341–362.

Naming speed is the ability to name a series of familiar objects or letters at a fast pace. It is known to be related to reading ability, although the exact nature of that relationship is debated among researchers. A review of research shows that naming speed predicts performance on most reading measures, including single word reading, pseudoword reading, and reading comprehension. The relation between naming speed and reading is strongest in timed reading tasks, and in languages that use consistent spelling conventions.

One way to examine the relationship between naming speed, reading, and other processes underlying reading is to look to populations with impairments. Children with dyslexia show poor performance on naming speed and phonological awareness tasks compared to peers. Wolfe and Bowers (1999) call this the double-deficit hypothesis (DDH), arguing that naming speed and phonological awareness are separate constructs and can be separately impaired. Empirical support for DDH is mixed due to a variety of factors, such as variation between studies in participant reading ability, and spelling rules of the languages studied.

Studies looking at naming speed instruction have found that interventions targeting naming speed directly tended to show limited or temporary improvements at best. In contrast, broad reading interventions lead to gains on reading measures and only sometimes on naming speed. An additional finding in intervention literature is that a child’s naming speed most strongly predicted how well she would respond to a reading intervention. Taken together, these findings suggest that although naming speed is a strong predictor of reading ability, it may be more effective to offer intervention targeting other reading processes.

Blogger: Laura Pauls, PhD Student

Tuesday, March 3, 2015

Processing Deficits in Children with Language Impairments

Archibald, L.M.D., & Noonan, N. B. (In press). Processing Deficits in Children with Language Impairments. To appear in E.L. Bavin & L. Naigles (eds), The Cambridge Handbook of Child Language, 2nd ed. Cambridge, UK: Cambridge University Press.

In this chapter, Archibald and Noonan review and evaluate theoretical accounts of specific language impairment (SLI), an unexpected and unexplained developmental delay in the onset or development of oral language in children. Children with SLI receive lower scores than age-matched peers on a variety of measures including many not related to language, but the language deficit in SLI is more severe than deficits in any other area.

The disproportionate linguistic impairment in SLI has resulted in investigations of cognitive mechanisms responsible for processing language-related (or domain-specific) information. Such processes include auditory processing and phonological processing. Many studies have reported SLI deficits on tasks tapping both of these processes.

The findings of impairments on nonlinguistic tasks in SLI groups have lead to a focus on cognitive mechanisms responsible for processing different kinds of information, only some of which may be related to language. These processes are considered domain-general and include attention, working memory, executive functions, and implicit learning.

It may be that the best explanation for the range of mixed findings reported is to consider SLI as resulting from a variety of possible paths. There may be several genetic and environmental factors that could contribute to a child being considered to have (or not have) a language delay. If this is the case, it will be necessary to understand each child’s profile of strengths and weaknesses to understand factors contributing to his/her language impairment profile.

Blogger: Areej Balilah

Wednesday, February 18, 2015

Phonological deficits in specific language impairment and developmental dyslexia: Towards a multidimensional mode

Ramus, F., Marshall, C.R., Rosen, S., & van der Lely, H.K.J. (2013). Phonological deficits in specific language impairment and developmental dyslexia: Towards a multidimensional model. Brain, 136, 630-645.

Children with specific language impairment (SLI) have an unexpected, developmental delay in the onset or developmental of oral language. Children with developmental dyslexia fail to learn to read at the expected rate despite adequate opportunities. SLI and dyslexia often co-occur leading to questions about distinctions between these impairments. Several views exist regarding the co-existence of these disorders: (1) SLI is a more severe form of dyslexia; (2) Phonological deficits are common to both SLI and dyslexia. Children with SLI also have impairments in other aspects of language (i.e., grammar, word knowledge); (3) The phonological deficits observed in SLI and dyslexia are qualitatively different.

These researchers compared models to fit data from 127 children who had completed measures of grammatical skills, sentence processing, manipulating sounds in words, discriminating sounds in words, and others. The data were explained by 3 factors as follows: (1) nonphonological skills – that is, measures not related to the sound structures of words including grammatical skills and sentence processing, (2) phonological awareness – that is, tasks requiring some sound manipulations in words, and (3) phonological representations – that is, tasks requiring recognition of the sound structures in words. The factors were associated with the different impairment profiles in unique ways: Children with both SLI and dyslexia had low scores on all three factors. Those with SLI-only scored low on the phonological representations and nonphonological skills factor, and those with dyslexia-only on the phonological awareness factor only.

The authors argued that there might be qualitative differences in the phonological deficits that characterize SLI and dyslexia. Those with SLI may have poor phonological representations stored in long-term memory, which makes it difficult for them to complete phonological awareness tasks too. Those with dyslexia, on the other hand, may have intact phonological representations, but have difficulty accessing and manipulating this information. Deficits in nonphonological skills may be characteristic of those with SLI, but also those who struggle with comprehending what they read rather than decoding words.

Blogger: Lisa Archibald

Monday, November 24, 2014

Estes, K. G., & Hurley, K. (2013). Infant‐directed prosody helps infants map sounds to meanings. Infancy, 18(5), 797-824.

Infant directed speech is an exaggerated and repetitive speaking style that adults use when addressing infants. This form of speech encompasses a higher pitch, greater pitch variation and longer durations of speech segments. Infant directed speech supports early language acquisition by helping infants break up the speech they hear into components and helps maintain infant attention. In this paper, the researchers examined how infant directed speech influences an infants’ ability to connect sounds with meanings, specifically words with objects.

In this study, 17-month-old infants were presented with pictures of a novel object while listening to a name for the object. The amount of time the child looked at the novel object was recorded. Typically, infants look at novel objects for a long time at first, but once they become familiar with the stimulus, they spend less time looking (i.e., they become habituated). This method is called a habituation word-learning task. In the first experiment, the infants heard adult directed speech, and in the second, infant-directed speech. A third experiment also used infant directed speech but included different examples of the same word being spoken (different pitch contours and durations of the same word).

The authors found that infants were able to learn the object-label associations when the stimuli were produced using infant directed speech. Infants’ word learning was improved when the labels were produced using infant directed speech that contained variability (Experiment 3).  This suggests that infants form stronger associations between objects and their labels when the sound of the labels contains variability (altered pitch and duration for the same label) such as those produced in Experiment 3. This variability mimics the variability found in naturalistic speech and appears to be critical in an infant’s ability to learn new words. 

Blogger: Monica DaSilva is completing her Masters of Science in Developmental Psychology in the Language and Working Memory Lab. Her work will examine how infant word learning is enhanced by prosodic cues in words (i.e., word stress).

Danahy Ebert, K., & Scott C. M. (2014). Relationships between narrative language samples and norm-referenced test scores in language assessments of school-age children. Language, Speech, and Hearing Services in Schools, 45, 337–350.

Speech-language pathologists rely on a number of tools to complete comprehensive assessments of language abilities in school-age children. Two types of tools are norm-referenced tests and criterion-referenced tests. Norm-referenced tests assess broad language skill and allow clinicians to determine the child’s level of ability by comparing his performance to scores from a large sample of other children. In contrast, criterion-referenced tests offer in-depth information about a smaller set of language skills, but use more naturalistic tasks, such as recounting a narrative.

This study compared the performance of school-age children on a variety of norm-referenced tests and narrative language samples. The authors found that performance on the two types of assessments was more closely related for younger children (6–8 years) than for older children (9–12 years). The study also examined the extent to which the tests agreed on which children where considered to be impaired. Agreement of identification rates between different norm-referenced tests and different aspects of the narrative language samples ranged from 37% to 77%. This showed that some children were identified by both tests, while others were only identified by one type of test.

The authors conclude that age must be considered when selecting criterion-referenced tests because different types of naturalistic language tasks are more appropriate for different ages. They also suggest that clinicians continue to use both types of testing in their assessments in order to gather a wealth of information about each child’s language ability.

Blogger: Laura Pauls, MCISc-SLP