Monday, March 9, 2015
Nemeth, D., Janacsek, K., Csifcsak, G., Szvoboda, G., Howard, J. H., & Howard, D. V. (2011). Interference between sentence processing and probabilistic implicit sequence learning. PLoS One, 6 (3).
The present study investigated whether sentences are processed via a language-specific mechanism, or a domain-general mechanism. The authors differentiated between two theories in the literature that account for how humans process sentences. The first is a “dual systems” theory, which suggests that humans possess two distinct systems that process language: The declarative system, which is responsible for learning words, and the procedural system, which is responsible for learning sequences, such as the learning of grammar. The second is a “single system” theory, which suggests that words and grammar are learned by the same non-language specific system. This system relies on the learning of the statistically predictable regularities within language.
To investigate whether sentences are processed by a domain-specific or domain-general system, the authors used a dual task paradigm. Participants completed a non-linguistic Alternating Serial Reaction Time (ASRT) task, which involved the learning of a non-linguistic sequence. While completing the ASRT task, participants were concurrently engaged in a sentence-processing task (linguistic), a word recognition task (linguistic control), or a mathematical addition task (non-linguistic control). The authors hypothesized that learning within the ASRT task would be diminished by concurrent engagement in the sentence-processing task, which would suggest that both tasks involve a domain-general sequence learning mechanism
The main finding was that engagement in the sentence-processing task reduced sequence learning in the ASRT task. It was interesting that the mathematics task did not diminish learning, as it was the most difficult of the concurrent tasks. This result suggested that the interference between the sentence processing and ASRT task was not due to task difficulty. Overall, the authors suggested that sentence processing involves a domain-general sequence learning mechanism.
Blogger: Nicolette Noonan, PhD Student
Thursday, March 5, 2015
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
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
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