Julie A. Van Dyke - US grants

DESCRIPTION (provided by applicant): Reading and language comprehension requires the ability to identify relationships between linguistic units that are frequently non-adjacent. This means that comprehenders must be able to store partially interpreted material (e.g., the subject of a sentence whose verb occurs much later, viz. The boy with the coat with the blue stripes and the flashy buttons on the collar that he bought on sale last Tuesday sang at the bus stop.) A frequent explanation for comprehension difficulty is that individuals differ on the amount of Working Memory (WM) capacity they can devote to maintaining this information. Yet recent research in the memory domain using the Speed-Accuracy Tradeoff (SAT) method suggests that the amount of information actively maintained in working memory is quite small-perhaps as little as 1 item. This leaves very little room for individual differences in memory capacity, and suggests that alternative explanations for comprehension failure must be found. The goal of the present project is to begin exploring these alternatives via the following three aims: 1) Adaptation of the Speed-Accuracy Tradeoff (SAT) method for use with poor readers. Adaptation is required because the method puts time-pressure on participants to respond in a particular fashion, and poor readers may have difficulty meeting this pressure due to insufficient reading ability or inhibitions caused by awareness of their reading disability. The availability of this method for use with a broader population will enable us to determine whether such a severe limit on WM capacity is characteristic of throughout the range of reading ability, or whether it is concomitant with acquired reading skill. 2) The SAT method is unique in providing precise measures of the speed with which participants may access the contents of memory. Research with skilled readers from college populations suggests a very fast cue-driven access mechanism that serves to compensate for the restricted WM capacity by quickly restoring necessary information into active memory. We will investigate whether individual differences in the speed with which readers can restore previously occurring information may provide an alternative account of comprehension failure. In order to more broadly sample reading ability, we will focus on the population of non- degree seeking adolescents sampled throughout the community. 3) A consequence of cue-driven memory access is interference from similar, but incorrect items also present in memory. Interference may be increased if lexical representations are poor or else if retrieval speed for the correct item is slowed by competitors. We employ the SAT method to distinguish these possibilities. These investigations will reveal whether individual differences in the way that comprehension processes interact with the contents of memory are qualitative or quantitative. This is important for determining the most judicious remediation methods, especially the value of differential stress on measures for increasing retrieval speed (i.e., fluency) versus those that increase accuracy (i.e., vocabulary knowledge). PUBLIC HEALTH RELEVANCE: A frequent explanation for reading and language comprehension difficulty is that individuals differ in their Working Memory (WM) capacity, yet recent research suggests that the amount of information actively maintained in WM is quite small-perhaps as little as 1 item. This leaves very little room for individual differences in memory capacity, and suggests that alternative explanations for comprehension failure must be found. The goal of this project is to begin exploring these alternatives using a novel extension of the Speed- Accuracy Tradeoff technique, which has been used widely in memory research with skilled readers, but never with such a broad range of reading ability as that proposed in the current project.

DESCRIPTION (provided by applicant): Poor reading ability has profound cognitive, emotional, and behavioral consequences for the developing child, and-if unremediated-eventually has economic consequences for the adult. Indeed, the 2003 report on Adult Literacy and Life Skills (Statistics Canada and OECD, 2005) estimates that 51percent of US adults aged 16-25 can read only simple texts and make only low-level inferences, a level termed below-basic, which is insufficient for attaining advanced educational and occupational goals. These statistics point to the need for understanding factors contributing to poor reading ability beyond the single-word level in the adult population. This application brings together findings from three largely independent research communities (memory, adult sentence and discourse processing, and reading disability) and creates a novel approach towards understanding poor comprehension. Whereas, the bulk of linguistically-based research into sentence and text-level comprehension has emphasized a limited set of general cognitive capacities (especially working memory capacity) as the source of comprehension difficulty, and focused primarily on the college-level population, this project is built around an architectural framework that emphasizes memory retrieval as the mechanism connecting word- reading skills and higher-level integrative skills. Building on memory research pointing to a severely limited active memory capacity, even for skilled readers, we assume that comprehension is primarily determined by the successful retrieval of information from passive memory. Thus, in our Specific Aim 1 we investigate the conditions leading to successful retrieval, including the way that different types of linguistic cus (phonological, morphological, syntactic, semantic, pragmatic) are combined, and the conditions leading to failed retrieval- namely the presence of memory interference. Our Specific Aim 2 combines long standing conclusions from memory research, suggesting that sensitivity to interference will be determined by the quality of to-be-retrieved representations, with research in reading disability, arguing that individuals will vary in the average quality of their word representations, which are determined by their reading experience and facility for processing different types of linguistic information. Finally, our Specific Aim 3 investigates the neurologica bases of sensitivity to retrieval interference, with primary focus on the neural networks that link skilled word reading to higher level processing, and the contribution of regions responsible for mediating interference at each level, especially left inferior frontal gyrus. We include both college and non-college community-based individuals (age 16-24), to provide a more representative sample of reading ability than in previous studies and thus increase the impact of our potential findings. In addition, we recruit a sample of beginning readers (age 7-9) for an initial investigation of the development of retrieval and sensitivity to interference. We expect tht this project will result in a new conception of sources of individual variability in reading comprehension, and a deeper understanding of how these develop in childhood and persist into adulthood.