Biomedical subjects

Ruth Lavis

Publications and source records attributed to Ruth Lavis.

3 recordsLinked to original sources

PubMed2005

Symbol-string sensitivity and adult performance in lexical decision.

In this study of adult readers, we used a symbol-string task to assess participants' sensitivity to the position of briefly presented, non-alphabetic but letter-like symbols. We found that sensitivity in this task explained a significant proportion of sample variance in visual lexical decision. Based on a number of controls, we show that this relationship cannot be explained by other factors including: chronological age, intelligence, speed of processing and/or concentration, short term memory consolidation, or fixation stability. This approach represents a new way to elucidate how, and to what extent, individual variation in pre-orthographic visual and cognitive processes impinge on reading skills, and the results suggest that limitations set by visuo-spatial processes constrain visual word recognition.

Adult↗

PubMed2004

Visual encoding mechanisms and their relationship to text presentation preference.

This study was designed to investigate the importance of spatial encoding in reading, with particular emphasis on visuo-spatial encoding mechanisms. Thirty one school children participated in the first study in which they were measured on their ability to solve a centrally presented spatial encoding task, as well as their sensitivity to the frequency doubling illusion across the retina. We found that both spatial frequency doubling sensitivity and performance in the spatial encoding task were correlated with reading, however these tasks were unrelated to each other. Furthermore, frequency doubling sensitivity was correlated with contextual reading, but not single-word reading, while the central spatial encoding task was correlated with both reading tasks. These findings may have functional implications for text presentation preference. Accordingly, in Experiment 2 we demonstrated that children with poor FDT sensitivity read more accurately when words were presented singularly rather than in a whole-text format. In conclusion, we suggest that contextual reading may depend upon two separate and functionally distinct visual encoding mechanisms--one central, important for the spatial discrimination of letters within words, and the other, a spotlighting mechanism important for spatial localization within a body of text. While both mechanisms may constrain reading efficiency, neither mechanism enforces an absolute limit on reading ability.

Child↗

PubMed2004

Symbol-string sensitivity and children's reading.

In this study of primary school children, a novel 'symbol-string' task is used to assess sensitivity to the position of briefly presented non-alphabetic but letter-like symbols. The results demonstrate that sensitivity in the symbol-string task explains a unique proportion of the variability in children's contextual reading accuracy. Moreover, developmental dyslexic readers show reduced sensitivity in this task, compared to chronological age controls. The results suggest that limitations set by visuo-spatial processes and/or attentional iconic memory resources may constrain children's reading accuracy.

Attention↗