Leon_Guerrero, S., Ozernov-Palchik, O., Gonzalez, M., Zuk, J., & Gaab, N. (Forthcoming). Using tablet technology to screen for reading disabilities in preschool and early kindergarten. In N. Kucirkova, J. Rowsell, & G. Fallon (Ed.), The Routledge International Handbook of Learning with Technology in Early Childhood . Taylor and Francis.
Leon_Guerrero, S., Smith, S., & Luk, G. (2016). Home language usage and cognitive control in bilingual preschoolers. In Cognitive control and consequences in the multilingual mind. Amsterdam: John Benjamins Publishing.Abstract

Cognitive control is fundamental to successful learning and goal-directed behavior in both adults and children. Bilingual experience has been shown to facilitate cognitive control across the lifespan because of the increased cognitive demand required in managing multiple languages on a daily basis. Building on previous research that primarily compared monolinguals and bilinguals categorically, the present study examined whether variation in non-dominant language usage moderates the developmental trajectory of cognitive control in a sample of heterogeneous Spanish-English bilingual preschoolers. Using a general linear model, we found a significant interaction between the proportions of Spanish use, chronological age and performance on a cognitive control task. Results suggest that daily bilingual usage moderates preschoolers’ development in cognitive control. While bilingualism is a multidimensional experience, for developing children, daily usage is an important quantifiable indicator of bilingualism when considering cognitive control. Research and educational implications are discussed in light of these findings.

Pollack, C., Leon_Guerrero, S., & Star, J. (2015). Exploring mental representations for literal symbols using priming and comparison distance effects , ZDM. 46 (2), 1-13.Abstract

Higher-level mathematics requires a connection between literal symbols (e.g., ‘x’) and their mental representations. The current study probes the nature of mental representations for literal symbols using both the priming distance effect, in which ease of comparing a target number to a fixed standard is a function of prime-target distance, and the comparison distance effect, in which ease of comparing two numbers depends on the distance between them. Can literal symbols that have been assigned magnitude access mental representations of quantity to produce distance effects? Forty participants completed number comparison tasks involving Arabic numerals and literal symbols, a training task, and a working memory task. While both distance effects were present with Arabic numerals, there was no evidence of either with literal symbols. Results suggest that literal symbols may not share the same mental representations of magnitude as other number formats or may access them differently. Additional research is needed to understand mental representations utilized in higher-level mathematics (e.g., algebra), which includes both Arabic numerals and literal symbols.