Reading development involves several changes in orthographic processing. A key question is, "how does the coding of letters develops in children learning to read?" Masked priming effects of transposition and substitution primes have been taken to index the importance of letter position and identity coding. Somewhat contradicting results…

We propose the use of the latent change and latent acceleration frameworks for modeling nonlinear growth in structural equation models. Moving to these frameworks allows for the direct identification of "rates of change" and "acceleration" in latent growth curves--information available indirectly through traditional growth…

Adults demonstrate difficulty and pronounced variability when developing second language (L2) grammatical knowledge and reading skills. We examine explanations in terms of individual differences in working memory (WM). Despite numerous studies, the association between WM and adult second language (L2) acquisition remains unclear, and longitudinal…

Although most psychological assessments are based on measures related to an individual's average level of performance, it has been proposed that measures of variability around one's average may provide unique individual difference information and have clinical significance. The current study investigated properties of within-person variability in…

Moment-to-moment intraindividual variability (IIV) in cognitive speed is a sensitive behavioral indicator of the integrity of the aging brain and brain damage, but little information is known about how IIV changes from being relatively low in young adulthood to substantially higher in older adulthood. We evaluated possible age group, sex, and task…

Although it has been proposed that the ability to compare numerical magnitudes is related to mathematics achievement, it is not clear whether this ability "predicts" individual differences in later mathematics achievement. The current study addressed this question in typically developing children by means of a longitudinal design that examined the…

Investigated the relation between infant expectations and reaction time (RT) at age 3 months, and Childhood IQ and RT at 4 years. Found that visual RT and manual RT in childhood correlated only marginally. Data suggested stability in RT between early infancy and childhood, or predictability of childhood IQ by infant RT and anticipation during…

Used Visual Expectation Paradigm to describe information processing changes and individual differences during first year of life. Found regular age changes in mean reaction time and variability but not in minimum reaction time, suggesting that growth rate of sensory-detection information is constant during first year but age changes occur in level…

Speculates on underlying processes for the reaction time variance and age differences in anticipation latency using the Visual Expectation Paradigm. Discusses the dichotomization of reactive and anticipatory behavior, limitations of longitudinal designs, drawbacks in using standard procedures and materials, and inferences that can be made…