My major research interests fall within the domain of Developmental Cognitive Neuroscience: I am interested in how we become fluent readers and math-users, and the behavioral and brain development which supports these skills. As a member of the former Educational Neuroscience Lab, and an affiliate of the Department of Education at Dartmouth, I am also interested in the possible impact of this research on educational practice and policy. My current work focuses on higher-level number processing, including cases of difficult or ambiguous number usage.
Negative Numbers: Understanding Less Than Nothing
My dissertation studies examined how we come to understand negative numbers, and the brain areas and systems supporting in this concept. Negative numbers are particularly difficult when first introduced, as they counterintuitively are worth literally less than nothing, yet have value. I examined simple negative number comparison in both adults and children, comparisons between historic dates (AD and BC) as a further bidirectional system, and adult arithmetic with negative numbers. An initial fMRI study with adult negative number comparisons was presented in April 2011 at CNS (see my 2011 poster) and has recently been accepted for publication at NeuroImage. Some of the developmental fMRI work on negative number understanding was presented in April 2012 at CNS (see my 2012 poster) and is currently in preparation for submission. A study on arithmetic with negative numbers is currently under review, and the historic date study will hopefully be submitted soon!
Timelines and Ambiguous Number Processing
One line of research focuses on historic dates, as these are stimuli which are numeric, yet involve an extra semantic meaning (e.g., 1492). A behavioral experiment determined that years of major events in Western history were responded to similarly to unassociated large numbers, regardless of context, including a normal numeric Distance Effect. However, dates showed different patterns of brain activity for the number versus event context. fMRI investigation determined that dates as events showed more temporal and frontal activity clusters than did dates as numbers. We can thus determine that even relatively weak contexts can bring semantic associations on-line in the brain, as stimuli which are visually identical show different activities. Such associations are only active when cued, though, and are not automatically evaluated with quantity (see my 2010 CNS poster for more details). I was awarded a Psi Chi Graduate Research Grant of $640 (used for participant payment) for this study.
A second phase of this study seeks to compare history majors, or students with increased experience in attributing semantic meaning to these large numbers (and likely increased familiarity with their meanings), to participants from the general population who have often taken only 1 or 2 history classes. Data from this project was presented at the 2010 annual Society for Neuroscience conference in San Diego, CA (see my 2010 SfN poster for more details).
Basic Math Skills and the Brain
Several projects have also taken a developmental approach to understanding these skills. We have scanned five- through eighteen-year-olds during a simple dot- and digit-comparison task to determine early routes of number and quantity understanding. We previously found that adults' brain activity during such simple comparisons was correlated with working memory, though this ability was not directly necessary for task performance (see [Gullick, Sprute, & Temple, 2011]), and are curious to see how this relationship changes across development and experience.
Reading Comprehension and ERPs
I have also investigated the importance of semantics and comprehension in reading. A previous study probed the influence of visualization on abstract and concrete nouns using ERP in Dr. Donna Coch's lab. We aimed to separate the automaticity of visualization (i.e., do concrete words always result in mental image generation?) from visualization effort (i.e., when we attempt to visualize abstract words' referents, are we perfoming the same processing as with concrete words?) in examinations of late processing waveforms. This project is currently in preparation for submission.
In future post-doctoral work, I am interested in examining disordered educational skill development, as in the case of dyslexia. More specifically, I am interested in examining the phonological skills of dyslexics in relation to the root of the disorder, and how different interventions may target certain systems. I aim to examine these questions as a Research Associate in the Developmental Cognitive Neuroscience Lab at Northwestern University.