Research Interests:

The goal of my research is to understand how the human brain supports the acquisition of concepts. Throughout my undergraduate and graduate work, I have combined behavioral and neuroimaging (fMRI and fNIRS) techniques to study the acquisition of concepts that are at the core of educational curricula (reading, writing and mathematics). My research goes beyond traditional approaches to developmental cognitive neuroscience by testing the youngest children to date during fMRI scanning (3- to 4-years-old), combining task-based and naturalistic fMRI paradigms, and employing computational models and sophisticated statistical analyses to characterize patterns of learning and development. The foci of my research have broad implications and can be used to inform educational policies by elucidating the constraints on and capabilities of these conceptual systems in early childhood.

Areas of Research:

Neural circuitry underlying numerical development

with Jessica Cantlon
Papers: Kersey & Cantlon, 2017, Journal of Neuroscience; Kersey & Cantlon, 2017, Langauge Learning & Development

Number is a fundamental human concept that supports mathematical cognition. This line of research examines the neural circuitry that underlies numerical processing in early childhood and how the development of this circuitry relates to cognitive development. These projects compare the development of numerical cognition to the development of other non-symbolic magnitudes (e.g., color and size) and to other cognitive domains (e.g., reading). This allows us to understand which aspects of the neural circuitry are distinct to number and which are shared. These projects utilize both task-based and "naturalistic" fMRI paradigms in order to better understand children's cognitive and neural development in the real world. Recently, we showed evidence of neural tuning to numerosity in the intraparietal sulcus of the youngest children tested to date with fMRI (3- to 6-year-olds; Kersey & Cantlon, 2017, JNeurosci). Current work focuses on the neural substrates that underlie the acquisition of number words and counting sequences.

Gender similarities in numerical development

with Jessica Cantlon, Kelsey Csumitta, Melissa Libertus, & Emily Braham
Papers: Kersey et al. (2018), npj Science of Learning

Recent public discussions have suggested that the under-representation of women in science and mathematics careers can be traced back to intrinsic differences in aptitude. However, true gender differences are difficult to assess because sociocultural influences enter at an early point in childhood. If these claims of intrinsic differences are true, then gender differences in quantitative and mathematical abilities should emerge early in human development. This line of work compares the performance of boys and girls in key areas of numerical processing across development. Importantly, we not only test for statistical differences, but also for statistical equivalence, which is important for being able to determine whether performance is quantitatively similar across gender groups. We find that across all stages of numerical development, analyses consistently revealed that boys and girls do not differ in early quantitative and mathematical ability, suggesting that boys and girls are equally equipped to reason about mathematics during early childhood (Kersey et al., 2018, npj Science of Learning). Current work tests whether these similarities extend to the neural processs that underlie mathematics development (media coverage from CNS 2018).

Development of Representational Systems for Writing & Reading

with Karin James; Brad Mahon
Papers: Kersey & James, 2013, Frontiers in Psychology

My undergraduate work explored the role of writing in the development of neural representations for letter perception. We find that when children learn letters by writing, the sensorimotor network for letter perception shows greater activation compared to watching someone else write letters (Kersey & James, 2013, Front Psych). Recently, I have renewed this line of work in a case study of a 13-year-old who developed alexia after her left inferior temporal cortex was removed during surgery. Interestingly, she was still able to read long strings of digits, suggesting a dissociation between representations for numbers and words. Over the course of a year, we have used fMRI and cognitive testing to track how her brain changed after surgery and how it continues to change as she recovers her reading skills.

Development of functional networks for processing and using tools

with Jessica Cantlon, Brad Mahon, Courtney Lussier, and Tyia Clark; Karin James
Papers: Kersey et al., 2016, Cerebral Cortex; James & Kersey, 2018, Developmental Science

In order to successfully use a tool, we must integrate information about what the tool looks like, how it is used, and what it can be used for. To support tool use, humans have developed a network of regions that are consistently recruited while processing tools. However, little is known about how this tool processing network develops. We showed that the core components of the tool-processing network in parietal and temporal cortex are established by age 4, but the network undergoes refinement between ages 4 and 8 (Kersey et al., 2016, Cerebral Cortex). In a related line of research, we showed that children also rely on regions of parietal cortex for reaching, grasping, and manipulating objects (James & Kersey, 2018, Dev Sci). These types of visually-guided actions are important for picking up and using tools.

Neural changes underlying learning in infants

with Lauren Emberson
Papers: Kersey & Emberson, 2016, Developmental Science

Infants' brains are able to begin learning about the world around them from the moment they are born. This area of research uses fNIRS (functional near-infrared spectroscopy) to examine changes in infants' brain activation (oxygenation) during perceptual learning. Specifically, we look at the changes in the hemodynamic response over several learning blocks and how the hemodynamic response relates to unexepcted perceptual events. We show that over the course of learning, regions in occipital, temporal, and frontal cortex show an inverted U-shape response (Kersey & Emberson, 2016, Dev Sci).

Research Methods:

Imaging Methods (Adults, Children, Infants)

fMRI & MRI: Functional Magnetic Resonance Imaging (fMRI) is a non-invase technique that measures changes in brain activity during perceptual and cognitive tasks. I employ a variety of designs including block- and event-related designs, adaptation paradigms, and naturalistic viewing paradigms. Magnetic Resonance Imaging (MRI) collects information about brain structure. We can then measure the thickness of the brain to assess how cognition and development are related to changes and individual variation in brain structure.

fNIRS: Functional near-infrared spectroscopy is a non-invase technique measures brain activity using near-infrared light sensor. Infants and young children who participate in NIRS studies wear a lightweight cap that contains the near-infred lights and sensors. This cap allows children to sit upright and move freely during the experimental task.

Behavioral Methods (Children)

Children's cognitive abilities are assessed through fun, interactive, game-like tasks. During my research studies, children may play games on a touchscreen computer to help us learn how they think about the world. Children may also play a variety of non-computer games to evaluate cognitive abilities such as working memory, counting, and numerical knowledge, or they may learn something new about math or reading in a one-on-one learning session with an experimenter. We may also collect information about math knowledge, verbal skills, and nonverbal skills using standardized assessments (e.g., TEMA and KBIT). Sometimes children wear eye trackers during the experiments so that we can see where they look when solving problems or learning something new!