McKenzie, Cameron

Office Location: 
Primary Area of Focus: 
Faculty Advisor: 
McClelland, James
Research Summary: 

I am a PhD student with Jay McClelland. The primary focus of my research is numerical cognition. At the moment I am working on modeling responses and response latencies in fraction comparison. This is important for two primary reasons. First, fractions play a critical role in understanding later mathematics such as algebra and calculus. We hope that studying the processes involved will lead to insights that are applicable in the classroom. Second, understanding the processes that underlie facility with mathematics is likely to yield basic scientific insights into the structure of cognition and the nature of learning. The behavioral and modeling results from this work are currently in preparation. A second focus is modeling responses and response times in line marking - a classic task used to index numerical representation in children and adults. The theme of this work is that, rather than indexing numerical representation, much of what we observe in the task comes out of the task constraints and the basic sensori-motor processes required to complete the task. I am also working in collaboration with Jay and Steve Hansen to understand the computational processes by which children come to understand basic mathematical procedures (addition and subtraction) through actions on their fingers. This builds off seminal work by Robert Siegler and Eric Jenkins.

In addition to my work on higher level cognition, I have a number of projects in development on somatic (bodily) sensory processing, especially in the domain of pain and touch, and visual/tactile/motor coordination. My interests here are both basic and practical. The deleterious changes in tactile acuity and movement seen in chronic pain seem to involve (maladaptive) learning via both central and peripheral mechanisms. Insights from psychology and neuroscience may provide pathways to treatment. When patients are immobilized to treat injury, the affected body part undergoes a period of sensori-motor deprivation. Even in the absence of injury, such deprivation leads to problematic changes in how the brain treats the body part. In collaboration with Nick Karyannis, I am developing a behavioral "prehabilitation" protocol that addresses this problem by providing sensory and motor stimulation to immobilized patients. Also in the domain of the somatic senses, I am also looking at both behavioral and neural aspects of tactile attention, in collaboration with Justin Gardner.

Although I am not actively pursuing this work at the moment, I have an historical and ongoing interest in decision making, especially perceptual decision making and economic decision making. My interests here cover both modeling of human behavior and understanding the neurobiological circuits that underlie simple decisions. In previous work with Phillip Smith, we demonstrated that when a pair of neurons with biologically plausible firing statistics are integrated in a recurrent loop, the resultant firing rates have similar statistical properties to human response latencies in perceptual decision making tasks. This suggests that recurrence may provide a general mechanism for decision making.