Kendal Foster
Research Interests
I am generally interested in using mathematical models to better understand human behaviour, in particular decision making and information uptake. My current projects involve:
- various applications of Ratcliff's diffusion decision model, such as the optimality of a choice given that future options have uncertainty
- using response time data to reveal evidence of information processing, such as simple pattern recognition
I also have some experience with modelling the spread of infectious diseases and maintain an interest in epidemiology as well.
Publications
- Foster, K. & Singmann, H. (under review). Another Approximation of the First-Passage Time Densities for the Ratcliff Diffusion Decision Model
Software Development
I have published the fddm package for the R language for statistical computing that provides the probability density function and cumulative distribution function of the diffusion decision model (e.g., Ratcliff & McKoon, 2008) with across-trial variability in the drift rate.
The package is available on CRAN and can be installed in R with the command install.packages("fddm"). Furthermore, the source code is available on the rtdists GitHub.
The code in the R package is written in C++, and I have ported the density function to work as a custom probability distribution in the Stan modeling language. Formal integration into the Stan modeling language is ongoing, but there is a workaround version available here.
Conference Attendance
Previous Conferences
- Implementation of the Diffusion Decision Model with Across-Trial Variability in the Drift Rate. Prepared a notebook for StanConnect 2021, Session on Cognitive Science and Neuroscience. (November 2021).
- Another approximation of the first-passage time densities for the Ratcliff diffusion decision model. Presented as a Virtual MathPsych Talk at the 54th Annual Meeting of the Society for Mathematical Psychology. (July 2021).
- Evaluating the speed of different approximations to the density function of the diffusion decision model. Presented as a Virtual MathPsych Poster at the 53rd Annual Meeting of the Society for Mathematical Psychology. (July 2020).
- The Spread of Cholera Through Water Networks. Presented at the Mathematical Association of America Undergraduate Student Poster Session, Joint Mathematics Meetings. (January 2018).
Education
- 2019-current: PhD in Mathematics for Real-World Systems. University of Warwick.
Supervisors:
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- Dr Henrik Singmann (Department of Experimental Psychology, University College London)
- Dr Joshua de Leeuw (Department of Cognitive Science, Vassar College)
- Dr Emmanouil Konstantinidis (Department of Psychology, University of Warwick)
- Professor Colm Connaughton (Mathematics Institute, University of Warwick)
- 2018-2019: MSc in Mathematics for Real-World Systems. University of Warwick. Distinction.
MSc Projects:
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- Fast approximations to the first-passage time densities for the Ratcliff diffusion decision model with variable drift rate. Supervisor: Dr Henrik Singmann (Department of Psychology, University of Warwick)
- Using response time data to categorize statistical learning behavior. Supervisor: Dr Joshua de Leeuw (Department of Cognitive Science, Vassar College)
Research Study Group: Data analytics approach to extreme events in space weather. Supervisors: Dr Sandra Chapman (University of Warwick) and Malcolm Dunlop (Rutherford Appleton Lab)
- 2014-2018: BA in Mathematics. Vassar College.
- Mathematics Research Fellow at the Undergraduate Research Summer Institute at Vassar College (Summer 2017)
- Attended Thayer School of Engineering at Dartmouth College (Summer 2016)
Contact
B1.29, Complexity Science, Zeeman Building