Date of Award

Summer 7-16-2021

Degree Type


Degree Name

Doctor of Philosophy (PhD)




Criss, Amy H.


Delta Plots, Diffusion Model, Recognition Memory, Response Bias, Stimulus Bias

Subject Categories

Cognitive Psychology | Psychology | Social and Behavioral Sciences



Decisions that are generally considered to be determined by memory (memorial decisions) are influenced by factors beyond just our memory. Our perceptions, desires, preconceived notions and our actual memory all influence how we utilize our memories in order make decisions and our general ability to navigate our world. For example, consider trying to identify former high school classmates at your high school reunion vs. at a random location outside your hometown. Your memory for the former high school classmates is the same between these two scenarios, but your expectations are not. Thus, it is intuitive to assume that your expectations may provide a differential influence on your behavior between these two scenarios. This can be thought of as a difference in biases in the sense that you are biased to assume attendees at your high school reunion are former high school classmates irrespective of encountering any specific attendee. Now imagine another scenario wherein your former classmates always wear your high school colors. If you encounter a person wearing these colors, you may use that as strong evidence that they are former classmates. These scenarios are meant to represent two different types of biases that influence memorial decisions, herein referred to as response and stimulus bias, respectively. Response bias refers to a bias in favor of one response option over the other regardless of the evidence and stimulus bias refers to overweighting certain evidence as being in favor of one response options over the other. The reunion scenario depicts response bias because the bias is present regardless of the information provided by your experience at the reunion. The high school colors scenario depicts stimulus bias because the perception of the school colors is necessary to bias your judgement toward assuming the wearer is a high school classmate. Much research has focused on understanding the variety of factors that contribute to memorial decisions. The current project is designed to scrutinize and expand upon the current understanding of the influence of bias in simple memorial decisions. To that end, I first provide an overview of bias in simple memorial decisions in the context of traditional metrics including Signal Detection Theory (SDT) and The Diffusion Model (DM). I propose an alternate analysis framework utilizing the response time predictions made by the DM and provide converging evidence from an underutilized metric, delta plots, which provide more information about the dynamics of the decision than do traditional metrics. Finally, I end with a discussion and summary of findings with proposals for the field regarding how to conceptualize bias in simple memorial decisions.


Open Access