Master of Arts, The Ohio State University, 2017, Psychology

Conflict in the Stroop task is measured by both response time and accuracy. The amount of conflict differs depending on the response modality, verbal vs. manual. We applied a model for multichoice decision making (and confidence), the RTCON2 model (Ratcliff & Starns, 2013) to the data from four experiments, 2 variants with 2-choice manual responses, one with 4-choice manual response and vocal response, and a 4-choice touch screen experiment. Changes in the rate of information accumulation captured conflict effects for the manual response and touch screen versions, but not for the vocal response version. Adding an extra non-decision time parameter allowed RTCON2 to accurately capture the data patterns in the vocal response version. However in order to fully understand conflict in the vocal response Stroop, a model of conflict processing in the vocal system must be developed.

Committee: Roger Ratcliff (Advisor); Gail McKoon (Committee Member); Jay Myung (Committee Member) Subjects: Psychology

Master of Science, The Ohio State University, 2015, Psychology

Presentation of stimuli has been shown not to facilitate later forced-choice perceptual identification, in which two response alternatives were presented on the screen at test. Several models were developed to explain performance in these paradigms, but none addressed the time course of processing. In this study, we examined the effect of prior study on performance by modeling accuracy and response times as well as eye fixation data. The model assumes two racing diffusing processes in which evidence accumulation rate (drift rate) differs as a function of the response alternative being currently viewed. Change in performance between the different study conditions (studied target, studied foil, or studied neither) was accounted for by a change in drift rate. Even without the eye tracking data, the model successfully fit choice behavior, response time distributions, and many of the eye fixation results.

Committee: Roger Ratcliff (Advisor); Ian Krajbich (Committee Member); Alex Petrov (Committee Member) Subjects: Cognitive Psychology; Psychology

Master of Arts, The Ohio State University, 2012, Psychology

A new version of a diffusion model for confidence judgments is presented. The original version of the model, RTCON, has previously been fit to quantile reaction times and confidence judgments from item recognition memory experiments. Here, we explore recent applications of a new version of the model to an associative recognition paradigm. Much of the research examining various models of memory has focused on differences in the shapes of z-ROC curves across tasks and has used these differences to argue for the existence of multiple memory processes. In an associative recognition task, our single-process model is able to fit and explain a variety of z-ROC shapes as well as individual differences in these shapes while simultaneously fitting quantile reaction times. The model and data show that the standard signal detection and dual-process interpretations of z-transformed receiver operating characteristic (z-ROC) functions are wrong. These results undermine some of the primary support for the existence of multiple memory processes.

Committee: Roger Ratcliff PhD (Advisor); Gail McKoon PhD (Committee Member); Per Sederberg PhD (Committee Member) Subjects: Cognitive Psychology