Name: David A. Illingworth

School of Psychology – Ph.D. Dissertation Defense Presentation

Date: Tuesday, June 11, 2019

Time: 10:00am

Location: J. S. Coon building, Room 148

Advisor: Rick Thomas, Ph.D. (Georgia Tech)

Dissertation Committee Members:

Jamie Gorman, Ph.D. (Georgia Tech)

Christopher Hertzog, Ph.D. (Georgia Tech)

Dobromir Rahnev, Ph.D. (Georgia Tech)

Karen Feigh, Ph.D. (Georgia Tech)

Title: Hypothesis-Guided Testing Behavior: The Role of Generation, Metacognition, and Search

Abstract: Hypothesis testing is the act of acquiring information to challenge or promote a decision-maker’s beliefs (i.e., hypotheses) in diagnostic tasks.  To date, theorists have conceptualized this behavior as a consequence of implementing one of many possible heuristics for selecting tests, each tailored to optimize some task-relevant goal (e.g., reduce the likelihood of an erroneous diagnosis).  Heuristics can account for a number of observed testing phenomena (e.g., pseudo-diagnostic search), but have difficulty explaining more nuanced testing behavior such as decisions to terminate data acquisition.  Moreover, current theory has yet to address how updating a decision-maker’s beliefs influences test preference, as hypothesis testing is often studied independent of other events inherent to hypothesis evaluation.  The current work examined the role of belief in testing and search termination by evaluating a novel extension of the HyGene architecture (Thomas, Dougherty, Sprenger & Harbison, 2008) built as a cognitive process account for hypothesis testing.  Experiments 1 and 2 found limited support for hypothesis-driven valuation, as participants showed minimal signs of sensitivity to the diagnostic value of information depositories.  Experiment 3 revealed a relation between belief and foraging duration such that less confidence early in a trial predicted more test exploitation.  Model fitting indicated participants implemented a conservative threshold when determining the value of continued testing.  Experiment 4 revealed cost-sensitivity in testing behavior, as well as an experience-driven contrast effect.  Participants who experienced high costs early in the experiment generally engaged in less testing behavior than those who experienced low costs.  The current work provides mild support for the predictions of the HyGene architecture, but clearly demonstrate a role for metacognitive self-assessment in decisions to terminate search and highlight the interaction of access costs with experience of costs when people perceive the value of engaging in testing behavior.