Date of Degree
Access restricted until 07/13/2019
PhD (Doctor of Philosophy)
First Committee Member
Second Committee Member
Gaeth, Gary J.
Third Committee Member
Levin, Irwin P.
Fourth Committee Member
Cole, Catherine A.
Fifth Committee Member
Windschitl, Paul D.
Anchoring and Adjustment is a ubiquitous heuristic process in judgment and decision making. Although there is clear evidence that the anchor biases final estimates, there is disagreement about the process individuals use to arrive at the final estimate. The competing works observe the final estimates of the individuals under different conditions to find support for one or the other theory. I posit that the best way to study the mechanism in which the response is influenced is to observe the process by which participants come to the final response. In this vein, my work provides methodologies to surreptitiously observe individuals selecting the final response. My observations step towards providing a more nuanced process underlying the anchoring phenomenon. I posit that process of selecting a response by the individuals after getting influenced by the anchor is like searching for a response in the number space.
I further propose that this search will be biased in systematic ways. First bias is due to the individuals’ tendency to search for a response more intensively in ‘the adjacent possible’ or the areas of search nearby the current area they are searching. I show that the search for the response is thus, dominated by adjustments to adjacent possible responses indicating a search process constrained by selective accessibility. This search will require adjustment but will be impacted by selective accessibility of the information rendered accessible by the initial anchor.
Second bias is due the characteristics of the numerical search space itself. I suggest that the mental representation of numbers, just like mental representation of physical space, will have landmarks. I call them numerical landmarks. I propose that the presence of these numerical landmarks influences the individuals’ search of a response after they are influenced by an anchor. Essentially, I want to show that numerical anchors will share the characteristics of the mental representation of physical landmarks and will bias the search of an answer in the numerical space. With the help of five studies I propose to show the impact of numerical anchors on anchoring and adjustment bias and show that 1) Numerical landmarks, when presented on a scale, will grab more attention, 2) numerical landmarks are perceived to be bigger and more distinct than they actually are, and, 3) numerical landmarks act as decision nodes.
Additionally, the use of relatively low-order-cognition anchoring contexts (e.g., perceptual anchoring) adds to the literature by demonstrating anchoring and adjustment bias in non-numeric domains.
Individuals need to make a number judgments in their daily lives. A lot of these judgments are quantitative estimates of entities, for instance ‘how much money to save for the post-graduation road trip’. Often, when individuals make these estimates, they are biased towards the first piece of information that comes to their mind. For instance, if I ask individuals to think of the last two digits of their phone number, and, then ask them to estimate the number of pages in a book, their responses will be heavily biased to the last two digits of their phone number. This first piece of information is known as the ‘anchor’. Although, the robust influence of anchor on judgments is well established across various fields, the actual process behind how anchor leads to biased judgments is not clear.
I shed light on the underlying processes behind the anchoring phenomenon. Because I use novel methodologies, my work extends anchoring to non-numeric domains (such as domains of haptics and sounds) and shows that anchoring can take place in perceptual domains as well. I show that the underlying mechanism resembles a physical search. While establishing the link between numbers and physical space, I show that numerical cognition (i.e., the way we represent and process numbers in our minds) shares an important feature with physical cognition (i.e., the way we represent and process physical space in our minds) – landmarks. Specifically, I introduce the concept of numerical landmarks, establish their properties, and, demonstrate how they influence the anchoring.
Adjustment, Anchoring, Judgments, Numerical Cognition
xiii, 79 pages
Includes bibliographical references (pages 59-69).
Copyright © 2017 Gaurav Jain
Jain, Gaurav. "The hitchhiker's guide to numerical space: of anchors, landmarks and adjustment." PhD (Doctor of Philosophy) thesis, University of Iowa, 2017.