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Author ORCID Identifier


Campus-Only Access for One (1) Year

Document Type


Degree Name

Doctor of Philosophy (PhD)

Degree Program


Year Degree Awarded


Month Degree Awarded


First Advisor

Kyle Cave

Subject Categories

Cognition and Perception | Cognitive Psychology | Psychology


Our estimate of the magnitude of a stimulus is influenced by the context in which that stimulus appears. The central tendency bias, which refers to a bias towards the central tendency of the stimulus distribution used in the experiment, is one example of how the context i.e., the stimulus distribution over time, affects our estimates of the stimulus magnitude. In Experiments 1, 2, and 3, we sampled stimulus orientations from a constrained range to demonstrate for the first time that orientation estimates are affected by the central tendency bias. Most studies on orientation estimation sample from the full range of possible stimulus orientations, from between –90 and 90 degrees, and observe the oblique effect. The oblique effect refers to an attractive bias towards -45 and 45 degrees and a repulsive bias away from 0 and 90 degrees. We propose that this oblique effect is not a special bias, but another instantiation of the central tendency bias. When stimulus orientations are sampled from a constrained range, the central tendency bias is observed, whereas when stimulus orientations are sampled from the full range between –90 and 90, the oblique effect is observed. We propose a mathematical model that can generate both the oblique effect and the central tendency bias using serial dependency. In Experiment 3, we show that whether there is a change or no change in the magnitude of the central tendency bias or the oblique effect is driven by whether there is a change or no change in the underlying serial dependency. Finally, in Experiment 3 and 4, a critical model assumption is validated. Through empirical and modeling approaches, we demonstrate that serial dependency can give rise to both the oblique effect and the central tendency bias.