The Central Tendency Bias Influences Orientation Estimation

Our estimate of the magnitude of a stimulus is influenced by the context in which thatstimulus appears. The central tendency bias, which refers to a bias towards the central tendency ofthe stimulus distribution used in an experiment, is one example of how the context i.e., the stimulusdistribution over time, affects our estimates of the stimulus magnitude. Although the centraltendency bias has been shown to affect the estimation of most feature dimensions—visual andnon-visual—no such bias has been reported in the estimation of the orientation feature dimension.In this study, we ask whether orientation estimation is affected by the central tendency bias.Stimulus orientations were sampled from a constrained range in Experiment 1 to demonstrate forthe first time that the central tendency bias influences orientation estimates. This effect wasreplicated in Experiments 2a and 2b, in which skewed stimulus distributions revealed that the biaswas not towards the mode of the stimulus distribution. These results highlight that the centraltendency bias is a regularity that affects the estimation of the magnitude of every feature dimension,including orientation. Identifying additional regularities that persist across feature dimensions andunderstanding the mechanisms that give rise to such regularities can be a useful approach toenhance our understanding of perceptual processing.