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When participants view and then reproduce simple objects thatvary along a continuous dimension such as length or shade, orwhen they view images of faces that vary in emotional expression,their estimates tend to be biased toward the average value of thepresented objects, a phenomenon that has been modeled as theresult of a Bayesian combination of prior category knowledge withan imprecise memory trace (Corbin, Crawford & Vavra, 2017;Huttenlocher, Hedges & Vevea, 2000). Whereas previous workdescribed a general cognitive strategy based on data aggregatedacross participants, here we examined individual differences instrategy. Thirty-six participants viewed and reproduced 496morphed face stimuli that ranged from angry to happy. We foundsubstantial variation in the bias patterns participants produced.Individuals’ estimates were well fit by a model that positedattraction toward three categories, one at the happy end of therange, one at the angry end, and one that captured the entire rangeof presented stimuli, and by allowing the weight given to eachcategory to vary by participant.

We report the results of an experiment probing the relative influence of centering and anchoring biases in recon-structive memory for line lengths. On each of 90 trials participants (N=120) viewed a target line, which they reproduced aftera delay by adjusting a response line. We manipulated the starting size of this response line in three conditions: one providedan anchoring bias opposite the centering bias (expand condition), one in the same direction (contract condition) and one thatprovided no anchoring bias (control). We eliminated the centering bias in the expand condition, increased it in the contract con-dition, and showed an attenuated centering bias in the control condition. We discuss the implications for these results in relationto cognitive models of stimulus reproduction that employ the method of serial reproduction. We suggest that experiments ofthis type should carefully control for the possible influence of anchoring biases in reconstructive memory.

Spatial memory research has attributed systematic bias in location estimates to a combination of a noisy memory trace with a prior structure that people impose on the space. Little is known about intraindividual stability and interindividual variation in these patterns of bias. In the current work, we align recent empirical and theoretical work on working memory capacity limits and spatial memory bias to generate the prediction that those with lower working memory capacity will show greater bias in memory of the location of a single item. Reanalyzing data from a large study of cognitive aging, we find support for this prediction. Fitting separate models to individuals' data revealed a surprising variety of strategies. Some were consistent with Bayesian models of spatial category use, however roughly half of participants biased estimates outward in a way not predicted by current models and others seemed to combine these strategies. These analyses highlight the importance of studying individuals when developing general models of cognition.