Sample Size Bias in Judgments of Perceptual Averages

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Andrew Smith Ph.D, Associate Professor (Creator)
Appalachian State University (ASU )
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Abstract: Previous research has shown that people exhibit a sample size bias when judging the average of a set of stimuli on a single dimension. The more stimuli there are in the set, the greater people judge the average to be. This effect has been demonstrated reliably for judgments of the average likelihood that groups of people will experience negative, positive, and neutral events (Price, 2001; Price, Smith, & Lench, 2006)and also for estimates of the mean of sets of numbers (Smith & Price, 2010). The present research focuses on whether this effect is observed for judgments of average on a perceptual dimension. In 5 experiments we show that people’s judgments of the average size of the squares in a set increase as the number of squares in the set increases. This effect occurs regardless of whether the squares in each set are presentedsimultaneously or sequentially; whether the squares in each set are different sizes or all the same size; and whether the response is a rating of size, an estimate of area, or a comparative judgment. These results are consistent with a priming account of the sample size bias, in which the sample size activates arepresentation of magnitude that directly biases the judgment of average.

Additional Information

Paul C. Price and Nicole M. Kimura, Andrew R. Smith and Lindsay D. Marshall (2014) "Sample Size Bias in Judgments of Perceptual Averages" Journal of Experimental Psychology: Learning, Memory, and Cognition Vol. 40, No. 5, 1321–1331. Version of record available @ DOI: (10.1037/a0036576)
Language: English
Date: 2014
judgements-of-average, perceptual-judgement, size-judgement, numerosity-perception

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