ERIC Number: EJ1057443
Record Type: Journal
Publication Date: 2014-Sep
Abstractor: As Provided
Reference Count: 35
Sample Size Bias in Judgments of Perceptual Averages
Price, Paul C.; Kimura, Nicole M.; Smith, Andrew R.; Marshall, Lindsay D.
Journal of Experimental Psychology: Learning, Memory, and Cognition, v40 n5 p1321-1331 Sep 2014
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 presented simultaneously 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 a representation of magnitude that directly biases the judgment of average.
Descriptors: Sample Size, Statistical Bias, Visual Perception, Pictorial Stimuli, Experiments, Task Analysis, Cognitive Processes, Cognitive Psychology, Undergraduate Students, Computer Assisted Testing, Statistical Analysis, Robustness (Statistics)
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Publication Type: Journal Articles; Reports - Research
Education Level: Higher Education; Postsecondary Education
Authoring Institution: N/A
Identifiers - Location: California; North Carolina