Category Size Bias in Probability Judgments (#256)

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How to Cite this Report

APA Style

Hannah Perfecto, Leif D. Nelson Don A. Moore. Category Size Bias in Probability Judgments. (2016, September 03). Retrieved 15:40, September 25, 2017 from http://www.PsychFileDrawer.org/replication.php?attempt=MjU2

MLA Style

"Category Size Bias in Probability Judgments" Hannah Perfecto, Leif D. Nelson Don A. Moore. 03 Sep 2016 17:31 25 Sep 2017, 15:40 <http://www.PsychFileDrawer.org/replication.php?attempt=MjU2>

MHRA Style

'Category Size Bias in Probability Judgments', Hannah Perfecto, Leif D. Nelson Don A. Moore, , 03 September 2016 17:31 <http://www.PsychFileDrawer.org/replication.php?attempt=MjU2> [accessed 25 September 2017]

Chicago Style

"Category Size Bias in Probability Judgments", Hannah Perfecto, Leif D. Nelson Don A. Moore, , http://www.PsychFileDrawer.org/replication.php?attempt=MjU2 (accessed September 25, 2017)

CBE/CSE Style

Category Size Bias in Probability Judgments [Internet]. Hannah Perfecto, Leif D. Nelson Don A. Moore; 2016 Sep 03, 17:31 [cited 2017 Sep 25]. Available from: http://www.PsychFileDrawer.org/replication.php?attempt=MjU2

Reference to Original Report of Finding Isaac, M. S., & Brough, A. R. (2014). Judging a part by the size of its whole: The category size bias in probability judgments. Journal of Consumer Research, 41(2), 310-325.
Title Category Size Bias in Probability Judgments
If the original article contained multiple experiments, which one did you attempt to replicate? e.g., you might respond 'Study 1' or 'Experiment 4'. Study 1
Link to PDF of Original ReportView Article
Brief Statement of Original Result Participants were shown a row of balls numbered 1-15 that varied in color. When most balls were gray, participants gave higher odds of drawing a specific gray ball (#8); when gray balls were the minority, participants reported lower odds.
Type of Replication Attempted Highly Direct Replication
Result Type Successful Replication
Difference? Same Direction, .001
Number of Subjects 1146
Number of Subjects in Original Study 211
Year in which Replication Attempt was Made 2015
Name of Investigators (Real Names Required) Hannah Perfecto, Leif D. Nelson Don A. Moore
Detailed Description of Method/Results Participants were shown a row of balls numbered 1-15 and were asked to report the likelihood of drawing ball #8, which was gray. Half of participants saw balls 1-5 black, 6-10 gray, 11-15 white(small category condition); half saw balls 1-2 black, 3-13 gray, 14-15 white (large category condition).

Participants were first asked the likelihood of drawing ball #8, then asked the likelihood of drawing a gray ball.

Replicating the original results, we found that participants in the large category condition reported a higher likelihood of drawing ball #8 (24.39%) than did participants in the small category condition (17.34%), t(1144)=5.44, p < .001.
Any Known Methodological Differences
(between original and present study)?
No. Although we did add an additional question to the survey, to test an additional hypothesis (asking the likelihood of drawing a gray ball), this was on a separate page and should not have affected responses to the original question.
Email of Investigator
Name of individuals who
actually carried out the project
H.P. posted the study on MTurk and analyzed the data.
Location of ProjectUniversity of California, Berkeley (online)
Characteristics of Subjects
(subject pool, paid, etc.)
Adults tested through internet
Amazon Mechanical Turk
Where did these subjects reside?United States
Was this a Class Project?No
Further Details of Results as pdf
Additional Comments
Email of Original Investigator
Quantitive Information
I have complied with ethical standards for experimentation on human beings and, if necessary, have obtained appropriate permission from an Institutional Review Board or other oversight group.
TAG: Attention TAG: JDM TAG: Language TAG: Learning TAG: Memory TAG: Perception TAG: Performance TAG: Problem Solving TAG: Social Cognition TAG: Social Psychology TAG: Thinking

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