Abstract
Subjects were given an experimental task in which they had to play the role of a quality-control researcher for a company. They had to consider a hypothetical experiment that involves testing a sample of batteries from a truck load, which may or may not be substandard. In the main experiment, subjects were given information about the prior probability of substandard truck loads (base rate), the degree of variability of battery life, and the mean difference between standard and substandard batteries, all of which are formally relevant to the decision, and they were also told the number of batteries in the truck (population size) that is formally irrelevant. The task was to decide (intuitively) how many batteries to test to achieve a specified error rate using a specified decision rule. In a second study, subjects were given a similar scenario, but asked to rate which pieces of information would be relevant to the decision. Subjects showed themselves to be sensitive to the effects of sample variability and base rate when making intuitive design decisions, though an odd effect of the mean difference factor was observed. There is also clear confirmation of a bias-to-weight sample size by population size as reported in earlier research using different kinds of judgmental tasks.
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References
Ajzen, I. (1977). Intuitive theories of events and the effects of base rate information on prediction.Journal of Personality and Social Psychology, 35, 303–314.
Bar-Hillel, M. (1979). The role of sample size in sample evaluation.Organisational Behavior and Human Performance, 24, 245–257.
Bar-Hillel, M., & Fischhoff, B. (1981) When do base rates affect predictions?Journal of Personality and Social Psychology, 41, 671–680.
Berkeley, D., & Humphreys, P. (1982) Structuring decision problems and the “bias” heuristic.Acta Psychologica, 50, 201–252.
Beyth-Marom, R., & Arkes, H. R. (1983) Being accurate is not necessarily Bayesian—Comments on Christensen-Szalanski and Beach.Organisational Behavior and Human Performance, 31, 255–257.
Beyth-Marom, R., & Fischhoff, B. (1983) Diagnosticity and pseudodiagnosticity.Journal of Personality and Social Psychology, 45, 1185–1197.
Christensen-Szalanski, J. J. J., & Beach, L. R. (1982) Experience and the base rate fallacy.Organisational Behavior and Human Performance, 29, 270–278.
Christensen-Szalanski, J. J. J., & Beach, L. R. (1983) Believing is not the same as testing— A reply.Organisational Behavior and Human Performance, 31, 258–261.
Cohen, L. J. (1981). Can human irrationality be experimentally demonstrated?Behavior and Brain Sciences, 4, 317–370.
Cohen, L. J. (1982) Are people programmed to commit fallacies? Further thought about the interpretation of data on judgment.Journal for the Theory of Social Behavior, 12, 251–247.
Evans, J. St. B. T., Barston, J. L., & Pollard, P. (1983). On the conflict between logic and belief in syllogistic reasoning.Memory and Cognition, 11, 295–306.
Evans, J. St. B. T., & Dusoir, A. E. (1977). Proportionality and sample size as factors in intuitive statistical judgment.Acta Psychologica, 41, 129–137.
Evans, J. St. B. T., & Pollard, P. (1985). Intuitive statistical inferences about the normally distributed data.Acta Psychologica, 60, 57–71.
Fischhoff, B., & Beyth-Marom, R. (1983). Hypothesis evaluation from a Bayesian perspective.Psychological Review, 90, 239–260.
Kahenman, D., & Tversky, A. (1972). Subjective probability: A judgment of representativeness.Cognitive Psychology, 3, 430–454.
Kahneman, D., & Tversky, A. (1973). On the psychology of prediction.Psychological Review, 80, 237–251.
Kahneman, D., & Tversky, A. (1982). On the study of statistical intuition.Cognition, 12, 325–326.
Kahneman, D., Slovic, P., & Tversky, A. (1982).Judgment under uncertainty: Heuristics and biasis Cambridge: Cambridge University Press.
Manis, M., Avis, N. E., & Cardoze, S. (1981). A reply to Bar-Hillel and Fischhoff.Journal of Personality and Social Psychology, 41, 681–683.
Manis, M., Dovalina, I., Avis, N. E., & Cardoze, S. (1980). Base rates can affect individual predictions.Journal of Personality and Social Psychology, 38, 287–298.
Nisbett, R. E., & Ross, L. (1980).Human inference: Strategies and shortcomings of social judgment Englewood-Cliffs, N.J., Prentice-Hall.
Peterson, C.R., & Beach, L.R. (1967). Man as an intuitive statistician.Psychological Bulletin, 1, 29–46.
Pollard, P., & Evans, J. St. B. T. (1983). The role of representativeness in statistical inference: A critical appraisal. In J. St. B.T. Evans (Ed.),Thinking and reasoning: Psychological approaches London: Routledge and Kegan Paul.
Slovic, P., Fischhoff, B., & Lichtenstein, S. (1977). Behavioral decision theory.Annual Review of Psychology, 228, 1–39.
Tversky, A., & Kahneman, D. (1971). The belief in the “law of small numbers.”Psychological Bulletin, 76, 105–110.
Tversky, A., & Kahneman, D. (1980). Causal schemata in judgments under uncertainty. In M. Fishbein (Ed.),Progress in social psychology Hillsdale, NJ: Erlbaum.
Tversky, A., & Kahneman, D. (1983). Extensional vs intuitive reasoning: The conjunction fallacy in probability judgment.Psychological Review, 90, 293–315.
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Evans, J.S.B.T., Bradshaw, H. Estimating sample-size requirements in research design: A study of intuitive statistical judgment. Current Psychology 5, 10–19 (1986). https://doi.org/10.1007/BF02686592
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DOI: https://doi.org/10.1007/BF02686592