Ordinary people do not ignore base rates

2007 ◽  
Vol 30 (3) ◽  
pp. 272-274 ◽  
Author(s):  
Donald Laming
Keyword(s):  
Mental Arithmetic ◽  
Bayes Theorem ◽  
Base Rate ◽  
Ordinary People ◽  
Base Rates ◽  
Base Rate Neglect ◽  
Target Article

AbstractHuman responses to probabilities can be studied through gambling and through experiments presenting biased sequences of stimuli. In both cases, participants are sensitive to base rates. They adjust automatically to changes in base rate; such adjustment is incompatible with conformity to Bayes' Theorem. ”Base-rate neglect” is therefore specific to the exercises in mental arithmetic reviewed in the target article.

BASE RATE NEGLECT FOR THE WEALTH OF INTERACTING PEOPLE

2010 ◽  
Vol 13 (05) ◽  
pp. 607-619 ◽  
Author(s):  
DIEMO URBIG
Keyword(s):  
Information Processing ◽  
Social Learning ◽  
Learning Process ◽  
Base Rate ◽  
Human Information Processing ◽  
Base Rates ◽  
Base Rate Neglect ◽  
Positive Externalities ◽  
Rate Information

Previous research investigating base rate neglect as a bias in human information processing has focused on isolated individuals. This study complements this research by showing that in settings of interacting individuals, especially in settings of social learning, where individuals can learn from one another, base rate neglect can increase a population's welfare. This study further supports the research arguing that a population with members biased by neglecting base rates does not need to perform worse than a population with unbiased members. Adapting the model of social learning suggested by Bikhchandani, Hirshleifer and Welch (The Journal of Political Economy100 (1992) 992–1026) and including base rates that differ from generic cases such as 50–50, conditions are identified that make underweighting base rate information increasing the population's welfare. The base rate neglect can start a social learning process that otherwise had not been started and thus base rate neglect can generate positive externalities improving a population's welfare.

scholarly journals BASE-RATE NEGLECT AS A FUNCTION OF BASE RATES IN PROBABILISTIC CONTINGENCY LEARNING

2008 ◽  
Vol 90 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Florian Kutzner ◽  
Peter Freytag ◽  
Tobias Vogel ◽  
Klaus Fiedler
Keyword(s):  
Base Rate ◽  
Contingency Learning ◽  
Base Rates ◽  
Base Rate Neglect

Probabilistic fallacies

1996 ◽  
Vol 19 (1) ◽  
pp. 31-31 ◽  
Author(s):  
Henry E. Kyburg
Keyword(s):  
Bayes Theorem ◽  
Base Rate ◽  
Reference Class ◽  
Base Rates ◽  
The Way

AbstractTwo distinct issues are sometimes confused in the base rate literature: Why do people make logical mistakes in the assessment of probabilities? and why do subjects not use base rates the way experimenters do? The latter problem may often reflect differences in an implicit reference class rather than a disinclination to update a base rate by Bayes' theorem. Also important are considerations concerning the interaction of several potentially relevant base rates.

scholarly journals Base rate of ovarian cancer on algorithms in patients with a pelvic mass

2020 ◽  
Vol 30 (11) ◽  
pp. 1775-1779
Author(s):  
Anne Lone Denny Rolfsen ◽  
Alv A Dahl ◽  
Are Hugo Pripp ◽  
Anne Dørum
Keyword(s):  
Ovarian Cancer ◽  
False Negative ◽  
Pelvic Mass ◽  
Bayes Theorem ◽  
Case Finding ◽  
Base Rate ◽  
University Hospital ◽  
Predictive Score ◽  
Base Rates ◽  
Risk Of Malignancy

ObjectiveAlgorithms have been developed to identify ovarian cancer in women with a pelvic mass. The aim of this study was to determine how the base rates of ovarian cancer influence the case finding abilities of recently developed algorithms applicable to pelvic tumors. We used three ovarian cancer algorithms and the principle of Bayes’ theorem for risk estimation.MethodsFirst, we evaluated the case finding abilities of the Risk of Malignancy Algorithm, the Rajavithi–Ovarian Predictive Score, and the Copenhagen Index in a prospectively collected sample at Oslo University Hospital of 227 postmenopausal women with a 74% base rate of ovarian cancer. Second, we examined the case finding abilities of the Risk of Malignancy Algorithm in three published studies with different base rates of ovarian cancer. We applied Bayes’ theorem in these examinations.ResultsIn the Oslo sample, all three algorithms functioned poorly as case finders for ovarian cancer. When the base rate changed from 8.2% to 43.8% in the three studies using the Risk of Malignancy Algorithm, the proportion of false negative ovarian cancer diagnoses increased from 1.2% to 3.4%, and the number of false positive diagnosis increased from 4.6% to 14.2%.ConclusionThis study demonstrated that the base rate of ovarian cancer in the samples tested was important for the case finding abilities of algorithms.

Enhancing sensitivity to base-rates: Natural frequencies are not enough

2007 ◽  
Vol 30 (3) ◽  
pp. 262-263
Author(s):  
Edmund Fantino ◽  
Stephanie Stolarz-Fantino
Keyword(s):  
Natural Frequency ◽  
Natural Frequencies ◽  
Base Rate ◽  
Present Evidence ◽  
Base Rates ◽  
Base Rate Neglect ◽  
Rate Information ◽  
Trial Setting

AbstractWe present evidence supporting the target article's assertion that while the presentation of base-rate information in a natural frequency format can be helpful in enhancing sensitivity to base rates, method of presentation is not a panacea. Indeed, we review studies demonstrating that when subjects directly experience base rates as natural frequencies in a trial-by-trial setting, they evince large base-rate neglect.

scholarly journals Experts use base rates in real-world sequential decisions

2021 ◽  
Author(s):  
Daniel Link ◽  
Markus Raab
Keyword(s):  
Real World ◽  
Cognitive Biases ◽  
Real Life ◽  
Base Rate ◽  
Decision Makers ◽  
Decision Strategies ◽  
The Real ◽  
Base Rates ◽  
Base Rate Neglect ◽  
Specific Category

AbstractHuman behavior is often assumed to be irrational, full of errors, and affected by cognitive biases. One of these biases is base-rate neglect, which happens when the base rates of a specific category are not considered when making decisions. We argue here that while naïve subjects demonstrate base-rate neglect in laboratory conditions, experts tested in the real world do use base rates. Our explanation is that lab studies use single questions, whereas, in the real world, most decisions are sequential in nature, leading to a more realistic test of base-rate use. One decision that lends itself to testing base-rate use in real life occurs in beach volleyball—specifically, deciding to whom to serve to win the game. Analyzing the sequential choices in expert athletes in more than 1,300 games revealed that they were sensitive to base rates and adapted their decision strategies to the performance of the opponent. Our data describes a threshold at which players change their strategy and use base rates. We conclude that the debate over whether decision makers use base rates should be shifted to real-world tests, and the focus should be on when and how base rates are used.

scholarly journals On the generality and cognitive basis of base-rate neglect

2021 ◽  
Author(s):  
Elina Stengård ◽  
Peter Juslin ◽  
Ulrike Hahn ◽  
Ronald van den Berg
Keyword(s):  
Cognitive Modeling ◽  
Probabilistic Reasoning ◽  
Base Rate ◽  
Small Subset ◽  
Large Set ◽  
Problem Space ◽  
Integration Model ◽  
Large Variability ◽  
Base Rates ◽  
Base Rate Neglect

ABSTRACTBase rate neglect refers to people’s apparent tendency to underweight or even ignore base rate information when estimating posterior probabilities for events, such as the probability that a person with a positive cancer-test outcome actually does have cancer. While many studies have replicated the effect, there has been little variation in the structure of the reasoning problems used in those studies. In particular, most experiments have used extremely low base rates, high hit rates, and low false alarm rates. As a result, it is unclear whether the effect is a general phenomenon in human probabilistic reasoning or an anomaly that applies only to a small subset of reasoning problems. Moreover, previous studies have focused on describing empirical patterns of the effect and not so much on the underlying strategies. Here, we address these limitations by testing participants on a broader problem space and modelling their response at a single-participant level. We find that the empirical patterns that have served as evidence for base-rate neglect generalize to the larger problem space. At the level of individuals, we find evidence for large variability in how sensitive participants are to base rates, but with two distinct groups: those who largely ignore base rates and those who almost perfectly account for it. This heterogeneity is reflected in the cognitive modeling results, which reveal that there is not a single strategy that best captures the data for all participants. The overall best model is a variant of the Bayesian model with too conservative priors, tightly followed by a linear-additive integration model. Surprisingly, we find very little evidence for earlier proposed heuristic models. Altogether, our results suggest that the effect known as “base-rate neglect” generalizes to a large set of reasoning problems, but may need a reinterpretation in terms of the underlying cognitive mechanisms.

Base-rate respect meets affect neglect

2007 ◽  
Vol 30 (3) ◽  
pp. 285-286
Author(s):  
Paul Whitney ◽  
John M. Hinson ◽  
Allison L. Matthews
Keyword(s):  
Decision Making ◽  
Real World ◽  
Process Model ◽  
Base Rate ◽  
Dual Process ◽  
Emotional Processes ◽  
Base Rate Neglect ◽  
Target Article ◽  
Affective Influences

AbstractWhile improving the theoretical account of base-rate neglect, Barbey & Sloman's (B&S's) target article suffers from affect neglect by failing to consider the fundamental role of emotional processes in “real world” decisions. We illustrate how affective influences are fundamental to decision making, and discuss how the dual process model can be a useful framework for understanding hot and cold cognition in reasoning.

Direct experience is ecologically valid

1997 ◽  
Vol 20 (4) ◽  
pp. 777-778 ◽  
Author(s):  
Adam S. Goodie
Keyword(s):  
Methodological Issue ◽  
Base Rate ◽  
The State ◽  
Direct Experience ◽  
Base Rates ◽  
Target Article

Koehler's (1996t) target article raised, and various commentators discussed, two issues that seem far separated but actually have a great deal in common. These are the value of “ecologically valid” research and the effect of direct experience on base-rate usage. Koehler discussed the former as a methodological issue and the latter as a normative one, and no commentator chose to incorporate them, but directly experienced base rates are a good example of ecologically valid research. The state of the literature with regard to directly experienced base rates is reviewed, and the emerging perception, that direct experience has a profound Bayesian effect on base-rate usage, is rejected.

Implications of natural sampling in base-rate tasks

2007 ◽  
Vol 30 (3) ◽  
pp. 270-271 ◽  
Author(s):  
Gernot D. Kleiter
Keyword(s):  
Structural Properties ◽  
Rate Sensitivity ◽  
Bayes Theorem ◽  
Base Rate ◽  
Conditional Probabilities ◽  
Base Rates ◽  
Essential Properties ◽  
Human Understanding ◽  
Natural Sampling ◽  
Per Se

AbstractThe hypothesis that structural properties and not frequencies per se improve base-rate sensitivity is supported from the perspective of natural sampling. Natural sampling uses a special frequency format that makes base-rates redundant. Unfortunately, however, it does not allow us to empirically investigate human understanding of essential properties of uncertainty – most importantly, the understanding of conditional probabilities in Bayes' Theorem.

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