Base-rate expectations modulate the causal illusion

Blanco, Fernando; Matute, Helena

doi:10.1371/journal.pone.0212615

Cited by 11 publications

(9 citation statements)

References 61 publications

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“…In most similar studies with the traditional task (with the trials arranged in random order), a common finding is that null contingencies are overestimated when the probability of the outcome is high (see reviews in Matute et al, 2015Matute et al, , 2019. Here, Experiment 2 presented a null contingency condition with high chances of remission: in fact, the training in the Infrequent-Control group in which the symptoms were absent in 90% of the trials is almost identical to previous studies that showed strong overestimations of effectiveness, or causal illusions (Blanco et al, 2014;Blanco and Matute, 2019), except for the fact that the trials were separated into two phases, one for P(O| C), and one for P(O| ∼C). This difference seems to have abolished the causal illusion, as Experiment 2 shows clearly that most participants correctly identified the null contingency.…”

Section: Methodological Aspectssupporting

confidence: 60%

When Success Is Not Enough: The Symptom Base-Rate Can Influence Judgments of Effectiveness of a Successful Treatment

2020

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Patients' beliefs about the effectiveness of their treatments are key to the success of any intervention. However, since these beliefs are usually formed by sequentially accumulating evidence in the form of the covariation between the treatment use and the symptoms, it is not always easy to detect when a treatment is actually working. In Experiments 1 and 2, we presented participants with a contingency learning task in which a fictitious treatment was actually effective to reduce the symptoms of fictitious patients. However, the base-rate of the symptoms was manipulated so that, for half of participants, the symptoms were very frequent before the treatment, whereas for the rest of participants, the symptoms were less frequently observed. Although the treatment was equally effective in all cases according to the objective contingency between the treatment and healings, the participants' beliefs on the effectiveness of the treatment were influenced by the base-rate of the symptoms, so that those who observed frequent symptoms before the treatment tended to produce lower judgments of effectiveness. Experiment 3 showed that participants were probably basing their judgments on an estimate of effectiveness relative to the symptom base-rate, rather than on contingency in absolute terms. Data, materials, and R scripts to reproduce the figures are publicly available at the Open Science Framework: https://osf.io/emzbj/.

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Section: Methodological Aspectssupporting

confidence: 60%

When Success Is Not Enough: The Symptom Base-Rate Can Influence Judgments of Effectiveness of a Successful Treatment

2020

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“…In a study by Blanco and Matute ( 2019 , Experiment 1), participants were either pre-trained to expect a high outcome base rate or not pre-trained in a zero-contingency learning task; they found that participants who were exposed to a high base rate in pre-training showed reduced illusory causation in causal judgements compared to control participants, despite witnessing an identical high base rate zero-contingency cue-outcome relationship. In a subsequent study, they showed the reverse effect, where participants who were pre-trained on a low outcome base rate showed an inflated illusory causation effect relative to control participants (Blanco & Matute, 2019 , Experiment 2). These findings suggest that causal illusions can be influenced by prior expectancies about the base rate of outcome occurrence.…”

Section: Discussionmentioning

confidence: 99%

Causal illusions in the classroom: how the distribution of student outcomes can promote false instructional beliefs

et al. 2020

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Teachers sometimes believe in the efficacy of instructional practices that have little empirical support. These beliefs have proven difficult to efface despite strong challenges to their evidentiary basis. Teachers typically develop causal beliefs about the efficacy of instructional practices by inferring their effect on students' academic performance. Here, we evaluate whether causal inferences about instructional practices are susceptible to an outcome density effect using a contingency learning task. In a series of six experiments, participants were ostensibly presented with students' assessment outcomes, some of whom had supposedly received teaching via a novel technique and some of whom supposedly received ordinary instruction. The distributions of the assessment outcomes was manipulated to either have frequent positive outcomes (high outcome density condition) or infrequent positive outcomes (low outcome density condition). For both continuous and categorical assessment outcomes, participants in the high outcome density condition rated the novel instructional technique as effective, despite the fact that it either had no effect or had a negative effect on outcomes, while the participants in the low outcome density condition did not. These results suggest that when base rates of performance are high, participants may be particularly susceptible to drawing inaccurate inferences about the efficacy of instructional practices.

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“…The illusion of causality and OD effects have been observed with outcomes presented as discrete events (i.e., "patient recovers" versus "patient does not recover") and with different distributions of continuous outcomes (Chow et al, 2019;Double et al, 2020). The influence of a high outcome probability can also be found in real-world health beliefs, where treatments that are not scientifically validated to be efficacious are commonly used for the treatment of illnesses that have a high rate of spontaneous remission akin to a high base-rate of recovery (e.g., Echinacea use and the common cold, Barrett et al, 2010;Karsch-Völk et al, 2014; see also Blanco & Matute 2019).…”

Section: Outcome Presentmentioning

confidence: 99%

Instruction on the Scientific Method Provides (Some) Protection Against Illusions of Causality

Chow,

Goldwater,

Colagiuri

et al. 2024

Open Mind

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People tend to overestimate the efficacy of an ineffective treatment when they experience the treatment and its supposed outcome co-occurring frequently. This is referred to as the outcome density effect. Here, we attempted to improve the accuracy of participants’ assessments of an ineffective treatment by instructing them about the scientific practice of comparing treatment effects against a relevant base-rate, i.e., when no treatment is delivered. The effect of these instructions was assessed in both a trial-by-trial contingency learning task, where cue administration was either decided by the participant (Experiments 1 & 2) or pre-determined by the experimenter (Experiment 3), as well as in summary format where all information was presented on a single screen (Experiment 4). Overall, we found two means by which base-rate instructions influence efficacy ratings for the ineffective treatment: 1) When information was presented sequentially, the benefit of base-rate instructions on illusory belief was mediated by reduced sampling of cue-present trials, and 2) When information was presented in summary format, we found a direct effect of base-rate instruction on reducing causal illusion. Together, these findings suggest that simple instructions on the scientific method were able to decrease participants’ (over-)weighting of cue-outcome coincidences when making causal judgements, as well as decrease their tendency to over-sample cue-present events. However, the effect of base-rate instructions on correcting illusory beliefs was incomplete, and participants still showed illusory causal judgements when the probability of the outcome occurring was high. Thus, simple textual information about assessing causal relationships is partially effective in influencing people’s judgements of treatment efficacy, suggesting an important role of scientific instruction in debiasing cognitive errors.

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Base-rate expectations modulate the causal illusion

Cited by 11 publications

References 61 publications

When Success Is Not Enough: The Symptom Base-Rate Can Influence Judgments of Effectiveness of a Successful Treatment

When Success Is Not Enough: The Symptom Base-Rate Can Influence Judgments of Effectiveness of a Successful Treatment

Causal illusions in the classroom: how the distribution of student outcomes can promote false instructional beliefs

Instruction on the Scientific Method Provides (Some) Protection Against Illusions of Causality

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