Illusions of causality occur when people develop the belief that there is a causal connection between two events that are actually unrelated. Such illusions have been proposed to underlie pseudoscience and superstitious thinking, sometimes leading to disastrous consequences in relation to critical life areas, such as health, finances, and wellbeing. Like optical illusions, they can occur for anyone under well-known conditions. Scientific thinking is the best possible safeguard against them, but it does not come intuitively and needs to be taught. Teaching how to think scientifically should benefit from better understanding of the illusion of causality. In this article, we review experiments that our group has conducted on the illusion of causality during the last 20 years. We discuss how research on the illusion of causality can contribute to the teaching of scientific thinking and how scientific thinking can reduce illusion.

The illusion of control consists of overestimating the influence that our behavior exerts over uncontrollable outcomes. Available evidence suggests that an important factor in development of this illusion is the personal involvement of participants who are trying to obtain the outcome. The dominant view assumes that this is due to social motivations and self-esteem protection. We propose that this may be due to a bias in contingency detection which occurs when the probability of the action (i.e., of the potential cause) is high. Indeed, personal involvement might have been often confounded with the probability of acting, as participants who are more involved tend to act more frequently than those for whom the outcome is irrelevant and therefore become mere observers. We tested these two variables separately. In two experiments, the outcome was always uncontrollable and we used a yoked design in which the participants of one condition were actively involved in obtaining it and the participants in the other condition observed the adventitious cause-effect pairs. The results support the latter approach: Those acting more often to obtain the outcome developed stronger illusions, and so did their yoked counterparts.

Teaching based on active methodologies emphasizes the importance of giving students a leading role in the learning process. With the implementation of the European Higher Education Area, universities have undergone a reform that significantly increased student involvement in the teaching–learning process. The University of the Basque Country (UPV/EHU) responded to this change by introducing its own educational model: IKD i³. The general objective of this research is to explore the effect of the IKD i³ strategy on the teaching staff of the UPV/EHU. The study aims to identify the active methodologies adopted by the teaching staff and the reasons behind the use (or not) of these methodologies. A total of 403 teachers participated in the study, and their opinions were gathered freely to accurately represent their viewpoints. The results reveal that teaching staff at the UPV/EHU utilize active methodologies, with the most frequent being problem-based learning, cooperative learning, and the case study method. The reasons for incorporating these methodologies vary and include both benefits for students and advantages related to teaching, while the rationale for not using active methodologies is based on the lack of training, time constraints, and having a large number of students. Interestingly, the teachers who expressed these arguments were primarily those who were not familiar with or actively participating in the IKD i³ educational model. We believe that while our findings validate the UPV/EHU’s IKD i³ educational model, they also highlight the importance of universities not only having an educational model but also fostering a culture that encourages the active engagement of teaching staff. This commitment is essential to effectively develop and implement such a model.

Cognitive illusions are often associated with mental health and well‐being. However, they are not without risk. This research shows they can interfere with the acquisition of evidence‐based knowledge. During the first phase of the experiment, one group of participants was induced to develop a strong illusion that a placebo medicine was effective to treat a fictitious disease, whereas another group was induced to develop a weak illusion. Then, in P hase 2, both groups observed fictitious patients who always took the bogus treatment simultaneously with a second treatment which was effective. Our results showed that the group who developed the strong illusion about the effectiveness of the bogus treatment during P hase 1 had more difficulties in learning during P hase 2 that the added treatment was effective.

It is generally assumed that the way people assess the relationship between a cause and an outcome is closely related to the actual evidence existing about the co-occurrence of these events. However, people’s estimations are often biased, and this usually translates into illusions of causality. Some have suggested that such illusions could be the result of previous knowledge-based expectations. In the present research we explored the role that previous knowledge has in the development of illusions of causality. We propose that previous knowledge influences the assessment of causality by influencing the decisions about responding or not (i.e., presence or absence of the potential cause), which biases the information people are exposed to, and this in turn produces illusions congruent with such biased information. In a non-contingent situation in which participants decided whether the potential cause was present or absent (Experiment 1), the influence of expectations on participants’ judgments was mediated by the probability of occurrence of the potential cause (determined by participants’ responses). However, in an identical situation, except that the participants were not allowed to decide the occurrence of the potential cause, only the probability of the cause was significant, not the expectations or the interaction. Together, these results support our hypothesis that knowledge-based expectations affect the development of causal illusions by the mediation of behavior, which biases the information received.