The Impact of Perceptual (Dis)fluency on Causality Heuristics in an Associative Learning Paradigm

When people face challenging mental tasks, they tend to become more attentive and engage in more deliberate, careful reasoning, often referred to as System Two thinking. This mode of reasoning can reduce dependence on intuitive, effortless thinking, known as System 1, which is prone to cognitive biases. One such bias is the Illusion of Causality, where individuals mis- takenly perceive a causal relationship between unrelated events in associative learning contexts. Díaz-Lago and Matute (2019a) found that a superficial perceptual feature, such as a difficult- to-read font, can weaken the strength of this illusion. Our study sought to explore whether perceptual disfluency—making something harder to perceive—could similarly reduce the illusion’s strength across different conditions. In our first experiment, we investigated whether changing the contrast between text and background in a contingency learning task would affect the illusion of causality. Although we successfully created conditions of fluency and disfluency in a 200-participant online experi- ment, the results showed no effect of contrast on the strength of the illusion. Following this null result, our second experiment, with 100 participants, focused on manip- ulating font type to test if we could replicate the findings of Díaz-Lago and Matute (2019a). Contrary to their results, we found that different font types had no significant impact on the il- lusion’s strength, even though this manipulation also created varying levels of task fluency and disfluency. These findings suggest that not all forms of cognitive (dis)fluency influence biases in the same way. They emphasize the need to reevaluate and refine our understanding of how (dis)fluency affects cognitive processes and biases.