Cognitive appeal promotes the persistence of inefficient solutions and hinders cumulative cultural evolution.

Through cumulative cultural evolution, human populations discover novel solutions that allow them to solve complex problems. However, populations also reliably develop and sustain practices that are costly yet appear to have no effect on their stated outcome, such as bloodletting, divination, and malicious sorcery. Here, we show that ineffective, costly solutions can develop and be maintained because of their cognitive appeal. In a pre-registered transmission-chain experiment, participants were tasked with developing a solution to a problem over several trials, after which they passed instructions onto the subsequent generation. The visual appearance of the experimental task was manipulated to vary the extent to which cognitive biases could interfere with participants' expectations of efficacy, enabling a direct test of the effect of cognitive appeal on cumulative cultural evolution. Participants in the low-appeal treatment (n = 240) progressively develop more efficient solutions across generations. Participants in the high-appeal treatment (n = 240), in contrast, produce costlier solutions, and we did not observe a statistically significant increase in efficiency over the course of the experiment. These results suggest that, even under conditions favorable to cumulative cultural evolution, a form of cognitive appeal can alone prevent the process and promote the emergence and cultural persistence of ineffective solutions.