Disfluent fonts do not help people to solve math and non-math problems regardless of their numeracy

Prior research has suggested that perceptual disfluency activates analytical processing and increases the solution rate of mathematical problems with appealing but incorrect answers (i.e., the Cognitive Reflection Test, hereafter CRT). However, a recent meta-analysis does not support such a conclusion. We tested here whether insufficient numerical ability can account for this discrepancy. We found strong evidence against the disfluency effect on the problem-solving rate for the Numerical CRT problems regardless of participants’ numeracy and for the Verbal CRT non-math problems (n = 310, Exp. 1) even though simple instructions to pay attention to and reflect upon the Verbal CRT problems substantially increased their solution rate (n = 311, Exp. 2). The updated meta-analysis (k = 18) yielded close-to-zero effect, Hedge’s g = -0.01, 95% CI[-0.05, 0.03] and decisive evidence against the disfluency effect on math problems, BF0+ = 151.6. Thus, perceptual disfluency does not activate analytical processing.