Study 1: confirmation of the Dunning-Kruger effectThey did two studies. In study 1 (N=183) they administered two measures. The first was the Cognitive Reflection Task (CRT). This is a test consisting of four math problems. They also administered the Need for Cognition (NC) scale. This measures how people view their own analytic ability and engagement. In this study the Dunning-Kruger effect was again found. The worse people performed at the CRT, the more the overestimated their own performance. The highest scoring people slightly underestimated their own performance (see figure to the right).
A second finding was that the scores on NC were more strongly associated with how people estimated their own performance than with their actual performance (CRT). This suggests that the self-overestimation effect (the Dunning-Kruger effect) distorts the scores on the NC scale. The more people overestimate their analytic performance, the more they also tend to overestimate their analytic engagement; in other words the extent to which they enjoy analytic challenges. Thus, the lowest scoring respondents, who operated more on an intuitive than on an analytic level, unjustly thought of themselves as relatively analytical.
Study 2: confirmation that the low scorers do not realize they don't think very analyticallyTo test the effect which was found in study 1, a second study was done (N=341) in which the two previous measures were used in addition to another measure, the Heuristics-and-biases battery (H&B) which is another performance based measure for analytical (versus intuitive) thinking. The findings are shown in the figure on the right. The Dunning-Kruger effect is shown even more strongly than in study 1. There is a strong self-overestimation effect for the lowest scoring respondents and a strong underestimation effect for the highest performing respondents.
Reflection: Dunning-Kruger as an obstacle for progressThe most intuitively (versus analytically) thinking people both overestimate their own analytic performance but also their tendency to engage in analytical thinking (need for cognition). This confirms the existence of the problem that the least capable people generally are the ones who recognize the least their need for development.
A study by Pennycook et al. (2015) shows that analytic thinking is associated with several factors which are psychologically relevant to everyday life. Analytic thinkers tend to be less gullible, more open to change, more creative, and more open to the use of technology. These, to me, sound like important factors if we want to keep making progress in the world.