This study contributes to the growing debate over the narrow ideological discourse in economics education and calls for greater pluralism. Using a randomized controlled experiment with 2,735 economics students from 10 countries, we examine how authority and ideological biases—shaped by mainstream training—affect students’ evaluations of economic statements. When source attributions are randomly switched from mainstream to non-mainstream or removed, agreement levels drop significantly, suggesting that students rely more on the perceived authority and ideological alignment of sources than on the content itself. These biases intensify with academic progression: PhD students show the strongest effects, despite being the most likely to claim they judge arguments on substance alone. Political orientation further amplifies these patterns, particularly among right-leaning students, and significant gender differences emerge, with male students showing stronger bias toward mainstream sources. Our findings highlight how ideology and authority shape economic training, limiting students' critical engagement and reinforcing a narrow intellectual framework.