highly significantp < 0.0001
However, there was a highly significant ( p < 0.0001; d = 2.41) performance difference in favor of the VP group which doubled its test scores with 60.8 points (SD = 9.6) and showed a stronger effect size (d VP = 3.3 vs. d SGT = 1.42) than the SGT group which achieved 40.3 points (SD = 7.2).