Intervention participants exhibited greater improvements from pretest to posttest in inhibition ( 3.2 % , 95 % CI : 0.0 to 6.5 ; d = 0.27 ) and cognitive flexibility ( 4.8 % , 95 % CI : 1.1 to 8.4 ; d = 0.35 for group difference in pre-to-post change score ) compared with control .