Table 1.

Summary of findings in Experiment 1.

	Adults	7-Year-Olds	5-Year-Olds
Discrimination accuracy
Overall	0.92	0.82	0.74
Easy trials	1.00	0.99	0.89
Difficult trials	0.71	0.68	0.59
Discrimination RT (ms)
Overall	900	825	1075
Easy trials	805	655	955
Difficult trials	1204	1032	1177
Control
Easy task choices	0.75	0.49	0.51
Optimizers (out of 30)	70% (N = 21)	3% (N = 1)	3% (N =1)
Task monitoring
Composite score (out of 2)	1.88	1.09	0.90
Proficient monitors (out of 30)	77% (N = 23)	37% (N = 11)	17% (N = 5)
Performance monitoring
Absolute	0.13	0.05	0.11
Relative (out of 30)	83% (N = 25)	50% (N = 15)	37% (N = 11)