Table A1. OLS regression estimates of age, gender, error rate, and expectancy and value on the ERN and Pe, excluding children scoring less than 3 on the intrinsic task value subscale.

Variables Child age	(1) ERN (FCz)	(2) ΔERN (FCz)	(3) Pe (Pz)	(4) ΔPe (Pz)
Child age	-0.147 (0.812)	1.296 (0.952)	-1.704* (0.990)	-0.341 (1.405)
Child gendera	0.458 (1.363)	2.186 (1.598)	-1.614 (1.661)	-1.941 (2.358)
Error rate (percent incorrect)b	-3.433 (4.241)	2.834 (4.973)	-2.093 (5.170)	-14.350* (7.337)
Perceived competence beliefs (expectancy)	0.630 (0.916)	0.806 (1.074)	3.741*** (1.117)	3.231** (1.585)
Intrinsic task value beliefs (value)	0.040 (1.382)	0.987 (1.621)	-3.638** (1.685)	-3.863 (2.391)
Observations	47	47	47	47
R-squared	0.037	0.111	0.300	0.229

Note. Standard errors are in parentheses.

^***p<0.001,

^**p<0.01,

^*p<0.05.

^aMale = 0, Female = 1

^bExpressed as a decimal between 0 and 1