Table 6.

Linear, quadratic, and cubic regression analyses results

	R 2	Adj R 2a	F	df	P	AIC	Model
d-prime
Visuospatial 1-back task
Linear	0.085	0.084	138.62	1,1498	<0.001	−1323.2
Quadratic	0.090	0.089	74.29	2,1497	<0.001	−1330.4
Cubic	0.091	0.089	49.68	3,1496	<0.001	−1328.9
Visuospatial 2-back task
Linear	0.211	0.211	400.69	1,1498	<0.001	−647.0
Quadratic	0.213	0.212	202.18	2,1497	<0.001	−648.1
Cubic	0.214	0.212	135.52	3,1496	<0.001	−648.0
Verbal 1-back task
Linear	0.117	0.116	197.99	1,1498	<0.001	−1826.5	Y = 3.984 − 0.011
Quadratic	0.118	0.117	99.94	2,1497	<0.001	−1826.2
Cubic	0.118	0.117	66.98	3,1496	<0.001	−1825.3
Verbal 2-back task
Linear	0.212	0.211	402.60	1,1498	<0.001	−723.7
Quadratic	0.219	0.218	209.83	2,1497	<0.001	−735.3
Cubic	0.219	0.217	139.82	3,1496	<0.001	−733.4
Reaction times
Visuospatial 1-back task
Linear	0.158	0.157	280.16	1,1498	<0.001	−7705.5
Quadratic	0.163	0.162	145.50	2,1497	<0.001	−7712.9
Cubic	0.163	0.161	96.94	3,1496	<0.001	−77100.9
Visuospatial 2-back task
Linear	0.063	0.063	101.57	1,1498	<0.001	−7144.7
Quadratic	0.079	0.078	64.09	2,1497	<0.001	−7167.6
Cubic	0.079	0.077	42.84	3,1496	<0.001	−7166.0
Verbal 1-back task
Linear	0.116	0.115	195.65	1,1498	<0.001	−7578.7
Quadratic	0.119	0.117	100.69	2,1497	<0.001	−7581.9
Cubic	0.119	0.117	67.08	3,1496	<0.001	−7579.9
Verbal 2-back task
Linear	0.080	0.080	130.66	1,1498	<0.001	−7171.2
Quadratic	0.095	0.094	78.36	2,1497	<0.001	−7193.0
Cubic	0.095	0.093	52.25	3,1496	<0.001	−7191.1

Akaike’s Information Criterion (AIC) was used to select the best model for each variable. The models are presented in milliseconds for reaction times

^aAdj R ² (adjusted R ²)