Table 3. Unstandardized Estimates (and Standard Errors) of Multilevel Models Predicting Working Memory Performance.

Fixed Effects	N-back	Memory updating
Intercept, γ00	1.07***(.01)	1.04***(.02)
IIV Control, γ03	.09**(.03)	.14(.09)
Difficulty, γ10	−.04***(.001)	−.07***(.002)
Age, γ01	−.001(.0003)	.−.002 (.0009)
Average Control, γ02	.02* (.01)	.04 (.02)
IIV Control × Difficulty, γ11	−.02***(.004)	−.03***(.007)
Random Effects
Level 2 (τ00)	.003***	.02***
Level 1 (σ2)	.01***	.04***
R2 (Level 1)	.78	.43
R2 (Level 2)	0	.10

^***p< .001

^**p< .01

^*p< .05

R² values were calculated using pseudo R² (Raudenbush & Bryk, 2002)