Table 3.

HLM results for cognitive gain.

	Cognitive gain
	B (SE)	t (sig)
LEVEL-1 PREDICTORS
Gender	−0.40 (0.26)	1.53 (0.12)
Age	−0.11 (0.04)	−2.64 (0.01)
One's position in relation to CZPD	−0.68 (0.05)	−13.64 (<0.001)
LEVEL-2 PREDICTOR
Group synergy	0.77 (0.25)	2.96 (0.005)

Women are coded as 1, men as 0; for synergy 0 = non-synergic groups, 1 = weak synergy, 2 = strong synergy; B = unstandardized HLM coefficient. SE, standard error. A two-level model was tested (individual—group); CZPD, collaborative zone of proximal development.