Table 3.

Linear and quadratic change in child temperament over time.

Temperament Outcome	Intercepts				Linear		Quadratic			Model Comparison
	γ00: M	SE	t-ratio	γ10: M	SE	t-ratio	γ20: M	SE	t-ratio	ΔX2 (4)	p
Activity Levela	4.08	.07	59.47**	.52	.08	6.43***	–	–	–	–	–
Sadnessb	3.60	.07	48.50***	−.48	.08	−6.24***	–	–	–	–	–
High-Intensity Pleasurea	6.30	.06	101.64***	−.95	.09	−11.04***	–	–	–	–	–
Low-Intensity Pleasurec	5.66	.06	100.01***	−.39	.07	−5.88***	–	–	–	–	–
Approacha	5.43	.08	66.79***	.53	.22	2.36*	−.47	.13	−3.59***	23.10	< .001
Cuddlinessc	5.68	.06	94.57***	−1.10	.18	−6.11***	.57	.12	4.92***	28.41	< .001
Distress to Limitationsb	3.96	.08	50.93***	.42	.19	2.19*	−.43	.12	−3.50***	18.83	.001
Fearfulnessb	3.43	.09	37.81***	.36	.23	1.57+	−.65	.15	−4.44***	16.99	.002
Perceptual Sensitivitya,b	4.58	.10	44.68***	.40	.24	1.66+	−.30	.14	−2.11*	9.99	.040
Duration of Orientationc	4.68	.08	55.33***	−.03	.08	−.32	–	–	–	–	–
Falling Reactivityb	4.94	.06	76.78***	−.10	.07	−1.46	–	–	–	–	–

Note: γ’_s (M) represent the average, or fixed effects. SE = standard error. Chi-square difference test (ΔX²) yields model comparison between the linear and quadratic models. Model comparison statistics are presented when the quadratic term is significant and significant ΔX². Negative quadratic effects reflect concave trajectories; positive quadratic effects reflect convex trajectories. Higher values reflect more/greater/longer Activity Level, Cuddliness, Sadness, High-Intensity Pleasure, Low-Intensity Pleasure, Fearfulness, Approach, Falling Reactivity, Distress to Limitations, Duration of Orientation, and Perceptual Sensitivity.

^*p < .05.

^**p < .01.

^***p < .001.

⁺p < .10.

^aSubscales loaded on the Surgency/Positive Affectivity.

^bSubscales loaded on the Negative Affect.

^cSubscales loaded on the Regulatory Capacity/Effortful Control.