Table 1.

Mixed model results

Model	Response variable	Fixed predictor variables	Random effects	LRT	P	B (SE)	n	AICc
1	Mean reward per choice trial	Proportion of risky choices	Family	0.004	0.948	0.005 (0.08)	30
2	ΔTL	Starting TL	Family	1.86	0.173	−0.16 (0.10)	26
3	Cage entry body weight	ΔTL	Family	8.72	0.003	16.83 (4.71)	26
4	BWC	ΔTL	Family	5.19	0.023	−11.75 (4.38)	26
5	Variable reward chosen	Scale (ΔTL)	Family/Bird	7.51	0.006	0.17 (0.07)	26	10151.26
		Scale (BWC)		10.25	0.001	0.20 (0.08)
		Scale (ΔTL) × scale (BWC)		1.59	0.207	0.09 (0.07)
6	Variable reward chosen	Scale (Juvenile TL)	Family/Bird	0.21	0.645	0.03 (0.08)	26	10160.06
		Scale (BWC)		4.77	0.029	0.19 (0.08)
		Scale (Juvenile TL) × scale (BWC)		0.09	0.768	−0.02 (0.06)
7	Variable reward chosen	Scale (BWC)	Family/Bird	3.22	0.073	0.17 (0.08)	26	10159.96
		Amount:Plentya		0.82	0.366	−0.25 (0.22)
		Effort:Hardb		1.11	0.292	−0.27 (0.21)
		Amount × Effort		0.47	0.492	0.21 (0.30)
8	Variable reward chosen	Scale (BWC)	Family/Bird	4.64	0.031	0.18 (0.08)	26	10156.35
9	Variable reward chosen	Scale (ΔTL)	Family/Bird	1.90	0.169	0.13 (0.08)	26	10159.10
10	ln(Learning speed)	ΔTL	Family	1.99	0.159	−2.56 (1.86)	22
11	ln(Learning speed)	BWC	Family	0.03	0.853	0.01 (0.05)	26
12	ln(Learning speed)	Juvenile TL	Family	0.32	0.573	0.57 (1.05)	22
13	ln(Learning speed)	Amount:Plentya	Family	0.91	0.341	1.45 (0.99)	26
		Effort:Hardb		0.03	0.865	1.11 (1.11)
		Amount × Effort		1.61	0.204	−1.73 (1.45)
14	Variable reward chosen	Scale (Learning speed)	Family/Bird	0.45	0.500	−0.06 (0.09)	26

Scaled continuous fixed predictors are used in models 5–9 for the purposes of comparing effect sizes. Starting TL is telomere length measured by T/S ratio at day 5. BWC is Body Weight Change. ΔTL is developmental telomere attrition from day 5 to day 56. Juvenile TL is telomere length measured by T/S ratio at day 56. Learning speed is the number of autoshaping trials until the bird first pecked the lit key.

^aReference group for Plenty is Lean. ^bReference group for Hard is Easy.