Table 3.

Fixed estimates of the best-fitting models of population-wide personality change in adult pigtailed macaques

Outcome	Akaike w_i	Significant predictors	R ²	R² with ID	RMSE	RMSE with ID	f ²
Sociability = Sex + entry age + 1st test tenure + time elapsed + (sex × entry age) + (sex × 1st test tenure) + (sex × time elapsed)
	0.83	Sex^***	0.31	0.70	0.83	0.57	0.45
		1 st test tenure^***
		Time elapsed^***
		Sex × entry age interaction^***
		Sex × 1st test tenure interaction^***
		Sex × time elapsed interaction^*
Cautiousness = Sex + entry age + 1st test tenure + (sex × entry age)
	0.25	Sex^***	0.18	0.68	0.91	0.60	0.22
		Entry age^***
		1st test tenure^***
Aggressiveness = Sex + entry age + time elapsed + (sex × time elapsed)
	0.17	Entry age^***	0.05	0.51	0.97	0.77	0.05
Fearfulness = Sex + time elapsed + (sex × time elapsed)
	0.36	Time elapsed^***	0.03	0.65	0.98	0.64	0.04
		Sex × time elapsed interaction^***

Equations show the best-fitting model, as determined by highest Akaike weight (w_i). Significant predictors are those variables with coefficients that differed significantly from zero in the more informative models. R² without subject ID describes the variance in personality explained by the model as shown, and R² with ID describes the variance explained by the model with ‘ID’ included as a predictor. Root-mean-square error (RMSE) describes model residuals, and Cohen's f² is a measure of effect size.

P < 0.05

** P < 0.01

^***

P < 0.001.