Table 1.

Effects of experimental treatment and previous helpful acts on (A) the number and (B) duration of reaching events, using GLMMs with a negative binomial or gamma distribution (log-link), respectively.

(A)	Number of reaching events	Estimate	SE	Z	p
	Intercept	1.587	0.207	7.666	<0.001
	Food and partner treatment	0.887	0.164	5.391	<0.001
	Partner treatment	0.083	0.170	0.490	0.624
	Pulls in experience phase	0.064	0.026	2.419	0.016
(B)	Total duration of reaching	Estimate	SE	t	p
	Intercept	2.206	0.282	7.832	<0.001
	Food and partner treatment	0.729	0.207	3.513	<0.001
	Partner treatment	−0.068	0.210	−0.324	0.746
	Pulls in experience phase	0.070	0.038	1.867	0.062

Both models used Focal ID [model (A) N = 25; model (B) N = 24] as a random factor, with (B) also using Partner ID as a second random factor. All treatments are in comparison to the “food present” treatment. Significant p-values are marked in bold, non-significant trends are underlined.