Table 5.

Predictive effect of speech preference on language in Experiment 1 (speech vs. non-speech; top) and Experiment 2 (speech vs. monkey calls; bottom).

	Exp. 1: Speech vs. Non-Speech - Words Understood
	SIBS-A				SIBS-TD
	R2Δ	B	SE	95 % CI	R2Δ	B	SE	95 % CI
Constant	.11*	39.97	5.06	[29.69, 50.24]	.00	31.33	3.57	[24.15, 38.50]
SPI		1.61	.77	[.04, 3.16]		.00	.66	[−1.33, 1.34]
	Exp. 1: Speech vs. Non-Speech - Words Produced
	SIBS-A				SIBS-TD
	R2Δ	B	SE	95 % CI	R2Δ	B	SE	95 % CI
Constant	.05	49.57	3.18	[43.01, 56.04]	.00	45.07	2.56	[39.93, 50.20]
SPI		.63	.49	[−.36, 1.61]		.05	.48	[−.91, 1.00]
	Exp. 2: Speech vs. Monkey Calls - Words Understood
	SIBS-A				SIBS-TD
	R2Δ	B	SE	95 % CI	R2Δ	B	SE	95 % CI
Constant	.04	37.61	4.76	[27.99, 47.22]	.02	37.21	4.13	[28.89, 45.53]
SPI		.90	.69	[−.49, 2.28]		−.61	.64	[−1.89, .68]
	Exp. 2: Speech vs. Monkey Calls - Words Produced
	SIBS-A				SIBS-TD
	R2Δ	B	SE	95 % CI	R2Δ	B	SE	95 % CI
Constant	.09†	48.20	2.95	[42.23, 54.16]	.00	44.85	2.79	[39.24, 50.46]
SPI		.82†	.43	[−.04, 1.68]		−12	.43	[−99, .75]

^***p < .001.

^**p < .01.

^*p < .05.

^†p < .10.