. Author manuscript; available in PMC: 2022 May 1.

Published in final edited form as: Infant Behav Dev. 2021 Apr 10;63:101560. doi: 10.1016/j.infbeh.2021.101560

Table 3.

Trend Analysis Statistics and Percentage of Children who Passed at Least One Item Each Visit (Study 1)

Variable	Modality	ANOVA statistics				% of children who passed at least one item at each age specified
		Linear trend		Quadratic trend

		η²_G	p	η²_G	p	12 mo	15 mo	18 mo	24 mo	30 mo

RJA	Multimodal	.45	<.001	.046	.006	87	96	98	100	100
	Auditory	.52	<.001	.068	.011	46	64	66	84	95
Composite IJA	Multimodal	.035	.023	~0	.88	100	98	100	100	100
	Auditory	.004	.44	.002	.54	100	100	98	100	100
Higher-level IJA	Multimodal	.44	<.001	.024	.14	30	57	81	77	93
	Auditory	.36	<.001	.049	.018	17	32	45	61	75
Lower-level IJA^a	Multimodal	.38	<.001	.064	.01	70	40	19	23	7
	Auditory	.42	<.001	.001	.80	83	68	53	39	25

Note. RJA = responds to joint attention, IJA = initiates joint attention. N = 47. Generalized eta squared (η²_G) and p values are from a repeated measures analysis of variance with infant age (12, 15, 18, 24, and 30 months) as the repeated measure. No cubic or quartic trends were statistically significant (median η²_G = .005 and .010, range = .002–.010 and ~0–.045, and median p value = .50 and .27, range = .092–.69 and .056–.84, respectively).

Exclusively lower-level IJA