Table 1.

Accuracy was calculated by dividing the proportion of time infants looked at the target picture by the total amount of time infants looked at both the target and distracter pictures. All accuracy measures represent the percent of time infants attended to the target during the designated analysis window.

Looking Accuracy Results.

	Overall	Domain		Early Window		Late Window
	Accuracy	Sounds	Verbal	Sounds	Verbal	Sounds	Verbal
15 months	53.69	54.87	52.51	50.18	50.16	59.56	54.86
20 months	60.711	61.25	60.17	57.73	54.24	64.77	64.75
25 months	65.102	64.38	65.84	58.35	61.38	70.39	70.3
Low Proficiency	52.60	54.72	50.49	49.73	47.97	59.72	53.01
Mid Proficiency	62.263	64.224	60.295	58.7	55.31	69.75	65.28
High Proficiency	64.643	61.54	67.746,7	57.83	62.50	65.26	72.99

Significant as compared to:

¹15 months, p < .003,

²15 months, p < .0001,

³Low Proficiency, p < .0001,

⁴Low Proficiency Sounds, p < .0003,

⁵Low Proficiency Verbal, p < .003,

⁶Low Proficiency Verbal, p < .0001,

⁷High Proficiency Sounds, p < .0003. Note that F-values are cited in the text.