Table 3. Mean Hourly Rates of Behavioral Measures at Each Age.

	Age
	6	12	18	24	30	36
Makes contact	10.01	7.64	3.65	2.52	1.81	1.54
Breaks contact	7.91	4.26	2.22	1.53	1.06	.96
Initiates play	3.41	3.08	3.14	2.54	2.48	1.47
Receives play	2.25	1.66	1.57	1.10	.76	.32
Scratches	4.04	3.13	5.01	3.84	5.28	3.29
Initiates aggression	.01	.11	.18	.20	.32	.32
Receives aggression	.12	.20	.38	.53	.38	.29
Avoids	.68	1.77	2.18	1.94	1.99	1.65