Table 1.

Summary of research design.

Generation	Description	Tests and measures	Time/age of assessment
F0	Lactating dams rearing cross-fostered offspring in standard vs. communal nests	Frequency of postpartum maternal behavior	Postpartum days 1–6
F1	Male and female offspring reared in standard vs. communal nests	Weights (g)	PND 1, 28, 35, 60
		Open-field testing	PND 65 (adulthood)
	Female offspring, mated at PND 70, rearing own offspring in standard nests	Litter size, weight, and performance in a retrieval test	Postpartum day 0
		Frequency of postpartum maternal behavior	Postpartum days 1–6
		Lactational aggression	Postpartum day 7
		Hypothalamic receptor binding density (OT and V1a)	Postpartum day 28
F2	Female grand-offspring that are reared in standard nests by F1 communal vs. standard reared female offspring	Weights (g)	PND 1
		Open-field testing	PND 65 (adulthood)
	Female offspring, mated at PND 70, rearing own offspring in standard nests	Litter size, weight, and latency to retrieve pups	Postpartum day 0
		Frequency of postpartum maternal behavior	Postpartum days 1–6
		Lactational aggression	Postpartum day 7
		Hypothalamic receptor binding density (OT and V1a)	Postpartum day 7