Table 1.

Mean proportion of looking at the unfair and unequal outcomes compared to chance level (0.5).

	Condition	Proportion	p	d
12-15-month-olds
With siblings (n = 25)	Unfair	M = .59	p < .001*	d = .99
	Unequal	M = .51	p = .68	d = .08
Without siblings (n = 32)	Unfair	M = .49	p = .47	d = .13
	Unequal	M = .51	p = .77	d = .05
Gave preferred toy (n = 14)	Unfair	M = .57	p = .03*	d = .67
	Unequal	M = .48	p = .63	d = .13
Gave non-preferred toy (n = 13)	Unfair	M = .50	p = .90	d = .04
	Unequal	M = .53	p = .08	d = .52
Gave non-preferred toy + Kept both toys (n = 24)	Unfair	M = .51	p = .47	d = .15
	Unequal	M = .52	p = .21	d = .26
9-month-olds
Sharers (n = 21)	Unfair	M = .56	p = .005*	d = .68
	Unequal	M = .50	p = .92	d = .02
Non-sharers (n = 7)	Unfair	M = .47	p = .38	d = .36
	Unequal	M = .50	p = .96	d = .02

^*Significantly different from chance