(a) Likeability and (b) age judgments of participants with (filled bars) and without siblings (unfilled bars) in each face age group from (a) Face Age Group 1 (M=0.30 years, SD=0.09, age range=0.08–0.57 year), (b) Face Age Group 2 (M=1.57 years, SD=0.52, age range=0.58–2.16 years), (c) Face Age Group 3 (M=3.67 years, SD=0.83, age range=2.17–4.66 years), to (d) Face Age Group 4 (M=5.48 years, SD=0.55, age range=4.67–6.50 years). **p < 0.01, *p < 0.05, Error bars: SE.