Task

Age of child (in months)

18 mos.

24 mos.

30 mos.

36 mos.

Cognitive skills

Gender self-labeling (percentage correct)

68%

88%a

93%d

Labeling of friend

43%

37%b

39%b

Nonverbal sorting (placing pictures in boxes)

48%

56%a,d

69%a

84%

Sorting to verbal cues

22%

67%

90%

96%

Correct use of gender words

Mom/Dad

98%

97%c

100%

Boy/Girl

75%d

88%d

98%

Man/Woman

53%d

79%d

94%

He/She

42%a

79%a

91%

Her/Him

27%a

63%a,d

83%

Stereotype learning

Clothes (percentage identifying correctly)

37%a

59%a

74%

Toys

24%

38%

53%

Tasks

-

32%c

39%c

Occupations

-

27%b,c

35%b,c

Preference behavior

Percentage of time spent with same-sex toys

32%

42%a

45%a

62%

Percentage of time spent with other-sex toys

25%

25%

25%a

21%a

Percentage same-sex photo choice as playmate

33%

52%

Sex of actual playmates (percentage same sex)

57%b

67%b

73%