Table 2.

Cumulative percentages of infants performing at each level by age/months (Max Stacks/Nests/Affixes)

	Age
Action	10	11	12	13	14
Stacking
No stacking	84%	73%	55%	34%	13%
Stack 1 item	16%	22%	35%	39%	46%
Stack 2 items	0%	4%	6%	17%	24%
Stack 3+ items	0%	1%	3%	8%	14%
Nesting
No nesting	72%	55%	51%	41%	33%
Nest 1 item	24%	36%	40%	41%	42%
Nest 2 items	3%	6%	7%	13%	21%
Nest 3+ items	0%	2%	2%	5%	4%
Affixing
No affixing	74%	55%	34%	22%	16%
Affix 1 item	24%	36%	45%	45%	43%
Affix 2 items	4%	6%	18%	16%	21%
Affix 3+ items	0%	2%	3%	17%	20%