Rovee-Collier (1999)

Childhood Milestones.pdf

3mos

• [Physical support] Any form of contact with a platform is assumed to keep an object from falling (Baillargeon, 1995)

5mos

• [Object] 5-month-old infant who observes a triangle emerge from and return behind an occluder, and who then observes a disk emerge from and return behind that same occluder, can correctly posit the existence of two objects behind the occluder (and can eventually use pattern and color to individuate objects as well; Wilcox & Baillargeon, 1998; Wilcox, 1999).

6mos

• [Number] 6mos can solve ratio = 2:1(reviewed in Xu & Spelke, 2000)
• [Causal] Launching. Leslie, A. M. (1982) Leslie, A. M. & Keeble, S. (1987) Oakes, L. M. & Cohen, L. B. (1990).

7.5mos

• [Support] In both conditions, look longer at the wide box than at the narrow box. Fail to consider geometric center.

Wang, S., Zhang, Y., & Baillargeon, R. (2016). Young infants view physically possible support events as unexpected: New evidence for rule learning. Cognition, 157, 100–105. https://doi.org/10.1016/j.cognition.2016.08.021

9mos

• [Number] 5+5 and 10-5 (McKrink and Wynn, 2004)
• [Causal] “discriminate between launching and ‘triggering’ events (in which one object approaches and contacts another object, which then begins to move faster than the first object)” (Kominsky, J. F. et al., 2017)

10mos

• [Number] 10mos can solve ratio = 3:2(reviewed in Xu & Spelke, 2000)

12mos

• [Physical support] Can also consider the amount and distribution of contact between the platform and the object (Baillargeon, 1995)
• [Language acquisition] Learn novel words through frequent frames (Mintz Tobin, 2006)