Answer: B - Infants are able to assess visual depths when they are placed at the top of a flight of stairs beginning at 2 months of age.
Key Takeaway: Infants are able to assess depth properly at approximately 2 months of age. If you place an infant at that age at the top of a flight of stairs, he or she will be able to quickly assess the danger and be reluctant to move. Of course, many will make a suicidal leap off of a high spot but that is a function of their environment in the same way that they put objects in their mouths. It does not mean that they cannot assess the depth of distance properly.
