Yea it seems obvious to me that the child simply thinks that this object's name is 'Mama', and he thinks it's really cool and important because daddy kept telling him about this Mama object and teaching him to like it.
It takes a level of cognitive sophistication to think that an image on one object (an iPhone) actually represents a different object in the real world. It's incomprehensible to a baby, goes without thinking starting at the age of 2 or so, and hence represents a certain intellectual or artistic sophistication to explicitly call into question later in life: http://en.wikipedia.org/wiki/The_Treachery_of_Images
