Recognition of iconicity doesn't come for free.

Iconicity--resemblance between a symbol and its referent--has long been presumed to facilitate symbolic insight and symbol use in infancy. These two experiments test children's ability to recognize iconic gestures at ages 14 through 26 months. The results indicate a clear ability to recognize how a gesture resembles its referent by 26 months, but little evidence of recognition of iconicity at the onset of symbolic development. These findings imply that iconicity is not available as an aid at the onset of symbolic development but rather that the ability to apprehend the relation between a symbol and its referent develops over the course of the second year.