From my experience teaching basic computer literacy skills to individuals in the 60+ age range there have been several instances where people have exclaimed that they don't understand the symbology used for buttons etc simply due to lack of exposure.

So for example the floppy disk icon is synonymous with the save function, magnifying glass = zoom etc.

This is also combined with a reluctance to 'just try' incase they perform a function they cannot undo.

It maybe the case that clear labelling using text is used in place of icons.