An interesting talk about two surveys Lis did about icons and their meanings.
I found this talk in a comment by larsiusprime in the comment section of a Hacker News post. Lis Pardi did a survey on whether people of certain age groups can identify icons that reference old objects such as the floppy disk. I found the data pretty interesting (majority can identify successfully) and her arguments that try to explain it are sound (context gives meaning).
The talk is In Defense of the Floppy Disk by Lis Pardi.