Here's a breakdown of the possible origins:
* Pricking up the ears: The act of raising one's ears is an instinctive response to sound, showing interest or alertness. This gesture is present in many animals and humans alike. This is likely the most direct connection to "all ears."
* Figurative language: "All ears" is a metaphor, implying that a person is fully focused on listening and not paying attention to anything else. This is similar to how we say "eyes glued to the screen" for someone watching intently.
* Historical usage: The phrase "all ears" first appeared in print in the 16th century. The earliest recorded use was in 1548, in a play by John Heywood. It's likely that the phrase was already in common use by this time, however.
While the exact origin remains elusive, the meaning of "all ears" is clear: it describes someone who is eagerly waiting to hear what you have to say and giving you their undivided attention.