Ralph was in a minor car accident in the grocery store parking lot. He backed his car into another car that was also backing out of a parking space. The other driver honked but Ralph didn't stop. Why not?

Ralph technically had the right-of-way.
The honking did not cross his sensory threshold.
Ralph became confused by driving backwards, confusing the gas pedal
with the brake.
His sensory memory perceived the honk but thought it was directed at
someone else.

The honking did not cross his sensory threshold.