Organizational structures, motion and contrast can affect the way a message is decoded.
Good designers build in factors which are attended to involuntarily and automatically.
Similarly, organization and structure help those who are already attending. No one knew what the noise was, but the insistent wail could not be ignored. The siren went from ear piercing high, lowered, then screamed again. Bright lights flashed in the halls. Before anyone knew what was happening, their attention was captured.