In the audiovisual CST v3 testing, improvement in speech recognition for the auditory-plus-visual mode was observed at which head angle?

• A. 0°
• B. 20°
• C. 40°
• D. 60°

Answer: (B)

Multisensory integration drives better speech recognition when both what you hear and what you see line up well. The head angle changes how easily you can read the speaker’s lips and how the sound arrives at your ears, so there’s an optimal offset where the audiovisual signal combines most effectively. A modest turn of about twenty degrees tends to keep the lips clearly visible for lip-reading while preserving useful auditory cues, producing the strongest audiovisual benefit. If the head is turned too far, lip-reading becomes harder and the auditory signals are not as favorable, so the improvement from adding visual information diminishes. Thus, the greatest enhancement in auditory-plus-visual performance is seen at roughly twenty degrees.