How far should the stimulus be placed from the face?

• A. 12-15 inches away from the nose and slightly above eye level
• B. 6-8 inches away
• C. 24 inches away from the nose
• D. 12-15 inches away from the chin

Answer: (A)

Positioning a visual stimulus correctly is essential for a reliable response. You want it at a distance and angle that lets the observer see it clearly with a natural gaze and without having to contort the head or eyes.

The best placement is about 12–15 inches from the nose and slightly above eye level. This keeps the stimulus within a comfortable viewing range so the eyes don’t strain, and it avoids interference from the nose. Being slightly above eye level helps maintain a neutral head position and prevents occlusion, making the stimulus easy to notice quickly.

Distances that are too close, like 6–8 inches, can cause crowding and nose-related blocking, while a distance like 24 inches makes the stimulus small and harder to detect. Placing the stimulus from the chin would require looking downward, changing posture and potentially delaying the response. So the 12–15 inch distance from the nose, slightly above eye level, provides a stable, easily perceivable position for consistent results.