Relative size perception at a distance is best at eye level

Area of Science:

• Visual perception
• Psychophysics
• Spatial cognition

Background:

• Accurate relative size judgments are crucial for navigating and interacting with the environment.
• Previous research suggests object size perception can be influenced by viewing distance and object height relative to the observer.

Purpose of the Study:

• To investigate how the accuracy of relative size judgments is affected by the relationship between object size and the observer's eye level.
• To evaluate two hypotheses explaining size perception: horizon localization and height-in-visual-field heuristic.

Main Methods:

• Participants made relative size judgments for objects positioned at varying distances (30.5 m and 23.8 m) from the observer.
• Experiments were conducted in both indoor hallway and outdoor settings.
• Accuracy of size judgments was systematically recorded.

Main Results:

• Size judgment accuracy was consistently higher for objects located near the observer's eye level.
• Performance differences were observed across different experimental conditions, including indoor and outdoor environments.
• The findings support the notion that visual cues related to height in the visual field influence size perception.

Conclusions:

• Relative size perception is optimized when objects are near the horizon or eye level.
• The results suggest that observers utilize heuristics based on height in the visual field, rather than solely relying on distance perception.
• Visual information independent of distance cues plays a significant role in accurate size perception.