Table 1.

The summary of advantages and disadvantages of each method for measuring distance perception.

Methods	Advantages	Disadvantages
Verbal report	Intuitively clarify and simple	Influenced by cognitive correction and the observer’s cognition of distance; not suitable to be used alone
Perceptual distance matching	accurate; be applied in the vista space (> 30 m) and used in both real environment and VR environment	Affected by participant’s cognitive factors
Successive Equal-appearing Intervals of Distance Judgment Measurement		Confuse the measurements of exocentric distance and egocentric distance
Blind Walking	Accurate	Take time and effort; easily produce practice and fatigue effects; difficultly applied to far space
Blind-walking gesturing	Integrate the distance and direction judgment, accurate	The same as blind walking
Blindfolded throwing	Simple and time-saving	Participants are required to have a high level of sports ability; inaccurate
Blind rope pulling	Accurate, can be applied to study the elder and patients, even in a narrow space	Participants need to be familiar with rope pulling. The complexity of experimental design affects task performance.
Triangulation-by-pointing	Investigate the rich psychological process; expand the research topic to 3D space	Inaccurate; complex calculation procedure, require larger test space, and takes time and effort
Triangulation-by-walking	More accurate than triangulation-by-pointing, other advantages are the same as Triangulation-by-pointing	The same as Triangulation-by-pointing