Why do objects appear enlarged under water?
Arq. bras. oftalmol
;
66(supl.5): 69-76, set.-out. 2003. ilus, tab, graf
Article
in English
| LILACS
| ID: lil-360369
ABSTRACT
Objects appear enlarged in water by less than the 4/3 angular magnification. The usually appear beyond their optical distance and slightly enlarged in linear size, but not in accordance with size-distance in variance (SDI). We investigated whether misperceptions of angular size could explain the discrepancies. Twenty observers viewed targets of various sizes and distances within transparent tanks 40cm long containing air or water. They judged distance by hidden reaching, and linear or angular size by adjusting the size of a target in air at a further distance. Matched distance was close to physical distance in air and optical distance in water. All size matches were close to true linear size, and were larger in water than in air. Angular size matches were much too small to explain departures from SDI. Size perception under water is best explained by incomplete adaptation to optical distortion, and by the use of various size cues.
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Space Perception
/
Size Perception
/
Water
/
Adaptation to Disasters
/
Distance Perception
Limits:
Adolescent
/
Adult
/
Female
/
Humans
/
Male
Language:
English
Journal:
Arq. bras. oftalmol
Journal subject:
Ophthalmology
Year:
2003
Type:
Article
Affiliation country:
United kingdom
Institution/Affiliation country:
University of Stirling/GB
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